New data from phase IIIb study reinforces safety profile of Roche’s Hemlibra in people with haemophilia A

Roche announced results from the second interim analysis of the phase IIIb STASEY study, which reinforce the safety profile of Hemlibra (emicizumab) characterised in the phase III HAVEN clinical programme. In the STASEY study, Hemlibra was effective with no new safety signals identified in adults and adolescents with haemophilia A with factor VIII inhibitors, which was consistent with previous safety observations. Further new interim data suggest that people on Hemlibra may be able to undergo certain minor surgeries without additional preventative (prophylactic) coagulation factor. These data were presented at the International Society on Thrombosis and Hemostasis (ISTH) 2020 Virtual Congress, 12-14 July 2020.

“These important safety data continue to add to the extensive clinical evidence reinforcing Hemlibra’s potential to redefine the standard of care for people with haemophilia A,” said Levi Garraway, M.D., Ph.D., Chief Medical Officer and Head of Global Product Development. “The STASEY study reflects our continued focus on providing valuable insights that meet the needs of the haemophilia community and enhance our understanding of Hemlibra in clinical practice.”

The second interim analysis of the STASEY study included data from 193 patients with haemophilia A with factor VIII inhibitors, who received Hemlibra prophylaxis once-weekly. No cases of thrombotic microangiopathy or serious thrombotic events (TEs) related to Hemlibra were reported, and no new safety signals were observed. Thirty-three (17.1%) people reported a Hemlibra-related adverse event (AE). The most common AEs, occurring in 10% or more of people in the STASEY study, were common cold symptom nasopharyngitis (12.4%), headache (11.9%) and injection-site reaction (ISR) (11.4%). The ISRs reported were either mild or moderate in severity and no patients discontinued due to ISR. Annualised bleed rates (ABR) were also consistent with previously reported observations from the phase III HAVEN studies.

A separate analysis described management and outcomes of minor and unplanned major surgeries in patients receiving Hemlibra, although not a formal surgery endpoint in STASEY. Results suggest people with haemophilia A with factor VIII inhibitors who undergo certain minor surgeries whilst receiving Hemlibra may not need additional preventative coagulation factor. The majority of minor surgeries (n=20/31) were performed without the use of preventative coagulation factor (64.5%) and, of these, 85% (n=17/20) did not result in treated post-operative bleeds. Of the unplanned major surgeries (n=9), eight were managed with prophylactic coagulation factor, four of which resulted in bleeds managed successfully with recombinant factor VIIa. These findings are consistent with results observed in a previous analysis of surgeries in the pivotal HAVEN studies.

STASEY is a single-arm, multicentre, open-label, phase IIIb clinical study where patients received Hemlibra for an average of 50.9 weeks. The ABR of all bleeds, including treated bleeds, treated spontaneous bleeds, treated joint bleeds and treated target joint bleeds were low, with 167 patients (85.6%) experiencing zero treated bleeds. In the STASEY study there were two TEs unrelated to Hemlibra reported. One was a ST-elevation myocardial infarction in a person with pre-existing risk factors, which the treating physician assessed as unrelated to Hemlibra. The second was a hypertrophic clot at the site of a tooth extraction, a known complication of the procedure.

Hemlibra is approved to treat people with haemophilia A with factor VIII inhibitors in more than 90 countries worldwide and for people without factor VIII inhibitors in more than 70 countries worldwide, including the US, EU and Japan. Hemlibra has been studied in one of the largest clinical trial programmes in people with haemophilia A with and without factor VIII inhibitors, including five completed phase III studies. The STASEY study is the largest open-label study primarily assessing the safety and tolerability of a medicine for people with haemophilia A with factor VIII inhibitors.