Patterns of tertiary prophylaxis in Canadian adults with severe and moderately severe haemophilia B

Area of Science:

• Hematology
• Internal Medicine
• Pharmacology

Background:

• Severe and moderately severe FIX deficiency (haemophilia B) can lead to bleeding and joint destruction.
• Prophylaxis with coagulation factor IX concentrate is standard for children but less characterized in adults with established joint disease.
• Tertiary prophylaxis aims to manage bleeding in adults with pre-existing joint damage.

Purpose of the Study:

• To understand the current Canadian experience with tertiary prophylaxis in adult males with severe and moderately severe haemophilia B.
• To characterize the use of prophylaxis, including frequency and duration, in this patient population.
• To assess the impact of tertiary prophylaxis on bleeding rates and factor utilization.

Main Methods:

• An observational study conducted across seven Canadian Hemophilia Treatment centres from 2009 to 2011.
• Inclusion criteria: adult males (≥ 18 years) with baseline FIX:C ≤ 2%.
• Data collection on prophylaxis use, infusion regimens, bleeding rates, and factor consumption.

Main Results:

• 34% of moderately severe haemophilia B subjects and 52% of severe haemophilia B subjects received prophylaxis.
• Most prophylaxis was continuous (≥45 weeks/year), with 81% using once or twice weekly infusions.
• Median annual bleeding rates were similar for prophylaxis (5 bleeds/year) and on-demand treatment (4 bleeds/year), but factor utilization was significantly higher with prophylaxis (196,283 U/year vs. 46,361 U/year).

Conclusions:

• Approximately 50% of adults with severe haemophilia B in Canada are using continuous tertiary prophylaxis.
• This practice is increasing and requires further study to fully evaluate its benefits and risks.
• The findings highlight a shift in treatment paradigms for adult haemophilia B patients with established joint arthropathy.