# Sean McCarthy

> Sean McCarthy is the chairman, president and CEO of CytomX Therapeutics, a clinical-stage biopharma in South San Francisco building 'Probody' conditionally activated antibodies that switch on inside the tumor and stay quiet everywhere else. An Oxford-trained cancer biologist turned operator, he has run CytomX since 2011, taking it from a venture-backed startup to a Nasdaq-listed company with partnerships across Bristol Myers Squibb, AbbVie, Amgen, Astellas, Moderna and Regeneron.

- **Role:** Chairman, President & CEO at CytomX Therapeutics
- **Organizations:** CytomX Therapeutics, Pappas Ventures (former), SGX Pharmaceuticals (former), Millennium Pharmaceuticals (former), Schering-Plough DNAX Research Institute (former), Rady School of Management Dean's Advisory Council
- **Education:** D.Phil., Cancer Biology, University of Oxford, St. John's College, MBA, UC San Diego, Rady School of Management, B.Sc., Biochemistry and Pharmacology, King's College, University of London
- **Known for:** Co-led CytomX from venture-backed startup through 2015 Nasdaq IPO and into clinical-stage operations, Brokered major partnerships with Bristol Myers Squibb, AbbVie, Amgen, Astellas, Moderna and Regeneron, Author of 17 peer-reviewed scientific publications

## Career timeline

- **1990s** — Post-doctoral training at Schering-Plough DNAX Research Institute
- **2000s** — Research leadership and program management of biologics discovery at Millennium Pharmaceuticals
- **2006** — VP Business Development at SGX Pharmaceuticals; helped lead pivot to oncology and 2006 IPO
- **2006-2010** — Transactional partner at Pappas Ventures, investing in therapeutics, devices, diagnostics
- **2010-12** — Joined CytomX Therapeutics as Chief Business Officer
- **2011-08** — Appointed President and CEO of CytomX, joined the Board
- **2015** — CytomX IPO on Nasdaq (CTMX)
- **2019-01** — Became Chairman of the Board of CytomX in addition to CEO role
- **2025** — CytomX presents initial Varseta-M (EpCAM Probody ADC) data in colorectal cancer

## Achievements

- Co-led CytomX from venture-backed startup through 2015 Nasdaq IPO and into clinical-stage operations
- Brokered major partnerships with Bristol Myers Squibb, AbbVie, Amgen, Astellas, Moderna and Regeneron
- Author of 17 peer-reviewed scientific publications
- Named inventor on six issued patents and more than 23 filed patent applications
- Member of the Dean's Advisory Council at UCSD Rady School of Management

## Latest updates

- **2025-08** — Interviewed on BiotechTV walking through Probody masking science, EpCAM ADC (Varseta-M) data, IFN-alpha2b and partnered programs.
- **2025** — CytomX reports positive Varseta-M data in late-line colorectal cancer.

## Links

- Website: https://cytomx.com
- LinkedIn: https://www.linkedin.com/in/sean-mccarthy-37485a7/
- Twitter/X: https://twitter.com/cytomxinc

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Profile page: https://yespress.io/sean-mccarthy
Published by YesPress — https://yespress.io
Last updated: 2026-05-15