The recombinant, GlycoPEGylated coagulation factor IX product Rebinyn® is now available in the US for the treatment of patients with hemophilia B.
Last May, Rebinyn was approved by the US Food and Drug Administration for on-demand treatment and control of bleeding episodes as well as perioperative management of bleeding in adults and children with hemophilia B.
The product is not approved for routine prophylaxis or immune tolerance induction in hemophilia B patients.
The full prescribing information is available at www.Rebinyn.com.
Rebinyn is also approved for use in the European Union, where it is known as nonacog beta pegol or by the brand name Refixia.
There, the product is approved for use as prophylaxis, for on-demand treatment of bleeding, and for control of bleeding related to surgical procedures in adolescents (older than 12 years of age) and adults with hemophilia B.
The US and European approvals of nonacog beta pegol (N9-GP) were based on results from the paradigm™ clinical trials. Results from the paradigm 4 trial were published in Thrombosis Research in May 2016.
Paradigm 4 was an extension trial enrolling patients who had participated in the phase 3 trials paradigm 2 and paradigm 3.
In paradigm 2, researchers assessed N9-GP as treatment and prophylaxis in previously treated patients with hemophilia B. In paradigm 3, researchers assessed N9-GP in hemophilia B patients undergoing surgical procedures.
Paradigm 4 included 71 patients (ages 13 to 70) who continued to receive N9-GP as on-demand treatment (40 IU/kg for mild/moderate bleeds and 80 IU/kg for severe bleeds) or prophylaxis (10 IU/kg or 40 IU/kg once-weekly). Sixty-five patients completed treatment.
None of the patients developed factor IX inhibitors. Two patients had transient binding antibodies to N9-GP, but there was no sign that these antibodies had an inhibitory effect.
Four patients developed anti-CHO antibodies, but only 2 of these patients were still positive for these antibodies at the end of the trial.
There were a total of 155 adverse events. However, only 4 of these (in 3 patients) were considered possibly or probably related to N9-GP.
These events consisted of an injection site rash in 1 patient, 2 overdoses in 1 patient, and neutropenia in 1 patient. The rash and neutropenia resolved, and the patient who overdosed recovered without complications.
The researchers said the success rate for the treatment of reported bleeds was 94.6%. Most bleeds (87.9%) were resolved with a single injection of N9-GP, but 9.2% required 2 injections, and 2.9% required 3 or 4 injections.
The median annualized bleeding rate for patients on prophylaxis was 1.05 (interquartile range [IQR], 0.00–2.20) overall. It was 1.36 (IQR, 0.00-2.23) for the 10 IU/kg arm and 1.00 (IQR, 0.00-2.03) for the 40 IU/kg arm.
There were 14 patients on prophylaxis who underwent 23 minor surgical procedures.
The hemostatic response was considered “excellent” (better than expected/predicted for the procedure in question) in 19 procedures and “good” (as expected) in 2 procedures. In the remaining 2 procedures, hemostatic responses were not determined.