An experimental antibody treatment targeting HER2 variants produced powerful results in patients with advanced
bile duct cancers, according to findings published in The Lancet Oncology. For a phase
2b clinical trial, James Harding, MD, and col- leagues recruited 87 patients with bile duct cancer
to receive zanidatamab administered via IV every 2 weeks. All cancers were advanced, driven by HER2
variants, and had stopped responding to chemo- therapy. Overall, 41% of patients responded to the
drug, with their tumors shrinking by more than a third; by comparison, only 5% to 15% of patients
responded to chemotherapy. The most common side effects of zanidatamab were diarrhea, with 37%
experiencing GI symptoms; other side effects included infusion-related reactions, pain at the in-
jection site, nausea, or influenza-like symptoms. Dr. Harding noted that responses occurred quick-
ly, with half of patients showing some benefit from zanidatamab within 1.8 months. “It also
appeared to be quite durable, with a median duration of re- sponse of 12.9 months,” he added. “This
shows clear anti-cancer activity in this patient subset and
warrants further exploration.”
