New Data Released on Long-Acting Hemophilia B Treatment

Note: The following is the edited version of a press release issued by CSL Behring. The original release can be found here.

On December 7, 2015, CSL Behring presented data from its Phase III PROLONG-9FP clinical program evaluating the efficacy and long-term safety of its investigational long-acting fusion protein linking recombinant coagulation factor IX with recombinant albumin (rIX-FP). The data, from an ongoing extension study and two pivotal Phase III studies, assessed rIX-FP for routine prophylaxis in previously-treated adults with hemophilia B, at dosing intervals of up to 14 days. The findings were presented during an oral presentation at the American Society of Hematology’s (ASH) 57th ASH Annual Meeting and Exposition in Orlando, along with a second abstract reporting efficacy and safety results of rIX-FP in patients undergoing surgical procedures.
“The findings from the ongoing extension study are promising and confirm the data we saw in our pivotal studies, with prolonged dosing intervals of up to 14 days with rIX-FP for routine prophylaxis,” said Elena Santagostino, M.D., Ph.D., Professor in the Medical School of Clinical and Experimental Hematology at the University of Milan/IRCCS Maggiore Hospital, and lead investigator. “rIX-FP has been developed with a pharmacokinetic profile that allows for less frequent dosing. Through this ongoing study, we are continuing to evaluate longer treatment intervals and the potential impact on preventing bleeding in select patients.”
Key Study Findings

• Efficacy and safety of rIX-FP in previously-treated children, adolescents, and adults (Oral Presentation Abstract #548): The first abstract reported on two completed Phase III studies (CSL654-3001 and CSL654-3002) assessing the safety and efficacy of rIX-FP for prophylaxis treatment in previously-treated patients (ages 1 to 61) with hemophilia B (factor IX activity ≤2%). The first study (CSL654-3001) included 63 patients, ages 12 to 61. These patients either received prophylaxis treatment (once every seven days for six months and then, if eligible, a 10- or 14-day prophylaxis treatment interval for 12 to 18 months) or only on-demand treatment for six months and then switched to seven-day prophylaxis treatment. The second study (CSL654-3002) included 27 children (ages 1 to 11) who received seven-day prophylaxis treatment for approximately 12 months. Overall, the median annualized spontaneous bleeding rate (AsBR) was 0.00 for all treatment intervals.During the extension study, 76 patients from the phase III studies continued their prophylaxis regimen but additional patients switched to longer treatment intervals, including the 10- and 14-day intervals in patients younger than 12 and more prolonged treatment intervals in patients older than 18. At least 50 patients achieved 100 exposure days of treatment without developing an inhibitor to factor IX or antibodies to rIX-FP. Overall, no serious adverse reactions were seen during the studies and favorable long-term tolerability was demonstrated.

“At CSL, we focus our world-class research and development to help people with serious medical conditions, such as hemophilia B, live full lives,” said Dr. Andrew Cuthbertson, Chief Scientific Officer and Director of R&D, CSL Limited. “These latest results from our pivotal research program demonstrate the potential for rIX-FP to help patients maintain factor IX levels over a long period of time with greater freedom from frequent infusions. This is an important attribute for patients who require a prophylactic regimen but don’t want treatment to disrupt their active lives.”

• rIX-FP in previously-treated patients undergoing surgery (poster presentation abstract #2298): The second abstract reported on a surgical sub-study included in the Phase III studies, including the ongoing extension study, as part of the global PROLONG-9FP clinical program. This abstract evaluated the use of rIX-FP in five major orthopedic surgeries to prevent bleeding during and post-surgery in four patients with hemophilia B. For all procedures, the investigators rated the response as “excellent” or “good,” and a single pre-operative dose of rIX-FP maintained hemostasis during surgery. Over the 14-day perioperative period, patients needed six or seven infusions. The median rIX-FP consumption prior to surgery and post-surgery was 340 IU/kg, which was lower than with conventional therapies. None of the patients developed inhibitors to factor IX or antibodies to rIX-FP.