Roche reported positive interim data from its second Phase III emicizumab (ACE910) trial, HAVEN 2, demonstrating that prophylactic use of the bispecific monoclonal antibody (mAb) reduced the number of bleeding episodes in children under the age of 12 years with haemophilia A and factor VIII inhibitors. Emicizumab was administered by subcutaneous injection, once weekly.
The interim HAVEN 2 data, in 19 children treated for a median of 12 weeks, were consistent with data from the first Phase III study, HAVEN 1, which were reported in December 2016. HAVEN 1, evaluating emicizumab prophylaxis in adolescent and adults aged 12 years and older with hemophilia A and factor VIII inhibitors, met both its primary and all secondary endpionts. The trial found that emicizumab prophylaxis resulted in a statistically significant, and clinically meaningful reduction in the number of bleeds when compared with no prophylaxis, or in comparison with prior prophylaxis with bypassing agents. Secondary endpoints included a statistically significant reduction in the number of bleeds over time with emicizumab in patients who received prior bypassing agent prophylaxis treatment.
Roche said data from HAVEN 1 and the interim HAVEN 2 results would be presented at a forthcoming meeting, and also submitted to regulators. HAVEN 2 is an open-label study and aims to enrol 60 children who receive emicizumab prophylaxis for 52 weeks.
Release of the interim HAVEN 2 results coincides with World Hemophilia Day on April 17th. Sandra Horning, M.D., chief medical officer and head of global product development at Roche, stated, “Managing haemophilia A with inhibitors to factor VIII is especially challenging for children and their caregivers, because bleeding is difficult to control and current treatments require frequent intravenous infusions. We are encouraged that once-weekly subcutaneous emicizumab prophylaxis showed a clinically meaningful reduction in the number of bleeds over time in children and are pleased to share these results with the community as we join in celebrating World Hemophilia Day.”
In February Roche reported on the European Haemophilia Consortium website the death of a patient enrolled in HAVEN 1, although the firm said in a statement that the death was unrelated to emicizumab treatment. “The investigator's assessment is that the cause of death was the rectal haemorrhage, and that this is not related to emicizumab.” News of the patient death follows reports in November 2016 that the drug had been associated with a number of thrombosis-related serious adverse events, raising concerns emicizumab's prospects for winning regulatory approval.
Two other Phase III emicizumab studies are ongoing. HAVEN 3 is evaluating prophylaxis with emicizumab administered once a week or every other week, in patients aged 12 years and over with haemophilia A without inhibitors to factor VIII. The HAVEN 4 study is assessing emicizumab prophylaxis dosed every four weeks in patients aged 12 years and older with haemophilia A with or without inhibitors to factor VIII.
Emicizumab is designed to bind to both factors IXa and X and restore the normal blood clotting process. The drug was originally discovered by Roche’s majority-owned Chugai, and is in development by Roche, Chugai and Roche's wholly owned Genentech operation.