First-in-Class Oncology

Restoring Native Tumor Suppression to Treat Cancer

Papyrus Therapeutics is developing protein replacement tumor suppressor therapies — a new modality with no direct competition. Our lead candidate, PYTX-004, restores lost OPCML function to shut down cancer signaling networks.

Explore Our Science

93%

Tumor reduction in PDX models

RTKs selectively targeted

188

Mice across 12 in-vivo studies

Survival with IO combination

About Papyrus

A New Paradigm in Cancer Therapy

Tumor suppressor genes regulate cell growth and their loss drives cancer development. Despite decades of research, tumor suppressors have been considered "undruggable" — until now.

OPCML is unique among tumor suppressors: it acts at the external cell surface, enabling intravenous protein replacement therapy without gene therapy. When cancer silences OPCML through methylation, receptor tyrosine kinases become unregulated, driving tumor growth. PYTX-004 restores this lost regulation.

Founded by Professor Hani Gabra and the late Dr Paul Blake, Papyrus Therapeutics is a Delaware-registered C-corporation with 100% company-owned IP and over a decade of research investment.

First-in-Class

No approved tumor suppressor replacement therapy exists. We are creating a new therapeutic category.

Strong IP

Patent portfolio covering the OPCML platform, IgLON family variants, and combination strategies. 100% company-owned.

Published Science

Nature Genetics, Cancer Discovery, EMBO Reports, Nature Communications, Clinical Cancer Research.

Low Toxicity Profile

Restoring normal regulation, not imposing synthetic inhibition. Normal cells are resistant to PYTX-004.

Our Science

The OPCML Anti-Scaffold Mechanism

PYTX-004 works through a unique multi-step mechanism — the Stairway to Conviction — each step validated by orthogonal experiments with pre-registered falsifiability tests.

Selective RTK Binding

OPCML selectively binds 9 activated receptor tyrosine kinases — HER2, HER4, FGFR1, FGFR3, EphA2, AXL, TYRO3, MET, and VEGFR3 — while sparing EGFR, HER3, and others. This selectivity drives efficacy without pan-RTK toxicity.

Raft Relocalisation & Dephosphorylation

OPCML chaperones activated RTKs into lipid rafts, where the phosphatase PTPRG dephosphorylates them. The RTKs are then ubiquitinated and destroyed. This "anti-scaffold" mechanism collapses both MEK/ERK and PI3K/AKT signaling.

Strong Monotherapy Efficacy with Low Toxicity

PYTX-004 demonstrates profound single-agent anti-tumour activity across 10 in vivo studies with up to 93% tumour destruction. Normal cells are unaffected by PYTX-004 — OPCML restores native regulation rather than imposing synthetic inhibition, yielding a favourable safety profile.

Combination Synergy

PYTX-004 shows 10x synergy with trastuzumab, additivity with cisplatin, and doubles survival when combined with anti-PD-1 checkpoint inhibitors in syngeneic models — with intratumoral CD8 T-cell reconstitution.

Pipeline

Development Programs

Our lead program targets ovarian cancer, with expansion into HER2+ breast cancer and other solid tumors where OPCML is silenced.

Compound	Indication	Stage
PYTX-004 (OPCML-Fc)	Ovarian Cancer (incl. Clear Cell)	IND-Enabling
PYTX-004	HER2+ Breast Cancer	Preclinical
PYTX-004 + IO	Solid Tumors (Combination)	Preclinical
IgLON Platform	Multi-cancer (Next-Gen Variants)	Discovery

Leadership

Our Team

World-class expertise spanning translational oncology, drug development, and biotech commercialisation.

Prof Hani Gabra, PhD FRCP

Founder & President

Translational medical oncologist with 30+ years experience. Professor Emeritus, Imperial College London. Former VP Early Clinical Development, AstraZeneca. Former CMO, BerGenBio.

Adam Marsh, PhD

AI/ML Bioinformatics

Computational biology and machine learning for drug discovery. University of Delaware. Leads AI-enabled therapeutic platform development and IgLON domain engineering.

Prof James Lorens, PhD

Board Director & SAB Chair

35+ years in oncology research and biotech. Founding Scientist, Rigel Pharmaceuticals. Founder, BerGenBio. Developed the first AXL targeting agent into the clinic.

Scientific Advisory Board

Guided by World-Class Science

Prof Michael Birrer, MD PhD

Genomics of gynecological cancers. Vice-Chancellor, University of Arkansas for Medical Sciences.

Prof R. Charles Coombes

Cancer drug development. Professor of Medical Oncology, Imperial College London.

Prof Carl-Henrik Heldin

Signal transduction and RTK biology. Uppsala University. Chairman, Nobel Foundation.

Prof Jean Paul Thiery

Discoverer of epithelial-mesenchymal transition. CNRS / Guangzhou National Laboratory.