SOUTH SAN FRANCISCO, Calif.—Catalyst Biosciences, Inc., a biopharmaceutical company focused on developing novel subcutaneous (SQ) therapies for hemophilia and other inherited bleeding disorders, announced today that it has received guidance from the U.S. Food and Drug Administration and the European Medicines Agency on a pivotal Phase 3 trial design for Marzeptacog alfa (activated), known as MarzAA. The open-label trial will evaluate the efficacy of SQ MarzAA to treat episodic bleeding in individuals with hemophilia A or B with inhibitors.

 

MarzAA is a potent, subcutaneously administered, next-generation recombinant Factor VIIa variant. Catalyst previously completed a Phase 2 open-label SQ prophylaxis trial of MarzAA, which met the trial’s primary and secondary endpoints in 2019. The preclinical and clinical data support not only MarzAA’s potential use for treatment of episodic bleeding episodes, but also further clinical testing for on-demand treatment of bleeds in individuals with hemophilia, Glanzmann Thrombasthenia, Factor VII deficiency and other bleeding disorders.

 

“Now that we have received regulatory feedback, we have initiated preparations for a Phase 3 trial of MarzAA in individuals with hemophilia A or B with inhibitors,” stated Nassim Usman, Ph.D., president and chief executive officer of Catalyst. “We plan to enroll the first patient before year end, however that date is dependent on the readiness of our trial sites and improvements in the current effects of COVID-19 on clinical trial execution. At present, manufacturing and drug supply are unaffected for our clinical trials.”

 

The Phase 3 Crimson-1 (Subcutaneous Marzeptacog Alfa [Activated] For On demand Treatment and Control of Bleeding Episodes in Subjects with Hemophilia A or Hemophilia B with Inhibitors) study will enroll individuals who experience episodic bleeding. Crimson-1 will be an open-label global trial, evaluating the safety and efficacy of SQ MarzAA in the treatment of approximately 230 bleeding episodes in approximately 75 patients, compared with their prior standard of care in a similar number of bleeding episodes.

 

The study will assess the effectiveness of SQ MarzAA, using up to 3 doses to treat a bleeding episode. The primary endpoint will be hemostatic efficacy, using a standard 4-point assessment scale.