Catalyst Biosciences
Syringe in vial Photo courtesy of
BOSTON—The activated factor VIIa variant marzeptacog alfa has demonstrated efficacy as prophylaxis for patients with hemophilia A or B who also have inhibitors, according to researchers.
Three patients have completed dosing with marzeptacog alfa in a phase 2/3 study.
None of these patients experienced bleeding during treatment, and none have developed antidrug antibodies or reported injection site reactions.
As for the other 2 patients enrolled in this study, 1 withdrew consent, and 1 died of an adverse event unrelated to marzeptacog alfa.
Howard Levy, chief medical officer of Catalyst Biosciences, Inc., presented these data at the 2018 Hemophilia Drug Development Summit.
The trial is sponsored by Catalyst Biosciences, the company developing marzeptacog alfa.
Results
The goal of this ongoing trial is to determine whether daily subcutaneous injections of marzeptacog alfa can eliminate or minimize spontaneous bleeding episodes. The primary endpoint is a reduction in annualized bleed rate (ABR) compared to each individual’s recorded historical ABR.
Thus far, the trial has enrolled 5 patients with hemophilia A or B and inhibitors. (Catalyst would not disclose how many patients have hemophilia A and how many have hemophilia B).
One patient with a historic ABR of 26.7 completed the trial with no bleeds after 50 days of treatment with marzeptacog alfa at 60 µg/kg.
This patient had previously experienced a bleed on day 46 when receiving marzeptacog alfa at 30 µg/kg, and the patient experienced another bleed 16 days after the end of dosing at 60 µg/kg.
A second patient with a historic ABR of 16.6 had no bleeds when receiving marzeptacog alfa at 30 µg/kg for 50 days.
And a third patient with a historic ABR of 15.9 had no bleeds when receiving marzeptacog alfa at 30 µg/kg for 44 days.
“The data from these 3 individuals support the efficacy of [marzeptacog alfa] to reduce annualized bleed rates after daily subcutaneous injections,” said Nassim Usman, PhD, chief executive officer of Catalyst Biosciences.
“Importantly, to date, we have not observed any injection site reactions nor any anti-drug antibodies after more than 200 subcutaneous doses of [marzeptacog alfa].”
A fourth patient with a historic ABR of 18.3 had a fatal hemorrhagic stroke on day 11 that was considered unrelated to marzeptacog alfa. The patient had previously treated hypertension that was going untreated at the time of death.
A fifth patient with a historic ABR of 12.2 withdrew consent.