A Study of LY3541860 in Adult Participants With Relapsing Multiple Sclerosis

Inclusion criteria

• Participants must meet criteria for relapsing forms of multiple sclerosis, including relapsing-remitting multiple sclerosis based on the 2017 revision of the McDonald diagnostic criteria (Thompson et al. 2018) with a relapsing course (RMS) activity according to Klineova and Lublin 2018.
• Participants must have 1 of these:

• at least 1 documented relapse within the previous year
• at least 2 documented relapses within the previous 2 years, or
• at least 1 active GdE brain lesion on an MRI scan in the past 180 days prior to screening.
• Have an Expanded Disability Status Scale (EDSS) score of less than or equal to (≤) 5.5 at screening and randomization.

Exclusion criteria

• Have had a diagnosis of:

• primary progressive multiple sclerosis (MS) according to the 2017 revision of McDonald diagnostic criteria (Thompson et al. 2018), or
• nonactive secondary progressive MS ( Klineova and Lublin 2018).
• Meet criteria for neuromyelitis optica spectrum disorder (Wingerchuk and Lucchinetti 2022).
• Have a history of clinically significant central nervous system (CNS) disease.
• Have had a confirmed relapse with systemic corticosteroid administration <30 days prior to randomization.
• Have more than 20 active GdE brain lesions on screening MRI scan.
• Have received any of these medications or treatments.
• Have a current or recent acute, active infection.
• Have current serious or unstable illnesses.
• Have any other clinically important abnormality at screening or baseline.