The main purpose of this prospective, multi-center, open-label phase 3 study was to assess the efficacy of prophylactic treatment with Human-cl rhFVIII, the first human cell-line derived recombinant FVIII, in previously treated patients (PTPs) with severe haemophilia A.
Patients were to receive 30–40 international units (IU) FVIII of Human-cl rhFVIII per kg every other day for 6 months. Efficacy of preventing and treating bleeds were judged using objective criteria taking the monthly bleeding rate and the number of infusions needed to manage a break-through bleed into account. In-vivo recovery (IVR) was determined at the beginning of the study and after 3 and 6 months. FVIII:C was measured by validated chromogenic (CHR) and one-stage (OS) assays in a central laboratory, which also assigned drug potencies. Inhibitor activity was determined using the Nijmegen modification of the Bethesda assay before the first administration and at defined intervals thereafter. Thirty-two patients between 18 and 75 years of age were enrolled from 11 centres in Europe and treated prophylactically for 6.0±0.9 months (mean ± SD) with a mean prophylactic dose of 32.8 IU/kg. Sixteen patients never bled, 11 patients bled once and 5 more than once. The mean total and spontaneous monthly bleeding rate was 0.188±0.307 and 0.095±0.211, respectively. Efficacy of the prophylactic treatment was “excellent” in all patients for spontaneous BEs and “excellent” or “good” in all patients but one for all types of bleeds. All treatments of bleeds were rated as “excellent” (71.4%) or “good” (28.6%). The IVR at baseline was 2.6±0.5 % per IU/kg for the CHR and 2.2±0.5 % per IU/kg for the OS assay and remained stable during the study. A total of 2921 infusions were given in the study. Human-cl rhFVIII was well tolerated and no patient experienced a related serious adverse event. No FVIII inhibitors were detected.
The data indicate that Human-cl rh FVIII is safe and efficacious in preventing and treating bleeds in PTPs with severe haemophlia A.
Knaub:Octapharma AG: Employment. Lissitchkov:Octapharma AG: PI Other. Tuddenham:College London: Consultancy, Employment, Gene therapy for hemophilia A, Gene therapy for hemophilia A Patents & Royalties, Research Funding. Collins:Octapharma AG: Consultancy. Oldenburg:d and e: Baxter, Bayer, Biotest, CSL-Behring, Grifols, Inspiration, NovoNordisk, Octapharma, Pfizer e: Biogen IDec, Swedish Orphan Biovitrum: Honoraria, Research Funding. Bichler:Octapharma AG: Employment.
Asterisk with author names denotes non-ASH members.