Treatment Effectiveness for Resolution of Multiple Sclerosis Relapse in a US Health Plan Population.

Introduction: Timely and effective resolution of multiple sclerosis (MS) relapse is critical to minimizing residual deficits, which can result in neurologic disability. Oral corticosteroids (OCS) and intravenous corticosteroids [intravenous methylprednisolone (IVMP)] are earlier line treatments; alternatives include repository corticotropin injection (RCI; H.P. Acthar Gel), plasmapheresis (PMP), and intravenous immunoglobulin (IVIG). Contemporary insight into the use of relapse treatments and their effectiveness is needed.

Objective: To evaluate relapse rates, frequency of treatments used, and treatment effectiveness (i.e., relapse resolution).

Methods: A retrospective analysis of patients ages 18-89 years experiencing MS relapse from 1 January 2008 to 30 June 2015 was conducted using administrative claims data. MS relapse was defined based on established claims-based methodology. The first claim for relapse treatment (i.e., prescription or administration) was used to designate the treatment group and relapse date, respectively. Relapses occurring ≤ 30 days were considered an episode. The first relapse episode was identified for every patient. Treatment was deemed effective in resolving the relapse if no additional relapses followed within the episode; otherwise, the relapse was considered unresolved. A 5-day OCS taper following IVMP administration, designated IVMP ± OCS, was allowed. Relapse frequency, treatment use, and relapse resolution were quantified. Relapse resolution was likewise evaluated in patients continuously enrolled for 12 months before and after first treatment with RCI or PMP/IVIG, with PMP/IVIG administrations within 7 days of each other being considered a single course of therapy.

Results: During the study period, 9574 patients experienced ≥ 1 relapse; 26.0% of patients had ≥ 2 relapses/year. The mean number of relapse episodes was 2.6 over a mean follow-up of 2.7 years for an annualized relapse rate of 1.0. Corticosteroids were the first treatment used in 90.4% of relapses (OCS = 51.8%, IVMP = 38.6%), followed by IVIG (6.0%), RCI (2.2%) and PMP (1.5%). The proportion of patients achieving relapse resolution with their first treatment was 90.5% with OCS (n = 5710), 47.8% with IVMP ± OCS (n = 3425), 96.9% with RCI (n = 195), 50.7% with PMP (n = 73), and 43.9% with IVIG (n = 171). Among continuously enrolled patients (n = 373), relapse resolution was 95.7% with RCI (n = 232) and 66.0% with PMP/IVIG (n = 141); significant cohort differences were observed.

Conclusions: As demonstrated in other studies, OCS were generally effective. However, real-world effectiveness varied with other treatments. Relapse resolution of the first treatment with OCS was higher than with IVMP ± OCS; similarly, relapse resolution was higher with RCI as the first treatment than with PMP/IVIG. Results demonstrate RCI's effectiveness in appropriate patients. Limitations pertaining to claims-based research apply.

Funding: Mallinckrodt Pharmaceuticals (Bedminster, NJ).