CytomX Therapeutics (CTMX) investor relations material

Platform and pipeline overview

• Focus on oncology biologics using a proprietary Probody Therapeutic Platform, which employs antibody masking to improve the therapeutic window for potent anti-cancer agents.

• Two lead clinical programs: CX-2051 (EPCAM-targeted masked ADC) and CX-801 (masked interferon alpha 2B).

• Masking technology enables targeting of tumor-specific protease activity, activating drugs locally in cancer tissue and reducing off-target toxicity.

• EPCAM is a highly expressed, stable antigen in colorectal cancer (CRC), making it an attractive, broadly applicable target.

• No patient selection for EPCAM expression required, supporting an all-comer approach in CRC.

Clinical data and safety profile

• Phase 1 CX-2051 study in late-line CRC showed a 28% objective response rate and 94% disease control rate in heavily pretreated patients.

• Progression-free survival reached 5.8 months, outperforming current fourth-line standards (PFS 3.5–3.7 months, ORR 1–2%).

• Safety profile is favorable: no dose-limiting toxicities, manageable hematologic effects, and GI toxicity consistent with TOPO-1 inhibitors.

• Masking strategy appears effective, with no observed pancreatic or liver toxicity, differentiating from prior EPCAM-targeted agents.

• One grade 5 adverse event (GI toxicity leading to kidney injury in a patient with a solitary kidney) was deemed an outlier; study continues with enhanced monitoring.

Development plans and future directions

• Three expansion cohorts (7.2, 8.6, 10 mg/kg) fully enrolled; 70+ patient data update expected in Q1 2026, with six months' follow-up for most.

• Next steps include dose selection based on response, PFS, and adverse event analysis, with a randomized study against standard of care planned for 2026.

• Combination studies with bevacizumab and chemotherapy are planned to move CX-2051 into earlier CRC treatment lines.

• Broader development aims for pan-tumor applications, leveraging EPCAM’s expression in multiple solid tumors.

• CX-801 phase 1 in melanoma progressing, with translational biomarker data expected in Q4 and combination data with Keytruda planned for 2026.