Roche Reports Final Results from Phase IIIb STASEY Trial of Hemlibra in People with Hemophilia A and Factor VIII Inhibitors

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On July 19, Roche presented the final analysis results of the Phase IIIb study of Hemlibra (emicizumab) for hemophilia A at the 2021 Congress of the International Society on Thrombosis and Haemostasis (ISTH 2021). The data confirmed the favorable safety profile of Hemlibra and were consistent with the Phase III HAVEN clinical program. This analysis showed that long-term treatment with Hemlibra revealed no new safety signals in adult and adolescent patients with hemophilia A who have developed factor VIII inhibitors.

Nearly one-third of patients develop Factor VIII inhibitors, a class of antibodies that bind to and block the activity of replacement Factor VIII. Compared with patients without Factor VIII inhibitors, those with inhibitors are at a higher risk of frequent bleeding episodes, including life-threatening bleeding.

Hemlibra is a bispecific antibody directed against factor IXa and factor X that brings together the two proteins required for the natural coagulation cascade—factor IXa and factor X—to restore the coagulation process in patients with hemophilia A. To date, Hemlibra has been approved in more than 100 countries worldwide for the treatment of patients with hemophilia A with factor VIII inhibitors, and in more than 80 countries worldwide for the treatment of patients with hemophilia A without factor VIII inhibitors.

The final analysis of the STASEY study included data from 193 patients with hemophilia A with factor VIII inhibitors, who received once-weekly Hemlibra prophylaxis for 2 years (mean treatment duration: 103.1 weeks). The analysis revealed no Hemlibra-related thrombotic microangiopathy or serious thrombotic events (adverse events [AEs] observed in patients with bleeding disorders). In this study, the most common AEs occurring in ≥10% of patients were arthralgia (17.1%), common cold symptoms (nasopharyngitis; 15.5%), headache (15.0%), injection site reactions (ISRs), and pyrexia (10.9%). Hemlibra-related AEs were reported in 35 patients (18.1%), with ISRs being the most frequent (9.8%).

Furthermore, the STASEY study further confirmed that Hemlibra is associated with a low incidence of anti-drug antibodies (ADA). Ten patients (5.2%) tested positive for ADA, of whom 5 (2.6%) were classified as having ADA with in vitro neutralizing activity. In all 10 patients, ADA development did not affect the efficacy or safety of Hemlibra; no patient experienced a decrease in Hemlibra plasma concentrations due to ADA, nor did any patient experience bleeding. Additionally, ADA cleared over time, as all patients tested negative for ADA at their final visit.

In the STASEY study, Hemlibra also continued to demonstrate efficacy in bleeding control, with 82.6% of patients experiencing no treated bleeding events. The annualized bleeding rate was consistent with the results previously reported in the pivotal HAVEN studies.

Source: New data for Roche’s Hemlibra reinforce safety profile in people with haemophilia A