Jazz Pharmaceuticals announced that the U.S. Food and Drug Administration (FDA) has granted accelerated approval to Ziihera (zanidatamab-hrii) for the treatment of adult patients with previously treated, unresectable, or metastatic HER2-positive biliary tract cancer (BTC). This approval marks a significant advancement in the treatment landscape for this aggressive cancer, offering a new chemotherapy-free option.
Clinical Trial Data
The FDA's accelerated approval is based on data from the Phase IIb HERIZON-BTC-01 study. The study demonstrated a 52% objective response rate (ORR) in patients treated with Ziihera, with a median duration of response (DOR) of 14.9 months. These results highlight the potential of Ziihera to provide meaningful clinical benefit in a patient population with limited treatment options.
Ziihera: A Novel HER2-Targeted Bispecific Antibody
Ziihera is a bispecific antibody that targets two different epitopes of the HER2 protein, which is often overexpressed in biliary tract cancer. HER2 protein stimulates quick growth of cancer cells. This dual-targeting mechanism aims to provide a more comprehensive blockade of HER2 signaling, potentially leading to improved anti-tumor activity. Ziihera is the first dual HER2-targeted bispecific antibody and chemotherapy-free therapy approved for BTC in the United States.
Ongoing and Future Studies
Jazz Pharmaceuticals is currently conducting the Phase III HERIZON-BTC-302 study, evaluating Ziihera in combination with standard-of-care therapy as a first-line treatment for patients with HER2-positive BTC. This study is intended to serve as the confirmatory trial to convert the accelerated approval to a full approval. Additionally, Ziihera is being investigated in late-stage studies for gastroesophageal adenocarcinoma (GEA) and metastatic breast cancer. Top-line data from the GEA study are expected in the second quarter of 2025. The company is also evaluating Ziihera in the phase II DiscovHER-Pan-206 pan-tumor study in HER2-positive solid tumors.
Safety Profile
It is important to note that serious adverse reactions occurred in 53% of patients who received Ziihera in the clinical trial. The most common adverse reactions were diarrhea, infusion-related reactions, abdominal pain, and fatigue. Healthcare professionals should carefully monitor patients for these potential side effects.
Collaboration and Commercialization
Jazz Pharmaceuticals acquired exclusive rights to develop and commercialize Ziihera in all territories except Asia/Pacific (where the drug has been licensed to BeiGene) from Zymeworks in 2022. The commercial launch of Ziihera in the United States is expected before the end of the year. Rob Iannone, Jazz's chief medical officer, stated the company looks forward to advancing research of zanidatamab in BTC and other HER2-expressing solid tumors, with the goal of improving outcomes for more people diagnosed with these difficult-to-treat HER2-positive cancers.
