Inspiration Biopharmaceuticals, Inc., announced in July that the US Food and Drug Administration (FDA) had placed a clinical hold on clinical trials evaluating the safety and efficacy of IB1001, an intravenous recombinant factor IX (rFIX) being investigated for the treatment and prevention of bleeding episodes in people with hemophilia B. Inspiration had planned to launch the product in the first half of 2013.
The clinical hold affects two ongoing IB1001 clinical trials—one in adults, the other in children. The first is a phase III study evaluating the safety and efficacy of IB1001 to treat and prevent bleeding episodes in adults with hemophilia B. The second is a phase III/IIIb study evaluating the safety and efficacy of IB1001 to treat and prevent bleeding episodes in previously treated children with hemophilia B. A previous adult study has completed its primary analysis period.
Inspiration had reported to the FDA that, during the course of routine laboratory evaluations conducted as part of an ongoing phase III clinical trial, it had discovered that a higher proportion of individuals treated with IB1001 had developed antibodies to proteins from the Chinese hamster ovary (CHO), than was expected based on earlier study data. CHO host cells are used to manufacture the therapy. Inspiration has notified clinical sites within and outside the US to hold treatment of patients with IB1001.
Small amounts of host cell protein are expected and documented in recombinant therapeutic products of all types. However, the higher than expected rate of anti-CHO antibody development in people treated with IB1001 prompted Inspiration to initiate a thorough investigation.
A total of 86 people with hemophilia B have received IB1001 in clinical studies to date. So far no adverse events related to the development of antibodies to CHO protein have been reported. Further, no relationship has been observed between the development of anti-CHO protein reactivity and the development of antibodies to factor IX. Inspiration continues to follow subjects who were enrolled in clinical trials of IB1001 to collect safety-related information. It will share this information with regulators.
“As always, the safety of participants in our clinical programs is our primary concern. We are conducting a full investigation into the root cause of these antibodies,” said John P. Butler, Chief Executive Officer of Inspiration. “We have already made progress in identifying potential options to reduce antibody formation and will continue to work with the FDA on plans to move the IB1001 program forward. At Inspiration we are committed to developing the best possible treatment options for people with hemophilia, and this commitment drives our IB1001 program.”
Source: Inspiration news release dated July 10, 2012