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. 2025 Aug;14(4):1641-1656.
doi: 10.1007/s40120-025-00773-3. Epub 2025 Jun 16.

Real-World Treatment Outcomes in Black, Hispanic, Asian, and White People with Multiple Sclerosis Treated with Fumarates in the USA

Sophia Woodson  1 , Edward J Gettings  2 , Chu-Yueh Guo  3 , Sylvia Klineova  4 , Jong-Mi Lee  5 , Rebecca S Romero  6 , Aljoeson Walker  7 , Kinyee Fong  8 , Jason P Mendoza  8 , Nicholas Belviso  8 , Boyang Bian  8 , James B Lewin  8 , Sai L Shankar  9
Affiliations

Real-World Treatment Outcomes in Black, Hispanic, Asian, and White People with Multiple Sclerosis Treated with Fumarates in the USA

Sophia Woodson et al. Neurol Ther. 2025 Aug.

Abstract

Introduction: Multiple sclerosis (MS) is a heterogeneous disease affecting a diverse population. Compared with white people with MS (PwMS), Black PwMS have more severe disease and higher incidence of MS, whereas Hispanic PwMS experience earlier onset disease; however, MS is not adequately studied in these groups. We compared the effectiveness of fumarates across Black, Hispanic, Asian, and white PwMS.

Methods: This retrospective analysis using the Komodo Health database included PwMS. Patients with a claim for diroximel fumarate or dimethyl fumarate were followed from disease-modifying therapy (DMT) initiation to loss of follow-up or discontinuation. Outcomes included annualized relapse rate (ARR), time to post-index first relapse, healthcare resource use (HRU), healthcare costs (HCCs), and change in absolute lymphocyte counts (ALCs). Race/ethnicity was self-reported.

Results: This study included 6800 PwMS (Black, n = 1241; Hispanic, n = 777; Asian, n = 132; white, n = 4650). The average exposure duration of fumarates was 449-559 days. Black PwMS had higher baseline disease burden versus white PwMS, were less likely to have commercial insurance plans, and were more likely to reside in a state with a higher poverty rate. ARRs (12-month pre-index to post-index) were significantly reduced across groups. The Kaplan-Meier estimated proportion of relapse-free patients at 2 years was similar across groups (Black, 77.0%; Hispanic, 75.4%; Asian, 81.7%; white, 80.5%). There was a smaller decline in ALC from month 0 to month 12 in Black PwMS versus other racial/ethnic groups.

Conclusion: Consistent with prior studies, these results demonstrate the effectiveness of fumarates across racial and ethnic MS subgroups. This is the largest analysis to date of the treatment effects of any individual class of DMT in Black and Hispanic PwMS. Infographic available for this article.

Keywords: Dimethyl fumarate; Diroximel fumarate; Effectiveness; Minority populations; Multiple sclerosis.

Plain language summary

Multiple sclerosis (MS) is a condition where the body’s immune system mistakenly attacks the protective coating around nerves, called myelin, causing damage to nerves in the brain and spinal cord. It causes symptoms like extreme tiredness (fatigue), muscle weakness, and poor coordination. People from racial and ethnic minority groups, such as Black, Hispanic, and Asian communities, are underrepresented in MS research. Therefore, less is known about MS in these communities. Using an insurance database, researchers looked at de-identified health claims of people with MS in the USA who received fumarate medicines between 2017 and 2022. Fumarates are a type of medicine used to treat MS. Researchers compared information from Black, Hispanic, Asian, and white people with MS, including (1) how often people had a MS relapse (new symptoms or the worsening of old symptoms); (2) how many people did not have MS relapses for ≥ 2 years; and (3) how treatment affected people’s white blood cell count. The researchers found that fumarate medicines worked similarly for all racial and ethnic groups. All groups had fewer relapses after treatment. Around eight in 10 people (75–82%) did not have a relapse after 2 years. Black people with MS had worse MS before treatment compared with other groups. Black people with MS also had fewer decreases in the level of some white blood cells. The findings of this study suggest that fumarate medicines work well for people with MS regardless of their racial or ethnic background. INFOGRAPHIC.

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Conflict of interest statement

Declarations. Conflicts of Interest: Sophia Woodson served on scientific advisory or data safety monitoring boards for MSSA and Sanofi, and served on speaker bureaus for Biogen, Bristol Myers Squibb, and Genentech. Edward J. Gettings, Jong-Mi Lee, and Aljoeson Walker declare that they have no competing interests. Chu-Yueh Guo has received consulting fees from Genentech and Horizon. Sylvia Klineova declares having non-promotional speaking with Biogen and Alexion, advisory work with Amgen and TG Therapeutics, and research support from Biogen. Rebecca S. Romero has received consulting fees from Alexion, EMD Serono, Genentech, Horizon, and TG Therapeutics. Kinyee Fong, Jason P. Mendoza, Nicholas Belviso, Boyang Bian, James B. Lewin, and Sai L. Shankar are all employees of Biogen and may hold stock in the company. Ethical Approval: This study was a retrospective analysis of de-identified data from the Komodo Health database and did not involve any new studies with human or animal subjects. As such, ethical approval or informed consent was not required.

Figures

Fig. 1
Fig. 1
Patient selection. DMT disease-modifying therapy, ICD-9-CM International Classification of Diseases, Ninth Revision, Clinical Modification, ICD-10 International Classification of Diseases, Tenth Revision, MS multiple sclerosis, PwMS people with MS. aICD-9-CM diagnosis code 340 or ICD-10 code G35
Fig. 2
Fig. 2
a ARR 12 months pre-index and post-index and b post-index adjusted ARR ratio vs. white PwMS. ARR calculated as the total number of relapses observed divided by the total number of patient-years observed. Estimated via Poisson model adjusting for repeated measures correlation. Error bars represent the 95% CI. ARR annualized relapse rate, CI confidence interval, MS multiple sclerosis, PwMS people with MS. aBased on Poisson model adjusting for baseline relapse rate, age, sex, and MS severity score. Rate ratio > 1 favors the white racial group
Fig. 3
Fig. 3
Time to first post-index relapse in Black, Hispanic, Asian, and white PwMS. CI confidence interval, MS multiple sclerosis, PwMS people with MS. aRelapses were defined as an MS-related inpatient claim with a primary diagnosis of MS or an outpatient MS-related diagnosis and prescription claim for an intravenous steroid, adrenocorticotropic hormone, total plasma exchange, or a high-dose oral corticosteroid ≤ 7 days after the outpatient visit. bCox proportional hazards model was adjusted for age, sex, baseline relapses, and MS severity score. p values are based on a modified version of the Pepe and Fleming test comparing the difference in adjusted Kaplan–Meier survival curve versus white (reference group)
Fig. 4
Fig. 4
Estimated ALC at baseline and 12 months post-index. Patients included must have had an ALC measure at month 0 and ≥ 1 subsequent ALC measurement. Too few ALC data from Asian people with MS were obtained for the analysis to be meaningful. p values represent the estimated mean trend difference between the specified race group vs. white at the noted time point. Error bars represent the 95% CI. ALC absolute lymphocyte count, CI confidence interval, MS multiple sclerosis
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