Regeneron advances anticoagulant antibody program

US biotech Regeneron Pharmaceuticals (Nasdaq: REGN) has announced positive Phase II results for two novel monoclonal antibodies targeting distinct domains of Factor XI, supporting its bid to bring new blood thinners to the market.

Regeneron is a battle with Bristol Myers Squibb (NYSE: BMY)/Johnson & Johnson (NYSE: JNJ), Bayer (BAYN: DE) and privately held Anthos to bring the first factor XI anticoagulant product to market. Regeneron explained that the $20 billion atrial fibrillation market is currently dominated by direct oral anticoagulants that target factor Xa. While these are effective at reducing thrombotic events, they carry an elevated risk of bleeding, the firm noted.

Regeneron said that REGN7508 (catalytic domain) is designed to maximize anticoagulant activity while minimizing bleeding risk, and REGN9933 (A2 domain) is designed to provide an additional option for patients with the highest bleeding risk who would otherwise not be candidates for currently available anticoagulants. Per the Phase II results, there was a robust antithrombotic effect for each antibody, and no clinically-relevant bleeding was observed in any treatment arm.