Adherence, treatment utilization, clinical and economic outcomes of patients with sickle cell disease with recurrent vaso-occlusive crises treated with recently approved chronic therapies in the US

Abstract

Aim: To describe real-world adherence, treatment utilization, vaso-occlusive crises (VOC) and economic outcomes in patients with sickle cell disease (SCD) with recurrent VOC treated with L-glutamine, voxelotor or crizanlizumab in the US. Materials & methods: In this retrospective study, patients with SCD with recurrent VOC who received L-glutamine, voxelotor, or crizanlizumab were identified from theMerative™ MarketScan R Research Databases between 1 January 2015 and 30 September 2022. Eligible patients had ≥12 months continuous enrollment before and after the first chronic therapy claim (i.e., index date). Number of VOC, treatment utilization, healthcare resource utilization and healthcare costs were summarized for 12 months before (baseline) and after (follow-up) the index date. The proportion of days covered (PDC; i.e., proxy for adherence) for the index chronic therapy was measured during the 12-month follow-up period. Results: Overall, 440 patients initiated a recently approved chronic therapy (L-glutamine, n = 254; voxelotor, n = 110; crizanlizumab, n = 76) andmet inclusion criteria. Mean (standard deviation [SD]) number of VOC during baseline and follow-up were similar for patients treated with any index therapy (n = 440; 7.21 [8.82] vs 7.27 [9.85]); this was similar across patients treated with L-glutamine, crizanlizumab, and voxelotor, respectively. Mean (SD) PDC for patients with any index therapy was 0.37 (0.29); results were similar across patients treated with L-glutamine, crizanlizumab, and voxelotor. Healthcare resource utilization during the 12-month baseline and follow-up periods were comparable. Mean (SD) total costs for patients initiating a recently approved chronic therapy increased by ∼50% or $38,111 during followup (follow-up, $118,235 [$177,125]; baseline, $80,125 [$120,950]; p < 0.001); most of the increased costs ($27,108 [71.1%]) were a direct result of recently approved chronic therapies. Conclusion: Patients initiated on L-glutamine, voxelotor or crizanlizumab had low adherence (based on PDC), continued to experience frequent VOC, and incurred higher healthcare costs mostly due to the costs of these therapies. This highlights the need for additional treatment options for patients with SCD with recurrent VOC.