CSL Behring presents Phase I/III rVIII-SingleChain hemophilia A data at 2015 ISTH Congress

Data Presented during Late Breaking Session at the 2015 ISTH Congress showed:

• Patients using rVIII-SingleChain prophylactically to prevent bleeding were well controlled when dosed only two or three times weekly
• Prophylactic dosing resulted in low annualized spontaneous bleeding rates and the majority of treated bleeds were controlled with only one dose
• rVIII-SingleChain had improved pharmacokinetic parameters compared with octocog alfa, the comparator

CSL Behring today presented data from a Phase I/III study on the efficacy and safety of its novel investigational recombinant factor VIII single chain (rVIII-SingleChain) in adolescents and adults with hemophilia A during a late breaking abstract session at the 2015 International Society on Thrombosis and Haemostasis (ISTH) Congress. Overall, patients using rVIII-SingleChain to prevent bleeding (prophylaxis) were well controlled with two to three infusions per week and developed no inhibitors.

Patients using rVIII-SingleChain to prevent bleeding had low annualized bleeding rates (median ABR of 1.14), and an annualized spontaneous bleeding rate (AsBR) of 0.00. rVIII-SingleChain had improved pharmacokinetic parameters compared with octocog alfa, the comparator. Of 848 bleeds treated in the study, 94 percent were successfully controlled with no more than two infusions of rVIII-SingleChain, with 81 percent controlled by only one infusion. The majority of bleeding events treated with rVIII-SingleChain and assessed by investigators (94 percent of 835 assessed bleeding events) were rated as excellent or good. The data are part of the AFFINITY Phase I/III study, an open-label, multi-center trial examining the safety, efficacy and pharmacokinetics of rVIII-SingleChain compared with recombinant human antihemophilic factor VIII (octocog alfa). Study design details for rVIII-SingleChain (CSL627) are available at clinicaltrials.gov.

“In this large-scale study, we observed relatively low annualized bleeding rates and a median of zero spontaneous bleeding events with rVIII-SingleChain for routine prophylaxis for patients with hemophilia A,” said Professor Ingrid Pabinger-Fasching, M.D., of the Medical University of Vienna, Austria and lead investigator of the pivotal trial. “As the first and only single chain recombinant factor product, rVIII-SingleChain has the potential to offer improved protection from bleeding with less frequent dosing, and an excellent safety profile thus far.”

Results presented in the late breaking session included data on more than 14,000 exposure days in 146 patients on prophylaxis and 27 patients treated 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. Among patients in the prophylaxis group, 32 percent were dosed twice weekly and 54 percent received treatment three times per week. The most common adverse events were naso-pharyngitis, arthralgia, and headache. Overall, rVIII-SingleChain was well tolerated and no inhibitors have been reported.

“Our novel rVIII-SingleChain was specifically designed to improve the stability and provide longer-lasting hemostatic efficacy of factor VIII, thereby addressing the need to provide hemophilia A patients with a treatment that may require fewer infusions while maintaining its therapeutic effect,” said Dr. Andrew Cuthbertson, Chief Scientific Officer and Director of R&D, CSL Limited. “These pivotal data are promising and are supportive of CSL Behring’s commitment to bringing this therapy to the market, and to helping improve the care of people living with hemophilia A.”