Hemophilia A and B with Inhibitors in Patients ≥12 Years of Age (explorer7)
The efficacy of Alhemo in patients with hemophilia A and B with inhibitors was evaluated in the explorer7 trial (NCT04083781), a multi-national, multi-center, open-label, phase 3 trial that investigated the safety and efficacy of Alhemo for routine prophylaxis in 91 adults (58 HAwI and 33 HBwI) and 42 adolescents (22 HAwI and 20 HBwI) male patients with hemophilia A or B with inhibitors who have been prescribed, or are in need of, treatment with bypassing agents. Eptacog alfa was the rFVIIa used in explorer7. Patients were excluded if they had a history, current signs or symptoms, or at high risk of thromboembolic events, ongoing or planned immune tolerance induction treatment, in addition to patients with planned major surgery.
Among the 133 patients treated with Alhemo in the trial the mean age was 29 years (range: 12 to 79); 42 patients were 12 to <18 years of age, 89 patients were 18 to 64 years of age, and 2 patients were ≥65 years of age, and all were male. Seventy-eight (78) patients were White, 37 patients were Asian, 9 patients were Black or African American, 6 patients had race information unreported, and 3 patients were American Indian or Alaska Native; 6 patients identified as Hispanic or Latino, 122 patients identified as not Hispanic or Latino and 5 patients had ethnicity information unreported.
The trial was comprised of 4 arms, two randomized arms and two non-randomized arms:
• Arms 1 and 2: 52 patients (27 HAwI, and 25 HBwI), previously treated on-demand, were randomized 1:2 to no prophylaxis (arm 1: on demand treatment with bypassing agents) or Alhemo prophylaxis (arm 2), with stratification by hemophilia type (HAwI, HBwI) and prior 24-week bleeding rate (< 9 or ≥9)
• Arms 3 and 4: 81 additional patients (53 HAwI and 28 HBwI) treated with Alhemo prophylaxis
Treatment with Alhemo included a loading dose of 1 mg/kg on the first day and a once-daily dose of 0.20 mg/kg starting on the second day. The dose was individualized to 0.25 mg/kg or 0.15 mg/kg if Alhemo plasma concentration measured once after 4 weeks of treatment was <200 ng/mL or >4000 ng/mL, respectively. Measurement of concizumab-mtci plasma concentration after 4 weeks was used to optimize the daily maintenance dose. In the trial, a total of 108 patients received their individualized dose, 1 patient on 0.15 mg/kg, 79 patients on 0.20 mg/kg and 28 patients on 0.25 mg/kg.
Efficacy was evaluated in hemophilia A and B patients with inhibitors when all patients in arms 1 and 2 had completed at least 24 or at least 32 weeks, respectively), by comparing the number of treated bleeding episodes between Alhemo prophylaxis (arm 2) and no prophylaxis (arm 1). Using a negative binomial model, a ratio of the annualized bleeding rates (ABR) was estimated to 0.14 (p<0.001), corresponding to a reduction in ABR of 86% for subjects on Alhemo prophylaxis compared to no prophylaxis. The estimated mean ABR was 1.7 [95%CI: 1.01; 2.87] for patients on Alhemo prophylaxis (arm 2) and 11.8 [95%CI: 7.03; 19.86] for patients on no prophylaxis (arm 1).