Human-cl rhFVIII, a new generation recombinant factor VIII of human origin, appears to be associated with a low inhibitor incidence in patients with severe hemophilia A, according to interim findings from the ongoing NuProtect study.
In 66 evaluable previously untreated patients with at least 20 days of exposure to human-cl rhFVIII, the cumulative incidence of high-titer and low-titer inhibitor development was 12.8% and 8.4%, respectively, Ellis J. Neufeld, MD, reported at the annual meeting of the European Association for Haemophilia and Allied Disorders.
The median age at first treatment was 13 months (range of 3-135 months). Of 59 patients with available F8 gene analysis, 44 had high-risk mutations and 47 had null mutations; 1 had no mutation identified. After a median of 11.5 treatment exposure days, 8 of the 66 patients developed high-titer inhibitors and 5 developed low-titer inhibitors; 4 of those were transient, said Dr. Neufeld of Harvard Medical School, Boston.
Only two of the patients developed an inhibitor, including one high- and one low-titer inhibitor, after 20 exposure days. Among the 13 inhibitor patients, 12 had an F8 mutation identified; all were null, and 11 were high risk.
In a prior study of 201 patients with previously treated severe hemophilia A, no inhibitors were reported with human-cl rhFVIII – which is produced in human cells without chemical modification or protein fusion. The NuProtect study is looking at immunogenicity, efficacy, and safety in previously untreated patients. Final data are expected in 2018, Dr. Neufeld noted.
Dr. Neufeld disclosed financial ties to Octapharma, the sponsor of NuProtect, and numerous other pharmaceutical companies.