# CytomX Therapeutics

> CytomX Therapeutics is a clinical-stage, oncology-focused biopharmaceutical company in South San Francisco that engineers conditionally activated antibody therapeutics through its proprietary PROBODY platform. By masking a drug's binding site and unmasking it only in the tumor microenvironment - where specific proteases cut a cleavable linker - CytomX aims to hit cancer targets that are otherwise too toxic to drug, widening the therapeutic window for antibody-drug conjugates, T-cell engagers and cytokines. Its wholly owned pipeline is led by CX-2051, an EpCAM-targeting PROBODY ADC for metastatic colorectal cancer, alongside masked interferon CX-801 and T-cell engager CX-904, and it partners its technology with Amgen, Astellas, Bristol Myers Squibb, Moderna and Regeneron.

- **Founded:** 2008
- **Headquarters:** South San Francisco, California, United States
- **Founders:** Patrick Daugherty (Scientific Founder (UC Santa Barbara professor)), Nancy Stagliano (Co-Founder & early CEO), Frederick Gluck (Co-Founder)
- **Team size:** ~120 employees (reduced ~40% in 2025 restructuring to focus on lead programs)
- **Products:** PROBODY Platform, CX-2051 (varsetatug masetecan), CX-801, CX-904
- **Notable:** Pioneered the PROBODY conditional-activation platform for antibody therapeutics., Completed a NASDAQ IPO in October 2015 (ticker CTMX)., Secured platform collaborations with five major pharma companies: Amgen, Astellas, Bristol Myers Squibb, Moderna and Regeneron.

## Products & services

- **PROBODY Platform** — Proprietary technology that combines an antibody with a masking peptide and a protease-cleavable linker. The mask blocks binding in healthy tissue; tumor-associated proteases cleave the linker to unmask activity in the tumor microenvironment.
- **CX-2051 (varsetatug masetecan)** — Wholly owned, first-in-class PROBODY antibody-drug conjugate targeting EpCAM with a topoisomerase-1 inhibitor payload; lead program in advanced metastatic colorectal cancer. Reported ~28% overall response rate in interim Phase 1 data.
- **CX-801** — Wholly owned masked interferon alpha-2b PROBODY therapeutic; being studied in combination with KEYTRUDA in advanced melanoma.
- **CX-904** — Conditionally activated (masked) T-cell engager targeting EGFR, developed under collaboration with Amgen.

## Achievements

- Pioneered the PROBODY conditional-activation platform for antibody therapeutics.
- Completed a NASDAQ IPO in October 2015 (ticker CTMX).
- Secured platform collaborations with five major pharma companies: Amgen, Astellas, Bristol Myers Squibb, Moderna and Regeneron.
- Reported ~28% overall response rate in interim Phase 1 data for CX-2051 against the long-undruggable EpCAM target in metastatic colorectal cancer (2025).
- Advanced first-in-class masked ADC, masked T-cell engager and masked interferon candidates into the clinic.
- Raised $100 million financing to extend cash runway into Q2 2027.

## Latest updates

- **2026-01** — Announced 2026 business update and R&D milestones: Phase 1 colorectal cancer expansion update for CX-2051 expected in Q1 2026, a CX-2051 plus bevacizumab combination study planned to start Q1 2026, and initial CX-801 + KEYTRUDA melanoma data anticipated by end of 2026.
- **2025-05** — Reported positive interim Phase 1 data for CX-2051 in advanced metastatic colorectal cancer, including an approximately 28% overall response rate.
- **2025-01** — Announced 2025 strategic pipeline priorities and corporate update, including ~40% headcount reduction to extend runway and focus on lead programs.
- **2025** — Secured $100 million financing extending cash runway into Q2 2027.

## Links

- Website: https://cytomx.com
- LinkedIn: https://www.linkedin.com/company/cytomx-therapeutics
- Twitter/X: https://twitter.com/cytomxinc

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Profile page: https://yespress.io/cytomx-therapeutics
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Last updated: 2026-07-15