CytomX Therapeutics (CTMX) underscored its strategic focus on Varseta-M, an EpCAM-targeting antibody-drug conjugate (ADC) in late-stage colorectal and gastrointestinal cancers, during its presentation at Wells Fargo’s 21st Annual Healthcare Conference. The company also detailed its interferon program CX-801 for late-line metastatic melanoma, leveraging its Probody masking technology to enhance intratumoral immune activation while mitigating systemic side effects. With over $350 million in cash and a 90-employee R&D-focused team in the San Francisco Bay Area, CytomX highlighted its robust pipeline and financial strength as it prepares for pivotal clinical milestones in the coming years.
Varseta-M, originally known as CX-2051, is designed to target EpCAM—a protein overexpressed in over 90% of colorectal cancer cases—making it a potential game-changer in late-line metastatic settings, where the 5-year survival rate stands at just 13%. The drug has already enrolled 113 patients in Phase 1 trials, testing doses of 7.2, 8.6, and 10 mg/kg every three weeks. Early safety data indicate low hematologic toxicity and no interstitial lung disease, though high-grade diarrhea remains the most notable adverse event. CytomX is also expanding Varseta-M into gastroesophageal junction (GEJ) cancer, where EpCAM expression exceeds 80%, and pancreatic and biliary tract cancers, where expression rates are around 50%. The company plans to announce updated Phase 1 data for Varseta-M by late 2024, including overall survival insights and a registrational strategy, with combination studies with chemotherapy (5-FU backbone) set to begin in the same period.
In melanoma, CytomX’s CX-801—a dual-masked interferon alfa-2b ADC—has shown promise in late-line settings after dual checkpoint therapy. Phase 1 monotherapy trials have already exceeded pegylated interferon’s approved dose, and a combination arm with Merck’s Keytruda (pembrolizumab) is underway. Early biomarker data from five monotherapy patients revealed activation of immune-responsive genes, PD-1/PD-L1/LAG-3 induction, and T-cell recruitment into tumor sites, suggesting potent intratumoral activity. CytomX’s masking strategy aims to preserve immune activation while reducing systemic interferon side effects.
Looking ahead, CytomX anticipates initial data from Varseta-M’s bevacizumab combination study and CX-801’s safety/efficacy in the first half of 2025. A registrational study for Varseta-M is targeted for the first half of 2027. Meanwhile, the company’s stock has seen a 70% return over the past year, though its beta of 2.14 reflects higher volatility. Five analysts have already upgraded CTMX’s earnings outlook, and the stock traded around $3.71 at the time of the Wells Fargo presentation, with minor intraday fluctuations.
CytomX’s CEO, Sean McCarthy, emphasized Varseta-M’s first-in-class status in EpCAM targeting, noting its potential to address an emerging global health crisis in younger colorectal cancer patients. He also highlighted the company’s ability to expand beyond colorectal cancer, citing strong biomarker data supporting its broader therapeutic potential. The presentation underscored CytomX’s balance of clinical momentum and financial resilience as it navigates a competitive biotech landscape.
