On January 8, 2026 CytomX Therapeutics, Inc. (Nasdaq: CTMX), a leader in the field of masked, conditionally activated biologics, reported a business update and anticipated milestones for 2026.
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"We are excited to build on our transformational progress at CytomX with Varseta-M and will be focused on advancing this novel, potential first-in-class ADC towards a registrational study in late-line CRC. Varseta-M was specifically designed to address a broad, unselected CRC patient population based on the universally high and uniform expression of EpCAM. The promising initial clinical activity we have presented to date in Phase 1 dose escalation underscore this potential. We look forward to providing CRC Phase 1 expansion data later this quarter," said Sean McCarthy, D.Phil., chief executive officer and chairman of CytomX.
Dr. McCarthy continued, "Given our highly encouraging start in late line CRC we aim to move rapidly towards a potentially registrational trial and advance Varseta-M into earlier lines of CRC treatment to maximize impact in this area of high unmet medical need. We also plan to capitalize on our platform leadership by progressing our broader pipeline of PROBODY Therapeutics, including our masked interferon-alpha-2b program, CX-801, in combination with KEYTRUDA in advanced melanoma."
Clinical Program Updates and 2026 Milestones:
Varsetatug masetecan (EpCAM PROBODY Topo-1 ADC, CX-2051)
Varseta-M Phase 1 dose expansions across the 7.2 mg/kg, 8.6 mg/kg, and 10 mg/kg doses, administered every three weeks (Q3W) are ongoing with a focus on selecting a dose or doses for a potential registrational study in advanced CRC.
Total Phase 1 study enrollment is projected to reach approximately 100 patients by the planned Varseta-M Phase 1 update in Q1 2026.
The Company aims to align with the FDA in 2026 on a potential registrational study design for Varseta-M monotherapy in advanced CRC.
A Phase 1 Varseta-M combination study with bevacizumab in CRC is expected to start in Q1 2026, data from which is intended to inform potential late-phase development in earlier lines of CRC.
Initiation of Phase 1 expansion cohort(s) in additional indications is planned for 2H 2026.
CX-801 (PROBODY Interferon alpha-2b)
The CX-801 Phase 1 study is ongoing with a focus in advanced melanoma. CX-801 monotherapy dose escalation has reached the fourth dose level.
CX-801 monotherapy has been well tolerated at dose levels exceeding the approved dose of unmasked IFNα2b.1
In May 2025, Phase 1 dose escalation of CX-801 in combination with KEYTRUDA was initiated. Dose escalation of CX-801 in combination with KEYTRUDA is currently enrolling the 2nd dose level.
CX-801 monotherapy biomarker data in advanced melanoma patients were presented at the 2025 Society of Immunotherapy of Cancer (SITC) (Free SITC Whitepaper) Annual Meeting that support CX-801’s mechanism of action and the ongoing combination study with KEYTRUDA (pembrolizumab).
Initial clinical data for CX-801 in combination with KEYTRUDA in advanced melanoma is anticipated by the end of 2026.
KEYTRUDA is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA
CytomX JP Morgan Healthcare Conference Presentation
Dr. Sean McCarthy will present at the JP Morgan Healthcare Conference on January 14, 2026, at 9 a.m. PST. Participants may access the live webcast of the conference call from the Events and Presentations page of CytomX’s website at View Source
(Press release, CytomX Therapeutics, JAN 8, 2026, View Source [SID1234661851])