This was a retrospective cohort study utilizing the IQVIA PharMetrics® Plus claims database from 01 August 2019 through 31 May 2022.

The database is comprised of fully adjudicated (i.e., paid by the health plan) medical and pharmacy claims and is representative of the commercially insured United States population. Adults treated with ofatumumab (OMB), oral disease-modifying therapies (DMTs) (dimethyl fumarate, diroximel fumarate, monomethyl fumarate, fingolimod, siponimod, ozanimod, ponesimod, teriflunomide, cladribine) or platform self-injectable DMTs (glatiramer acetate, interferon beta-1a, peginterferon beta-1a, interferon beta-1b) between 01 August 2020, through 30 November 2021, were identified. The date of the first incident DMT (OMB, oral DMT, or injectable DMT) during the identification window served as the index date. The baseline period was the 12 months before the index date, and the follow-up period was at least 6 months after the index date. Patients treated with OMB were selected first to maximize sample size, and these patients were allowed to have an oral or injectable DMT in the baseline period. Patients without OMB use during the identification period were categorized into the oral DMT or platform self-injectable DMT cohort based on the first-observed incident DMT during the identification period. For the purpose of this study, platform self-injectable DMTs were referred to as 'self-injectable DMTs.'

Inclusion criteria:

• Patients with 1 claim or more for ofatumumab, a newly initiated oral DMT (dimethyl fumarate, fingolimod, teriflunomide, cladribine, siponimod, ozanimod, diroximel fumarate, monomethyl fumarate, ponesimod) or a newly initiated self-injectable DMT (daclizumab, glatiramer acetate, interferon beta-1a, peginterferon beta-1a, interferon beta-1b) occurring during the index window.
• Patients with 12 months or more of pre-index continuous enrollment [CE] with medical and pharmacy benefits.
• Patients with 6 months or more of post-index CE with medical and pharmacy benefits.
• Patients with 2 or more non-ancillary outpatient medical claims (at least 30 days apart) with a diagnosis code for MS (International Classification of Diseases, 10th Revision, Clinical Modification [ICD-10-CM] code: G35) in any position or 1 or more inpatient claims with a diagnosis of MS in the first position during pre-index period.
• No data quality issues (defined as missing age or sex).
• Having two DMTs on the same day was very rare in MS patients per clinician's inputs, but if it happened, those patients were excluded from analysis.

This was a retrospective, noninterventional cohort study.