Canadian biotechnology company Zymeworks Inc. (NASDAQ:ZYME) announced on Friday that China's National Medical Products Administration (NMPA) has granted conditional approval of zanidatamab for the treatment of adults with previously treated, unresectable or metastatic HER2-positive biliary tract cancer.

Zanidatamab, the first dual HER2-targeted bispecific antibody approved for this indication in China, earned the approval based on data from the HERIZON-BTC-01 clinical study. Continued market authorisation will require confirmation of clinical benefit through additional trials.

Pharmaceutical company BeOne Medicines Ltd, Zymeworks' regional partner, secured the approval under its Asia Pacific licence and collaboration agreement with the company. Zymeworks will receive a USD20m milestone payment related to the approval and remains eligible for up to USD144m in further development and commercial milestone payments.

The company has already received USD61m in prior payments under the partnership and may earn tiered royalties up to 19.5% of net sales in BeOne's territories.

Zanidatamab was previously approved by the US Food and Drug Administration in November 2024 and received a positive opinion from the European Medicines Agency in April 2025 for the same indication.

Biliary tract cancer remains a high-need area with poor patient outcomes. 11% to 25% of cases are HER2-positive, making HER2 a key therapeutic target.