In this study, researchers will learn more about a study drug called BIIB091 in participants with MS who may be experiencing relapses. It is a 2-part study.

In Part 1, one set of participants will take either BIIB091 or diroximel fumarate (DRF). In Part 2, a different set of participants will take either a combination of BIIB091 and DRF or DRF alone.

The goal of the study is to learn more about the safety of BIIB091 and to compare the effects of the study drug when taken alone or together with DRF.

The main question researchers are trying to answer are:

* How many participants have new or worsening medical problems (adverse events) after taking BIIB091 or DRF?
* How many new areas of inflammation occur in the brain after treatment with BIIB091 and DRF?

Researchers will use magnetic resonance imaging (MRI) scans to compare images of the brain before and after treatment. They will also explore the effect of BIIB091 and DRF on the heart using electrocardiograms (ECGs).

The study will be done as follows:

* After screening, participants who joined Part 1 will be randomly assigned to receive either a high or low dose of BIIB091, or the standard dose of DRF.
* The results of Part 1 will be used to choose the best dose of BIIB091 to use in Part 2.
* Participants who join Part 2 will be randomly assigned to receive either a standard dose of DRF, a combo of BIIB091 and the standard dose of DRF, or a combo of BIIB91 with a low dose of DRF.
* Neither the researchers nor the participants will know which drug or dose the participants will receive in either part of the study.
* The treatment period will last 48 weeks in each part of the study. Participants will take the drugs by mouth 2 times a day.
* Each part will also have a follow-up safety period that lasts up to 2 weeks.
* In total, participants in each part will have 20 study visits, or more if they have a relapse. The total study duration for participants will be up to 54 weeks.

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)

The Boster Center for Multiple Sclerosis

Find clinical trials for Multiple Sclerosis (MS) in Nashville, TN

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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) (FUSION)

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Related conditions:

Multiple Sclerosis (MS) trials near Nashville, TN, USA:

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) (FUSION)

Find clinical trials for Multiple Sclerosis (MS) in Nashville, TN