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BIIB115

Phase 1

Healthy Volunteer | Small molecule | Neurology |Biogen Inc.|Last Updated: Jul 9, 2026

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLEDDMC
Total Trials1
Total Enrollment62

FDA Designations

No designations recorded

Clinical trial landscape

BIIB115 · 1 trial · 2 indications

Phase 1 1
NCT05575011A Study to Learn About the Safety of BIIB115 Injections and How BIIB115 is Processed in the Bodies of Healthy Adult Male Volunteers and of Pediatric Participants With Spinal Muscular Atrophy Who Previously Took Onasemnogene AbeparvovecHealthy Volunteer
ACTIVE NOT_RECRUITING62 Analytics
PHASE1ACTIVE NOT_RECRUITING
A Study to Learn About the Safety of BIIB115 Injections and How BIIB115 is Processed in the Bodies of Healthy Adult Male Volunteers and of Pediatric Participants With Spinal Muscular Atrophy Who Previously Took Onasemnogene Abeparvovec
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Study Endpoints

Primary Endpoints

Parts A, B, and B Long Term Extension (LTE): Number of Participants with Adverse Events (AEs) and Serious Adverse Events (SAEs)
Part A: Up to Day 393, Part B: Up to Day 720; Part B LTE: Up to Day 2520

An adverse event (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, symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not related to the medicinal (investigational) product. A serious adverse event (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.

Secondary Endpoints

Parts A, B, and B LTE: Concentration of BIIB115 in Cerebral Spinal Fluid (CSF)
Part A: Day 1 to Day 180, Part B: Day 1 to Day 720; Part B LTE: Day 720 to Day 2520
Part A: Terminal Elimination Half-Life (t½) of BIIB115 in CSF
Day 1 to Day 180
Parts A, B, and B LTE: Concentration of BIIB115 in Serum
Part A: Day 1 to Day 180, Part B: Day 1 to Day 720; Part B LTE: Day 720 to Day 2520
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Study Design & Arms

AllocationRANDOMIZED
MaskingQUADRUPLE
ModelSEQUENTIAL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Part A: Cohort 1: BIIB115 Dose 1EXPERIMENTALParticipants will receive a single dose of BIIB115, Dose 1, via IT bolus injection, on Day 1.
Part A: Cohort 2: BIIB115 Dose 2EXPERIMENTALParticipants will receive a single dose of BIIB115, Dose 2, via IT bolus injection, on Day 1.
Part A: Cohort 3:BIIB115 Dose 3EXPERIMENTALParticipants will receive a single dose of BIIB115, Dose 3, via IT bolus injection, on Day 1.
Part A: Cohort 4: BIIB115 Dose 4EXPERIMENTALParticipants will receive a single dose of BIIB115, Dose 4, via IT bolus injection, on Day 1.
Part A: Cohorts 1-4: BIIB115-Matching PlaceboPLACEBO_COMPARATORParticipants will receive a single dose of BIIB115-matching placebo, via IT bolus injection, on Day 1.
Part B: Cohort 5: BIIB115 Dose 3EXPERIMENTALPediatric SMA participants previously treated with onasemnogene abeparvovec will receive two doses of BIIB115, Dose 3, via IT bolus injection at two separate time points.
Part B: Cohort 6: BIIB115 Dose 4EXPERIMENTALPediatric SMA participants previously treated with onasemnogene abeparvovec will receive two doses of BIIB115, Dose 4, via IT bolus injectionat two separate time points.
Part B: Long Term Extension (LTE): BIIB115 Dose 4EXPERIMENTALPediatric SMA participants previously treated with onasemnogene abeparvovec who have completed Part B and are eligible will receive five doses of BIIB115, Dose 4, via IT bolus injection at separate time points for up to 60-month duration.

Interventions

NameTypeDescription
BIIB115DRUGAdministered as specified in the treatment arm
BIIB115-Matching PlaceboDRUGAdministered as specified in the treatment arm
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Eligibility Criteria

Age Range6 Months to 55 Years
SexALL
Healthy VolunteersYes
Study Sites17

Key Inclusion Criteria: Part A: * Male healthy participants aged 18 to 55 years, inclusive * Have a body mass index of 18 to 30 kilograms per meter square (kg/m\^2), inclusive * Must be in good health as determined by the investigator, based on medical history and screening evaluations Part B: *...

Countries:BelgiumCanadaFranceGermanyItalyNetherlandsPolandSouth KoreaUnited Kingdom
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Recent Changes (Last 90 Days)

LOWJul 9, 2026NCT05575011lastUpdatePostDate: changed
LOWJul 9, 2026NCT05575011lastUpdatePostDate: changed

Frequently asked questions about BIIB115

What is BIIB115 used for?

BIIB115 is an investigational small molecule being developed by Biogen for neurology. It is currently in Phase 1 clinical trials studying its safety and how it is processed in healthy adult male volunteers and pediatric participants with spinal muscular atrophy who previously took onasemnogene abeparvovec.

Who makes BIIB115?

BIIB115 is being developed by Biogen Inc., a biopharmaceutical company traded on the NASDAQ under the ticker symbol BIIB. The drug is currently in Phase 1 clinical development.

What phase is BIIB115 in?

BIIB115 is in Phase 1 clinical development. It is an investigational drug and has not been approved by regulatory authorities. The ongoing Phase 1 trial is active but not recruiting participants.

What clinical trials is BIIB115 in?

BIIB115 is being studied in a Phase 1 clinical trial with the identifier NCT05575011. This randomized, double-blind, placebo-controlled trial has an enrollment of 62 participants and is being conducted in Belgium, Canada, France, Germany, Italy, Netherlands, Poland, South Korea, and the United Kingdom.

Is BIIB115 a small molecule?

Yes, BIIB115 is a small molecule drug. It is being developed by Biogen for the treatment of spinal muscular atrophy, a neurological condition. The drug is currently in Phase 1 clinical trials.