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# CRL for Astellas Zolbetuximab BLA
- URL: https://www.fdaweb.com/crl-for-astellas-zolbetuximab-bla/
- Published: 2024-01-09T12:00:00.000Z
- Updated: 2026-09-14T14:19:57.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5156097

FDA issued a 1/4 complete response letter on the Astellas Pharma BLA for zolbetuximab, an investigational treatment for patients with locally advanced unresectable or metastatic human epidermal growth factor receptor 2 (HER2)-negative gastric or gastroesophageal junction adenocarcinoma whose tumors are claudin (CLDN) 18.2 positive. A company [statement](https://www.astellas.com/en/news/28731?ref=fdaweb.com) says FDA said the BLA could not be approved by the PDUFA action date of 1/12 due to unresolved deficiencies following its pre-license inspection of a third-party manufacturing facility for the drug.

“FDA has not raised any concerns related to the clinical data, including efficacy or safety, of zolbetuximab, and is not requesting additional clinical studies,” the statement says. “Astellas is working closely with FDA and the third-party manufacturer to establish a timeline to quickly resolve the agency’s feedback.”

Zolbetuximab is described as an investigational, first-in-class chimeric IgG1 monoclonal antibody that targets and binds to claudin 18.2, a transmembrane protein. It reportedly acts by binding to CLDN18.2 on the cancer cell surface of gastric epithelial cells. In pre-clinical studies, Astellas says, the binding interaction then induces cancer cell death by activating two distinct immune system pathways — antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity.