A Study to Assess the Safety, Tolerability, and Effect on Disease Progression of BIIB105 in Participants With Amyotrophic Lateral Sclerosis (ALS) and Participants With the ALS Ataxin-2 (ATXN2) Genetic Mutation

Study Overview
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Brief Summary
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The ALSpire Study is a clinical trial evaluating the investigational drug BIIB105 in adults living with amyotrophic lateral sclerosis (ALS). The ALSpire Study consists of two parts: Part 1: 6-month placebo-controlled study. During Part 1, participants are randomly assigned to receive either BIIB105 or placebo in a 3:1 or 2:1 ratio (depending on the participant's assigned Cohort). Part 2: up to 3-year long-term open-label extension. During Part 2, all participants receive BIIB105. The objectives of the study are to evaluate: The safety and tolerability of BIIB105 in people with ALS What the body does to BIIB105 (also called pharmacokinetics) What BIIB105 does to the body (also called pharmacodynamics) Whether BIIB105 can slow the worsening of clinical function

Detailed Description
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About BIIB105: - BIIB105 is an investigational drug designed to reduce the levels of a protein called ATXN2. It is administered intrathecally (via a procedure called lumbar puncture).

Official Title
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A Phase 1/2 Multiple-Ascending-Dose Study With a Long-Term Open-Label Extension to Assess the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Effect on Disease Progression of BIIB105 Administered Intrathecally to Adults With Amyotrophic Lateral Sclerosis With or Without Poly-CAG Expansion in the ATXN2 Gene

Conditions
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Amyotrophic Lateral Sclerosis

Intervention / Treatment
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* Drug: BIIB105
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Key Inclusion Criteria: Part 1: Ability of the participant to understand the purpose and risks of the study and indicate informed consent, and the ability of the participant or the participant's legally authorized representative, to provide signed and dated informed consent and authorization to use protected health information in accordance with national and local privacy regulations. No known presence or family history of mutations in the superoxide dismutase 1 (SOD1) or fused in sarcoma (FUS) genes. Participants in Cohorts A, B, C1 and D1, must meet the laboratory-supported probable, probable, or definite criteria for diagnosing ALS according to the World Federation of Neurology El Escorial criteria (revised according to the Airlie House Conference 1998 [Brooks 2000]). Participants in Cohort C2 and D2, must meet any of the prior conditions, but may also only meet clinically possible criteria for diagnosing ALS, or exhibit weakness attributable to ALS in the presence of ataxin-2 protein (ATXN2) intermediate repeats. In participants in Cohorts C2 and D2, confirmed intermediate cytosine-adenine-guanine/cytosine-adenine-adenine (CAG/CAA) repeat expansion in the ataxin-2 (ATXN2) gene as defined by at least 1 allele carrying 30 to 33 CAG/CAA repeats. Slow vital capacity (SVC) criteria: In participants in Cohorts A, B, C1, and D1, SVC ≥60% of predicted value as adjusted for sex, age, and height (from the sitting position). In participants in Cohort C2 and D2, SVC ≥50% of predicted value as adjusted for sex, age, and height (from the sitting position). If taking riluzole, participant must be on a stable dose for ≥30 days prior to Day 1 and expected to remain at that dose until the final study visit, unless the Investigator determines that it should be discontinued for medical reasons, in which case it may not be restarted during the study. Participants taking concomitant edaravone at study entry must be on a stable dose for ≥60 days prior to the first dose of study treatment (Day 1). Participants taking concomitant edaravone must be willing to continue with the same dose regimen throughout the study, unless the Investigator determines that edaravone should be discontinued for medical reasons, in which case it may not be restarted during the study. Edaravone may not be administered on dosing days of this study. Screening values of coagulation parameters including platelet count, international normalized ratio (INR), prothrombin time (PT), and activated partial thromboplastin time (aPTT) should be within normal ranges. Has an informant/caregiver who, in the Investigator's judgment, has frequent and sufficient contact with the participant as to be able to provide accurate information about the participant's cognitive and functional abilities at screening. Part 2: Ability of the participant to understand the purpose and risks of the study and indicate informed consent, and the ability of the participant or the participant's legally authorized representative to provide signed and dated informed consent and authorization to use protected health information in accordance with national and local privacy regulations Participants must have completed Study NCT04494256 Part 1 through Week 25 (Day 175 Visit for Cohorts A, B, C1, C2; Day 176 Visit for Cohorts D1, D2). This inclusion criterion does not apply to a participant if Part 1 was terminated by the Sponsor before the participant reached Week 25. Participants from Cohorts A, B, C1, and C2 must have a washout of ≥16 weeks between the last dose of study treatment received in Study NCT04494256 Part 1 and the first dose of BIIB105 received in Study NCT04494256 Part 2. Participants from Cohorts D1 and D2 do not require a washout period. If taking riluzole, participant must be on a stable dose for ≥30 days prior to Day 1 and expected to remain at that dose until the final study visit, unless the Investigator determines that it should be discontinued for medical reasons, in which case it may not be restarted during the study. Participants taking concomitant edaravone at study entry must be on a stable dose for ≥60 days prior to the first dose of study treatment (Day 1). Participants taking concomitant edaravone must be willing to continue with the same dose regimen throughout the study, unless the Investigator determines that edaravone should be discontinued for medical reasons, in which case it may not be restarted during the study. Edaravone may not be administered on dosing days of this study. Screening values of coagulation parameters including platelet count, INR, PT, and aPTT should be within normal ranges. Key Exclusion Criteria Part 1: History or positive test result at Screening for human immunodeficiency virus (HIV). Current hepatitis C infection. Current hepatitis B infection. History of alcohol or substance abuse ≤6 months of Screening that would limit participation in the study, as determined by the Investigator. Current or anticipated need, in the opinion of the Investigator, of a diaphragm pacing system during the study period. Presence of tracheostomy. In participants from Cohorts A, B, C1, and D1, history of myocardial infarction, as determined by the Investigator. In participants from Cohorts A, B, C1, and D1, poorly controlled type 1 or 2 diabetes mellitus defined as hemoglobin A1c (HbA1c) ≥8% during Screening. In participants in Cohorts A, B, and C1, prescreening ALSFRS-R slope >-0.4 points/month, where prescreening ALSFRS-R slope is defined as: (ALSFRS-R score at Screening - 48) / (months from date of symptom onset to date of Screening). This criterion is not applicable for Cohorts C2, D1, and D2. Treatment with another investigational drug (including investigational drugs for ALS through compassionate use programs) or biological agent within 1 month or 5 half-lives of study agent, whichever is longer, before Screening. Treatment with an approved disease-modifying therapy for ALS other than riluzole or edaravone within 1 month or 5 half-lives of therapy, whichever is longer, before completion of screening. Treatment with an antiplatelet or anticoagulant therapy that cannot safely be interrupted for lumbar puncture (LP) according to local standard of care and/or institutional guidelines, in the opinion of the Investigator or Prescriber. Female participants who are pregnant or currently breastfeeding and those intending to become pregnant during the study. Part 2: History or positive test result at Screening for HIV. If participants from Cohorts D1 and D2 who would seamlessly roll from Part 1 into Part 2 test positive for HIV during screening for Part 2 but are clinically asymptomatic, they may enroll in Part 2 at the discretion of the Investigator. Current hepatitis C infection. If participants from Cohorts D1 and D2 who would seamlessly roll from Part 1 into Part 2 test positive for hepatitis C during screening for Part 2 but are clinically asymptomatic, they may enroll in Part 2 at the discretion of the Investigator. Current hepatitis B infection. If participants from Cohorts D1 and D2 who would seamlessly roll from Part 1 into Part 2 test positive for hepatitis B during screening for Part 2 but are clinically asymptomatic, they may enroll in Part 2 at the discretion of the Investigator. History of alcohol or substance abuse ≤ 6 months of Screening that would limit participation in the study, as determined by the Investigator. Current or anticipated need, in the opinion of the Investigator, of a diaphragm pacing system during the study period. In participants from Cohorts A, B, C1, and D1, history of myocardial infarction, as determined by the Investigator. In participants from Cohorts A, B, C1, and D1, poorly controlled type 1 or 2 diabetes mellitus defined as HbA1c ≥8% during Screening. Treatment with another investigational drug (including investigational drugs for ALS through compassionate use programs; excluding BIIB105) or biological agent within 1 month or 5 half-lives of study agent, whichever is longer, before Screening. Treatment with an antiplatelet or anticoagulant therapy that cannot safely be interrupted for LP according to local standard of care and/or institutional guidelines, in the opinion of the Investigator or Prescriber. Female participants who are pregnant or currently breastfeeding and those intending to become pregnant during the study. NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Sequential Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Part 1: Cohort A<br>Participants with ALS will receive BIIB105 Dose 1, intrathecally (IT), as 3 loading doses on Day 1 and two later days, followed by two maintenance doses on two later days. | Drug: BIIB105<br>* Administered as specified in the treatment arm.<br>|
| Experimental: Part 1: Cohort B<br>Participants with ALS will receive BIIB105 Dose 2, IT, as 3 loading doses on Day 1 and two later days, followed by two maintenance doses on two later days. | Drug: BIIB105<br>* Administered as specified in the treatment arm.<br>|
| Experimental: Part 1: Cohort C1<br>Participants with ALS will receive BIIB105 Dose 3, IT, as 3 loading doses on Day 1 and two later days, followed by two maintenance doses on two later days. | Drug: BIIB105<br>* Administered as specified in the treatment arm.<br>|
| Experimental: Part 1: Cohort D1<br>Participants with ALS will receive BIIB105 Dose 4, IT, as 3 loading doses on Day 1 and two later days, followed by five maintenance doses on five later days. | Drug: BIIB105<br>* Administered as specified in the treatment arm.<br>|
| Experimental: Part 1: Cohort C2<br>Participants with polyQ-ALS will receive BIIB105 Dose 3, IT, as 3 loading doses on Day 1 and two later days, followed by two maintenance doses on two later days. | Drug: BIIB105<br>* Administered as specified in the treatment arm.<br>|
| Experimental: Part 1: Cohort D2<br>Participants with polyQ-ALS will receive BIIB105 Dose 4, IT, as 3 loading doses on Day 1 and two later days, followed by five maintenance doses on five later days. | Drug: BIIB105<br>* Administered as specified in the treatment arm.<br>|
| Placebo Comparator: Part 1: Cohorts A-D2: Placebo<br>Participants with ALS and polyQ-ALS for Cohorts A, B, C1 and C2 will receive matching placebo to BIIB105 as 3 loading doses on Day 1 and two later days, followed by two maintenance doses on two later days, and participants with ALS and polyQ-ALS for Cohorts D1 and D2 will receive matching placebo to BIIB105 as 3 loading doses on Day 1 and two later days, followed by five maintenance doses on five later days. | Drug: Placebo<br>* Administered as specified in the treatment arm.<br>|
| Experimental: Part 2: Cohorts A-C2: Open-Label<br>Participants who complete Cohorts A, B, C1, and C2 will receive BIIB105 Dose 3, IT, as 3 loading doses on Day 1 and two later days, followed up to thirty-eight maintenance doses, on up to thirty-eight later days. | Drug: BIIB105<br>* Administered as specified in the treatment arm.<br>|
| Experimental: Part 2: Cohorts D1, D2: Open-Label<br>Participants who complete Cohorts D1 and D2 will have a blinded Loading Dose Period, during which those who received placebo in Part 1 will receive BIIB105 Dose 4, IT, as 3 loading doses on Day 1 and two later days, while those who received BIIB105 in Part 1 will receive 2 loading doses of BIIB105 Dose 4, IT, on Days 1 and one later day, and placebo on Day 15. After the blinded Loading Dose Period, participants will receive BIIB105 Dose 4 up to thirty-eight maintenance doses, on up to thirty-eight later days. | Drug: BIIB105<br>* Administered as specified in the treatment arm.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Part 1: Number of Participants with Adverse Events (AEs) and Serious Adverse Events (SAEs) | 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 SAE is any untoward medical occurrence that at any dose results in death, places the participant at immediate risk of death, 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. | Up to Day 260 | 
| Part 2: Number of Participants with AEs and SAEs | 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 SAE is any untoward medical occurrence that at any dose results in death, places the participant at immediate risk of death, 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. | Up to Day 1184 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Part 1: Serum Concentrations of BIIB105 |  | Up to Day 176 | 
| Part 1: CSF Concentrations of BIIB105 |  | Up to Day 259 | 
| Part 1: Area Under the Serum Concentration-Time Curve from Time Zero to Infinity (AUCinf) |  | Up to Day 176 | 
| Part 1: Area Under the Serum Concentration-Time Curve From Time Zero to Time of the Last Measurable Concentration (AUClast) |  | Up to Day 176 | 
| Part 1: Maximum Observed Serum Concentration (Cmax) |  | Up to Day 176 | 
| Part 1: Time to Reach Maximum Observed Serum Concentration (Tmax) |  | Up to Day 176 | 
| Part 1: Elimination Half-Life (t1/2) in Serum |  | Up to Day 176 | 
| Part 1: Change From Baseline in Plasma Levels of Neurofilament Light Chain (NfL) |  | Up to Day 259 | 
| Integrated Parts 1 and 2: CSF Trough PK Concentration of BIIB105 |  | Up to Day 1183 | 
| Integrated Parts 1 and 2: Serum PK Concentration of BIIB105 |  | Up to Day 1009 | 
| Integrated Parts 1 and 2: Change From Baseline in Plasma Levels of NfL |  | Up to Day 1183 | 
| Integrated Parts 1 and 2: Change From Baseline in Slow Vital Capacity (SVC) |  | Up to Day 1183 | 
| Integrated Parts 1 and 2: Change From Baseline in Amyotrophic Lateral Sclerosis Functional Rating Scale - Revised (ALSFRS-R) Score | The ALSFRS-R is used to predict survival. The ALSFRS-R measures 4 functional domains, including respiratory, bulbar function, gross motor skills, and fine motor skills. There are 12 questions, each scored from 0 to 4, for a total possible score of 48, with higher scores representing better function. | Up to Day 1183 | 
| Integrated Parts 1 and 2: Change From Baseline in Muscle Strength, as Measured by Handheld Dynamometry (HHD) | Quantitative muscle strength will be evaluated using HHD, which tests isometric strength of multiple muscles using standard participant positioning. Approximately 8 muscle groups will be examined (per each side) in both upper and lower extremities. | Up to Day 1183 | 
| Integrated Parts 1 and 2: Time to Death or Permanent Ventilation | Permanent ventilation is defined as ≥22 hours of mechanical ventilation [invasive or noninvasive] per day for ≥21 consecutive days. | Up to Day 1184 | 
| Integrated Parts 1 and 2: Time to Death |  | Up to Day 1184 | 
| Integrated Parts 1 and 2: Time to Death, Incorporating Post-Study Withdrawal or Study Completion Vital Status Data |  | Up to Day 1184 |