Cost of immune tolerance induction according to its outcome in people with hemophilia A and inhibitors: results from the Co$tIT study.

BACKGROUND

Immune Tolerance Induction (ITI) is indicated for people with hemophilia A (PwHA) with inhibitors. It is not known whether the costs differ among ITI outcomes.

AIM: To assess the costs of clotting factor concentrates (CFC) according to ITI outcomes.

METHODS

This retrospective cohort study included 91 PwHA who completed a first course of ITI. We evaluated the costs with CFC 12 months before (pre-ITI), during and 12 months after ITI (post-ITI), according to ITI outcome. We compared costs in each period, between pre- and post-ITI, and evaluated the determinants of costs during ITI.

RESULTS

A total of 32 %, 38 % and 30 % of PwHA achieved complete (CS), partial success (PS), and failed ITI, respectively. The mean cost per PwHA during ITI was US$1.18 million; US$355,838 in CS, US$724,986 in PS, and US$2,653,217 in the failure group. During ITI, approximately 65 % of the variability of the mean cost/kg was explained by the outcome of ITI (failure or PS), duration of ITI, use of prophylactic bypassing agents, and use of incremental FVIII regimen. In post-ITI, we observed about 50 % and 22 % reduction of mean cost/kg in CS and PS, respectively, while failing ITI resulted in increased costs of over 100 % compared with pre-ITI. Regardless of the outcome, in post-ITI, the annualized bleeding rate reduced when compared with pre-ITI.

CONCLUSIONS

Costs with CFC during ITI were the lowest with CS, followed by PS and failure. In comparison with pre-ITI, successful ITI was associated with reduced costs, already noticed in the first year post-ITI.