AB Science Secures US Patent for Masitinib in mCRPC with Protection Extending to 2042

A biomarker-defined exclusivity window now anchors AB Science's intellectual property position in metastatic castrate resistant prostate cancer, with US patent US 12,648,944 formally granted by the United States Patent Office and protection running to May 2042. For generic manufacturers and biosimilar developers tracking oncology exclusivity timelines, the grant closes a competitive entry window in a therapeutic space that has seen no new docetaxel-combination registration in two decades.

The patent covers methods of treating mCRPC using masitinib and related compounds in a patient subpopulation defined by low metastatic involvement, specifically those with baseline alkaline phosphatase levels at or below 250 IU/L. That biomarker boundary is directly tied to study AB12003, in which masitinib at 6.0 mg/kg/day combined with docetaxel produced a statistically significant PFS benefit in this subgroup, with a hazard ratio of 0.79 (p=0.0087) and a 21% reduction in risk of progression versus control. In patients with ALP at or below 100 IU/L, the risk reduction reached 47% (hazard ratio 0.53, p=0.002).

The IP strategy here is instructive for regulatory affairs and clinical development teams: anchoring patent claims to a validated biomarker threshold rather than a broad indication narrows the claim but substantially strengthens its defensibility. The US grant mirrors coverage already in place under EP4175639 in Europe, and AB Science has filed counterpart applications in additional major markets, indicating a coordinated global exclusivity architecture.

The clinical context reinforces why this exclusivity position carries weight. Masitinib is positioned immediately following metastatic hormone-sensitive prostate cancer treatment, in patients eligible for chemotherapy where docetaxel remains the sole registered agent and no combination or replacement therapy has improved PFS or OS at the registration level. With mCRPC representing approximately 2% of all prostate cancer cases globally, and prostate cancer accounting for 397,000 deaths annually worldwide, the addressable population within the ALP-defined subgroup represents a discrete but commercially and clinically significant cohort.

For QA and regulatory leads monitoring the masitinib development program, the ongoing clinical work in mCRPC remains the next measurable checkpoint against which this exclusivity position will be tested.

Source: AB Science SA via GlobeNewswire, June 17, 2026.