Study to Learn If Tofersen (BIIB067) Can Delay ALS Symptoms and About Its Safety in Adults With a SOD1 Gene Mutation Who Have Not Yet Developed ALS Symptoms

Brief summary

Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.

In this study, researchers will learn more about the effects of a drug called tofersen, also known as BIIB067 and QALSODY®, in adults with amyotrophic lateral sclerosis (ALS) who have a superoxide dismutase 1 (SOD1) gene mutation. One of the causes of ALS is a change (or mutation) in the SOD1 gene, which causes abnormal SOD1 protein to be made. This abnormal protein can cause the motor neurons in people with ALS to break down and die. When neurons are damaged, they release a protein called neurofilament light chain, also known as NfL. Previous studies have shown that NfL levels are higher in people with SOD1-ALS, even before any ALS symptoms appear. In this study, researchers will look at the effect of tofersen treatment in the earlier stages of the disease, even before ALS symptoms appear. Researchers believe that giving tofersen to patients as early as possible may slow the onset of ALS symptoms and the progression of the disease. This study will have 4 parts. In Part A, participants will have their health monitored and NfL levels tested on a monthly basis, but they will not receive any study drug. Tofersen or placebo will be given to participants in Parts B, while all participants will receive tofersen in Parts C and D. The main question that researchers want to answer is: • How long does it take for ALS symptoms to appear? Researchers will also learn more about: * How many participants develop ALS symptoms within 24 months of the start of Part B * Changes in participants' ability to perform their daily activities * Changes in participants' ability to breathe * How many participants die or need long-term breathing support * Changes in NfL levels in the blood * Changes in SOD1 protein levels in the fluid around the brain and spinal cord * How many participants have adverse events or serious adverse events. Adverse events are health problems that may or may not be caused by the study drug. The study will be done as follows: * Participants will first be screened to check if they can join the study. The screening period will be up to 6 weeks. Participants will join the study only after reading and signing an informed consent form, also known as an ICF. * In Part A, participants with presymptomatic ALS will not get any study drugs. Researchers will check the levels of NfL in their blood. Participants will be closely checked for any signs or symptoms of ALS. * Once a participant's NfL levels rise to a certain amount, they will move onto Part B. * In Part B, participants will be randomly assigned to get either tofersen or a placebo. Neither participants nor researchers will know who gets tofersen or the placebo during Part B. A placebo looks like the study drug but contains no medicine. * Participants will get the first 3 doses of tofersen once every 14 days. Afterwards, they will continue getting maintenance doses every 28 days. * All doses will be given through an intrathecal (IT) injection done through a lumbar puncture procedure. This involves injecting the drug into the fluid surrounding the spinal cord in the lower back. * Participants who develop ALS symptoms during Part B will move to Part C to receive tofersen. * Participants who develop ALS symptoms during Part A will move to Part D to receive tofersen. * In both Parts C and D, participants will know they are receiving tofersen. * Throughout the study, doctors will measure any changes to the participants' function and quality of life using different questionnaires. Doctors will also take blood and urine samples. They will also check the participants' overall health and ask how they are feeling. * Participants will have a follow-up visit 28 days after their last dose of study drug. * Participants will be in this study for up to about 6.5 years.

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Last update posted Oct 20, 2026 · Synced Oct 23, 2026

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