Defactinib

Defactinib is an inhibitor of PTK2, also known as focal adhesion kinase (FAK), Pyk2, and MELK which was developed by Pfizer and licensed to Verastem Oncology as a potential treatment for solid tumors.
Development for mesothelioma was discontinued in 2015 due to lack of efficacy in a placebo-controlled phase II trial. Subsequent research in patients with specific NF2 mutations also found limited activity.
The co-packaged medication avutometinib/defactinib was approved for medical use in the United States in May 2025.