On November 6, 2025 CytomX Therapeutics, Inc. (Nasdaq: CTMX), a leader in the field of masked, conditionally activated biologics, reported third quarter 2025 financial results and provided a business update.

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"CytomX continued to execute against its pipeline priorities this quarter, highlighted by robust Phase 1 expansion enrollment for CX-2051. We remain on track for a CX-2051 Phase 1 data update in Q1 2026. Looking ahead to 2026, CX-2051 is well positioned as a first-in-class EpCAM-directed, topoisomerase-1 ADC designed to address the high unmet need in CRC and a wide range of other EpCAM-expressing indications. CytomX’s top priority is to advance CX-2051 towards a potential registrational study in advanced, late-line CRC. Additionally, we continue to plan for focused investments to further unlock the potential of CX-2051, including moving into earlier lines of CRC therapy and additional EpCAM positive cancers," said Sean McCarthy, D.Phil., chief executive officer and chairman of CytomX.

Dr. McCarthy continued "We are also pleased with the dose escalation progress for our PROBODY interferon alpha-2b, CX-801, and look forward to presenting encouraging initial biomarker data at SITC (Free SITC Whitepaper) which underscore this potent masked cytokine’s therapeutic potential in combination with checkpoint inhibitors in advanced melanoma."

Q3 2025 Pipeline Program Updates:

CX-2051 (EpCAM PROBODY Topo-1 ADC)

CX-2051 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.
In Q3 2025, dose expansion enrollment continued with the goal of supporting a potential registrational study of CX-2051 monotherapy in advanced CRC.
Phase 1 study enrollment is projected to reach approximately 100 patients by the planned CX-2051 Phase 1 update in Q1 2026.
A Phase 1b CX-2051 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 therapy.
Evaluation ongoing of multiple non-CRC, EpCAM-expressing tumor indications for potential future CX-2051 development.
CX-801 (PROBODY Interferon alpha-2b)

Society of Immunotherapy of Cancer (SITC) (Free SITC Whitepaper) 2025 Annual Meeting
CX-801 monotherapy biomarker data in advanced melanoma patients to be presented that support CX-801’s mechanism of action and the ongoing combination study with KEYTRUDA (pembrolizumab).
CX-801 monotherapy has been well tolerated at doses exceeding the approved dose of unmasked IFNα2b.1
Gene expression analysis of pre- and post-treatment patient tumor biopsies demonstrated consistently increased expression of interferon-stimulated genes.
Patients demonstrated evidence of T-cell and NK cell activation and upregulation of immune checkpoint genes, including PD-1 and PD-L1.
Evidence of sustained elevation of CXCL10 in the tumor but not the blood was observed, suggesting preferential CX-801 activity in the tumor versus the periphery.
PK analysis also demonstrated dose-proportional exposure of CX-801, which remained predominantly in its intact (masked) form in circulation.
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.
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.
Initial clinical data for CX-801 in the combination with KEYTRUDA in advanced melanoma is anticipated in 2026.
KEYTRUDA is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA

Corporate and Financial:

Corporate:
In October 2025, announced the appointment of Rachael Lester, MBA as Senior Vice President, Chief Business Officer.
Financial:
CytomX ended the third quarter of 2025 with $143.6 million of cash, cash equivalents and investments with expected cash runway to the second quarter of 2027.
Research Pipeline and Collaborations:
CytomX has research collaborations with Bristol Myers Squibb, Amgen, Astellas, Regeneron, and Moderna. Multiple drug discovery programs continue across our research collaborations with a focus on bispecific immunotherapies, including T-cell engagers.
At SITC (Free SITC Whitepaper) 2025, preclinical data will be presented for CX-908, a dually masked PROBODY T-cell Engager targeting CDH3 and CD3. CX-908 potently induced tumor regressions in established breast and lung cancer xenograft tumor models and demonstrated a 100-fold improvement in tolerability, including significantly reduced cytokine release vs. an unmasked CDH3xCD3 molecule.

Third Quarter 2025 Financial Results:

Cash, cash equivalents and investments totaled $143.6 million as of September 30, 2025, compared to $158.1 million as of June 30, 2025.

Total revenue was $6.0 million for the quarter ended September 30, 2025, compared to $33.4 million for the quarter ended September 30, 2024. The decrease in revenue was driven primarily by the completion of our performance obligations in the Bristol Myers Squibb collaboration and a decrease in Moderna activities due to Moderna budget considerations.

Total operating expense in the third quarter of 2025 was $21.7 million compared to $29.3 million in the third quarter of 2024, a decrease of $7.6 million.

Research and development expenses were $15.3 million for the three months ended September 30, 2025, a decrease of $6.1 million compared to the corresponding period of 2024. Reduced research and development expenses were primarily due to a reduction in CX-904 spend due to program de-prioritization in Q1 2025, reduced research expenses following the Q1 2025 restructuring, and lower CX-2051 manufacturing expenses which was partially offset by the increase in CX-2051 clinical spend.

General and administrative expenses were $6.4 million for the three months ended September 30, 2025, a decrease of $1.5 million compared to the corresponding period of 2024. The decrease in general and administrative expenses was primarily driven by personnel costs as well as patent and legal expenses.

(Press release, CytomX Therapeutics, NOV 6, 2025, View Source [SID1234659566])