The Impact Of Immunodeficiency On Patients Receiving Immunologic-Based Multiple Sclerosis Therapies

Immunologic-based therapies have become commonly used to treat multiple sclerosis (MS), with potential adverse effects on patient’s immunity. This study assesses the impact on healthcare resource utilization and costs among patients receiving rituximab, ocrelizumab, and natalizumab. Using the Pharmetrics Plus administrative insurance claims database (2014-2019), MS patients were identified, who had no history of immunodeficiency prior to treatment, at least one-year pre- and post-treatment index, with >30% compliance with treatment. Treated MS patients were aggregated and comparisons were made one year and beyond post index between those diagnosed with immunodeficiency, or not. Patients were Greedy matched on treatment plus all significant (p<0.10) demographic and clinical characteristics. 3,976 MS patients receiving rituximab, ocrelizumab, or natalizumab were identified with 190 diagnosed with immunodeficiency subsequent to treatment. Rituximab association with immunodeficiency included, 10.2% of MS patients, and 27.9% of all immunodeficiency. MS patients subsequently diagnosed with immunodeficiency had increased likelihood to be hospitalized (16.3% vs 7.8%, p<0.01), pneumonia (4.7% vs 1.7%, p<0.01), chronic sinusitis (8.4% vs 4.9%, p=0.03), higher hospitalization ($13,413 vs $2,425, p=0.02), and total costs ($119,121 vs $100,121, p=0.01), but not significantly different medication costs ($76,592 vs $79,677, p=0.34). Matched results highlighted similar differences in total costs ($103,927 vs $91,243; p=0.04) and all non-MS medication costs ($24,349 vs $18,117, p=0.05). Cohorts of patients with immunodeficiency became evident with each of the three immunologic-based treatments. Ominously, significant incremental costs were experienced by MS patients diagnosed with immunodeficiency, even after accounting for the various treatments and comorbidities.