An Open-Label, Randomized, Parallel, Multi-Center Trial Comparing the Safety and Efficacy of rFVIIa When Administered as I.V. Bolus or I.V. Continuous Infusion to Hemophilia Patients with Inhibitors during and after Surgery.
Authors: Pruthi Rajiv K. , Mathew Prasad , Valentino Leonard A. , Seremetis Stephanie V. 
Published: October 2019

Background and Purpose: Bolus infusion (BI) of recombinant FVIIa (rFVIIa) is effective for the treatment of bleeding and surgical prophylaxis in congenital hemophilia A or B patients with FVIII or IX inhibitors. In principle, continuous infusion (CI) of rFVIIa could maintain the hemostatic effect at a steady state while avoiding the peaks and troughs of repetitive BI. The purpose of this study was to compare the efficacy and safety of rFVIIa CI with rFVIIa BI in major surgery in hemophilia patients with inhibitors.

Methods: A 10-day, open-label, randomized, multicenter trial was conducted in hemophilia A or B patients (age > 5 yr) with inhibitors to FVIII or FIX who underwent elective major surgery. Patients received rFVIIa as an initial bolus dose of 90 μg/kg followed by intermittent i.v. bolus (90 μg/kg) or i.v. continuous (50 μg/kg/hr) infusion. BI was administered every 2 hours during surgery and through Day 5, then every 4 hours for Days 6 to 10. CI was administered at 50 μg/kg/hr through Day 5 and at 25 μg/kg/hr Days 6 to10. A third control group of 10 non-inhibitor hemophilia A or B patients who underwent similar surgery and were treated with FVIII or FIX (based on current standard of care and physician’s choice) was assessed to compare adverse event and coagulation profiles. Safety was assessed throughout the study periods. Efficacy was defined as having no treatment failures during the given time and was evaluated at 48 hours, 5 days, and 10 days postoperatively. Treatment was considered ineffective in patients who received more than 2 additional doses of rFVIIa beyond the protocol-defined doses during a 24 hour period. Patients who received alternative hemostatic therapy following the permitted two additional doses of rFVIIa were considered treatment failures.

Results: Twenty-four patients (12 CI arm, 12 BI arm) underwent 9 major types of surgeries. Knee (n=11) and hip (n=3) replacements were the most common surgeries. Recombinant FVIIa efficacy in major surgeries was 92% (11 CI, 11 BI) at 48 hours; 83% (10 CI) and 92% (11 BI) at Day 5; 83% (10 CI) and 75% (9 BI) at Day 10. Sixty-six rescue doses (rFVIIa, 90 μg/kg) were administered in the CI group (54 in one patient), and 7 in 3 patients in the BI group. Adverse events occurred more frequently in the CI treatment group (239; 141 in one patient) compared to the BI group (89 AEs); 64 AEs occurred in the control group. Eight patients (3 CI, 4 BI, 1 control) experienced 10 serious adverse events (SAEs). SAEs occurred most frequently in the BI treatment group (3 CI, 6 BI, 1 control). The types of SAEs were equally distributed among the three groups. There were no serious thromboembolic events reported during the study.

Conclusions: This summary of 24 major surgeries indicates that rFVIIa is effective as prophylactic therapy for major surgery in hemophilia A or B patients with inhibitors. The numbers of patients were too small to distinguish efficacy rates between the two groups. The safety profile for patients treated with rFVIIa (BI or CI) was similar to the profile for non-inhibitor patients treated with other factors. Presented on behalf of the NovoSeven in Surgery Study Investigators.