CSL Behring submits MAA to EMA for rVIII-SingleChain for patients with hemophilia A

In the pivotal clinical trial, rVIII-SingleChain met all primary endpoints.

Hemophilia A is a congenital bleeding disorder characterized by deficient or defective factor VIII; nearly all affected patients are male. People with hemophilia A may experience prolonged or spontaneous bleeding, especially into the muscles, joints, or internal organs. According to the World Federation of Hemophilia, about 1 in 10,000 people are born with hemophilia, the majority of whom have hemophilia A.

CSL chief scientific officer and director of R&D Andrew Cuthbertson said: "Our focused research and development and strong relationship with the bleeding disorders community led us to seek further advancements in the care and treatment of hemophilia.

"Today, we have the only recombinant single-chain factor VIII product in late-stage development for the management of hemophilia A. We look forward to, upon approval, providing this innovative specialty biotherapy to patients in the EU and European Economic Area."

The MAA is based on the AFFINITY clinical development program, which includes a phase I/III open-label, multi-center trial examining safety and efficacy.

The pharmacokinetics of rVIII-SingleChain compared with recombinant human antihemophilic factor VIII (octocog alfa) was also studied. Study design details for rVIII-SingleChain are available at clinicaltrials.gov (NCT01486927).

Results from the phase I/III study presented earlier this year at the International Society on Thrombosis and Haemostasis (ISTH) congress in Toronto showed that patients treating prophylactically had a median annualized bleeding rate (ABR) of 1.14 and a median annualized spontaneous bleeding rate (AsBR) of 0.00.

The data also showed that, of 848 bleeds treated in the study, 94 percent were controlled with no more than two infusions of rVIII-SingleChain, with 81 percent controlled by one infusion. Moreover, hemostatic control of a bleeding event treated with rVIII-SingleChain was assessed by the investigator as excellent or good 94 percent of the time (835 assessed bleeding events).

The results presented at ISTH included data on more than 14,000 exposure days in 146 patients on prophylaxis and 27 patients treating on demand for a bleeding event.

In total, 120 patients were treated for more than 50 days of exposure; 52 had more than 100 days of exposure. In the prophylaxis group, 32 percent of patients were dosed twice weekly and 54 percent received treatment three times per week; the regimen was determined by the investigator. The most common adverse events were naso-pharyngitis, arthralgia, and headache. No inhibitors were reported.