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.