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Sid Sijbrandij

Cancer Journey

cancer@sytse.com

Please email me if you want to look beyond the standard of care. I work with two full time people to follow up with everyone.

sytse.com/cancer

Feel free to share this presentation and above url with anyone

SID SIJBRANDIJ | CANCER JOURNEY

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2

  • Running Gitlab - ~$800M revenue publicly traded company with >2000 employees
  • Happily married to Karen, partner of over 25 years

Living the American dream after IPO'ing GitLab in 2021

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In 2022 I had pain while bench pressing, 6cm osteosarcoma

3

END OF 2022

  • But then at the end of 2022 I felt pain and went to the emergency room…
  • They detected a 6 cm tumor that had grown from my spine!
  • We found out in 2023 it was high grade bone cancer.

Became the start of a journey

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Standard of care treatment for osteosarcoma (bone cancer)

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START OF 2023

  1. Surgery including T5 vertebrae removal and spine fusion with a titanium frame
  2. Radiation (SBRT and proton beam)
  3. Chemo - 6 cycles (4 dox/cisplatin, 2 AIM) that were so intense that 4 blood transfusions were needed to keep me alive

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Also in 2022 Click chemistry won a nobel prize

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In 2017 I invested in click-chemistry for cancer in 2023 I took it

Single Patient IND

6

Since 2017 I invested in a company called Shasqi that uses click-chemistry to target cancer treatments.

Because biotech didn't believe in them I become their biggest shareholder but now I was becoming a patient as well!

This way my first single patient IND treatment. Opening my mind to what is possible outside of the standard of care.

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It came back locally and there was no treatment or trial

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2024

No trails available: My rare disease and rare HLA-type didn't qualify for any trials: It was time to step up and take charge of my own care…

My oncologist: “I have no more drugs I would recommend. Maybe you can find a trial.”

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I'll talk to anyone, I'll go anywhere, and I can be there anytime.

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I went founder mode on my cancer

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Maximal Diagnostics

Making Treatments

Treatments in Parallel

Scaling for Others

Elliot Hershberg coined the 'founder mode' with https://centuryofbio.com/p/sid

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Maximal Diagnostics, test even if unsure how to action

35TB of data publicly available on https://osteosarc.com/

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SINGLE CELL SEQUENCING

DNA / RNA SEQUENCING

PATHOLOGY STAINING

FREQUENT BLOOD TESTING

DRUG RESPONSE

TARGETED PET SCANS

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Passersby at AACR made a world model based on my scRNA

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Developing 10+ personalized drugs and diagnostics

Personalized TCR-T cell therapy

Personalized cancer vaccines (mRNA, DNA, peptide)

Custom binder for target found in my tumor (PANX3)

Personalized CAR-T cell therapy

Personalized radiodiagnostics

Custom antibody-drug conjugates targeting my tumor

Note: I didn't develop most of the drugs I ended up taking.

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I did many treatments in Parallel, not Serially

Treatments are usually tested one at a time

Most people run out of time as cancer spreads before finding a cure.

I'd rather die from side effects than from cancer

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"If it works, we won't know what cured you."

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The basics are not prohibitively expensive

Bulk RNA sequencing starting at $50

(and scale for deeper profiling)

Whole genome sequencing starting at $500

AI tools are very capable and $20+ per month

Many chemotherapies are available as low-cost generics

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Helping people look beyond standard of care

Book a free call online with one of our two team members who are available fulltime to help patients see what is available beyond the standard of care.

Poornima Parameswaran, Ph.D.

Bayli DiVita Dean, Ph.D.

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I started 15 companies in 15 months to increase access

Custom protein and peptide therapies in oncology

Personalized mRNA cancer vaccines

Cancer

Biology-matched, non-hormonal treatment exploration for endometriosis

Women’s Health

Rescuing drugs

Rescuing shelved oncology assets

Biobanking

Maximum Optionality

Diagnostics

Maximum Profiling

Monitoring

Biomarker-driven radiodiagnostics

Deep immune profiling & combination therapeutics for unresolved immune disorders

Autoimmune

AI Agents

Personalized bioinformatics

Yuga

Rare disease

Relit

Personalized oncolytic viruses

Minuteman

Comprehensive functional drug testing

Personalized ASOs

Stitchpoint

Rarivive

Perita

Personalized gene editing

Ignitus

Measure and restore mitochondrial energy capacity

Cardiovascular/Longevity

Personalized TCR cancer therapies

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Make the industry more Patient First

  1. Investigators can choose any federally compliant Institutional Review Board (IRB)
  2. Phase 1 (safety) without FDA approval (at most notification), IRB approval is sufficient
  3. Right to try (not market) after phase 1 is complete, reduce the invisible graveyards
  4. Market some drugs after phase 1 is complete with conditional approval
  5. Right to try data should overcome a very high bar to be held against an experimental drug
  6. For low drug volumes allow GMP-light, replacing production process checks with check on the output (GQP)
  7. Maximize survival instead of the current practice of minimizing liability to the practitioner
  8. Doctors inform you about oncology trials
  9. More extensive coverage of exploratory diagnostics like raw genomic sequencing data
  10. From approved molecules to approved algorithms and process, for truly personalized medicines
  11. Parallel treatments wherever reasonable, we don't need to know what cured you
  12. The patient controls their tumor tissue (tissue rights) and most tumors are completely sequenced
  13. Freedom to have an out of state doctor and nurse
  14. HIPAA adjustment to more easily gather data
  15. FTC involvement to make EMRs like Epic/Cerner interoperable with other systems
  16. Allow patients to share their data with all healthcare professionals and/or everyone (MOSL)
  17. Adopt a Context-Driven Evidence Approach For Reimbursing Rare Therapies
  18. Make the real time clinical trials pilot permanent

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I currently have no evidence of disease

BUILDING "THERAPEUTIC LADDER" OF BACKUP TREATMENTS

MRNA NEOANTIGEN VACCINE

MULTIPLE MRD TESTS

ONGOING SURVEILLANCE

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My therapeutic ladder went from 0 to ~25 treatments

Consider while MRD low / negative

MRD increasing

(by ctDNA or positive margins)

Local progression

Metastatic progression

  • mRNA neoantigen vaccine
  • Checkpoint inhibition

  • TCR T cells (w/o lymphodepletion)
  • Vaccine induced T cells (w/o lymphodepletion)
  • Additional checkpoint inhibition
  • Options for manipulating immune microenvironment
  • VEGFR / TAA vaccine
  • DNA neoantigen vaccine

  • Radioligand therapy
  • ADCs selected from options for high-expressing targets (B7-H3, EphA2, ROR2, AXL)
  • Radioligand therapy
  • ADCs
  • Intratumoral therapies
    • Chemotherapy
    • Immunotherapy
    • Oncolytic virus
    • Cell therapy
  • Surgery + intraop radiation
  • Cryoablation / RFA / PEF
  • Carbon ion radiation
  • B7H3/FAP CAR-T cells
  • TCR-T cells
  • GD2 CAR-T cells
  • TILs
  • ADCs
  • Drugs with activity in functional models
  • Drugs with activity in AI models
  • Drugs with genomic rationale
    • MDM2 inhibitors
    • PARP inhibitors

Current / planned treatments

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How we found a target and picked radioligand therapy

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SINGLE CELL SEQUENCING

DNA / RNA SEQUENCING

PATHOLOGY STAINING

FREQUENT BLOOD TESTING

DRUG RESPONSE

TARGETED PET IMAGING

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Identifying cancer cells from single cell sequencing

  • Sequence the tumor at single cell resolution

  • Separate cancer cells from surrounding normal cells

  • Focus on tumor specific expression

Putative tumor cells

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Comparing tumor and normal tissue reveals signal

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Integrated my tumor with public normal tissue to identify tumor-speficic genes

  • Tumor cells formed a distinct cluster

  • Examined the genes most distinct between tumor and normal cells

  • These genes pointed to targetable biology

My cancer cells express a strong fibroblast-like program

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Fibroblast program points to FAP as a target

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YES

Decision at stake: To fly to Germany for experimental radiotherapy?

YES

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Radiotherapy with FAP in Germany

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Radiotherapy with FAP in Germany

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Cancer responded, enabling surgery

Its gone!

26

f

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T-cell infiltration increased dramatically!

June 2024

Jan 2025

Apr 2025

Single Cell RNA Seq

tumor

tumor

tumor

T cells

T cells

T cells

June 2024: Aggressive Multimodal “Pre-Treatment”

Systemic and localized chemo-SBRT phase → Massive tissue damage and inflammation

Neoantigen vaccines → Early immune priming

Short course of PD-1 inhibitor

Jan 2025: 5 immunotherapies in parallel!

  1. CTLA-4 checkpoint blockade
  2. PD-1 checkpoint blockade
  3. NK cellular therapy
  4. IL-15 superagonist for NK/T-cell activation
  5. Oncolytic virus for Immune activation, tumor lysis

Apr 2025: Precision Targeted + Immunotherapy. Stromal targeting.

177Lu and ²²⁵Ac-FAPi → Targeted radiotherapy against fibroblasts

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Personalized mRNA Vaccine

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DNA / RNA SEQUENCING

PATHOLOGY STAINING

FREQUENT BLOOD TESTING

DRUG RESPONSE

TARGETED PET IMAGING

SINGLE CELL SEQUENCING

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Neoantigens ranked based on available data and algorithms

  • Neoantigens prioritized based on data from multiple samples, use of multiple algorithms, HLA binding predictions, and inclusion in prior vaccines
  • Availability of deep bulk RNA sequencing allowed use of variant allele expression for prioritization

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From project start

to injection in 6 months!

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Flow cytometry shows active T cells

  • T-cells are more active than healthy controls

  • A regulatory T-cell population is elevated

  • T-cell behaviour tracks with checkpoint inhibitor dosing

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Blood monitoring for tumor and immune signals

0

1

2

3

4

5

6

7

8

9

10

11

12

Vaccine

Neoantigen

Discovery

Monthly Blood Review

Flow cytometry panel

TCR Sequencing

MRD Testing

“Complete blood count” through high parameter flow cytometry. Distribution of immune cell types in PBMCs and sorting of T cells for further analysis

Single cell sequencing of T cells to measure abundance of specific clones (TCR-T or neo- antigen related, and other) and T cell phenotype. Bulk TCRseq to get full distribution of TCRs

Signatera, Personalis & Billion-to-one to measure ctDNA in blood. Exploring circulating tumor cell, RNA-based, and protein-based strategies as well.

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Creating a Personalized TCR-T

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SINGLE CELL SEQUENCING

DNA / RNA SEQUENCING

PATHOLOGY STAINING

FREQUENT BLOOD TESTING

DRUG RESPONSE

TARGETED PET IMAGING

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TCR-T process

Discovery & Verification Workflow

Collection �of tumor biopsy & blood or other T-cell containing samples

Prediction & Prioritization�of targets from tumor mutation sequencing and vaccine design

neoTCR Identification�using binding or functional screens on T cells from patient sample

Functional Verification �of neoTCR hits to prioritize for product selection

Product Selection�of 1 or more neoTCRs considering:

  1. Functionality
  2. Target diversity/abundance
  3. HLA diversity
  4. Tumor escape

1

2

3

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See expansion of relevant clones in single cell data

  • DYNC1H1 TCR expanded to 53 clones in April 2025 resection when tumor was essentially cleared

scRNAseq Clustering by Cell Phenotype (T2 Biopsy)

CD8 T cells

Proliferating

CD8 T cells

  • Colored dots show DYNC1H1-specific CD8+ T cells identified by discovery workflow in T2 biopsy including 2 clones for TCR-T.

scRNAseq Clustering by Cell Phenotype (T3 Resection)

Proliferating

CD8 T cells

CD8 T cells

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Selecting TCRs for therapy

Item

Criteria

Rationale

P01-F02

DYNC1H1

P01-G10

DYNC1H1

P02-A07

DYNC1H1

D3 or F3

TECPR1

1

TCR comes from antigen experienced T cell

Memory T cell has been selected in vivo and supports safety profile of TCR-T product

Memory phenotype

+

+

TBD

2

TCR comes from T cell showing tumor trafficking

T cell present (and expanded) in TIL population or recently trafficked through tumor supports tumor relevant targeting

Present and expanded in TILs

-

-

-

3

TCR targets truncal or high prevalence neoepitope expressed in most recent tumor biopsy

Increases likelihood that TCR-T product will be functional in patient

DYNC1H1

(high prevalence)

+

+

TECPR1

(truncal)

4

TCR targets HLA with no evidence of LOH

TCR requires HLA expression on tumor for function

C*07:01

+

B*27:05

(phased)

TBD

5

Evidence of multiple clonotypes generated by immune response

More clonotypes suggest a more robust immune response

At least 8 clonotypes identified

+

-

(only one)

TBD

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TCR shows strong EC50 for neoepitope and little response to wild-type peptide

TCR will be potently activated by presented peptide with little to no off-tumor safety issues

0.12 nM EC50

+

(0.05 nM EC50)

-

(43 nM EC50)

TBD

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TCR is CD8-independent

TCR will recognize tumor cells when edited into both CD4 and CD8 T cells

YES

+

-

TBD

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TCR kills multiple target cells pulsed with both minimal and long peptide when target cells in excess to T cells

Serial killing of target cells indicates potency while killing of long peptide-pulsed target cells suggests physiological antigen processing and presentation

~80% killing at 1:4 E:T ratio

+

(~80% killing)

-

(~45% killing)

TBD

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Functional screening

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SINGLE CELL SEQUENCING

DNA / RNA SEQUENCING

PATHOLOGY STAINING

FREQUENT MRD TESTING

DRUG RESPONSE

TARGETED RADIO DIAGNOSTICS

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Drug Response Testing with organoids (functional testing)

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  • Testing response of live cancer cells to a large number of FDA approved drugs, including immunotherapies, via mass changes
  • Testing response of mircoenvironment preserving cancer organoids to a large number of approved treatments, experimental treatments, and ADC payloads, via growth assays

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Organoid testing for additional options

  • Used to test potential ADC payloads, therapeutic hypotheses we could action with systemic drugs
  • Organoids from June 2024 biopsy highly sensitive to Trabectedin - holding in reserve in case needed

January 2025 biopsy testing

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T cell functional response to checkpoint inhibitors

  • Significant mass response seen for ipilimumab and dostartlimab
  • No significant mass response seen for any other checkpoint inhibitor drugs tested

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MDM2 as targeted therapy

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SINGLE CELL SEQUENCING

PATHOLOGY STAINING

FREQUENT MRD TESTING

TARGETED RADIO DIAGNOSTICS

DRUG RESPONSE

DNA / RNA SEQUENCING

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Very high regional expression around MDM2

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Tumor MDM2 expression is in top 0.3% of all cancers (comparing 2600 tumors)

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MDM2 expression much higher than predicted by copy-number.

I recently prevented a drug targeting it from being destroyed by the manufacturer!

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CAR-T Program

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SINGLE CELL SEQUENCING

DNA / RNA SEQUENCING

PATHOLOGY STAINING

FREQUENT MRD TESTING

DRUG RESPONSE

TARGETED RADIO DIAGNOSTICS

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B7-H3 as a seemingly good target…

Put together a CAR-T product featuring the latest scientific advances!

  • Synthetic, tuned receptor
  • Modifications for durability
  • Safety switches as a fail-safe

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… but Beijing scan spooked us about liver tox

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Now we are building a SNIPR system

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Investing in PANX3 as a potentially very clean target

By RNA, PANX3 is:

  • Highly expressed in my tumor (X axis)
  • Not highly expressed in any normal tissue in the GTEX database (Y axis)

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Sid Sijbrandij

Cancer Journey

cancer@sytse.com

Please email me if you want to look beyond the standard of care. I work with two full time people to follow up with everyone.

sytse.com/cancer

Feel free to share this presentation and above url with anyone

Thank you!

SID SIJBRANDIJ | CANCER JOURNEY