Objective:
Promote awareness of and an opportunity for dialogue regarding variability among prescribed regimens to enhance care for hemophilia A patients with inhibitors undergoing immune tolerance.
Methods:
Retrospective chart review of all severe hemophilia A patients receiving interdisciplinary inhibitor management home infusion support between March of 2013 and March of 2015. Excluded mild patients developing inhibitors postoperatively and those for which insufficient titer information was provided/available from prescribers. 14 patients met the inclusion criteria. We attempted to further categorize these regimens in to low and high dosing regimens as outlined in the International Immune Tolerance Study.
Summary:
We identified 14 patients on 7 different ITI regimens, none of whom expressly followed the “low or high dose regimens” of 50 units per kg 3 times a week or 200 units per kg daily. They were on either recombinant FVIII products (11) or vWF containing products (3). The reviewed population was followed by 11 different HTC’s which included 13 different prescribers. We noted time to tolerization (when information available), bleed rate, as well as the interventions and support offered patients by the homecare inhibitor team. Although the sample was small, a notable increase in bleeds was seen in those patients on regimens below100 units/kg/day. Time to tolerization was unavailable for 3 of the 14. Of the remaining 11, time to tolerization ranged from 1-45 months and there was no significant difference seen amongst regimens.
Conclusions:
Seven different regimens for ITI were prescribed for 14 unique patients across the country. All achieved successful immune tolerance, but there was variability in the frequency of spontaneous bleeds and time to tolerance. Exact time to tolerance was limited by both the inability to obtain lab values (titers) from the prescriber or long periods between titer levels. Immune tolerance induction dosing regimens have been long debated and several studies continue to attempt to provide clarity and guidance. A missing component of the research published to date is the importance of patient adherence and the benefit of prescriber/pharmacist/payer collaboration. Economic influences further complicate this as many HTC’s perceive pharmacies as competitors, rather than collaborators in care. Additionally, payers may limit networks or implement other barriers to refills. The authors wish to work collaboratively to remove these barriers and enhance outcomes.