BeOne Medicines Ltd. reported a 36% confirmed response rate for BGB-B2033 in one Phase 1 liver cancer dose group, with nine of 25 evaluable patients responding.
The rate came from nine confirmed responses among 25 patients who could be assessed after receiving 450 milligrams every three weeks. BeOne gave Sept. 22 as the data cutoff. The result applies to that dose group, rather than all doses tested. The estimated share of those nine responders whose responses lasted at least six months was 74.1%. The 74.1% estimate is conditional on a confirmed response; it does not describe response durability for the full dose group. Its 95% confidence interval ranged from 28.9% to 93.0%, leaving uncertainty around the estimate.
BeOne reported that 93.6% of patients had previously received PD-(L)1 treatment, while 61.7% had received both PD-(L)1 therapy and a tyrosine kinase inhibitor. Across dose levels, 5.3% of patients experienced treatment-related adverse events of Grade 3 or higher. Such events led 2.1% of patients to stop treatment.
BGB-B2033 is a bispecific antibody that binds GPC3 on tumor cells and 4-1BB, an immune receptor involved in T-cell activity. Its design aims to stimulate T cells near tumor cells expressing GPC3. The results do not show whether BGB-B2033 extends survival or outperforms another treatment.
The company targets the close of 2026 to launch worldwide studies intended to support registration of the drug for later-line liver cancer. A planned randomized, open-label Phase 3 study would enroll about 492 patients and compare BGB-B2033 with sorafenib or lenvatinib, selected by investigators. Overall survival is the study's primary endpoint. It had not begun recruiting as of Sept. 23.
