Jazz Pharmaceuticals plc announced that the company has completed the rolling submission of a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) seeking accelerated approval for the HER2-targeted bispecific antibody zanidatamab as a treatment for previously-treated, unresectable, locally advanced, or metastatic HER2-positive biliary tract cancer (BTC). If approved, zanidatamab would be the first HER2-targeted treatment specifically approved for BTC in the U.S. The BLA includes data from the Phase 2b HERIZON-BTC-01 trial of zanidatamab in previously treated HER2-positive BTC. The primary endpoint was confirmed objective response rate (cORR) by independent central review (ICR) in Cohort 1. Data as of Oct.

10, 2022, from the 80 HER2-positive BTC patients enrolled in Cohort 1 of the trial demonstrated a cORR of 41.3% [95% confidence interval (CI): 30.4, 52.8] with a Kaplan Meier (KM) estimated median duration of response (DOR) of 12.9 months [95% CI: 6.0-not estimable] by ICR. Historical response rates for 2L standard-of-care chemotherapy in patients with BTC are reported to be 5 to 15% 1,2. The KM estimated median progression-free survival (PFS) was 5.5 months [95% CI: 3.7, 7.2] with a range of 0.3 to 18.5 months. Zanidatamab demonstrated a manageable and tolerable safety profile, with only two patients (2.3%) in HERIZON-BTC-01 experiencing adverse events (AEs) leading to treatment discontinuation.

There were no Grade 4 AEs, and no deaths were considered treatment-related. The most common AEs were diarrhea and infusion-related reactions, which were predominately low-grade, reversible and manageable prophylactically with routine supportive care. These data were featured as an oral presentation at the American Society of Clinical Oncology (ASCO) Annual Meeting 2023, published in The Lancet Oncology, and included in the 2023 Best of ASCO® program.

Quality-of-life data from this trial were also presented at the European Society for Medical Oncology (ESMO) Congress 2023 and at the 2024 ASCO Gastrointestinal Cancers Symposium. The HERIZON-BTC-302 Phase 3 trial (NCT06282575 [4]) of zanidatamab in 1L advanced or metastatic HER2-positive BTC was recently initiated and is open for enrollment. The global, open-label, randomized trial will evaluate the efficacy and safety of zanidatamab in combination with standard-of-care therapy against standard-of-care therapy alone.

The primary objective of the study is to compare the efficacy of zanidatamab and chemotherapy (cisplatin plus gemcitabine) with or without the addition of a programmed death protein 1/ligand 1 (PD-1/L-1) inhibitor versus chemotherapy with or without a PD-1/L1 inhibitor in patients. HERIZON-BTC-302 is proposed as the confirmatory trial for zanidatamab in BTC.