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BIIB115

Phase 1

Healthy Volunteer | Small molecule | Other |Biogen Inc.|Last Updated: Jul 9, 2025

Success Probability
Approval Probability 71%
TA Base Rate26%
Adjusted LOA41%
ML RiskLOW_RISK
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Market & Valuation
rNPV $3.2B
Market Size $9.4B
Revenue Basis $1.6B
Competitors 6
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Trial Design
RandomizedDouble-BlindPLACEBO_CONTROLLEDDMCBiomarker
Total Trials1
Total Enrollment62
FDA Designations
No designations recorded
Clinical Trials (1)
NCT IDTitlePhaseStatusEnrollmentVelocityDesignStartCompletionLast UpdatedSitesCountries
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 AbeparvovecPHASE1 ACTIVE NOT_RECRUITING 62Oct 10, 2022Nov 14, 2031Jul 9, 202517 Belgium, Canada +7
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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 — 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)
LOWMay 26, 2026NCT05575011primaryCompletionDate: changed
LOWMay 24, 2026NCT05575011studyFirstPostDate: changed