Jazz Pharmaceuticals' Ziihera (zanidatamab) has received accelerated approval from the U.S. Food and Drug Administration (FDA) for the treatment of adult patients with previously treated, unresectable, or metastatic HER2-positive (IHC 3+) biliary tract cancer (BTC). This approval marks a significant advancement in the treatment landscape for patients with this aggressive cancer who have limited therapeutic options. Ziihera is administered intravenously at a dose of 50mg/mL.
The FDA's decision was based on data from the HERIZON-BTC-01 trial, a Phase 2b clinical trial evaluating zanidatamab as a single agent in patients with previously treated HER2-positive BTC. The trial, the largest of its kind for this patient population, met its primary endpoint, demonstrating a confirmed objective response rate (ORR) of 52% as determined by independent central review. The median duration of response (DOR) was 14.9 months.
Clinical Trial Data
The HERIZON-BTC-01 trial's results, initially presented at the American Society of Clinical Oncology (ASCO) Annual Meeting 2023 and published in The Lancet Oncology, showcased the potential of zanidatamab in this setting. Updated data presented at the ASCO Annual Meeting 2024 further supported the drug's efficacy. The accelerated approval is contingent upon verification and description of clinical benefit in a confirmatory trial, HERIZON-BTC-302, an ongoing Phase 3 trial evaluating zanidatamab in combination with standard-of-care therapy versus standard-of-care therapy alone in the first-line setting for patients with HER2-positive BTC.
Biliary Tract Cancer and HER2
Biliary tract cancer is a rare and aggressive group of cancers that occur in the bile ducts and gallbladder. HER2 (Human Epidermal Growth Factor Receptor 2) is a protein that promotes cell growth. In some BTC cases, HER2 is overexpressed, leading to more aggressive tumor growth. Identifying HER2-positive status via an FDA-approved test is crucial for determining Ziihera eligibility.
Ongoing Research
Jazz Pharmaceuticals is continuing to investigate zanidatamab in the HERIZON-BTC-302 trial to confirm its clinical benefits. This Phase 3 trial is designed to evaluate zanidatamab in combination with standard-of-care therapy as a first-line treatment. The results of this trial will be critical for the continued approval of Ziihera for this indication.
