Zymeworks' Zanidatamab Approved in China for HER2-high Biliary Tract Cancer

Zymeworks Inc., a biotechnology company, has achieved a significant milestone with the conditional approval of its innovative therapeutic agent, zanidatamab, in China. The National Medical Products Administration (NMPA) has approved this dual HER2-targeted bispecific antibody for patients suffering from previously treated, unresectable, or metastatic HER2-positive biliary tract cancer (BTC). This approval is notable as zanidatamab is the first and only bispecific antibody targeting HER2 in this specific cancer type in China.

The approval is based on data from the HERIZON-BTC-01 clinical study, highlighting zanidatamab's potential efficacy. It emphasizes the importance of continued clinical trials to confirm the benefits for patients with this challenging form of cancer. Zymeworks' partner, BeOne Medicines Ltd., formerly known as BeiGene, Ltd., facilitated this approval under an existing collaboration agreement with Zymeworks, underscoring the strategic partnership between the two entities.

Kenneth Galbraith, Chair and CEO of Zymeworks, expressed optimism regarding the impact of this approval, noting the high unmet needs and grim prognosis typically associated with HER2-positive BTC. He acknowledged the pivotal role of zanidatamab's clinical promise and Zymeworks' ongoing commitment to translating scientific innovation into tangible patient benefits globally. The approval in China represents a significant step forward in addressing the needs of patients with HER2-expressing cancers.

Under the collaboration agreement, Zymeworks has received $61 million in upfront funding and milestone payments, alongside co-development funding for zanidatamab clinical studies. With the conditional approval from the NMPA, Zymeworks is set to receive a $20 million milestone payment and remains eligible for up to $144 million in further development and commercial milestones. Additionally, Zymeworks will receive tiered royalties up to 19.5% on net sales in territories managed by BeOne Medicines.

The journey of zanidatamab has seen it approved by the U.S. Food and Drug Administration (FDA) in late 2024 for similar BTC indications. In early 2025, Jazz Pharmaceuticals, a Zymeworks partner, announced a favorable recommendation from the European Medicines Agency (EMA) Committee for Medicinal Products for Human Use (CHMP), advocating for zanidatamab's approval in treating advanced HER2-positive BTC.

Biliary tract cancers encompass gallbladder cancer and cholangiocarcinoma, accounting for a small percentage of digestive system tumors but often presenting poor prognoses. A significant subset of BTC patients exhibit HER2 positivity, making HER2 a validated target for therapeutic intervention. The incidence of BTC is increasing, particularly in Asia, highlighting the need for advanced therapies like zanidatamab.

Zanidatamab operates by simultaneously binding to separate HER2 monomers, leading to receptor internalization and surface reduction, thereby inhibiting tumor growth and inducing tumor cell death through various cytotoxic mechanisms.

Zymeworks, committed to advancing biotherapeutics, has engineered zanidatamab using its proprietary technology. The company is actively pursuing a robust pipeline of novel therapeutic candidates, emphasizing multispecific antibody therapeutics and antibody-drug conjugates. Strategic partnerships bolster Zymeworks' mission to address significant unmet medical needs, with several phase 1 studies currently recruiting. As zanidatamab undergoes regulatory scrutiny in the EU, it continues to be a promising contender for treating HER2-expressing cancers globally.