CytomX Therapeutics (CTMX) Jefferies Global Healthcare Conference summary

Platform and pipeline overview

• Advancing a multimodality Probody therapeutic platform, applying masking to T-cell engagers, antibody-drug conjugates (ADCs), and cytokines.

• Three clinical programs: CX-904 (EGFR CD3 T-cell engager), CX-2051 (masked anti-EpCAM ADC), and CX-801 (masked interferon alpha-2b).

• All programs target validated antigens, aiming to broaden the therapeutic window across tumor types.

• Multiple partnerships established across modalities, including with Amgen, BMS, Astellas, Regeneron, and Moderna.

• Over 15 active programs, with significant U.S. commercial rights retained for CX-904.

CX-904 (EGFR CD3 T-cell engager) phase I-A data

• Phase I data from 35 patients with EGFR-positive tumors showed encouraging safety and efficacy.

• Step dosing cohorts reported zero cytokine release syndrome, a first for T-cell engagers.

• Manageable safety profile: no GI toxicity, low-grade rash, and musculoskeletal events controlled with tocilizumab.

• In pancreatic cancer, 2/6 patients had confirmed partial responses, all had disease control, including deep, durable responses in heavily pre-treated patients.

• No confirmed activity in CRC; focus shifting to pancreatic, head and neck, and lung cancers for further enrollment.

Mechanistic insights and competitive landscape

• Probody platform enables consistent intratumoral unmasking, independent of cancer type or dose.

• No evidence that pancreatic cancer is uniquely suited for the platform; recent data suggest it may be more immunocompetent than previously thought.

• Other T-cell engagers targeting EGFR have shifted focus away from CRC due to lack of activity.

• CX-904 is the first T-cell engager to show activity in pancreatic cancer, a significant milestone.