the company announced January 8.
The monoclonal antibody was under priority review as the first agent specifically for locally advanced unresectable or metastatic HER2-negative gastric or gastroesophageal junction adenocarcinoma that is claudin 18.2-positive. Overexpression of claudin 18.2 in gastric cancer cells is associated with tumor growth and progression.
The FDA, however, could not approve zolbetuximab by the planned decision date of January 12, 2024, because of “unresolved deficiencies following its pre-license inspection of a third-party manufacturing facility for zolbetuximab,” according to the company press release.
Astellas “is working closely with the FDA and the third-party manufacturer to establish a timeline to quickly resolve” the issues, the company said.
Astellas also clarified that the FDA isn’t asking for additional efficacy and safety data. In phase 3 testing, zolbetuximab improved median progression-free and overall survival by about 2-3 months over chemotherapy alone.
If zolbetuximab is approved, “pathologists will have to be facile with claudin 18.2 testing as a companion diagnostic before [it] can be used,” Mark Lewis, MD, a gastrointestinal oncologist at Intermountain Healthcare in Murray, Utah, told this news organization.
The agent is also under review in Japan, Europe, and China.
A version of this article appeared on Medscape.com.