CytomX Announces Positive Interim Data From Phase 1 Dose Escalation Study of EpCAM Antibody Drug Conjugate (CX-2051) Candidate in Patients with Advanced Colorectal Cancer (CRC)

Core Insights - CytomX Therapeutics announced positive interim Phase 1 data for its EpCAM PROBODY ADC candidate, CX-2051, in advanced, late-line colorectal cancer (CRC) [2][3] - The study demonstrated a 28% confirmed response rate and a median progression-free survival of 5.8 months [1][13] - The company plans to initiate a Phase 2 study in the first half of 2026 [1][13] Patient Characteristics - A total of 25 advanced metastatic CRC patients were treated, with a median of 4 prior lines of therapy [6] - 64% of patients had liver metastases, 64% had KRAS mutations, and 96% were microsatellite stable [6] Efficacy Results - 28% of patients (5 out of 18) achieved confirmed partial responses according to RECIST v1.1 [1][6] - At the highest dose of 10 mg/kg, 43% of evaluable patients (3 out of 7) achieved confirmed partial responses [1][6] - The Disease Control Rate was 94% across the three dose groups [6] Safety Results - CX-2051 was generally well-tolerated with no dose-limiting toxicities observed [1][13] - Most treatment-related adverse events were Grade 1 or Grade 2, with common events including diarrhea, nausea, and fatigue [13] Development Plans - Dose expansions have been initiated at doses of 7.2 mg/kg, 8.6 mg/kg, and 10 mg/kg Q3W, with 20 patients expected to be enrolled at each level [13] - Additional Phase 1 data updates are anticipated by Q1 2026, and combination studies in earlier lines of CRC may begin in 2026 [13]