Data presented at ISTH meeting show a reduction in treated spontaneous and traumatic bleeds and mean annualised bleeding rate (ABR) of 1.7 with concizumab.

The results from the primary analysis were presented at the International Society of Thrombosis and Haemostasis Annual Congress (ISTH 2022) in London, UK.

Concizumab is an anti-tissue factor pathway inhibitor (TFPI) antibody in development for once-daily prophylactic treatment (regular treatment to prevent prolonged and spontaneous bleeding) by administration under-the-skin for all types of haemophilia. The use of concizumab is investigational and not approved by regulatory authorities.

The results showed an 86% reduction in treated spontaneous and traumatic bleeds when on concizumab prophylaxis, with an estimated mean ABR of 1.7 compared to 11.8 with no prophylaxis, fulfilling the primary objective. The overall median ABR of concizumab was zero, compared to 9.8 for no prophylaxis. Twenty-one (63.6%) people on concizumab experienced no treated bleeds, compared to two (10.5%) on no prophylaxis. The safety and tolerability profile of concizumab in this study was within the expected range, with no thromboembolic events reported after treatment restart.

“One of the most critical complications in the treatment of haemophilia is the development of inhibitors, as they render standard replacement therapy ineffective and severely limit treatment options for haemophilia B,” said explorer7 lead investigator Dr Victor Jiménez-Yuste, MD, Haematology Department, La Paz University Hospital, Madrid, Spain. “Based on the results of the explorer7 study, there is a potential for concizumab to become a new treatment option for people living with haemophilia A or B with inhibitors.”