PURPOSE

Regular prophylactic factor replacement is recommended as optimal therapy for hemophilia B. Factor concentrate with longer half-lives would allow successful prophylaxis as less frequent dosing would be less burdensome for patients and caregivers. Nonacog Beta Pegol (N9-GP), a glycopegylated factor IX with an extended half-life, has been established globally. However, real-world data from India remain limited. This study evaluates the safety, efficacy, and feasibility of low-dose N9-GP prophylaxis in Indian children/adolescents with hemophilia B.

METHODS

In this retrospective study, a total of seven patients with hemophilia B were included. Baseline assessments of the annualized bleeding rate (ABR), Functional Independence Score in Hemophilia (FISH), and Hemophilia Joint Health Score (HJHS) were conducted for all patients. Dosing was individualized (mean 34.76 IU/kg; range: 25-40 IU/kg every three weeks) based on patient weight, baseline ABR, and joint status, in accordance with resource-conscious protocols suitable for Indian settings. Patients were monitored for any adverse events throughout the study period. After 12 months of treatment, the ABR, FISH, and HJHS were reassessed and compared with baseline values. Screening for inhibitors was performed for all patients at the end of the 12-month period.

RESULTS

The mean age was 11.2 years, ranging from four years to 18 years. The mean overall ABR before using N9-GP was 21.1 (range 12 - 48) bleeds/year. After treatment with N9-GP, the mean overall ABR was 0.42 (0-1) bleeds/year. Six patients had target joints before starting treatment. At the end of 12 months of prophylaxis, only one patient had a target joint involving one joint with mobility and swelling significantly improved in the affected joint. Four patients remained bleed free on N9-GP prophylaxis. Three patients experienced minor bleeding once, which was just before the next dose of prophylaxis. Baseline mean HJHS was 26.71/124 (range 10 - 47). After 12 months on N9-GP, mean HJHS was 7.5/124 (range 0-16). Before treatment, the mean FISH score was 23.8/32 (range 17-29). After treatment, the mean FISH score was 31.4/32 (range 28 - 31). None of them developed any adverse drug reactions or thromboembolic events during the entire course of treatment. None of the patients developed inhibitors.  Conclusion: N9-GP has been shown to be well tolerated, safe, and efficacious in the treatment and prevention of bleeding episodes in people with hemophilia B.