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

Deep systematic validation underpins PYTX-004 — from molecular mechanism through to tumour destruction in vivo, each step confirmed by independent experimental approaches.

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.

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

Leadership

Our Team

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

Prof Hani Gabra, PhD FRCP

Founder, CSO & Executive Chairman

Internationally recognised translational medical oncologist; gynaecological cancer KOL; discoverer of OPCML. 30+ year academic career, 200+ peer-reviewed papers, >65,000 citations. Professor Emeritus in Medical Oncology, Imperial College London. Ex Chief Physician Scientist / VP / Head Clinical Discovery Unit, AstraZeneca; ex CMO and Director of Clinical Development, BerGenBio AS.

Prof James Lorens, PhD

Board Member, Chief Scientific Adviser & SAB Chair

35+ years academic and biotech experience across US and Europe. Founding Scientist and Head of Oncology, Rigel Pharmaceuticals (RIGL). Founder & CSO of BerGenBio AS — developed first AXL-targeting agent in clinic. Professor, Department of Biomedicine, University of Bergen Faculty of Medicine. Expert in RTK and AXL biology and translational science.

Prof Adam Marsh, PhD

VP Bioinformatics, Biomarkers & AI

Expert in epigenetics, computational and bioinformatic analyses of genomes and DNA methylation; drivers of disease and stress acclimation. 30-year academic career in statistics, big data, and computational infrastructure. Professor of Computational Biology and Epigenetics, University of Delaware.

Dr Tim Jones, PhD

Consultant — Protein Engineering & Biologics Development

Fc-fusion architecture and antibody engineering specialist with deep industry experience. Formerly VP Biology at Abzena and Director of Antibody Research at Oxford Genetics (UK). Lead developer for the PYTX-004 staged decision tree for IND-enabling construct selection.

Prof John Ladbury, PhD

Consultant / Scientific Advisor — RTK Biophysics

Receptor tyrosine-kinase liquid-liquid phase separation; biophysical characterisation of signalling condensates. Chair of Mechanistic Biology, University of Leeds. Former Chair of Molecular Biophysics, UCL; former Director of the Center for Biomolecular Structure and Function, UT MD Anderson Cancer Center. Independent consultant to Papyrus UK; expert on RTK condensate biology.

Scientific Advisory Board

Guided by World-Class Science

Prof Michael Birrer

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.