ArriVent BioPharma (AVBP) Study update summary

Study design and population

• Multicenter, open-label Phase 1 study in the US and China evaluating ARR-217 in advanced solid tumors, with a focus on GI cancers; 123 patients had received treatment by Aug. 5, 2026, including 113 with CRC.

• CRC patients were heavily pretreated, with a median of 3 prior systemic therapy lines; nearly all had received oxaliplatin and irinotecan, and nearly 60% had RAS mutations.

• Phase 1b dose optimization is ongoing at 5 and 6 mg/kg Q3W; 7 and 8 mg/kg dose levels were discontinued from the study design.

Efficacy

• At 6 mg/kg Q3W, ORR was 44.8% (13/29) and DCR was 93.1% (27/29), including 7 confirmed partial responses.

• Across 73 evaluable CRC patients treated at doses of 4 mg/kg or higher, ORR was 34.2% and DCR was 91.8%; median follow-up was 4.17 months.

• Responses were observed across RAS status, prior irinotecan use and treatment lines, including fourth-line-or-later disease; most responding patients remained on treatment at cutoff.

• Median follow-up at 6 mg/kg was just over 4 months; several patients remained on treatment beyond 6 months, with some approaching or exceeding 9 months.

• Cross-trial confirmed response rates for other CRC ADC programs were generally in the mid-teens to ~30%, compared with ARR-217's reported 44.8% ORR.

Safety and pharmacokinetics

• Treatment-related AEs were primarily low-grade GI and hematologic toxicities; at 6 mg/kg, Grade 3+ TRAEs occurred in 20.4% (10/49), including Grade 3 diarrhea in 2.0% (1/49).

• Across all doses, Grade 3+ TRAEs occurred in 30.1% (37/123), including neutropenia in 12.2% and diarrhea in 8.9%; no Grade 5 TRAEs or ILD were observed.

• MTD was not reached; one DLT at 8 mg/kg involved Grade 4 platelet decrease and Grade 4 neutropenia. One of 123 patients discontinued due to an AE.

• PK was dose-proportional, with minimal free payload exposure; ADC/therapeutic-antibody half-life was 3.2–4.0 days.