Zanidatamab in HER2- positive metastatic biliary tract cancer

In a research letter recently published on JAMA Oncology, the final analysis of the HERIZON-BTC-01 phase 2 trial show a clinical benefit for zanidatamab in HER2-positive metastatic biliary tract cancer.

HERIZON-BTC-01 phase 2 trial involved 80 patients with HER2-positive locally advanced, or metastatic biliary tract cancer with disease progression with or following prior gemcitabine-based therapy. This cancer has a median overall survival less than 13 months with first-line therapies and 6-9 months with subsequent chemotherapy; participants received zanidatamab, a dual HER2-targeted bispecific antibody. The median follow-up of this final analysis was 33.4 months, 21 more than the initial report; the confirmed objective response rate was 41,3%, the median duration of response was 14.9 months and the median overall survival was 15.5 months. Zanidatamab responders demonstrated reduced mean worst pain scores compared with baseline. As authors point out, «HERIZON-BTC-01 remains the largest trial with the longest reported median follow-up of a HER2-targeted treatment in HER2-positive biliary tract cancer. Durable responses were maintained; 2 patients with partial response from the primary analysis converted to complete response, supporting continued benefit with zanidatamab. These findings support the clinically meaningful benefit of zanidatamab for patients with treatment-refractory HER2-positive biliary tract cancer. The ongoing phase 3 HERIZON-BTC-302 trial is evaluating zanidatamab with standard-of-care first-line treatment in patients with HER2-positive biliary tract cancer», authors conclude.