The study evaluated the investigational bispecific antibody BGB-B2033 in patients with advanced hepatocellular carcinoma who had received at least one prior line of therapy.

This was a phase 1 study of BGB-B2033 administered as monotherapy in dose-escalation (DE) and dose-optimization (DO) cohorts. Patients with advanced hepatocellular carcinoma were enrolled across doses ranging from 300 mg to 1000 mg. The primary endpoints were safety and determination of recommended phase 2 dose (RP2D), and a secondary endpoint was objective response rate (ORR) by investigator assessment according to RECIST v1.1.

As of April 26, 2026, 110 (60 DE; 50 DO) patients with HCC were enrolled. Overall, 72% of patients had ≥2 lines of therapy and 66% had prior anti–PD-(L)1 and tyrosine kinase inhibitor exposure. Median study follow-up was 6.4 months (range, 0.3–13.3) for patients receiving 300, 600, and 1000 mg, and 4.1 months (range, 0.4–5.9) for patients receiving 450 and 900 mg.

Among 110 enrolled patients, adverse events occurred in 75% and treatment-related adverse events occurred in 52%. Grade 3 treatment-related adverse events were reported in 5% of patients. No grade 4 or grade 5 treatment-related adverse events were observed.

Confirmed ORRs in the dose-escalation cohorts were 28.6% (4/14) at 300 mg, 35.7% (5/14) at 600 mg, and 20.0% (2/10) at 1000 mg. In the dose-optimization cohorts, confirmed ORRs were 21.7% (5/23) at 450 mg and 16.0% (4/25) at 900 mg. One confirmed complete response was reported in the 300 mg cohort.

RP2D was determined to be 450 mg.