CytomX Therapeutics (CTMX) investor relations material

Technology and clinical focus

• Pioneered masked biologics, enabling targeted activation in tumor cells while sparing healthy tissue.

• Current focus is on two clinical programs, with lead attention on a masked EpCAM ADC (Varseta-M).

• Masking strategy aims to overcome dose-limiting toxicities seen in previous EpCAM-targeted therapies.

• ADC format chosen for its validated efficacy, using a topo-1 payload relevant to standard CRC care.

• Plans to expand beyond CRC to other EpCAM-expressing tumors, with additional indications to be explored in the second half of the year.

Clinical data and safety profile

• Early phase I data in late-line metastatic CRC showed a 28% objective response rate and 94% disease control.

• Median progression-free survival was 5.8 months in a heavily pretreated population.

• Safety profile showed manageable hematologic toxicity and 21% Grade 3 diarrhea, with no classic EpCAM toxicities like pancreatitis or liver toxicity.

• Prophylactic measures for diarrhea, such as loperamide, were implemented in later cohorts.

• Dose expansion ongoing at three dose levels, targeting about 100 patients for a comprehensive efficacy and safety assessment.

Development strategy and future plans

• Key metrics for dose selection include response rate, progression-free survival, and overall safety profile.

• Aiming to confirm initial efficacy and safety in a larger sample, with potential FDA discussions by mid-year.

• Registrational study targeted to start no later than the first half of 2027.

• Fast-to-market strategy in late-line CRC, with potential head-to-head studies against current standards like LONSURF/bevacizumab.

• Combination studies with bevacizumab starting this quarter, with plans to explore chemo and other novel combinations to move into earlier lines.