At the 2018 American Society of Hematology (ASH) Annual Meeting in San Diego, Dr. Howard Levy, Chief Medical Officer of Catalyst Biosciences discusses hemophilia and his company’s poster at the meeting: Updated Positive Interim Data from Its Phase 2/3 Study of Marzeptacog Alfa (Activated) in Individuals with Hemophilia A or B with Inhibitors.

Hemophilia is a bleeding disorder that slows the blood clotting process. People with this disorder experience prolonged bleeding following an injury, surgery, or having a tooth pulled. In severe cases, heavy bleeding occurs after minor trauma or in the absence of injury. Serious complications can result from bleeding into the joints, muscles, brain, or other internal organs. The major types of this disorder are hemophilia A and hemophilia B. Although the two types have very similar signs and symptoms, they are caused by mutations in different genes. People with an unusual form of hemophilia B, known as hemophilia B Leyden, experience episodes of excessive bleeding in childhood, but have few bleeding problems after puberty. Another form of the disorder, acquired hemophilia, is not caused by inherited gene mutations.

Catalyst Biosciences, Inc. (NASDAQ: CBIO), a clinical-stage biopharmaceutical company focused on developing novel medicines to address hematology indications, today announced additional positive interim data from its Phase 2/3 study of subcutaneous prophylactic Factor VIIa (FVIIa) variant marzeptacog alfa (activated) (MarzAA), currently being developed for the treatment of hemophilia A or B with inhibitors. The data were presented in a poster at the 60THAmerican Society of Hematology (ASH) Annual Meeting & Exposition on December 1, 2018 in San Diego.

“These results support the efficacy of MarzAA as a subcutaneous prophylactic treatment option for individuals with hemophilia A or B with inhibitors,” said Nassim Usman, Ph.D., chief executive officer of Catalyst. “We observed that bleeding in individuals with high annualized bleed rates is significantly reduced or eliminated during MarzAA treatment. With these new data from two additional individuals who have successfully completed the trial, we are optimistic about the potential for MarzAA treatment to achieve extremely low annualized spontaneous bleed rates with individualized, subcutaneous daily dosing.”

Dr. Howard Levy, chief medical officer of Catalyst, presented the updated results, including the new data from two additional subjects who have completed the Phase 2/3 MarzAA trial. The first subject, who had an annualized bleed rate (ABR) of 15.2, had no bleeds during 50 days of treatment with 30 µg/kg MarzAA. The second subject, who had an ABR of 22.2, experienced a bleed on Day 4 that did not require treatment. The subject continued on the 30 µg/kg dose level, as the bleed occurred within the first five days of dosing when FVIIa levels are still increasing to therapeutic levels and completed the trial with no additional bleeds during the treatment period.

To date, 13 subjects have consented and five have completed dosing in the Phase 2/3 MarzAA trial. These five subjects had an ABR range of 15.2-26.7 before MarzAA treatment. Three participants experienced no bleeds with individualized dosing of either 30 µg/kg or 60 µg/kg MarzAA and two others had clinically significant reductions in ABR. The median proportion of days with bleeding during the pre-study period was 11.9% and this was significantly reduced to a median of 0.5% during the treatment period. Through a total of more than 300 days of subcutaneous dosing, no injection site reactions or anti-drug antibodies to MarzAA have been detected. In one subject, two subcutaneous injections resulted in a mild localized hematoma that resolved without sequelae or treatment. Final data from the study are expected in the first half of 2019.