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Relapsing Forms of Multiple SclerosisPhase 2FUSIONNCT05798520

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)

A Phase 2 study testing BIIB091 and DRF in people with Relapsing Forms of Multiple Sclerosis, run by Biogen at 77 sites in 10 countries.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
Search all trials

Trial summary

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). Read more about this study

Who is it for?
Ages 18 to 55 years
Conditions the study is for
Relapsing Forms of Multiple Sclerosis
What is being tested?
BIIB091 and DRF
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
127 participants
Where
77 sitesin 10 countries
Study dates
25 Jul 2023to 10 Feb 2026
Phase
Phase 2
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 55 years
  • All sexes
  • No healthy volunteers
  • Adult

Who may be able to join

  • Diagnosis of RMS [relapsing-remitting multiple sclerosis (RRMS) or active secondary progressive multiple sclerosis (SPMS)] in accordance with the 2017 Revised McDonald criteria.
  • Time since MS symptom onset is <20 years.
  • Must have expanded disability status scale (EDSS) score of 0 through 5.0 at screening and baseline.
  • Must have at least 1 of the following occurring prior to Baseline (Day 1):
  • ≥2 clinical relapses in the last 24 months (but not within 30 days prior to Baseline [Day 1]) with at least 1 relapse during the last 12 months prior to randomization.
  • ≥1 clinical relapse within the past 24 months (but not within 30 days prior to Baseline [Day 1]) and ≥1 new brain MRI lesion (Gd-positive and/or new or enlarging T2 hyperintense lesion) within the past 12 months prior to randomization. The screening MRI could be used to satisfy this criterion (if needed for inclusion, local reading is required). For new or enlarging T2 hyperintense lesions, the reference scan cannot be >12 months prior to randomization.
  • ≥1 GdE lesion on brain MRI within 6 months prior to randomization.

Who cannot join

  • Diagnosis of primary progressive multiple sclerosis (PPMS) in accordance with the 2017 Revised McDonald criteria.
  • An MS relapse that has occurred within 30 days prior to Baseline (Day 1) or the participant has not stabilized from a previous relapse at the time of screening.
  • History of severe allergic, anaphylactic reactions or hypersensitivity reaction to BIIB091 or DRF, the excipients contained in the formulation, and if appropriate, any diagnostic agents to be administered during the study, including the following:
  • Known hypersensitivity to any components of the study treatment
  • Known hypersensitivity to previous fumarate or bruton's tyrosine kinase (BTK) inhibitor treatments
  • History of hypersensitivity to parenteral administration of Gd-based contrast agents
Show all 12Show fewer
  • Evidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection within the past 4 weeks prior to Baseline.
  • History of human immunodeficiency virus (HIV) infection or a positive or indeterminate test result at screening for HIV.
  • Current or history of hepatitis C infection regardless of viral load.
  • Current or history of hepatitis B infection.
  • Current enrollment or plan to enroll in any other drug, biological, device, clinical study, or treatment with an investigational drug or approved therapy for investigational use within 90 days prior to randomization or 5 half-lives of the drug or therapy, whichever is longer.
  • NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.

Trial locations and contacts

77 sites in 10 countries.

77 sites in 10 countries

United States23 sites

  • University of New Mexico

    Albuquerque, New Mexico, 87131-0001

  • University of Colorado School of Medic

    Aurora, Colorado, 80045

  • Alta Bates Summit Medical Center

    Berkeley, California, 94705

  • University of Cincinnati Physicians Company

    Cincinnati, Ohio, 45267

  • The Cleveland Clinic Foundation

    Cleveland, Ohio, 44195

  • The Boster Center for Multiple Sclerosis

    Columbus, Ohio, 43235

  • Neurology Clinic, PC

    Cordova, Tennessee, 38018

  • Fort Wayne Neurological Center

    Fort Wayne, Indiana, 46804

  • University of Kansas Medical Center Research Institute, Inc.

    Kansas City, Kansas, 66160

  • International Neurorehabilitation Institute

    Lutherville, Maryland, 21093

  • University of Wisconsin Hospital and Clinics

    Madison, Wisconsin, 53792

  • University of Miami Miller School of Medicine

    Miami, Florida, 33136

  • The Medical College of Wisconsin

    Milwaukee, Wisconsin, 53226

  • Vanderbilt MS Center

    Nashville, Tennessee, 37215

  • University of California at Irvine Medical Center

    Orange, California, 92868

  • South Shore Neurologic Associates, P.C.

    Patchogue, New York, 11772

  • The University of Texas Health Science Center San Antonio

    San Antonio, Texas, 78229-3900

  • HonorHealth Neurology

    Scottsdale, Arizona, 85251

  • Washington University

    St Louis, Missouri, 63110

  • University of South Florida

    Tampa, Florida, 33612

  • Holy Name

    Teaneck, New Jersey, 07666

  • Vero Beach Neurology and Research Institute

    Vero Beach, Florida, 32960

  • Wake Forest University - School of Medicine - Central

    Winston-Salem, North Carolina, 27157

Other trials in United States

Poland14 sites

  • COPERNICUS Podmiot Leczniczy Sp. z o. o.,

    Gdansk, 80-803

  • Samodzielny Publiczny Specjalistyczny Szpital Zachodni im. Jana Pawla II

    Grodzisk Mazowiecki, 05-825

  • Centrum Medyczne Pratia Katowice

    Katowice, 40-081

  • M.A. - LEK A.M.Maciejowscy SC.

    Katowice, 40-571

  • Nzoz Novo-Med

    Katowice, 40-650

  • Resmedica Sp.z o.o

    Kielce, 25-726

  • Szpital Uniwersytecki w Krakowie

    Krakow, 31-503

  • Centrum Neurologii K. Selmaj

    Lodz, 90-324

  • Instytut Zdrowia dr Boczarska-Jedynak sp.z.o.o, Sp.K

    Oświęcim, 32-600

  • Med-Polonia Sp. z o.o.

    Poznan, 60-693

  • NZOZ 'NEURO-KARD', 'Ilkowski i Partnerzy' Sp. Partn. Lek.

    Poznan, 61-853

  • Nzoz Palomed

    Rzeszów, 35-323

  • NeuroProtect Sp. z o.o.

    Warsaw, 01-684

  • Wielospecjalistyczne Centrum Medyczne Ibismed

    Zabrze, 41-800

Other trials in Poland

Bulgaria9 sites

  • 'MHAT Avis - Medica' OOD

    Pleven, 5800

  • UMHAT 'Dr. Georgi Stranski', EAD

    Pleven, 5800

  • UMHAT 'Sv. Georgi', EAD

    Plovdiv, 4002

  • MHATNP 'Sv.Naum', EAD

    Sofia, 1113

  • University First MHAT-Sofia, 'St. Joan Krastitel' EAD

    Sofia, 1142

  • Acibadem City Clinic Tokuda University Hospital Ead

    Sofia, 1407

  • DCC Neoclinic EAD

    Sofia, 1408

  • UMHAT "Sv. Ivan Rilski", EAD

    Sofia, 1431

  • Diagnostic Consultation Center CONVEX EOOD

    Sofia, 1680

Other trials in Bulgaria

Italy7 sites

  • Fondazione Istituto G.Giglio di Cefalù

    Cefalù, Palermo, 90015

  • IRCCS Ospedale Policlinico San Martino

    Genova, 16132

  • Azienda Ospedaliera Universitaria- Università degli Studi della Campania "Luigi Vanvitelli"

    Naples, 80138

  • Fondazione Istituto Neurologico Casimiro Mondino

    Pavia, 27100

  • I.R.C.C.S. Neuromed-Istituto Neurologico Mediterraneo

    Pozzilli, Isernia, 86077

  • Azienda Ospedaliera Universitaria Policlinico Tor Vergata

    Roma, 00133

  • Azienda Ospedaliera Universitaria Policlinico Umberto I - Università di Roma La Sapienza

    Roma, 00161

Other trials in Italy

Germany6 sites

  • Klinikum Bayreuth GmbH- Hohe Warte

    Bayreuth, Bavaria, 95445

  • Studienzentrum fur Neurologie und Psychiatrie

    Böblingen, Baden-Wurttemberg, 71034

  • Universitaetsklinikum Carl Gustav Carus TU Dresden

    Dresden, 01307

  • Universitaetsklinikum Duesseldorf AoeR

    Düsseldorf, North Rhine-Westphalia, 40225

  • ZNS - Zentrum fuer Neurologisch-Psychiatrische Studien

    Siegen, North Rhine-Westphalia, 57076

  • Neuropraxis Muenchen Sued

    Unterhaching, Bavaria, 82008

Other trials in Germany

Spain6 sites

  • Hospital del Mar

    Barcelona, 08003

  • Hospital Universitario Reina Sofia

    Córdoba, 14011

  • Hospital Universitario Virgen de la Arrixaca

    El Palmar, Murcia, 30120

  • Hospital Universitario Ramon y Cajal

    Madrid, 28034

  • Hospital Regional Universitario de Malaga

    Málaga, 29010

  • Hospital Universitario Quironsalud Madrid

    Pozuelo de Alarcón, Madrid, 28223

Other trials in Spain

Czechia5 sites

  • Fakultni nemocnice u sv. Anny v Brne

    Brno, 65691

  • Fakultni nemocnice Hradec Kralove

    Hradec Králové, 50005

  • Nemocnice Jihlava p.o.

    Jihlava, 58633

  • Fakultni Thomayerova nemocnice

    Praha 4-Krc, 14059

  • Krajska zdravotni a.s. - Nemocnice Teplice o.z.

    Teplice, 41529

Other trials in Czechia

Romania3 sites

  • S.C Neurocity S.R.L

    Bucharest, 11302

  • Spitalul Universitar de Urgenta Elias

    Bucharest, 11461

  • S.C Clubul Sanatatii SRL

    Campulung Muscel, 115100

Other trials in Romania

Switzerland3 sites

  • Inselspital - Universitaetsspital Bern

    Bern, 3010

  • Ospedale Regionale di Lugano

    Lugano, Canton Ticino, 6903

  • Universitaetsspital Zuerich

    Zurich, 8091

Other trials in Switzerland

Puerto Rico1 site

  • Caribbean Center for Clinical Research

    Guaynabo, San Juan, 00968

Other trials in Puerto Rico

About this study

Official title: A 2-Part, Multicenter, Randomized, Blinded, Active-Controlled Phase 2 Study to Sequentially Evaluate the Safety and Efficacy of BIIB091 Monotherapy and BIIB091 Combination Therapy With Diroximel Fumarate in Participants With Relapsing Forms of Multiple Sclerosis

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.

Read more

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.
Read the detailed description

The primary objectives of this study are to investigate the safety and tolerability of BIIB091 monotherapy in participants with relapsing multiple sclerosis (RMS) in Part 1 and to evaluate the effects of BIIB091 combination therapy with DRF compared with the DRF monotherapy arm on the key MRI measure of active central nervous system (CNS) inflammation in Part 2.

The secondary objectives of Part 1 of the study are to evaluate the effects of BIIB091 monotherapy on the MRI measures of active CNS inflammation and to assess the effect of BIIB091 monotherapy on QTc and other ECG parameters. The secondary objectives of Part 2 are to evaluate the effects of BIIB091 combination therapy with DRF compared with the DRF monotherapy arm on additional MRI measures of active CNS inflammation, the safety and tolerability of BIIB091 combination therapy with DRF in participants with RMS, and the effect of BIIB091 combination therapy with DRF on QTc and other ECG parameters.

Part 1 of the study was concluded normally. Sponsor decision was to not conduct part 2.

Being tested
BIIB091, DRF, Placebo
Keywords
Multiple Sclerosis, Diroximel fumarate, BIIB091
Medical subject headings
Multiple Sclerosis

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • BIIB091Drug

    Administered as specified in the treatment arm.

  • DRFDrug

    Administered as specified in the treatment arm.

  • PlaceboDrug

    Administered as specified in the treatment arm.

Study groups in NCT05798520
Study groupRoleWhat they receive
Part 1: BIIB091 High Dose + Matching Placebo for DRFExperimentalParticipants will receive BIIB091 high dose and matching placebo for DRF, orally, for up to 48 weeks.
Receives: Drug: BIIB091; Drug: Placebo
Part 1: BIIB091 Low Dose + Matching Placebo for DRFExperimentalParticipants will receive BIIB091 low dose and matching placebo for DRF, orally, for up to 48 weeks.
Receives: Drug: BIIB091; Drug: Placebo
Part 1: DRF + Matching Placebo for BIIB091Active comparatorParticipants will receive DRF standard dose and matching placebo for BIIB091, orally, for up to 48 weeks.
Receives: Drug: DRF; Drug: Placebo
Part 2: BIIB091 + DRF Standard DoseExperimentalParticipants will receive selected dose of BIIB091 (based on Part 1 data) and DRF standard dose, orally, for up to 48 weeks.
Receives: Drug: BIIB091; Drug: DRF
Part 2: BIIB091 + DRF Low DoseExperimentalParticipants will receive selected dose of BIIB091 (based on Part 1 data) and DRF low dose, orally, for up to 48 weeks.
Receives: Drug: BIIB091; Drug: DRF
Part 2: DRF + Matching Placebo for BIIB091Active comparatorParticipants will receive DRF standard dose and matching placebo for BIIB091, orally, for up to 48 weeks.
Receives: Drug: DRF; Drug: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Part 1: Number of Participants With Adverse Events (AEs)

    An AE is any untoward medical occurrence in a participant or clinical investigation participant administered a pharmaceutical product and that does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal (investigational) product or auxiliary medicinal product, whether or not related to the medicinal (investigational) product or auxiliary medicinal product.

    Measured: Day 1 up to Week 50

  2. Part 1: Number of Participants With Serious Adverse Events (SAEs)

    SAE is any untoward medical occurrence that at any dose results in death, in the view of the investigator, places the participant at immediate risk of death (a life-threatening event), requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, results in a congenital anomaly/birth defect or is a medically important event.

    Measured: From signing the informed consent form (ICF) to Week 50

  3. Part 2: Cumulative Number of New T1 Gadolinium-Enhancing (GdE) Lesions

    Measured: Week 8 to Week 16

Secondary outcomes (13)

  1. Part 1: Cumulative Number of New T1 Gadolinium-Enhancing (GdE) Lesions

    Measured: Week 8 to Week 16

  2. Part 1: Cumulative Number of New or Enlarging T2 Hyperintense Lesions

    Measured: Week 8 to Week 16

  3. Part 1: Cumulative Volume of New or Enlarging T2 Hyperintense Lesions

    Measured: Week 8 to Week 16

  4. Part 1: Mean Change From Baseline in QT Interval Corrected for Heart Rate Using Fridericia's Formula (QTcF), RR, PR, QRS, and QT Intervals

    Measured: Up to Week 50

  5. Part 1: Number of Participants With Change From Baseline in Heart Rate

    Measured: Up to Week 50

  6. Part 1: Number of Participants With Clinically Significant Electrocardiogram (ECG) Abnormalities

    Measured: Up to Week 50

  7. Part 2: Cumulative Number of New or Enlarging T2 Hyperintense Lesions

    Measured: Week 8 to Week 16

  8. Part 2: Cumulative Volume of New or Enlarging T2 Hyperintense Lesions

    Measured: Week 8 to Week 16

  9. Part 2: Number of Participants With AEs

    An AE is any untoward medical occurrence in a participant or clinical investigation participant administered a pharmaceutical product and that does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal (investigational) product or auxiliary medicinal product, whether or not related to the medicinal (investigational) product or auxiliary medicinal product.

    Measured: Day 1 up to Week 50

  10. Part 2: Number of Participants With SAEs

    SAE is any untoward medical occurrence that at any dose results in death, in the view of the investigator, places the participant at immediate risk of death (a life-threatening event), requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, results in a congenital anomaly/birth defect or is a medically important event.

    Measured: From signing of ICF up to Week 50

  11. Part 2: Number of Participants With Change From Baseline in QTcF, RR, PR, QRS, and QT intervals

    Measured: Up to Week 50

  12. Part 2: Number of Participants With Change From Baseline in Heart Rate

    Measured: Up to Week 50

  13. Part 2: Number of Participants With ECG Abnormalities as Assessed by 12-Lead ECG Measurements

    Measured: Up to Week 50

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted4 Apr 2023
  2. Study start25 Jul 2023
  3. Primary completion10 Feb 2026
  4. Study completion10 Feb 2026

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Sequential
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
127 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05798520
Sponsor's protocol ID
257MS201
Other IDs
2022-502552-31
Acronym
FUSION
Status last verified
Feb 2026
First submitted
23 Mar 2023
Last updated
20 Feb 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: In accordance with Biogen's Clinical Trial Transparency and Data Sharing Policy on https://www.biogentrialtransparency.com/

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing BIIB091 and DRF in people with Relapsing Forms of Multiple Sclerosis, run by Biogen at 77 sites in 10 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 7 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 20 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 77 sites in United States, Poland, Bulgaria, Italy, Germany and 5 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Part 1: Number of Participants With Adverse Events (AEs) (time frame: Day 1 up to Week 50). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05798520.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Feb 2026.

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