Mr. Ken d'Entremont reports

MEDEXUS STUDY SUPPORTS EFFICACY AND SAFETY OF IXINITY IN PEDIATRIC PATIENTS WITH SEVERE OR MODERATELY SEVERE HEMOPHILIA B

Medexus Pharmaceuticals Inc. today presented data from a phase 3/4 study that evaluated the pharmacokinetics (PK) safety and efficacy of Ixinity, an intravenous recombinant factor IX therapeutic, as a prophylactic treatment in previously treated pediatric patients under 12 years of age with severe or moderately severe hemophilia B, a hereditary bleeding disorder characterized by a deficiency of clotting factor IX in the blood.

In a poster presentation at the National Hemophilia Foundation (NHF) Bleeding Disorders Conference 2023 in National Harbor, Md., researchers reported that prophylaxis with Ixinity was associated with low annualized bleeding rates (ABRs), effective control of bleeding episodes, consistent PK and a consistent safety profile. See "about the study" herein for additional information about the study's methods, results and conclusions. Ixinity is currently approved for use in patients 12 years of age or older with hemophilia B.

"This study demonstrated the efficacy of Ixinity in the prevention and control of bleeding episodes in pediatric subjects while providing a favorable safety profile," commented Johnny Mahlangu, BSc, MBBCh, MMed, FCPath, the study's principal investigator. "The results bolster the overall utility of this recombinant factor IX agent in the treatment of individuals with hemophilia B."

"The data presented at BDC 2023 add to the growing body of evidence of Ixinity's efficacy and safety," said Mark Fosdal, DHSc, PA-C, director of scientific communications at Medexus and a coauthor of the study. "Subject to FDA approval of the pediatric indication, the accumulated data should give clinicians greater confidence in administering Ixinity to maintain reliably high factor IX levels long term, for all patients of all ages with hemophilia B."

About the study

The phase 3/4 study was a single-arm, open-label clinical trial evaluating the PK, safety and efficacy of Ixinity prophylaxis in 21 previously treated patients less than 12 years of age with severe (factor IX activity less than 1 per cent; n equals 13) or moderately severe (factor IX activity 1 per cent to less than 2 per cent; n equals eight) hemophilia B. The prophylaxis dose was based on Ixinity recovery from PK assessments, after a single intravenous infusion dose of 75 plus or minus five IU/kg, and was within the recommended prophylaxis dose of 35 to 75 IU/kilogram, twice weekly. The hemostatic efficacy of Ixinity was determined by calculating the ABR while on prophylaxis to prevent bleeding episodes, the number of infusions used to treat bleeding episodes, and overall ratings of efficacy by participants and investigators. Safety was evaluated by assessment of adverse events (AEs), physical examinations, vital signs and laboratory assessments.

The mean ABR for the entire study was 2.34 plus or minus 4.226 (median equals 0.86, range equals zero minus 18.7) for all bleeds and 0.63 plus or minus 1.257 (median equals 0, range equals zero minus 4.7) for spontaneous bleeds. One-third (33.3 per cent) of participants had no bleeds and more than 60 per cent (61.9 per cent) had zero spontaneous bleeds. Participants rated the hemostatic efficacy of Ixinity as "excellent" or "good" in 78.8 per cent of all episodes. Over all, investigators rated Ixinity prophylaxis as "effective;" there were three ratings of "partially effective" during the study. All investigator ratings for control over bleeding episodes were effective. Of the bleeding episodes that required treatment, 83.8 per cent resolved after one or two infusions.

There appeared to be no clinically important differences in results for participants younger than six years of age compared with those between six and 12 years of age. The younger age group experienced lower mean incremental recovery of clotting factor (0.731 versus 0.849 IU/dL: IU/kg) accompanied by a higher mean clearance (7.3 versus 6.1 millilitres/[kg multiplied by hr]), consistent with the PK pattern of factor IX in children aged 12 and younger when compared with use in adolescents and adults.

Over all, 76.2 per cent of participants had at least one AE; the most frequently reported AEs were nasopharyngitis (23.8 per cent) and bronchitis (14.3 per cent). Only one AE was considered possibly treatment related: a non-serious, moderate hypersensitivity reaction that led to the participant's withdrawal from the study.

About Ixinity

Ixinity [coagulation factor IX (recombinant)] lyophilized powder for solution for intravenous injection is a coagulation factor IX (recombinant) indicated in adults and children greater than or equal to 12 years of age with hemophilia B for on-demand treatment and control of bleeding episodes, perioperative management and for routine prophylaxis to reduce the frequency of bleeding episodes.

The most common adverse reaction observed in greater than 2 per cent of patients in clinical trials was headache.

Ixinity is approved by the Food and Drug Administration for sale and use in the United States only and is not intended for export outside the United States. Medexus makes no representation that Ixinity is appropriate for, or authorized for sale to or use by, persons who are not located in the United States.

About hemophilia B

Hemophilia B is a genetic bleeding disorder caused by a deficiency of coagulation factor IX, a protein needed to produce blood clots to stop bleeding. The clinical spectrum may include spontaneous or trauma-induced bleeding into joints, muscles and soft tissues, resulting in joint damage, reduction in mobility and severe arthritis, all of which negatively impact health-related quality of life. The primary aim of care is to prevent and treat bleeding by replacing the deficient clotting factor.

About Medexus Pharmaceuticals Inc.

Medexus is a leading specialty pharmaceutical company with a strong North American commercial platform and a growing portfolio of innovative and rare disease treatment solutions. Medexus's current focus is on the therapeutic areas of oncology, hematology, rheumatology, auto-immune diseases, allergy and dermatology.

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