Centessa takes a step towards a new haemophila mechanism

Haemophilia gene therapy developers look out. New competition could be on the horizon from Centessa Pharmaceuticals’ novel project SerpinPC, which today yielded promising phase 2 results. There are reasons for caution: the dataset was small, comprising just 22 patients, with no placebo control. But an 88% reduction in all bleeds with the highest dose, 1.2mg/kg, at 12 weeks versus baseline got investors’ attention, pushing Centessa shares up 16% this morning. The group hopes that SerpinPC could become a one-size-fits-all therapy, regardless of haemophilia type, severity or inhibitor status. Centessa now needs to prove the once-monthly project’s benefit in larger registrational studies, but did not give many details during a conference call today. Thrombotic events will also be closely watched given SerpinPC’s mechanism. The project is an activated protein C inhibitor designed to restore levels of prothrombinase – this in turn generates thrombin, which is needed for blood clotting. On this point, Centessa execs said they were encouraged by unchanged levels of D-dimer, a marker of excess thrombin. Even if SerpinPC succeeds it will have a hard time catching Roche’s approved haemophilia A therapy Hemlibra, which is forecast to sell around $5bn by 2026, according to Evaluate Pharma sellside consensus.