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Emergence of Immunotherapy in the Prevention and Treatment of Type 1 DM

Jean Uy-Ho, MD, FPCP, FPCEDM

Active consultant

UST Hospital, Manila Doctors Hospital

Sept 2, 2023

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Outline

Epidemiology of type 1 DM
Discuss the different stages of type 1 DM in relation to timing of immunotherapy use
Review the keys events in the pathogenesis of type 1 DM
Discuss the classification and mechanism of action of these immunotherapy agents
Enumerate immunotherapy agents with significant clinical trials in prevention and treatment of type 1 DM
Discuss challenges and future directions

Type 1 diabetes (T1D) is an autoimmune disease in which T cells attack and destroy the insulin-producing β cells in the pancreatic islets. Genetic and environmental factors increase T1D risk by compromising immune homeostasis. Although the discovery and use of insulin have transformed T1D treatment, insulin therapy does not change the underlying disease or fully prevent complications. Over the past two decades, research has identified multiple immune cell types and soluble factors that destroy insulin-producing β cells. These insights into disease pathogenesis have enabled the development of therapies to prevent and modify T1D. In this review, we highlight the key events that initiate and sustain pancreatic islet inflammation in T1D, the current state of the immunological therapies, and their advantages for the treatment of T1D.the chronic administration of insulin is only a replacement therapy still associated with a decreased life expectancy due to microvascular and macrovascular complications

The discovery of insulin 100 years ago dramatically changed the outlook for people with T1D, preventing this from being a fatal condition. As we celebrate the centenary of this milestone, therapeutic options for T1D are once more at a turning point. Years of effort directed at developing immunotherapies are finally starting to pay off, with signs of progress in new onset and even preventative settings. Here, we review a selection of immunotherapies that have shown promise in preserving β cell function and highlight future considerations for immunotherapy in the T1D setting

Discuss the application of immunotherapy

Proper patient selection ( disease stage)

Purpose (prevention, intervention)

Measurable Endpoints (metabolic and immune biomarkers)

posology and administration patterns, route and timing. the ideal time point for intervention and the biomarkers needed for monitoring the successful regulatory effect of the antigen-specific immunotherapy.

The last years have seen this knowledge transformed into actual antigen-specific immunotherapies with potential to restore selectively the breach of tolerance to β-cell autoantigens and halt the autoimmune aggression. However, so far, the results of both prevention and reversion trials in T1D have been rather discouraging,

In 1980’s Cyclosporin A provided the first evidence that the modulation of the immune system had therapeutic value in T1D by improving the metabolic control in patients at recent onset.⁶ However, the facts that insulin production eventually returned to baseline levels after withdrawal and that their adverse effects outweighed their benefits halted its advance into the clinics. Although well-tolerated, none have been able to surpass the clinical benefit that exogenous insulin administration has demonstrated over decades. immune cell-based strategies have also made their way into the clinical field.¹⁹ For example, trials with autologous tolerogenic dendritic cells (tolDCs) utologous ex vivo-expanded polyclonal regulatory T (T_reg) cells²¹^,²² have been conducted with promising results. hat they will not achieve long-term results because they are not targeting the fundamental cause of the disease—the breach of tolerance to self-antigens. circulating β-cell autoreactive memory CD4⁺ T cells have been detected in patients,²³ and both β-cell-specific CD4⁺ and CD8⁺ T cells. Neoepitopes enhanced binding to HLA molecules, eventually increasing T-cell reactivity.

GAD combined with aluminum hydroxide (GAD-alum) results were rather discouraging in terms of preservation of residual insulin secretion. although well-tolerated, the primary endpoint was not reached.⁵³ GAD-alum treatment is more efficacious in preserving C-peptide secretion in patients positive for HLA-DR3/DQ2—a haplotype associated with GAD65 autoimmunity—than in patients with a DR4/DQ8 genotype.⁵⁴^.focus is on administering a single peptide or multiple peptides from the same antigen to re-educate the immune system. These trials have presumably relied on mechanisms such as bystander suppression, by which a single antigen-specific T_reg cell can control effector T cells with different antigen specificity via cell-to-cell contact. Nanoparticles displaying a large density of autoantigenic peptide–MHC complexes, which bind to the T-cell receptor of autoreactive T cells in the absence of costimulatory signals.³³ In fact, peptide–MHC class I and peptide–MHC class II complexes have been employed to tackle both the CD8⁺ and the CD4⁺ arms of the autoimmune response, working through different mechanisms: while the first induces the differentiation of naturally occurring antigen-specific low-avidity CD8⁺ T cells into memory-like autoregulatory CD8⁺ T cells, the second triggers the conversion of cognate autoreactive CD4⁺ T cells into disease-suppressing antigen-specific type 1 T_reg cells and recruits regulatory B lymphocytes to the draining lymph nodes.⁵⁵^.Marrked disease heterogeneity and the probable existence of T1D endotypes⁸² need to be considered, because they could account for the differing genetic risk predisposition, severity of the autoimmune reaction, age at onset, disease course and response to treatment.¹⁷ Ideally, the immunointervention strategy should be personalized and tailored to the autoreactivity profile of each patient. there is an urgent need for reliable immune biomarkers able to monitor T1D autoreactivity progression, stratify patients prior to clinical intervention and characterize the response to immunomodulatory strategies

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Annual Incidence of type 1 DM by country

Warshauer et al. New Frontiers in the Treatment of Type 1 Diabetes . Cell Metabolism 31, January 7, 2020

Type 1 diabetes estimates in children and adults – 2022

In 2022,

8.75 M T1D overall cases

Annual incidence rate 1.8%/yr

29% DKA at diagnosis

T1D may present at any age, with recent data from the UK Biobank finding that throughout the first six decades of life, 42% of T1D occurs after the age of 30 and 58% occurs before or at the age of 30 (Thomas et al., 2018). Overall, there does not appear to be a gender bias, with males and females showing similar incidences of disease (Dabelea et al., 2014). Disease incidence varies worldwide, with Finland having the highest incidence of 62.5 cases per 100,000 person-years (Harjutsalo et al., 2013), compared with a much lower incidence of approximately 1 case per 100,000 person-years in China (Weng et al., 2018). (Redondo et al., 2008), and US children with an affected family member have a 5% risk of developing T1D by age 20 compared with a 0.3% risk in the general population (Bonifacio and Ziegler, 2010). Additionally, European and North American countries reported increasing incidences of T1D by approximately 2%–3% per year during the 20th century, a rate that is far greater than could be attributed purely to genetics and indicates environmental and/or behavioral cues as likely contributors t

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General approach to prevention and Treatment of Type 1 DM

Screening

Who?
What?
When?
Why?

Prevention?

When?
How

Intervention/Treatment

When
How?

Screen/Predict

HLA typing
Autoantibodies

Intervene

Immunotherapies
Insulin
Beta cell replacement

Prevent

Immunotherapies

Islet autoantibody screening aims to identify individuals in the target population with pre-symptomatic, Stage 1 or Stage 2 T1D. Advancements in islet autoantibody assays are enabling ultra-low blood volumes, including testing using capillary samples and dried bloodspots, which facilitate minimally invasive collection at home or in community settings.52,53 Several groups have tried to determine optimal ages for performing autoantibody screening; modeled data from international cohort studies suggest the sensitivity of one-off autoantibody screening between the ages of 3–5 years is 35% and can be improved to 50% with repeated population screening at both 2–3 years and 5–7 years.21,54 Notably, sampling from 2 years of age does not capture all children who will develop T1D and misses the small, but important, subset Islet autoantibody screening aims to identify individuals in the target population with pre-symptomatic, Stage 1 or Stage 2 T1D. Advancements in islet autoantibody assays are enabling ultra-low blood volumes, including testing using capillary samples and dried bloodspots, which facilitate minimally invasive collection at home or in community settings.52,53 Several groups have tried to determine optimal ages for performing autoantibody screening; modeled data from international cohort studies suggest the sensitivity of one-off autoantibody screening between the ages of 3–5 years is 35% and can be improved to 50% with repeated population screening at both 2–3 years and 5–7 years.21,54 Notably, sampling from 2 years of age does not capture all children who will develop T1D and misses the small, but important, subset of infants and toddlers who rapidly develop T1D in the first 2 years of life and who have the highest rates of DKA with the greatest risk for associated morbidities.36,37,55,56 Additional studies and analyses are needed to balance sensitivity, specificity, public health priorities, cost, and local resources when developing specific screening programs. Genetic risk factors can be used to identify the subset of children with an increased risk of T1D who would benefit most from islet autoantibody screening. Such an approach57,58 has also been used in GPPAD to efficiently identify children with the highest risk of developing T1D for prevention trials (e.g., in the Primary Oral Insulin Trial).59 Genetic risk can be broadly inferred through family history of T1D, as in T1D TrialNet, or assessed using a polygenic risk score in the general population. Some international programs, including GPPAD, evaluate polygenic risk scores from dried bloodspots collected as part of the existing Newborn Screening Program, thereby leveraging existing infrastructure and reducing the need for an additional screening intervention. As polygenic risk scores are a continuous scale, the threshold defining “at-risk” can be altered to suit the screening purpose. For example, lowering the threshold from the top 1% to the top 10% of infants by risk, reduces their risk of T1D from 10% to 2.4% but increases the number of future cases captured from 30% to 80%.16,19 A high threshold may be considered more effective if the primary goal is to enroll children into prevention trials, while lower thresholds may be better suited to efforts prioritizing DKA prevention, because they capture a greater proportion of future cases.36,38,55 Currently all polygenic risk scores for T1D have been developed using largely Caucasian datasets. While the incidence of T1D is higher in Caucasian individuals, a polygenic risk score that is either validated in or developed specifically for diverse ethnicities will be required for population-wide routine screening.

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Risk factors affecting development and progression of Islet Cell Autoimmunity

HLA class II DR4-DQ8 and DR3-DQ2 haplotypes
Age − younger
Autoantibodies ≥ 2 (esp. IAA and IA-2A)
1^st degree relatives of type 1 DM
Short breastfeeding, early cow’s milk exposure
Early introduction of Gluten
Gut microbiota: Bacteroides > Firmicutes
Low Vitamin D
Viruses: Coxsackie, Enterovirus, Rotavirus

Bauer et al. The Multifactorial Progression from the Islet Autoimmunity to Type 1 Diabetes in Children.

International Journal of Molecular Sciences. July 2021

Genetics plays a strong role in T1D risk, as demonstrated in monozygotic twin studies showing that 65% of twins of people with T1D will develop T1D themselves by age 60 Research shows that age plays a key role in how fast T1D progresses. Younger children typically progress faster through the stages of T1D than adults. TrialNet researchers are studying additional markers to more accurately predict who will develop T1D and when.

According to the database of genome-wide association studies, the human leukocyte antigen (HLA) class II haplotypes HLA-DR and HLA-DQ (HLA-DR3-DQ2 or HLA-DR4-DQ8 haplotypes) within the major histocompatibility complex (MHC) region contribute to approximately 50% of the genetic susceptibility by affecting T-cell recognition and tolerance to foreign and autologous molecules

Multiple islet autoantibodies progress to Stage 3 Clinical Disease

within 15 years (80-90%), lifetime risk 100%

Single islet autoantibody – only 15% progress to Stage 3 CD

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Who to screen for type 1 DM

First-degree relative 1 in 20

15-fold ↑ risk for T1D,

accounts for 10–15% of Type 1 DM cases

Besser et al. ISPAD clinical practice consensus guidelines 2022: Stages of type 1 diabetes in children and adolescents

1 in 300

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What and When to screen for Type 1 DM? Autoantibodies

Autoantibody screening at ages 2 and 6 years may provide for optimal sensitivity and PPV in public health settings

ISPAD clinical practice consensus guidelines

2022

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Why do we screen for type 1 DM?

Avoid DKA as first presentation of T1D
Prepare patients and families for the diagnosis of T1D
Facilitate enrollment in clinical prevention trials as part of prevention strategies
Provide early support and intervention to delay clinical diabetes

The rates of DKA at diagnosis range from 15% to 70% in Europe and North America and as high as 80% in under-resourced countries.34–39 DKA prevention at diagnosis has potential lifelong benefits, including avoidance of acute morbidity (cerebral oedema, shock), neurocognitive impairment, and mortality.40,41 There are also non-causal associations between DKA at onset and future risk of DKA,38,42 severe hypoglycemia42 and long

Identifying individuals at stages 0–2 of T1D may also offer an opportunity to alter clinical presentation. identifying and monitoring individuals in the preclinical stages of T1D development may reduce DKA at presentation by up to 90%.3

Currently more than 20% of diagnoses in children are made following presentation in diabetic ketoacidosis (DKA).33 Deaths from DKA at presentation still occur. Studies have suggested that identifying and monitoring individuals in the preclinical stages of T1D development may reduce DKA at presentation by up to 90%.34 Si

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Diabetes Trial Net.org

Stage 1

Stage 2

Stage 3

T1D Disease Progression

he initial development of T1D is characterized by presymptomatic autoimmune beta cell destruction.18 Over 90% of children with T1D have at least one islet specific antibody at diagnosis, and it is recognized that these can appear many years before diagnosis.19 The peak incidence of autoimmunity as measured by detectable circulating autoantibodies is under age 2. Up to five different autoantibodies have been identified in T1D. Individuals with a single autoantibody have a greater risk of T1D than individuals without autoantibodies, but less than 10% of those with a single autoantibody develop T1D within 10 years.

Not all with genetic risk will develop type 1, not all with immune activation, and not all with 1 AAb will develop type 1DM, once with multiple AAb, progressing to type 1 dm is inevitable

Vaccine Therapies for the Prevention of Type 1 Diabetes Mellitus Nikolai Petrovsky Pediatr Drugs 2003; 5 (9): 575-582

Not all individuals with islet-related autoantibodies progress to diabetes. This is reflected by the fact that the prevalence of islet autoantibodies in the general population is invariably higher than the actual prevalence of diabetes. This indicates that insulitis by itself does not inevitably lead to β-cell destruction, thereby raising the hope that intervention, e.g. with an immunomodulatory vaccine, even after development of insulitis, may still be able to avert type 1 diabetes development. Insulitis can be characterized as either benign (i.e. nondestructive) or malignant (i.e. destructive),[18] and theoretically it should be possible to prevent type 1 diabetes by averting the switch from benign to malignant insulitis. Indeed, this may be the main mode of action of immunostimulatory vaccines

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Diabetes Trial Net.org

Stage 1

Stage 2

Stage 3

The Stages of Type 1 DM

T1D Disease Progression

1Around 6 months prior to progression to stage 3, the autoimmune process accelerates and beta-cell loss progresses more rapidly.22,23 Eventually, beta-cell mass drops to a threshold (around 10–20%) associated with hyperglycaemia, metabolic decompensation and clinical symptoms of T1D. At diagnosis, many individuals will still be producing reasonable quantities of endogenous insulin, as evidenced by detectable levels of c-peptide.24,25 Over time, endogenous insulin production declines further, though the rate at which this occurs varies between individuals. A peak serum c-peptide response after stimulation of >0.2 nmol/L represents less than the fifth percentile of normal, but is still considered clinically valuable. More than 80% of individuals maintain a peak serum c-peptide response >0.2 nmol/L one year after diagnosis, 30% at four years, and then the proportion decreases with a longer duration of disease.26

.1Not all with genetic risk will develop type 1, not all with immune activation, and not all with 1 AAb will develop type 1DM, once with multiple AAb, progressing to type 1 dm is inevitable

Vaccine Therapies for the Prevention of Type 1 Diabetes Mellitus Nikolai Petrovsky Pediatr Drugs 2003; 5 (9): 575-582

Not all individuals with islet-related autoantibodies progress to diabetes. This is reflected by the fact that the prevalence of islet autoantibodies in the general population is invariably higher than the actual prevalence of diabetes. This indicates that insulitis by itself does not inevitably lead to β-cell destruction, thereby raising the hope that intervention, e.g. with an immunomodulatory vaccine, even after development of insulitis, may still be able to avert type 1 diabetes development. Insulitis can be characterized as either benign (i.e. nondestructive) or malignant (i.e. destructive),[18] and theoretically it should be possible to prevent type 1 diabetes by averting the switch from benign to malignant insulitis. Indeed, this may be the main mode of action of immunostimulatory vaccines

Jean: If we just rely on metabolic markers such as glucose testing, then we wont be able to catch patient in early disease phase. At stage 2 which is just IGT only 50% remaining beta cells.

The eventual overt manifestation of clinical symptoms becomes apparent only when most beta cells have lost function and many may havebeen destroyed.

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Diabetes Trial Net.org

Stage 1

Stage 2

Stage 3

The Stages of Type 1 DM

T1D Disease Progression

1Around 6 months prior to progression to stage 3, the autoimmune process accelerates and beta-cell loss progresses more rapidly.22,23 Eventually, beta-cell mass drops to a threshold (around 10–20%) associated with hyperglycaemia, metabolic decompensation and clinical symptoms of T1D. At diagnosis, many individuals will still be producing reasonable quantities of endogenous insulin, as evidenced by detectable levels of c-peptide.24,25 Over time, endogenous insulin production declines further, though the rate at which this occurs varies between individuals. A peak serum c-peptide response after stimulation of >0.2 nmol/L represents less than the fifth percentile of normal, but is still considered clinically valuable. More than 80% of individuals maintain a peak serum c-peptide response >0.2 nmol/L one year after diagnosis, 30% at four years, and then the proportion decreases with a longer duration of disease.26

.1Not all with genetic risk will develop type 1, not all with immune activation, and not all with 1 AAb will develop type 1DM, once with multiple AAb, progressing to type 1 dm is inevitable

The presence of two or more autoantibodies in children is associated with a > 80% risk of T1D and is therefore considered to represent stage 1 T1D (Table 1).18 Although beta cell mass is initially preserved, and metabolic function is seemingly normal at this stage, the individual will eventually develop clinical T1D As more beta cell function is lost, dysglycaemia (defined in the same way as impaired glucose tolerance or impaired fasting glucose) develops and this is referred to as stage 2 T1D. It is reported that the 5-year risk of clinical diabetes (stage 3) for an individual at stage 2 is around 75% but that with longer follow-up, the risk reaches approximately 100%.1

Vaccine Therapies for the Prevention of Type 1 Diabetes Mellitus Nikolai Petrovsky Pediatr Drugs 2003; 5 (9): 575-582

Not all individuals with islet-related autoantibodies progress to diabetes. This is reflected by the fact that the prevalence of islet autoantibodies in the general population is invariably higher than the actual prevalence of diabetes. This indicates that insulitis by itself does not inevitably lead to β-cell destruction, thereby raising the hope that intervention, e.g. with an immunomodulatory vaccine, even after development of insulitis, may still be able to avert type 1 diabetes development. Insulitis can be characterized as either benign (i.e. nondestructive) or malignant (i.e. destructive),[18] and theoretically it should be possible to prevent type 1 diabetes by averting the switch from benign to malignant insulitis. Indeed, this may be the main mode of action of immunostimulatory vaccines

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Diabetes Trial Net.org

Stage 1

Stage 2

Stage 3

Secondary Prevention

to delay type 1 DM

Primary Prevention

Intervention/Treatment

Accelerated Active Disease

Therapeutic Window of Opportunity

T1D Disease Progression

1Around 6 months prior to progression to stage 3, the autoimmune process accelerates and beta-cell loss progresses more rapidly.22,23 Eventually, beta-cell mass drops to a threshold (around 10–20%) associated with hyperglycaemia, metabolic decompensation and clinical symptoms of T1D. At diagnosis, many individuals will still be producing reasonable quantities of endogenous insulin, as evidenced by detectable levels of c-peptide.24,25 Over time, endogenous insulin production declines further, though the rate at which this occurs varies between individuals. A peak serum c-peptide response after stimulation of >0.2 nmol/L represents less than the fifth percentile of normal, but is still considered clinically valuable. More than 80% of individuals maintain a peak serum c-peptide response >0.2 nmol/L one year after diagnosis, 30% at four years, and then the proportion decreases with a longer duration of disease.26

The first is during the prodromal stage of T1D, which may persist for a number of years. At-risk individuals with ongoing β cell autoimmunity, identified by serum autoantibodies specific for various β cellautoantigens, are candidates for prevention of clinical onset of T1D (90–92). The second window of intervention is at the time of clinical onset. The goal here is to suppress β cell autoimmunity rescue residual β cell mass, and ideally reverse clinical diabetes. The third window of intervention is in long-standing T1D patients to protect residual β cell function. Evidence indicates that after T1D onset low but sustained C-peptide levels are observed (93, 94). Therefore,maintenance of a small amount of functional β mass may aid in the control of glycemia as well as limit morbidity.

.1Not all with genetic risk will develop type 1, not all with immune activation, and not all with 1 AAb will develop type 1DM, once with multiple AAb, progressing to type 1 dm is inevitable

Most patients recruited in T1D clinical trials exhibit a symptomatic hyperglycemia associated with an advanced destruction of their pancreatic β-cell mass—so-called stage 3 (clinical) disease. Thus, by the time of intervention, the damage is already done. In contrast, stage 1 patients, who are normoglycemic but positive for at least 2 aAbs, and stage 2 patients, who present dysglycemia (e.g., transient hyperglycemic peaks after a glucose challenge), exhibit humoral and cellular islet autoimmunity, but their β-cell mass and function are still preserved, which provides the opportunity to reorient the immune responses towards tolerance before irreversible damage.

It is henceforth accepted that adapting and searching for the best therapeutic window for a given treatment represents a first step towards personalized intervention. The rationale for targeting this pediatric population before any sign of autoimmunity is that, so far, all clinical trials using tolerogenic vaccination with β-cell-derived antigens have failed, both in new-onset diabetic and in at-risk aAb+ patients [24]. This is probably due to a late timing of treatment, i.e., after appearance of multiple aAbs and initiation of β-cell destruction, marking an advanced and active autoimmunity stage that cannot be properly controlled.

Vaccine Therapies for the Prevention of Type 1 Diabetes Mellitus Nikolai Petrovsky Pediatr Drugs 2003; 5 (9): 575-582

Not all individuals with islet-related autoantibodies progress to diabetes. This is reflected by the fact that the prevalence of islet autoantibodies in the general population is invariably higher than the actual prevalence of diabetes. This indicates that insulitis by itself does not inevitably lead to β-cell destruction, thereby raising the hope that intervention, e.g. with an immunomodulatory vaccine, even after development of insulitis, may still be able to avert type 1 diabetes development. Insulitis can be characterized as either benign (i.e. nondestructive) or malignant (i.e. destructive),[18] and theoretically it should be possible to prevent type 1 diabetes by averting the switch from benign to malignant insulitis. Indeed, this may be the main mode of action of immunostimulatory vaccines

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Greenbaum et al. Strength in numbers: opportunities for enhancing the development of effective treatments for T1D—the TrialNet experience. Diabetes 2018;67:1216–1225

Uncovering Pathways to Personalized Therapies in Type 1 Diabetes Linsley et al. Diabetes 2021;70:831–841

Timing is

Important!

T1D Disease Progression

Heterogeneity of T1D pathophysiology, variable clinical course

Best to intervene at Stage 1 or 2 where β-cell mass and function are still preserved,

intervention at stage 2 might represent the optimum time for maximal metabolic benefit from treating the lowest number of people.

As shown the risk for movement from stage 2 to stage 3 is quite high (not if but when)

An FDA approved agent is available to delay the onset of clinical T1D

—Nonlinear progression of b-cell loss characterizes stages of T1D. The peri-diagnostic period is highlighted, reflecting a period of accelerated b-cell dysfunction, superimposed on a slow progressive functional decline that begins prior to clinical diagnosis and continues through the early post-diagnostic interval (“Stage 3” disease, or clinical T1D). Observations of immunological acceleration occur within this period, presenting an opportunity for targeted immune intervention based on identification of individualized immune characteristics associated with rapid decline—both prior to diagnosis (blue box, “prevention therapy”) and after diagnosis (green box, “intervention

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Claire Deligne Personalized Immunotherapies for Type 1 Diabetes: Who, What, When, and How? J. Pers. Med. 2022, 12, 542.

Primary Prevention

Secondary Prevention / Delay T1D

Treatment/Intervention

Personalized Immunotherapies for Type 1 Diabetes: Who, What, When, and How? Claire Deligne 1

Figure 1. Stage-specific therapeutic intervention in T1D (type 1 diabetes). Stage 0 individuals, without aAbs (autoantibodies) but at risk for developing T1D owing to genetic and/or environmental triggers, are candidates for immunotherapies aiming at preventing T1D and preserving intact β-cell mass, such as antigen-specific and tolerance induction therapies. In subjects with stage 1 and stage 2 disease, characterized by the presence of one or more aAbs and a progressive dysglycemia, therapies aiming at dampening β-cell destruction and the engaged autoimmune process while favoring tolerancepromoting mechanisms (T-cell, B-cell depletion/inhibition/exhaustion, blockade of inflammatory cytokine signaling, adoptive Treg cell therapy) should be preferred. Therapeutic intervention focusing on replacing endogenous β cells by grafting pancreatic islets or in vitro differentiated β cells, together with tolerance-promoting drugs, should be reserved to stage 3 patients with clinically overt T1D and an advanced decline in β-cell number and function. Abbreviation: HLA, human leukocyte antigen.

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Immunotherapy: Changing from Symptom Management to Disease Modifying therapy

Although the discovery and use of insulin have transformed T1D treatment, insulin therapy does not change the underlying disease or fully prevent complications. Over the past two decades, research has identified multiple immune cell types and soluble factors that destroy insulin-producing β cells. These insights into disease pathogenesis have enabled the development of therapies to prevent and modify T1DThe discovery of insulin 100 years ago dramatically changed the outlook for people with T1D, preventing this from being a fatal condition. As we celebrate the centenary of this milestone, therapeutic options for T1D are once more at a turning point. Years of effort directed at developing immunotherapies are finally starting to pay off, with signs of progress in new onset and even preventative settings.

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Thymus

Proinflammatory

Cytokines

IL-2, IL-21, TNFɑ, IFN

Pancreatic lymph node

Pancreatic Islet

Environmental Triggers

Viruses

Etiopathogenesis of type 1 DM

T-cell autoreactivity is a major component of the immune response in T1D, with activated cells expressing markers of immune memory and self-renewal as hallmarks of disease (

Zhang et al. Journal of Trace Elements in Medicine and Biology . Antigen-specific immunotherapies in type 1 diabetes

Fig. 1. Mechanism of T cell-mediated beta cell destruction in T1D. T cells are enabled to identify self and non-self through positive selection, those with strong binding affinity to self-peptides are removed by negative selection. Some T cells that escape the central tolerance require action from peripheral mechanisms. APCs migrate from the pancreas take up and present diabetogenic auto-antigens and activate T cells; activated pathogenic T cells migrate to pancreatic islets and begin the process of beta cell destruction, eventually leading to T1D. Tregs attempt to prevent beta cell damage by secreting cytokines. Autoreactive B cells are also involved in beta cell damage. They activate autoreactive T cells, which act on islets by secreting inflammatory cytokines (IFN-γ, TNF, IL-17) and CTL-mediated killing; in turn, auto-reactive T cells provide help signals to auto-reactive B cells, which further exacerbate T1D by promoting the differentiation of auto-reactive B cells into plasma cells and the production of islet-specific AAbs. Bregs inhibit beta cell damage by secreting the cytokines IL-10 and TGF-γ. ZnT8 is the main autoantigen in T1D. The secretion of insulin granules can increase the exposure of ZnT8 autoantigen to the cell surface and initiate ZnT8 epitope-specific T cell-mediated beta cell destruction, resulting in T1D. As beta cells are destroyed, autoantigens release increases, amplifying the T cell-mediated immune response

Immune tolerance is divided into central tolerance and peripheral tolerance [24]. The former occurs in the thymus, passing through positive selection makes T cells able to recognize a peptide/major histocompatibility complex (pMHC), and the interaction between T cell receptor (TCR) and MHC/self-antigen complex. T cells that do not pass the central tolerance test undergo an intrinsic suicide program called negative selection to remove them and prevent auto-reactivity [24]. There is evidence that defects in thymic T cell negative selection related to insulin reactivity is a key factor in the genetic predisposition in T1DM [71]. The purpose of central selection is to ensure that T cells entering the periphery do not respond to their own antigens [24]. However, many self-reactive T cells still escape from thymic negative selection, which leads to the need for peripheral mechanisms to ensure that self-tolerance is maintained to prevent autoimmune diseases [72]. Peripheral immune tolerance may delete those escaped T cells in the peripheral lymphoid organs through various mechanisms including clone deletion, clone anergy, and immune suppression of regulatory T cells [73]. The most important mechanism is the presence of specific cell populations to suppress abnormal immune responses that unintentionally target their own tissues; Tregs develop in the thymus and periphery

are critical for maintaining tolerance [74]. Tregs include naturally arising Treg cells (Foxp3+ CD25+ CD4+ Tregs), induced Treg cells (iTreg), type 1 regulatory T cells (Tr1) that produce the immunosuppressive cytokine interleukin-10 (IL-10), and Type 3 helper T cells (Th3) that produce transforming growth factor beta (TGF-beta) [75]. Tregs are essential suppressors of unwanted autoimmune responses [76]. The mechanism of Tregs includes contact-dependent suppression and contact-independent suppression mechanisms [The former can inhibit costimulatory signals and cytokine secretion by connecting Cytotoxic T lymphocyte antigen 4 (CTLA-4) on Tregs to CD80/CD86 on APCs. The latter contact-independent mechanisms disrupt the metabolic state of T effector cells via the production of the immunosuppressive cytokines IL-10 and TGF-beta

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Proinflammatory

Cytokines

IL-2, IL-21, TNFɑ, IFN

Pancreatic lymph node

Etiopathogenesis of type 1 DM

Zhang et al. Journal of Trace Elements in Medicine and Biology . Antigen-specific immunotherapies in type 1 diabetes

Fig. 1. Mechanism of T cell-mediated beta cell destruction in T1D. T cells are enabled to identify self and non-self through positive selection, those with strong binding affinity to self-peptides are removed by negative selection. Some T cells that escape the central tolerance require action from peripheral mechanisms. APCs migrate from the pancreas take up and present diabetogenic auto-antigens and activate T cells; activated pathogenic T cells migrate to pancreatic islets and begin the process of beta cell destruction, eventually leading to T1D. Tregs attempt to prevent beta cell damage by secreting cytokines. Autoreactive B cells are also involved in beta cell damage. They activate autoreactive T cells, which act on islets by secreting inflammatory cytokines (IFN-γ, TNF, IL-17) and CTL-mediated killing; in turn, auto-reactive T cells provide help signals to auto-reactive B cells, which further exacerbate T1D by promoting the differentiation of auto-reactive B cells into plasma cells and the production of islet-specific AAbs. Bregs inhibit beta cell damage by secreting the cytokines IL-10 and TGF-γ. ZnT8 is the main autoantigen in T1D. The secretion of insulin granules can increase the exposure of ZnT8 autoantigen to the cell surface and initiate ZnT8 epitope-specific T cell-mediated beta cell destruction, resulting in T1D. As beta cells are destroyed, autoantigens release increases, amplifying the T cell-mediated immune response

Immune tolerance is divided into central tolerance and peripheral tolerance [24]. The former occurs in the thymus, passing through positive selection makes T cells able to recognize a peptide/major histocompatibility complex (pMHC), and the interaction between T cell receptor (TCR) and MHC/self-antigen complex. T cells that do not pass the central tolerance test undergo an intrinsic suicide program called negative selection to remove them and prevent auto-reactivity [24]. There is evidence that defects in thymic T cell negative selection related to insulin reactivity is a key factor in the genetic predisposition in T1DM [71]. The purpose of central selection is to ensure that T cells entering the periphery do not respond to their own antigens [24]. However, many self-reactive T cells still escape from thymic negative selection, which leads to the need for peripheral mechanisms to ensure that self-tolerance is maintained to prevent autoimmune diseases [72]. Peripheral immune tolerance may delete those escaped T cells in the peripheral lymphoid organs through various mechanisms including clone deletion, clone anergy, and immune suppression of regulatory T cells [73]. The most important mechanism is the presence of specific cell populations to suppress abnormal immune responses that unintentionally target their own tissues; Tregs develop in the thymus and periphery

are critical for maintaining tolerance [74]. Tregs include naturally arising Treg cells (Foxp3+ CD25+ CD4+ Tregs), induced Treg cells (iTreg), type 1 regulatory T cells (Tr1) that produce the immunosuppressive cytokine interleukin-10 (IL-10), and Type 3 helper T cells (Th3) that produce transforming growth factor beta (TGF-beta) [75]. Tregs are essential suppressors of unwanted autoimmune responses [76]. The mechanism of Tregs includes contact-dependent suppression and contact-independent suppression mechanisms [The former can inhibit costimulatory signals and cytokine secretion by connecting Cytotoxic T lymphocyte antigen 4 (CTLA-4) on Tregs to CD80/CD86 on APCs. The latter contact-independent mechanisms disrupt the metabolic state of T effector cells via the production of the immunosuppressive cytokines IL-10 and TGF-beta

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Proinflammatory

Cytokines

IL-2, IL-21, TNFɑ, IFN

Pancreatic lymph node

Antigen-Specific Vaccine

T-Effector Cell depletion

✔︎

T-Reg Induction

T-Reg Expansion

Cytokine Blockade

B lymphocyte

Depletion

Rationale behind immunotherapy for type 1 DM

Zhang et al. Journal of Trace Elements in Medicine and Biology . Antigen-specific immunotherapies in type 1 diabetes

Fig. 1. Mechanism of T cell-mediated beta cell destruction in T1D. T cells are enabled to identify self and non-self through positive selection, those with strong binding affinity to self-peptides are removed by negative selection. Some T cells that escape the central tolerance require action from peripheral mechanisms. APCs migrate from the pancreas take up and present diabetogenic auto-antigens and activate T cells; activated pathogenic T cells migrate to pancreatic islets and begin the process of beta cell destruction, eventually leading to T1D. Tregs attempt to prevent beta cell damage by secreting cytokines. Autoreactive B cells are also involved in beta cell damage. They activate autoreactive T cells, which act on islets by secreting inflammatory cytokines (IFN-γ, TNF, IL-17) and CTL-mediated killing; in turn, auto-reactive T cells provide help signals to auto-reactive B cells, which further exacerbate T1D by promoting the differentiation of auto-reactive B cells into plasma cells and the production of islet-specific AAbs. Bregs inhibit beta cell damage by secreting the cytokines IL-10 and TGF-γ. ZnT8 is the main autoantigen in T1D. The secretion of insulin granules can increase the exposure of ZnT8 autoantigen to the cell surface and initiate ZnT8 epitope-specific T cell-mediated beta cell destruction, resulting in T1D. As beta cells are destroyed, autoantigens release increases, amplifying the T cell-mediated immune response

Immune tolerance is divided into central tolerance and peripheral tolerance [24]. The former occurs in the thymus, passing through positive selection makes T cells able to recognize a peptide/major histocompatibility complex (pMHC), and the interaction between T cell receptor (TCR) and MHC/self-antigen complex. T cells that do not pass the central tolerance test undergo an intrinsic suicide program called negative selection to remove them and prevent auto-reactivity [24]. There is evidence that defects in thymic T cell negative selection related to insulin reactivity is a key factor in the genetic predisposition in T1DM [71]. The purpose of central selection is to ensure that T cells entering the periphery do not respond to their own antigens [24]. However, many self-reactive T cells still escape from thymic negative selection, which leads to the need for peripheral mechanisms to ensure that self-tolerance is maintained to prevent autoimmune diseases [72]. Peripheral immune tolerance may delete those escaped T cells in the peripheral lymphoid organs through various mechanisms including clone deletion, clone anergy, and immune suppression of regulatory T cells [73]. The most important mechanism is the presence of specific cell populations to suppress abnormal immune responses that unintentionally target their own tissues; Tregs develop in the thymus and periphery

are critical for maintaining tolerance [74]. Tregs include naturally arising Treg cells (Foxp3+ CD25+ CD4+ Tregs), induced Treg cells (iTreg), type 1 regulatory T cells (Tr1) that produce the immunosuppressive cytokine interleukin-10 (IL-10), and Type 3 helper T cells (Th3) that produce transforming growth factor beta (TGF-beta) [75]. Tregs are essential suppressors of unwanted autoimmune responses [76]. The mechanism of Tregs includes contact-dependent suppression and contact-independent suppression mechanisms [The former can inhibit costimulatory signals and cytokine secretion by connecting Cytotoxic T lymphocyte antigen 4 (CTLA-4) on Tregs to CD80/CD86 on APCs. The latter contact-independent mechanisms disrupt the metabolic state of T effector cells via the production of the immunosuppressive cytokines IL-10 and TGF-beta

Type 1 diabetes is a complex disease driven by pathogenic adaptive and innate responses leading to the dysfunction and

destruction of β cells (1–4). Although disease immunopathology is heterogeneous, T cells are considered to be the key mediators of β cell destruction/dysfunction for the majority of cases of human T1D (57). Consequently, T cells have been the focus of most strategies of immunotherapy. Suppression of pathogenic β cell-specific T cell reactivity in the islets long-term, while preserving acquired immunity is the ultimate goal for a givenimmunotherapy (Figure 1). Achieving this goal in the clinic,nhowever, has been elusive. To date, the most effective strategies have been broadly acting on the majority if not all T cells although protection has also been demonstrated by targeting B cells. Efficacy, however, is short-lived. Furthermore, systemic depletion and unwanted effects on protective immunity seen with anti-CD3 mAb therapy for instance, limit dosing and repeated application for efforts to extend β cell protection.

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Restore Tolerance to AutoAntigens

Insulin (Oral, Intranasal, Parenteral)
GAD65-Alum
Proinsullin

Antigen-Based therapies (Vaccine)

Increase T Regulatory Cells (CTLA4Ig Abatacept)
Reduce T Effector cells, (Teplizumab, ATG, Abatacept, Alefacept)
Reduce B lymphocytes, (Rituximab)

Immunomodulatory Agents

Immunosuppression

Anti-TNF alpha Golimumab and Etanercept
Anti-IL-21

Anti-inflammatory Agents

Expansion of Autologous T Regulatory cells and Tolerogenic Dendritic cells

Cell-Based Strategies

Classification of Immunotherapy agents for type 1 DM�

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Warshauer et al New Frontiers in the Treatment of Type 1 Diabetes. Cell Metabolism 31, January 7, 2020

PAST and PRESENT

2020 onwards

TIMELINE of IMMUNOTHERAPIES for TYPE 1 DM

B cell Ag

Vaccines

Insulin, GAD65, Proinsulin

1^st clinical trial on Teplizumab showing benefit

Cyclosporine — Large-scale trials in patients with recently diagnosed type 1 diabetes in Canada and France showed that remissions were twice as common in the cyclosporine-treated patients as compared with placebo [7]. Although the remissions also lasted longer, almost all patients required insulin again within three years. An analysis of subjects recruited into the Canadian-European cyclosporine trial showed that subjects who were insulinoma-associated 2 molecule (IA-2) negative at entry to the trial were more likely to respond to cyclosporine (with a decrease in insulin requirements and an increase in C-peptide secretion) than IA-2-positive subjects [8].

Figure 1. Timeline of important therapeutic discoveries in T1D and future therapeutic development. *Sotagliflozin only approved in Europe for T1D. FDA denied approval given risk of diabetic ketoacidosis.

Cell Metab. 2020 January 07; 31(1): 46–61New frontiers in the treatment of Type 1 diabetes Jeremy T. Warshauer, M.D.1,2, Jeffrey A. Bluestone, Ph.D.2,3, Mark S. Anderson, M.D., Ph.D.

several studies have demonstrated potential benefits of commencing immunotherapy in the early stages after clinical diagnosis. Whilst immunotherapy is a novel approach to the management of T1D, the majority of agents being investigated have a long history of routine use in other autoimmune diseases. Indeed, T1D is one of very few autoimmune disorders that is not currently treated with immunotherapy. To date, both general anti-inflammatory/immun osuppressive agents, and more specific/targeted treatments have been tested in stage 3 T1D.

One of the first attempts to utilize immunotherapy to prevent T1D progression involved the administration of Cyclosporin to individuals with recent onset of T1D. Whilst studies demonstrated Cyclosporin to be effective in inducing remission of T1D, its use was limited by the development of significant toxicities and side effects. However, these early studies paved the way for ongoing work in this field. More recently, in a pilot study, the combination of low dose of Cyclosporin with Methotrexate was shown to be effective in inducing remission of T1D in a way that was well tolerated by participants.

The first immunotherapy trials for T1D were conducted more than 35 years ago. No single study has demonstrated clinically significant benefits from therapy with an acceptable risk profile [23]. A French Cyclosporine Diabetes Study was the first clinical trial to test the immunological intervention in type 1 diabetes [24]. Cyclosporine A (CSA) disrupts TCR-mediated signal transduction, inhibiting T-cell activation and T helper IL-2 secretion [25]. Later, a few studies demonstrated a significant reduction in exogenous insulin requirement after one year of immune-suppressive drug CSA treatment [24,26]. After CSA removal, blood glucose control worsens, and autoantibody levels are return [27]. Furthermore, cyclosporin medication has been linked to renal and pancreatic β-cell toxicity [27]. Despite the lack of long-term effects and potential toxicity, these trials heralded a new clinical era centered on immunomodulatory strategies to delay or prevent T1D. Numerous interventions, including parenteral insulin administration, dietary exposures, broad-spectrum immunosuppressants, anti-inflammatory drugs, and T- or B-cell targeted immunosuppressants, have been tested to date. At the same time, a small number of clinical trials have revealed modest benefits. There are no clinically approved immunotherapies for autoimmune T1D now, but a few developments are listed in Table 1 or highlighted in Figure 2. Let us look at a few of these immunotherapies and how they might help T1D patients.

In 1994, Chatenoud and collaborators were the first to report a delay of diabetes onset when prediabetic non-obese diabetic mice were treated with an anti-CD3 antibody (9). In addition, when the treatment was administered to mice with recent onset diabetes, there was a long-lasting remission of disease in up to 80% of mice In 2005, in the first clinical trial with teplizumab, it was reported a reduction of therapeutic need for exogenous insulin, improved C-peptide response to a meal, and reduced blood glycated hemoglobin (10); these promising results further stimulated research in the field.

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Immunomodulatory Agents

Cell-Based Strategies

Anti-Inflammatory Agents

Mechanism of Action of Different Immunotherapy Agents for type 1DM

Cell Metab. 2020 January 07; 31(1): 46–61New frontiers in the treatment of Type 1 diabetes

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Cell Metab. 2020 January 07; 31(1): 46–61New frontiers in the treatment of Type 1 diabetes

Mechanism of Action of Different Immunotherapy Agents for type 1DM

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Immunotherapy agent Clinical Trials

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Teplizumab preserve insulin secretion in Stage 3 new onset T1DM (AbATE trial), a Phase II trial

Herold KC et al. Diabetes 2013

Teplizumab Preserves C-peptide in patients with New onset T1D RCT

Phase III trial

Lancet 2011 Aug 6;378(9790):487-97

Most prevention trials focus on those individuals at highest risk of developing disease to decrease the time to achieve the given study’s outcome and observe an answer. As discussed above, this risk is usually a

Herold and colleagues recruited 24 newly diagnosed individuals with T1D (within 6 weeks of diagnosis), half of whom received an escalating dose of Teplizumab each day for 2 weeks, while the placebo group received no antibody [34]. Importantly, 12 months after treatment, two thirds of the Teplizumab-treated group had C-peptide responses that were equivalent or higher than their response at study entry, whereas 10 out of the 12 control participants exhibited a decline in C-peptide response

A phase III trial of Teplizumab in 516 individuals however failed to meet its primary endpoint, a composite outcome comprising insulin dose and haemoglobin A1c (HbA1c) which had not been previously validated [40]. However, exploratory analyses showed that C-peptide declined less in the treated group than in the placebo group and that 5% of patients were not taking insulin at 1 year compared with no patients in the placebo group.

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HR: 0.41

CI 0.22 to 0.78

P = 0.006

Median time to diagnosis of type 1 DM

48.4 months in the teplizumab group

24.4 months in the placebo group

Teplizumab during the dysglycaemic phase of diabetes led to transient T cell modulation, which translated to a median delay in needing to start insulin of 3 years.58,59 Treatment involved 12–14 days of iv infusions. Treatment with Teplizumab was considered safe, with reported adverse events being similar to those in previous studies of Teplizumab such as mild infusion reactions, transient lymphopenia and rash. No significant long-term adverse effects were reported. However, repeated therapy is likely to be limited by the development of anti-drug antibodies. Teplizumab was granted breakthrough status by the FDA in 2019 and prime status by the EMA in 2020. A licensing submission has been made to the FDA and UK MHRA

Teplizumab prevention trial relating to intervention at stage 2 suggested that within this stage the drug appears to be more effective in individuals with more active disease with immune features that can be identified at the beginning of treatment.

the disease was diagnosed in 19 (43%) of the participants who received teplizumab and in 23 (72%) of those who received placebo. The hazard ratio for the diagnosis of type 1 diabetes (teplizumab vs. placebo) was 0.41 (95% confidence interval, 0.22 to 0.78; P=0.006 by adjusted Cox proportional-hazards model). The annualized rates of diagnosis of diabetes were 14.9% per year in the teplizumab group and 35.9% per year in the placebo group.

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Nov 17, 2022 BREAKING NEWS:�

The road to teplizumab has not been easy. In 2021, an FDA advisory committee recommended the approval of teplizumab to the FDA after a closely contested decision. At that time, the committee endorsed reservations about the decision given their uncertainties about efficacy. The FDA allowed Provention Bio to resubmit in early 2022 and, now, as of yesterday, the FDA has given the green light.��WHO BENEFITS?��The main benefit of Tzield therapy is that if started after initial diagnosis it delays full onset. In the FDA official press release (link below), John Sharretts, M.D., director of the Divsion of Diabetes, Lipid Disorders, and Obesity at the FDA, describes Tzield this way: "The drug's potential to delay clinical diagnosis of type 1 diabetes may provide patients with months to years without the burdens of the disease."��Simply put, a newly diagnosed person with T1D may not be fully dependent on external insulin for up to three years, compared to 6 months for most people today. During this time, Tzield slows the auto-immune progression allowing the natural ability to make insulin to continue longer and moderately reducing the risk of long term complications down the road.��That said, Tzield delays but does not stop or prevent the progression of the disease. Eventually, patients will require insulin injections for life. It is distinctly not a functional cure.��Tzield has no impact on a person who is already a fully-established T1D.

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ADA Updates Standards of Medical Care on �June 25, 2023 to include Teplizumab�

Recommendation

Teplizumab infusion to delay the onset of symptomatic Stage 3 T1D should be considered in selected individuals aged ≥8 years with stage 2 T1D.

Management should be in a specialized setting with appropriately trained personnel. B

This is the first study to test teplizumab’s ability to delay or prevent disease progression in those at high risk for developing T1D.

All study participants had two or more T1D autoantibodies and abnormal blood sugar levels (Stage 2 T1D) prior to enrollment, as identified by TrialNet Pathway to Prevention risk screening. Individuals in Stage 2 have a lifetime risk of clinical diagnosis (Stage 3 T1D) nearing 100%.

Researchers enrolled 76 people between the ages of 8 and 49; 55 were under age 18. All participants had at least one relative with type 1 diabetes.

Participants were randomly assigned to either the treatment group, which received a 14-day course of teplizumab, or the control group, which received a placebo. All participants regularly underwent oral glucose tolerance tests either until the study was completed or until they developed clinical type 1 diabetes.

Key Findings

This is the first study to show any drug can delay type 1 diabetes diagnosis a median of 2 years in adults and children at high risk.
72% of people in the control group developed clinical diabetes, compared to only 43% of the teplizumab group.
The median time for people in the control group to develop clinical diabetes (stage 3) was just over 24 months, while those in the treatment group had an average of 48 months before progressing to clinical diabetes (stage 3).
Researchers observed, as with other trials involving teplizumab, short-term side effects of rash and low white blood cell counts.
Subgroups of individuals may have had a better response to therapy than others.
The latest findings, published in Science Translational Medicine on March 3, 2021, show ongoing delay in diabetes in the teplizumab group. The median time to diabetes diagnosis in the teplizumab group was approximately 60 months (5 years), vs. approximately 27 months (2.3 years) in the placebo group.
In addition to having even more pronounced disease delay, those treated with teplizumab showed improved rates of insulin production. Participants receiving a placebo continued to show a decline in insulin production consistent with disease advancement.

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Co-Stimulation Modulation with Abatacept in Patients with New onset stage 3 T1D: an RCT

Lancet 2011 Jul 30; 378(9789): 412-419

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Abatacept for Delay of Type 1 Diabetes Progression in Stage 1 T1D: double masked RCT�

Effect of abatacept on the development of the primary end point of AGT/diabetes (HR 0.702; ; P=0.11)

C-peptide levels were higher in the abatacept-treated group at

month 12 (P = 0.03) no difference in 24 months

ARTICLE HIGHLIGHTS • Abatacept blocks the activation of T cells and slows b-cell loss in new-onset type 1 diabetes.

• We tested whether it would be effective earlier in the autoimmune process before glucose levels are impacted.

• We treated individuals with stage 1 diabetes with abatacept or placebo for 1 year and followed them.

•Although abatacept increased the C-peptide response and induced the immunological changes that we expected, it did not significantly delay the progression to abnormal glucose tolerance to the degree we anticipated.

• The signals are promising, however, that abatacept may modify the progression of type 1 diabetes.

12 months of abatacept treatment in 1 changed immune cells and improved C-peptide as previously shown in stage 3 but did not achieve the pre-set criteria for the delay of 2 diabetes in individuals at 1. Costimulation blockade may modify the progression of type 1 diabetes

The Abatacept Prevention Study opened in 2013 and enrolled 212 people between the ages of 6 and 45. All participants had at least one relative with T1D, two or more diabetes-related autoantibodies and normal glucose tolerance (stage 1 T1D). Risk was identified by TrialNet screening, which detects the autoantibodies that signal the disease in its earliest stages, often years before symptoms appear.

In the treatment phase of the study, participants received 14 intravenous (IV) infusions over one year—three in the first month, then monthly for 11 months.

The study found that while abatacept impacted immune response and preserved insulin production during the one-year treatment period, it did not meet the study goal of delaying progression to abnormal glucose tolerance (stage 2) or clinical diagnosis (stage 3). The group treated with abatacept maintained beta cell function better than the placebo group at 12 months. In addition, known effects of abatacept were detected on immune cells. However, 12 months after treatment ended, beta cell function was the same for both groups and effects on immune cells had reversed. The early effect was not sustained.

Objective: Previous studies showed that inhibiting lymphocyte costimulation reduces declining β-cell function in individuals newly diagnosed with type 1 diabetes. We tested whether abatacept would delay or prevent progression of type 1 diabetes from normal glucose tolerance (NGT) to abnormal glucose tolerance (AGT) or to diabetes and the effects of treatment on immune and metabolic responses.

Research design and methods: We conducted a phase 2, randomized, placebo-controlled, double-masked trial of abatacept in antibody-positive participants with NGT who received monthly abatacept/placebo infusions for 12 months. The end point was AGT or diabetes, assessed by oral glucose tolerance tests.

Results: A total of 101 participants received abatacept and 111 placebo. Of these, 81 (35 abatacept and 46 placebo) met the end point of AGT or type 1 diabetes diagnosis (hazard ratio 0.702; 95% CI 0.452, 1.09; P = 0.11) The C-peptide responses to oral glucose tolerance tests were higher in the abatacept arm (P < 0.03). Abatacept reduced the frequency of inducible T-cell costimulatory (ICOS)+ PD1+ T-follicular helper (Tfh) cells during treatment (P < 0.0001), increased naive CD4+ T cells, and also reduced the frequency of CD4+ regulatory T cells (Tregs) from the baseline (P = 0.0067). Twelve months after treatment, the frequency of ICOS+ Tfh, naive CD4+ T cells, and Tregs returned to baseline.

Conclusions: Although abatacept treatment for 1 year did not significantly delay progression to glucose intolerance in at-risk individuals, it impacted immune cell subsets and preserved insulin secretion, suggesting that costimulation blockade may modify progression of type 1 diabetes.

We conducted a phase 2, randomized, placebo-controlled, double-masked trial of abatacept in antibody-positive participants with NGT who received monthly abatacept/placebo infusions for 12 months. The end point was AGT or diabetes, assessed by oral glucose tolerance tests. RESULTS A total of 101 participants received abatacept and 111 placebo. Of these, 81 (35 abatacept and 46 placebo) met the end point of AGT or type 1 diabetes diagnosis (hazard ratio 0.702; 95% CI 0.452, 1.09; P = 0.11) The C-peptide responses to oral glucose tolerance tests were higher in the abatacept arm (P < 0.03). Abatacept reduced the frequency of inducible T-cell costimulatory (ICOS)+ PD1+ T-follicular helper (Tfh) cells during treatment (P < 0.0001), increased naive CD4+ T cells, and also reduced the frequency of CD4+ regulatory T cells (Tregs) from the baseline (P = 0.0067). Twelve months after treatment, the frequency of ICOS+ Tfh, naive CD4+ T cells, and Tregs returned to baseline. CONCLUSIONS Although abatacept treatment for 1 year did not significantly delay progression to glucose intolerance in at-risk individuals, it impacted immune cell subsets and preserved insulin secretion, suggesting that costimulation blockade may modify progression of type 1 diabetes.

Pearson et al. 100 years post-insulin: immunotherapy as the next frontier in type 1 diabetes. Immunotherapy Advances, 2021, Vol. 1, No. 1, 1–14

Abatacept A further example of a T cell-directed immunotherapy is the cytotoxic T lymphocyte-associated antigen 4 (CTLA4)-Ig fusion protein, Abatacept. CTLA-4 is naturally expressed at high levels in regulatory T cells; it interacts with the same ligands as the T cell costimulatory receptor CD28 but binds to them with higher affnity. CTLA-4-Ig fusion proteins such as Abatacept therefore bind to the costimulatory ligands CD80 and CD86 on antigen-presenting cells and inhibit their interaction with T cell CD28 ([55]; Fig. 2). Since CD28 costimulation provides an important ‘second signal’ to promote full T cell activation, inhibiting this with CTLA4-Ig would be expected to be immunosuppressive. When CTLA-4-Ig was administered to NOD mice early, around the time insulitis frst develops, only 11% of the mice went on to become diabetic compared with 87% in the controltreated group, while later administration had little effect [56]. Surprisingly, however, mice expressing CTLA-4-Ig transgenically from birth showed exacerbated diabetes development, with 100% of mice diabetic by 24 weeks compared with only 8.3% of the non-transgenic NOD mice [57]. This is now thought to refect the role of CD28 in the development of Tregs which have immunosuppressive function [58]. In the context of Treg defciency, and an absence of CD28 signalling since birth, it was proposed that alternative costimulatory pathways had compensated for the lack of CD28 in these mice [57]. Therapeutic targeting of the CD28 pathway therefore requires careful consideration regarding impacts on the Treg population, and timing of administration is likely to be important. The CTLA-4-Ig molecule Abatacept was trialled in 112 patients (6–45 years of age) diagnosed with T1D within the last 100 days. Infusions were given intravenously on days 1, 14, and 28 and then monthly for 2 years. Abatacept was able to slow the decline in β cell destruction and function for an estimated 9.6 months [59], with higher C-peptide levels still observed in the treated group, compared to placebo, 1 year after therapy cessation [60]. This protective effect was associated with a reduced CD4+ central memory T cell population and B cell population, as well as increased Tregs and naive CD4+ T cells [61]. Recent data suggest that analysis of circulating follicular helper T cells (Tfh) prior to Abatacept treatment may prove useful in predicting the subsequent clinical response [62]. Following on from the study in new onset T1D, Abatacept is currently being trialled in people at risk of T1D development (NCT01773707).

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Alefacept in Stage 3 T1D�

Uncovering Pathways to Personalized Therapies in Type 1 Diabetes

Linsley et al. Diabetes 2021;70:831–841

It binds to CD2 and mediates depletion of T effector cells and improve T Reg cells

Approved tx for psoariasis

Figure 3—Frequencies of regulatory T cells (Treg) and effector T cells (Teff) following use of anti–T-cell immunomodulatory therapy correlate with persistence or loss of insulin secretory capacity. Shown are stimulated C-peptide area under the curve (AUC) measurements from the T1DAL trial of alefacept (top left panel) and the START trial of ATG (top right panel), documenting transient preservation of b-cell function following alefacept treatment. The bottom panels display a ratio of the frequencies of regulatory and effector T lymphocytes in peripheral blood during these clinical trials, illustrating a marked increase in this ratio during the period of C-peptide preservation in T1DAL but not in START. Data are adapted from Rigby et al. (17) and Gitelman et al. (34).

Pearson et al. 100 years post-insulin: immunotherapy as the next frontier in type 1 diabetes. Immunotherapy Advances, 2021, Vol. 1, No. 1, 1–14

Alefacept

Alefacept is another Ig fusion protein comprising two LFA-3 molecules bound to the Fc portion of human IgG1. It binds to CD2 and mediates depletion of antigen experienced effector/memory T cells. Memory T cells are an attractive target in autoimmune disease and are believed to be less sensitive to costimulation blockade drugs such as Abatacept. Alefacept inhibits the proliferation of T cells in mixed lymphocyte reactions in a manner that depends on Fc-receptor binding [63]. In the T1DAL study, Alefacept was delivered by intramuscular injection in two 12-week courses to 33 individuals within 100 days of T1D diagnosis, while 16 individuals received placebo treatment [64]. The primary endpoint was not met, since the difference between C-peptide measurements in a 2h mixed-meal tolerance test (MMTT) at 12 months was not signifcant (P = 0.065); however, the secondary endpoint, involving C-peptide measurement in a 4-h MMTT at the same timepoint was met (P = 0.019). It was suggested that the curtailed recruitment following voluntary withdrawal of Alefacept by the manufacturer may have reduced the power to detect the impact of treatment. Follow-up analysis suggested benefcial effects were maintained 15 months after therapy cessation, with Alefacept-treated individuals exhibiting higher C-peptide levels than placebo-treated individuals, a signifcantly lower insulin requirement, and substantially lower rates of hypoglycaemia [65].

Alefacept is an LFA3-Ig fusion protein that binds CD2, which predominates on these effector T cells (Rigby et al., 2015). Following two 12- week course treatments over 36 weeks in recently diagnosed , overall insulin requirement did not decrease, hba1c did not improve to suggest diabetes reversal, no current clinical trials

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Results: The 1-year mean AUC C-peptide was significantly higher in subjects treated with ATG (0.646 nmol/L) versus placebo (0.406 nmol/L) (P = 0.0003) but not in those treated with ATG/GCSF (0.528 nmol/L) versus placebo (P = 0.031). HbA_1c was significantly reduced at 1 year in subjects treated with ATG and ATG/GCSF, P = 0.002 and 0.011, respectively.

Conclusions: Low-dose ATG slowed decline of C-peptide and reduced HbA_1c in new-onset T1D. Addition of GCSF did not enhance C-peptide preservation afforded by low-dose ATG. Future studies should be considered to determine whether low-dose ATG alone or in combination with other agents may prevent or delay the onset of the disease.

A further trial in 89 individuals within 100 days of T1D diagnosis confirmed that low-dose ATG (2.5 mg/kg) resulted in clinical benefit, with C-peptide levels 57% higher in recipients of low-dose ATG, compared with recipients of placebo, at the 1-year timepoint [53]. Side-by-side comparison with the ATG/GCSF combination revealed that the low-dose ATG monotherapy was favourable [53], and a separate study confirmed that GCSF alone did not preserve β cell function [54]. Thus, low-dose ATG remains an interesting candidate for further development. Notably, attempts to compare β cell preserving interventions across multiple clinical trials identified low-dose ATG and anti-CD3 immunotherapy as the treatments showing the greatest impact on C-peptide preservation [55].

�

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Rituximab, B-Lymphocyte Depletion, and Preservation

of Beta-Cell Function in recent onset T1D

n engl j med 361;22 nejm.org november 26, 2009

rituximab (RTX), a monoclonal antibody specific to B-cell surface protein CD20. Although RTX treatment of T1DM caused significant B cell depletion, the long-term efficacy has not been established yet [41]. One study showed efficacy in preserving beta cell function for 1 year; Extended follow-up of participants, whereas such therapy showed limited effect after 2 years, the improvement in C-peptide preservation was limited to the early period after RTX and disappeared 30 months later [42]. Thus, pan-B-cell-depletion is not very effective as used and frequent depletion might be required to minimize the presence of autoreactive B cells.

IV infusion in 4 doses over a period of 22 days,

with 49 Rituximab and 29 placebo aged 8–40 years of age

outcome measure was stimulated C-peptide levels in a MMTT after 1 yr

mean C-peptide levels were 20% higher in the Rituximab-treated group

(0.56 pmol/ml Rituximab grp vs. 0.47 pmol/ml placebo group)

treatment signifcantly reduced HbA1c (6.76% vs. 7.00%) and decreased the required insulin dose (0.39U ± 0.22/kg of body weight vs. 0.48 U ± 0.23/kg).

initial improvements were shortlived and C-peptide continued to decline thereafter. CD19+ B cell counts had substantially recovered by 6 months post-treatment

it is possible that Rituximab may show enhanced clinical effcacy in younger <7 years individuals and possibly in the ‘at risk’ population.

Depletion of B cells with rituximab was tested in a phase 2 trial of new-onset type 1 diabetes; four infusions over 22 days led to significantly slower C-peptide decline over 1 year, however, 30 month follow up same as control
Researchers are now looking at suppressing both B and T cells, by giving 4 weeks of rituximab followed by 2 years of abatacept to people at high risk for developing type 1 diabetes. Another ongoing study of note involves the anti-malarial drug hydroxychloroquine, which reduces T-cell activation, also in high-risk individuals.

Pearson et al. 100 years post-insulin: immunotherapy as the next frontier in type 1 diabetes. Immunotherapy Advances, 2021, Vol. 1, No. 1, 1–14

Anti-CD20 immunotherapy Rituximab binds to CD20 expressed on the surface of B cells, leading to their destruction mediated via antibodydependent cell-mediated cytotoxicity, apoptosis, and complement-dependent cytotoxicity [83, 84]. It is important to note that Rituximab does not deplete all B cells, as plasma cells, which secrete antibodies, do not express CD20 and other B cell subsets such as B1 cells, germinal centre B cells and tissue-resident B cells may be less sensitive to depletion. Rituximab has shown effcacy in a number of different autoimmune diseases including systemic lupus erythematosus and rheumatoid arthritis. To explore the beneft of B cell depletion in T1D, pre-clinical studies were conducted by studying transgenic hCD20 NOD mice, expressing human CD20 on B cells [79]. In these hCD20 NOD mice, a single cycle of anti-CD20 antibody administration (9-day treatment cycle: 0.5 mg/ ml at day 0, followed by three injections of 0.25 mg/ml at 3-day intervals), was able to both delay and reduce the development of T1D. Importantly, similar to anti-CD3 immunotherapy [26], anti-CD20 administration was able to reverse diabetes, with over one third of mice in remission. Studies evaluating the repopulation of cells in NOD mice found that the protection of anti-CD20 mice was associated with increased regulatory immune cells [79, 85–87] and reduced proinfammatory cytokines secretion by, and activation of, islet T cells [88]. Following the positive outcomes in pre-clinical models, Rituximab was trialled in individuals with recent-onset T1D. The therapy was administered by intravenous infusion in 4 doses over a period of 22 days, with 49 individuals receiving Rituximab and 29 receiving placebo [89]. The primary outcome measure was stimulated C-peptide levels in a MMTT 1 year after the initial infusion. Results from this clinical trial suggested clear beneft of B cell depletion: mean C-peptide levels were 20% higher in the Rituximab-treated group (0.56 pmol/ml in the Rituximab group vs. 0.47 pmol/ml in the placebo group) and treatment also signifcantly reduced glycated haemoglobin levels (6.76% vs. 7.00%) and decreased the required insulin dose (0.39U ± 0.22/kg of body weight vs. 0.48 U ± 0.23/kg). In common with other clinical trials, the initial improvements were shortlived and C-peptide continued to decline thereafter. Of note, CD19+ B cell counts had substantially recovered by 6 months post-treatment initiation suggesting the possibility that benefts might be increased if the depletion could be sustained. In addition, the participants recruited to this study were aged 8–40 years of age [89]; however, given the prevalence of B cells in the pancreas of individuals diagnosed with T1D before 7 years of age [82], it is possible that Rituximab may show enhanced clinical effcacy in younger individuals and possibly in the ‘at risk’ population.

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Rituximab, B-Lymphocyte Depletion, and Preservation

of Beta-Cell Function

n engl j med 361;22 nejm.org november 26, 2009

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Rituximab followed by Abatacept should be more

effective for more people over time

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Efficacy and safety of anti-interleukin (IL)-21 in combination with liraglutide in adults recently diagnosed with type 1 diabetes�

A phase II randomised double-blind, double-dummy, placebocontrolled study was conducted in recent-onset individuals with T1D, where they received either anti-IL21, anti-IL-21 with liraglutide, liraglutide alone or placebo (77 individuals per treatment arm) [109]. Liraglutide is a glucagon-like peptide 1 receptor agonist, which works by increasing insulin secretion from the pancreas and decreasing glucagon release. Thus, liraglutide improves β cell function. Von Herrath and colleagues found that in all treated groups, HbA1C was lowered compared to placebos; however, in the combination of anti-IL-21 with liraglutide, a smaller reduction in C-peptide following a MMTT was observed, suggesting enhanced β cell function in the combination group, compared to single treatment groups. It will be important to enlarge the study and determine how long the effects may last following cessation of treatment.

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Efficacy and safety of anti-interleukin (IL)-21 in combination with liraglutide in adults

recent onset T1DM�

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Efficacy and safety of anti-interleukin (IL)-21 in combination with liraglutide in adults

recent onset T1DM�

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Prevention Trials�T-cell Based Tx in Stages 1 and 2 Type 1 DM

Trial	Drug	(n)	Age	Parameter	Time	Result #1	Result#2	P value
Anti-CD3	Teplizumab	76	<18 y/o	1. Median time to Stage 3 T1D 2. % dev Stage 3 T1D	5 yrs	48.4 mos vs. 24.4 mos	43% vs. 72% HR: 0.41	0.006
CTLA4 Ig	Abatacept	212	<18 y/o	Time to Stage 1 or Stage 2 C-peptide	8 yrs	35% vs. 41% HR 0.702 P = 0.11	Higher for Abatacept No difference at 24mos	P<0.03

A total of 76 participants (55 [72%] of whom were ≤18 years of age) underwent randomization — 44 to the teplizumab group and 32 to the placebo group. The median time to the diagnosis of type 1 diabetes was 48.4 months in the teplizumab group and 24.4 months in the placebo group; the disease was diagnosed in 19 (43%) of the participants who received teplizumab and in 23 (72%) of those who received placebo. The hazard ratio for the diagnosis of type 1 diabetes (teplizumab vs. placebo) was 0.41 (95% confidence interval, 0.22 to 0.78; P=0.006 by adjusted Cox proportional-hazards model). The annualized rates of diagnosis of diabetes were 14.9% per year in the teplizumab group and 35.9% per year in the placebo group. There were expected adverse events of rash and transient lymphopenia. KLRG1+TIGIT+CD8+ T cells were more common in the teplizumab group than in the placebo group. Among the participants who were HLA-DR3–negative, HLA-DR4–positive, or anti–zinc transporter 8 antibody–negative, fewer participants in the teplizumab group than in the placebo group had diabetes diagnosed. CONCLUSIONS Teplizumab delayed progression to clinical type 1 diabetes in high-risk participants. (Funded by the National

The largest effect of teplizumab treatment was found in the first year: diabetes was diagnosed in only 3 of 44 participants (7%) in the teplizumab group, in contrast to 14 of 32 participants (44%) in the placebo group

The effects of teplizumab were greatest in the first 3 years after administration. Among the participants in whom diabetes was diagnosed, 41% had the disease within the first year after randomization, and the risk was lowest at that time for those exposed to teplizumab. The relatively rapid rate of progression to clinical diabetes in the placebo group reflects the very high risk among children with autoantibodies.5,26,27 Indeed, our observations among young persons who did not yet have clinical disease reflect the likely progression when two or more autoantibodies and dysglycemia are found and are consistent with our report of high rates of beta-cell death in these persons.26-28 Preclinical studies suggested that an active autoimmune response is needed for the actions of an anti-CD3 monoclonal antibody29,30; thus, earlier interventions (i.e., during stage 1) may be less efficacious. Consistent with such observations, the response to teplizumab was greatest among participants with C-peptide responses that were below the median.

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Intervention Trials�T-cell Based Tx Stage 3 New onset type 1 DM

Trial	Drug	(n)	Age	Parameter	Time	Result	Result	P value
Anti-CD3	Teplizumab 2 weeks course	24	7–30	MMTT C-peptide	1 year	66% ↑ vs. 83%↓	114.2 vs. 66.7 nmol/L	<0.01
Low dose ATG + GCSF	2.5mg/kg ATG+ GCSF	25	12–45	MMTT C-peptide	1 year	4.3% ↑ vs. 39%↓	0.74 vs. 0.43 nmol/L/min	0.05
CTLA4Ig	Abatacept	112	6–45	MMTT C-peptide	2 years	9.6 months delay in decline	0.378 vs. 0.238 nmol/L	0.0029
T1DAL	Alefacept IM Two 12 wk course	49	12–35	MMTT C-peptide: 1°: 2 hours 2°: 4 hours	1 year	1°: +0.015 vs. −0.115 nmol/L	2°: +0.015 vs. −0.156 nmol/L	0.065 0.019

Immunotherapy Advances, 2021, Vol. 1, No. 1, 1–14

Herold and colleagues recruited 24 newly diagnosed individuals with T1D (within 6 weeks of diagnosis), half of whom received an escalating dose of Teplizumab each day for 2 weeks, while the placebo group received no antibody [34]. Importantly, 12 months after treatment, two thirds of the Teplizumab-treated group had C-peptide responses that were equivalent or higher than their response at study entry, whereas 10 out of the 12 control participants exhibited a decline in C-peptide response.

(Otelixizumab) in 80 individuals with new onset T1D also showed a slower deterioration of β cell function in those receiving anti-CD3 treatment [35]. Preservation of even a small amount of residual insulin secretion, measured by C-peptide, can provide long-standing health benefits [36].

Perdigoto AL, Preston-Hurlburt P, Clark P, et al. Treatment of type 1 diabetes with teplizumab: clinical and immunological follow-up after 7 years from diagnosis. Diabetologia 2019;62(4):655–64. http://doi.org/10.1007/s00125-018-4786-9

ATG is a polyclonal IgG targeting multiple T cell antigens and mediating cellular depletion:

Initial small studies in humans with recent-onset T1D suggested ATG administration may help preserve β cell function [46, 47]; however, in a phase II randomised multi-center, placebo-controlled trial involving 58 individuals within 100 days of T1D diagnosis, ATG (6.5 mg/kg administered over a 4-day course) did not preserve β cell function [48, 49]. This failure was linked to a decrease in the Treg to T-effector memory ratio in ATG treated individuals between baseline and 6 months, since effector memory CD4+ T cells were poorly depleted relative to the other T cell subsets examined

A subsequent trial in 25 individuals with established T1D (between 4 months and 2 years post-diagnosis) used a lower dose of ATG (2.5 mg/kg administered as 0.5 mg/kg on day 1 and 2 mg/kg on day 2) and combined the treatment with Granulocyte colony-stimulating factor (GCSF) in line with previous preclinical data [45]. This approach appeared to result in protection of the β cells; on average, subjects who received placebo experienced a 39% reduction in C-peptide over 1 year, while those who received ATG/GCSF experienced a 4.3% increase over the same time period [50]. The relative resistance of CD4+ effector memory T cells to depletion was also evident in this trial, but Tregs appeared to be preserved

A further trial in 89 individuals within 100 days of T1D diagnosis confirmed that low-dose ATG (2.5 mg/kg) resulted in clinical benefit, with C-peptide levels 57% higher in recipients of low-dose ATG, compared with recipients of placebo, at the 1-year timepoint [52].

Thus, low-dose ATG remains an interesting candidate for further development.

Notably, attempts to compare β cell preserving interventions across multiple clinical trials identified low-dose ATG and anti-CD3 immunotherapy as the treatments showing the greatest impact on C-peptide preservation

Abatacept

A further example of a T cell-directed immunotherapy is the cytotoxic T lymphocyte-associated antigen 4 (CTLA-4)-Ig fusion protein, Abatacept. CTLA-4 is naturally expressed at high levels in regulatory T cells; it interacts with the same ligands as the T cell costimulatory receptor CD28 but binds to them with higher affinity. CTLA-4-Ig fusion proteins such as Abatacept therefore bind to the costimulatory ligands CD80 and CD86 on antigen-presenting cells and inhibit their interaction with T cell CD28 ([55]; Fig. 2). Since CD28 costimulation provides an important ‘second signal’ to promote full T cell activation, inhibiting this with CTLA4-Ig would be expected to be immunosuppressive

The CTLA-4-Ig molecule Abatacept was trialled in 112 patients (6–45 years of age) diagnosed with T1D within the last 100 days. Infusions were given intravenously on days 1, 14, and 28 and then monthly for 2 years. Abatacept was able to slow the decline in β cell destruction and function for an estimated 9.6 months [59], with higher C-peptide levels still observed in the treated group, compared to placebo, 1 year after therapy cessation [60]. This protective effect was associated with a reduced CD4+ central memory T cell population and B cell population, as well as increased Tregs and naive CD4+ T cells

Recent data suggest that analysis of circulating follicular helper T cells (Tfh) prior to Abatacept treatment may prove useful in predicting the subsequent clinical response

Alefacept is another Ig fusion protein comprising two LFA-3 molecules bound to the Fc portion of human IgG1. It binds to CD2 and mediates depletion of antigen experienced effector/memory T cells. Memory T cells are an attractive target in autoimmune disease and are believed to be less sensitive to costimulation blockade drugs such as Abatacept. Alefacept inhibits the proliferation of T cells in mixed lymphocyte reactions in a manner that depends on Fc-receptor binding [63]. In the T1DAL study, Alefacept was delivered by intramuscular injection in two 12-week courses to 33 individuals within 100 days of T1D diagnosis, while 16 individuals received placebo treatment [64]. The primary endpoint was not met, since the difference between C-peptide measurements in a 2h mixed-meal tolerance test (MMTT) at 12 months was not significant (P = 0.065); however, the secondary endpoint, involving C-peptide measurement in a 4-h MMTT at the same timepoint was met (P = 0.019). It was suggested that the curtailed recruitment following voluntary withdrawal of Alefacept by the manufacturer may have reduced the power to detect the impact of treatment. Follow-up analysis suggested beneficial effects were maintained 15 months after therapy cessation, with Alefacept-treated individuals exhibiting higher C-peptide levels than placebo-treated individuals, a significantly lower insulin requirement, and substantially lower rates of hypoglycaemia

IL-2 therapy

An additional immunotherapeutic approach directed at T cells centres on the selective expansion of Tregs using the cytokine IL-2. Although IL-2 was originally described as a growth factor for conventional T cells, it subsequently became clear that a major biological function for IL-2 is to regulate immune responses by supporting the homeostasis of Tregs. A role for IL-2 in immune regulation indicated why defects in IL-2, or in genes that contribute to IL-2 signalling, are associated with autoimmune diseases, including T1D [66, 67]. Since Tregs express high levels of CD25, a component of the high-affinity IL-2 receptor, this sparked the idea that they might be selectively targeted by low doses of IL-2. The use of IL-2 to suppress immune responses is an extraordinary example of the same agent being used at different doses for opposing purposes, since high-dose IL-2 is used to promote anti-tumour responses in cancer patients. In the light of this, the field has moved in two directions: one involving careful dosing to identify regimens that activate Tregs without activating effector cells [70], and the other involving the generation of mutant IL-2 therapeutics aimed at avoiding the detrimental In the light of this, the field has moved in two directions: one involving careful dosing to identify regimens that activate Tregs without activating effector cells [70], and the other involving the generation of mutant IL-2 therapeutics aimed at avoiding the detrimental activation of NK cells, eosinophils, and effector T cells. Boosting Treg numbers by cell therapy in combination with IL-2 administration is also being explored

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Intervention Trials �B lymphocyte Based Tx Stage 3 New onset type 1 DM

Trial	Drug	(n)	Age	Parameter	Time	Result	Result	P value
Anti-CD20	Rituximab	87	8–40	MMTT C-peptide HbA1c Insulin dose	1 year	20% higher 6.76% vs. 7.0% 0.39 u/kg vs. 0.48 u/kg	0.56 vs. 0.47 nmol/L	0.03

Immunotherapy Advances, 2021, Vol. 1, No. 1, 1–14

Rituximab binds to CD20 expressed on the surface of B cells, leading to their destruction mediated via antibody-dependent cell-mediated cytotoxicity, apoptosis, and complement-dependent cytotoxicity [83, 84]. It is important to note that Rituximab does not deplete all B cells, as plasma cells, which secrete antibodies, do not express CD20. Rituximab has shown efficacy in a number of different autoimmune diseases including systemic lupus erythematosus and rheumatoid arthritis. Rituximab was trialled in individuals with recent-onset T1D. The therapy was administered by intravenous infusion in 4 doses over a period of 22 days, with 49 individuals receiving Rituximab and 29 receiving placebo [89]. The primary outcome measure was stimulated C-peptide levels in a MMTT 1 year after the initial infusion. Results from this clinical trial suggested clear benefit of B cell depletion: mean C-peptide levels were 20% higher in the Rituximab-treated group (0.56 pmol/ml in the Rituximab group vs. 0.47 pmol/ml in the placebo group) and treatment also significantly reduced glycated haemoglobin levels (6.76% vs. 7.00%) and decreased the required insulin dose (0.39U ± 0.22/kg of body weight vs. 0.48 U ± 0.23/kg). In common with other clinical trials, the initial improvements were short-lived and C-peptide continued to decline thereafter. Of note, CD19+ B cell counts had substantially recovered by 6 months post-treatment initiation suggesting the possibility that benefits might be increased if the depletion could be sustained.

it is possible that Rituximab may show enhanced clinical efficacy in younger individuals and possibly in the ‘at risk’ population.

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Intervention Trials� Targeting inflammatory cytokines Stage 3 New onset T1DM

Trial	Drug	(n)	Age	Parameter	Time	Result	Result	P value
Anti-IL21	Anti-IL21 +Liraglutide 4arms	304	18-45	MMTT C peptide	54 weeks	Slower decline 48% higher vs. placebo	Lower HbA1c with lower insulin dose	P<0.01
Anti TNFα	Etanercept	18	7–18	MMTT C-peptide	6 months	+39% vs. -20%		0.05
Anti TNFα	Golimumab	84		C peptide Insulin dose	52 weeks	Higher C-peptide Lower Insulin dose

Immunotherapy Advances, 2021, Vol. 1, No. 1, 1–14

TNFα-targeting therapies were administered to newly diagnosed T1D patients to test whether they could preserve β cell function. Etanercept, a recombinant soluble TNF-receptor fusion protein that binds to TNFα was trialled in 18 subjects with newly diagnosed T1D. In this randomised, double-blind, placebo-controlled feasibility study over 24 weeks, Etanercept was shown to increase mean C-peptide levels by 39% from baseline whereas a mean decrease of 20% was observed in the placebo group

Golimumab, an anti-TNFα monoclonal antibody previously approved for the treatment of rheumatoid arthritis and ulcerative colitis, has also been tested in newly diagnosed individuals with T1D [101]. This phase II randomised, double-blind, placebo-controlled study involved 56 participants receiving Golimumab and 28 participants receiving placebo, and resulted in significantly higher C-peptide and lower insulin use in the treatment group after 52 weeks.

IL-21 is the characteristic cytokine made by follicular helper T cells (Tfh cells), that provide help for B cell antibody production, and therefore plays an important role in humoral immunity.

A phase II randomised double-blind, double-dummy, placebo-controlled study was conducted in recent-onset individuals with T1D, where they received either anti-IL21, anti-IL-21 with liraglutide, liraglutide alone or placebo (77 individuals per treatment arm) [109]. Liraglutide is a glucagon-like peptide 1 receptor agonist, which works by increasing insulin secretion from the pancreas and decreasing glucagon release. Thus, liraglutide improves β cell function. Von Herrath and colleagues found that in all treated groups, HbA1C was lowered compared to placebos; however, in the combination of anti-IL-21 with liraglutide, a smaller reduction in C-peptide following a MMTT was observed, suggesting enhanced β cell function in the combination group, compared to single treatment groups. It will be important to enlarge the study and determine how long the effects may last following cessation of treatment.

A phase II randomised double-blind, double-dummy, placebocontrolled study

4 arms: anti-IL21, anti-IL-21 with liraglutide, liraglutide alone, placebo (77 individuals per arm

In all treated groups, HbA1C was lowered compared to placebo

anti-IL-21 with liraglutide, a smaller decline in C-peptide following a MMTT was observed, suggesting enhanced β cell function in the combination group, compared to single treatment groups. It will be important to enlarge the study and determine how long the effects may last following cessation of treatment.

IL-21 antibody provides “low-grade and transient immunomodulation,” while the glucagon-like peptide (GLP)-1 receptor agonist liraglutide improves β-cell function, and they hypothesized that the combination of both agents “could enable β-cell survival with a reduced risk of complications compared with traditional immunomodulation.”

For the trial, 307 adults aged an average of 28.4 years with a recent (≤20 weeks) diagnosis of type 1 diabetes and a peak C-peptide concentration of at least 0.2 nmol/L were randomly assigned to receive 54 weeks of treatment with anti-IL-21 plus liraglutide, either treatment alone, or placebo.

Anti-IL-21 was given intravenously at a dose of 12 mg/kg every 6 weeks, while liraglutide was self-administered once daily as subcutaneous injections, with a target dose of 1.8 mg. All treatments were given alongside a treat-to-target insulin regimen.

Thomas Pieber (Medical University of Graz, Austria) and co-investigators report that participants in the combination therapy group experienced a significantly smaller decrease in mixed-meal tolerance test (MMTT)-stimulated C-peptide levels from baseline to week 54 than those given placebo, with reductions of 10% and 39%, respectively.

These findings suggest that the combination “was significantly better than placebo at preserving endogenous insulin secretion,” say the researchers, noting that the effect “was accompanied by nearly complete maintenance of fasting baseline C-peptide secretion and a reduction in the need for exogenous insulin by almost a third.”

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Effect of Verapamil on Pancreatic Beta Cell Function in Newly Diagnosed Pediatric Type 1 Diabetes A Randomized Clinical Trial

Age: 7 to 17 years
Verapamil uptitrated to 5.8 mg/kg/d)
C-peptide at 52 weeks

Verapamil = 0.65 pmol/L,
Plabebo = 0.44 pmol/L
30% higher C-peptide level with verapamil

C-peptide level ≥ 0.2 pmol/mL

Verapamil group 95%
Placebo 71 %

Forlenza et al. JAMA February 24, 2023.

Thioredoxin-interacting protein overexpression has been shown to induce pancreatic beta cell apoptosis and be involved in glucotoxicity-induced beta cell death in culture and mouse models.6 Calcium channel blockers, such as verapamil, reduce thioredoxin-interacting protein expression and beta cell apoptosis7-9 and may be beneficial in beta cell preservation after a type 1 diabetes diagnosis.

An extended-release formulation of verapamil was used. The drug dose was dependent on each participant’s weight and was started with 60 mg/d or 120 mg/d. The dose was escalated at 2- to 4-week intervals to a maximum of dose of 360 mg/d for participants weighing more than 50 kg. The dose was held, decreased, or discontinued if adverse events occurred. Eight participants (17%) in the verapamil group and 8 participants (20%) in the placebo group experienced a nonserious adverse event considered to be related to treatment. In the verapamil group, 3 participants experienced electrocardiogram abnormalities (prolonged PR interval in 1 participant, seconddegree heart block and prolonged PR interval in 1 participant,

71% of the placebo group had a peak C-peptide level of 0.2 pmol/mL or greater 52 weeks after diagnosis even though this percentage was less than the 95% of the verapamil group with a peak C-peptide level of 0.2 pmol/mL or greater

weighed 30 kg or greater due to the commercially available dosing options for extended-release verapamil.

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Other Ongoing Trials

Abrocitinib and ritlecitinib (oral)

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Challenges in Immunotherapy

Heterogeneity, with nonuniform rate of progression, in immune profiles and in response to therapy.

Proper timing of intervention coinciding with greatest disease activity to obtain maximum benefit

Search for common immune biomarkers for early detection as well as for monitoring the effects of a given immunotherapy.

Uncovering Pathways to Personalized Therapies in Type 1 Diabetes

Linsley et al. Diabetes 2021;70:831–841

Uncovering Pathways to Personalized Therapies in Type 1 Diabetes Peter S. Linsley, Carla J. Greenbaum, and Gerald T. Nepom Diabetes 2021;70:831–841Recent studies, however, have highlighted heterogeneity associated with progression, with nonuniform rate of insulin loss and distinct features of the peri-diagnostic period. Likewise, there is heterogeneity in immune profiles and outcomes in response to therapy.

These include therapy timed to periods of disease activity, use of patient stratification biomarkers to align therapeutic target with disease endotype, pharmacodynamic biomarkers to achieve personalized dosing and appropriate combination therapies, and efficacy biomarkers for “treat-to-target” strategies.

The goal of personalized medicine in T1D is to predict the optimal drug, or dose of a drug, for each individual patient.

In the TrialNet Oral Insulin study, while the overall results were negative, the cohort of individuals with the most rapid progression and thus presumably with active disease responded to therapy

immune “flare.

A second hypothesis posits that the acceleration in b-cell dysfunction occurs when the system has reached a tipping point, in which a chronic slow loss of function eventually results in “sudden”collapse. documenting rapid fall in secretion and increase in glucose after 50% loss of b-cell mass represent acceleration of b-cell injury from any cause that in turn further promotes immune-mediated damage.

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Conclusion

Among T1D, personalized medicine tailoring the right treatment to the right patient at the right time is crucial.

Different immunotherapy agents have been tested in clinical trials but most fell short in achieving durable therapeutic benefits.

Enrollment in ongoing clinical trials can aid in identifying best responders

Teplizumab was the first FDA approved immunotherapy agent to delay disease progression in high-risk stage 2 T1D and should be considered.

Longitudinal studies are needed to identify the length of benefit from additional doses of treatment and whether combination treatments will work better

Personalized Immunotherapies for Type 1 Diabetes: Who, What, When, and How? Claire Deligne

heterogeneity of T1D pathophysiology may dictate the choice and response to immunotherapies, and how tailoring the right treatment to the right patient at the right time can turn the tide toward clinical benefit by halting the autoimmune β-cell destruction. Moving to more personalized medicine in T1D implies a better categorization and monitoring of disease progression and aggressiveness identified by sets of biomarkers that will provide guidance to “when, who, how, and what” before launching T1D intervention or prevention trials.

different strategies, including B-cell depletion, T-cell modulation, cytokine targeting, and antigen-specific tolerance

induction. Overall, these strategies still fall short in achieving durable therapeutic benefits. These failures are open to several explanations, such as a late patient enrollment into a majority of these trials, at a time when most cells are already destroyed, and a disease heterogeneity that has been largely overlooked. There are indeed several T1D “endotypes”, exhibiting distinct clinical and biological features (age of onset, genetic polymorphisms, severity and composition of the immune infiltrates, magnitude of -cell destruction)

tailoring the right treatmentto the right patient at the right time can turn the tide toward clinical benefit by halting the autoimmune -cell destruction. Moving to more personalized medicine in T1D implies a better categorization and monitoring of disease progression and aggressiveness identified by sets of biomarkers that will provide guidance to “when, who, how, and what” before launching T1D intervention or prevention trials.

so-called stage 3 (clinical) disease. Thus, by the time of intervention, the damage is already done. In

contrast, stage 1 patients, who are normoglycemic but positive for at least 2 aAbs, and stage 2 patients, who present dysglycemia (e.g., transient hyperglycemic peaks after a glucose challenge), exhibit humoral and cellular islet autoimmunity, but their -cell mass and function are still preserved, which provides the opportunity to reorient the immune

responses towards tolerance before irreversible damage. It is henceforth accepted thatadapting and searching for the best therapeutic window for a given treatment represents a first step towards personalized intervention

Metabolic markers (C-peptide, HbA1c and insulin requirement) are useful in the clinical phase of T1D (Stage 2 and 3) but need to develop biomarkers (e.g. T Regulatory cell to T Effector cell ratio) to monitor progress of treatment especially for the early preventive phase

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Thank you for Listening