# A Study to Learn About the Safety of BIIB091 and Its Effect on Brain Inflammation When Taken Alone or With Diroximel Fumarate (DRF) in Adults With Relapsing Forms of Multiple Sclerosis (MS)

> **NCT05798520** · PHASE2 · COMPLETED · sponsor: **Biogen** · enrollment: 127 (actual)

## Conditions studied

- Relapsing Forms of Multiple Sclerosis

## Interventions

- **DRUG:** BIIB091
- **DRUG:** DRF
- **DRUG:** Placebo

## Key facts

- **NCT ID:** NCT05798520
- **Lead sponsor:** Biogen
- **Sponsor class:** INDUSTRY
- **Phase:** PHASE2
- **Study type:** INTERVENTIONAL
- **Status:** COMPLETED
- **Start date:** 2023-07-25
- **Primary completion:** 2026-02-10
- **Final completion:** 2026-02-10
- **Target enrollment:** 127 (ACTUAL)
- **Last updated:** 2026-02-20


## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT05798520

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration NCT05798520, "A Study to Learn About the Safety of BIIB091 and Its Effect on Brain Inflammation When Taken Alone or With Diroximel Fumarate (DRF) in Adults With Relapsing Forms of Multiple Sclerosis (MS)". Retrieved via AI Analytics 2026-06-09 from https://api.ai-analytics.org/clinical/NCT05798520. Licensed CC0.

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