The US Food and Drug Administration (FDA) has granted Orphan Drug designation to Centessa Pharmaceutical’s SerpinPC , a new activated protein C (APC) inhibitor designed to treat hemophilia B.
The designation, announced by news release, follows the results of a phase 2a study showing that SerpinPC at the highest dose reduced the median annualized bleeding rate for all bleeds by 88% and for spontaneous joint bleeds by 94% in patients with severe hemophilia A and B.
“We believe SerpinPC has the potential to offer patients with hemophilia B a convenient subcutaneous option that is designed to prevent and reduce bleeds without the risk of thrombosis,” Saurabh Saha, MD, PhD, chief executive officer of Centessa, said in the press release.
Serpins are protease inhibitors that regulate coagulation and fibrinolysis, and they have become an important target in the treatment of hemophilia. SerpinPC is a biological drug candidate that is designed to rebalance coagulation in patients with hemophilia by inhibiting APC and subsequently allowing greater thrombin generation.
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In Centessa’s phase 2a study, part of the AP-0101 proof-of-concept study, SerpinPC was assessed at 3 doses—0.3 mg/kg, 0.6 mg/kg, and 1.2 mg/kg—administered subcutaneously over 24 weeks. It was well tolerated in 23 male patients with severe hemophilia A or B who were not on prophylactic therapy, with no long-term increases in D-dimer levels and no cases of thrombosis.
All 22 patients who completed the study elected to join a 48-week open-label extension study on a flat subcutaneous dose of 60 mg of SerpinPC, which will be administered every 4 weeks. That study is ongoing, and Centessa will report 2-year follow-up data in the fourth quarter of 2022.
Centessa Pharmaceuticals announces Orphan Drug designation granted to SerpinPC for the treatment of hemophilia B. News release. Centessa Pharmaceuticals plc; September 14, 2022.