AB Science: Masitinib receives FDA and EMA authorization for confirmatory phase 3 trial in metastatic castrate-resistant prostate cancer

Core Viewpoint - The FDA and EMA have authorized a confirmatory Phase 3 trial for masitinib in metastatic castrate-resistant prostate cancer (mCRPC), utilizing a biomarker-driven patient selection approach to target those most likely to benefit from the treatment [1][2]. Study Design - Study AB22007 is a multicenter, randomized, double-blind, placebo-controlled Phase 3 trial designed to confirm the efficacy and safety of masitinib in combination with docetaxel for mCRPC patients [3]. - The trial will enroll 600 patients, with a primary endpoint of radiographic progression-free survival (rPFS) and overall survival as the first secondary endpoint [4]. Medical Need - Masitinib is positioned to address a high unmet medical need in mCRPC patients who have relapsed after hormone treatments, as there are currently no registered drugs for use in combination with docetaxel in this patient population [5][6]. - Metastatic prostate cancer has a 5-year survival rate of approximately 30%, highlighting the critical need for effective treatments [7]. Patient Population - The estimated population of mCRPC patients eligible for chemotherapy is around 75,000 in the EU and 50,000 in the USA [8]. - The biomarker alkaline phosphatase (ALP) has been validated to predict the response to masitinib in mCRPC patients, indicating a potential new first-line treatment option [8]. Efficacy Results - The combination of masitinib and docetaxel showed a significant progression-free survival (PFS) benefit, with a hazard ratio of 0.79, indicating a 21% reduction in the risk of progression compared to control [10]. - A greater treatment effect was observed in patients with lower baseline ALP levels, with a 47% reduced risk of progression in those with ALP ≤ 100 IU/L [11]. Safety Profile - The safety profile of masitinib in combination with docetaxel was acceptable, with no new safety signals observed, marking a successful example of a Phase 3 trial that improved PFS [13]. Patent Protection - AB Science has filed a patent application for methods of treating mCRPC with masitinib, which has been granted by the European Patent Office, providing protection until 2042 for the treatment of mCRPC in patients with low metastatic involvement [14][15].