Benzinga | Sep 9, 2021 07:39AM EDT

Centessa Pharmaceuticals Announces Data From Proof-of-Concept Study Of SerpinPC In Severe Hemophilia A And B Patients Not On Prophylaxis

Centessa Pharmaceuticals plc ("Company") (NASDAQ:CNTA), together with subsidiary ApcinteX Limited ("ApcinteX"), today announced positive topline results from the Phase 2a part of AP-0101, the six-month repeat dose portion of its ongoing first-in-human proof-of-concept study evaluating SerpinPC in severe hemophilia A and B patients.

AP-0101 is a Phase 1/2a proof-of-concept study evaluating SerpinPC, an inhibitor of activated protein C ("APC"), in 23 male subjects with either severe hemophilia A or B who were not on prophylaxis.1 The Phase 2a part of the study assessed the safety, tolerability and pharmacokinetics across three dose cohorts (0.3 mg/kg, 0.6 mg/kg and 1.2 mg/kg) of SerpinPC administered as a subcutaneous (SC) injection every 4 weeks over a 24-week period (6 total doses). Reduction in the annualized bleeding rates (ABRs) were exploratory outcomes. Although eligible, none of the patients in the study had inhibitors.

SerpinPC was well-tolerated. As previously disclosed, one subject with a history of a skin disorder discontinued treatment on SerpinPC due to an injection site reaction. No other SerpinPC-related adverse events have been recorded. There was no reported sustained elevation in D-dimer, a sensitive measure of excess thrombin generation, throughout the 24-week study. Two subjects had anti-drug antibodies and remained on treatment without apparent impact on ABRs.

In the highest dose cohort, SerpinPC reduced the self-reported all bleeds ABR by 88% during the last 12 weeks of treatment (pre-specified primary assessment period) as compared to the all bleeds ABR prospectively measured during the pre-exposure observation period. In the highest dose cohort, five out of eight subjects had zero or one bleed during the 12-week pre-specified primary assessment period. Self-reported spontaneous joint bleeds ABR was reduced by 94% in the highest dose cohort. ABR reductions were similar between patients with either hemophilia A or hemophilia B.