Economic Outcomes and Real-World Adherence of Patients With Sickle Cell Disease With Recurrent Vaso-Occlusive Crises Treated With L-Glutamine, Voxelotor, and Crizanlizumab in the United States

OBJECTIVES: Three chronic therapies, L-glutamine, voxelotor, and crizanlizumab, were recently approved by US regulators for the treatment of sickle cell disease (SCD). This study aimed to describe economic outcomes of patients with SCD with recurrent vaso-occlusive crises (VOCs) treated with these therapies in the United States.

METHODS: This retrospective analysis used the Merative^TM MarketScan^® Databases from 01/01/2015‒09/30/2022 to identify patients with SCD, ≥2 VOCs/year during any 2 consecutive years, and ≥12 months’ continuous enrollment before and after the second VOC in the second consecutive year. Patients with ≥1 claim for L-glutamine, voxelotor, or crizanlizumab at any point were included; the first claim was the index date. Patients were required to have ≥12 months’ continuous enrollment pre- and post-index. Demographics were assessed at index. VOCs and costs were summarized for 12 months pre- and post-index. Proportion of days covered (PDC) for index therapies was measured during follow-up. Comparative pre-post analyses were conducted for costs using paired t-tests; p<0.05 was considered statistically significant.

RESULTS: In total, 440 patients initiated a recently approved chronic therapy (L-glutamine: 254; voxelotor: 110; crizanlizumab: 76) and met inclusion criteria. Mean age was 23.4 (standard deviation [SD]: 11.4) years. Mean number of VOCs [SD] in the follow-up and baseline periods was similar (follow-up: 7.27 [9.85]; baseline: 7.21 [8.82]) for those initiating chronic therapy (n=440). Mean PDC (SD) for index therapies was 0.37 (0.29). Mean total costs [SD] increased by $38,111 during follow-up (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.

CONCLUSIONS: Although not all recently approved chronic therapies are indicated for VOC reduction, patients experiencing recurrent VOCs who received these therapies had low adherence and continued to experience frequent VOCs leading to increased costs. These results highlight the need for improved treatment options for this population.