Skip to content
Clinical Trials – home

Rare diseases

Investigational molecules

Locations

Our offerNewsroom

Not recruitingRare disease

Study of Tofersen for Adults with Presymptomatic Amyotrophic Lateral Sclerosis (ALS) Due to SOD1 Gene Mutation

Verified siteInvestigationalNo placebo
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying a condition known as Amyotrophic Lateral Sclerosis (ALS), which is associated with a specific genetic change called the SOD1 gene mutation. The study is investigating a treatment called BIIB067, also known as Tofersen. Tofersen is a solution that is injected into the spinal canal, a method known as intrathecal use. The purpose of the study is to evaluate how effective Tofersen is in adults who carry the SOD1 mutation but do not yet show symptoms of ALS.

The study will begin with a period where participants' natural health progression is observed. After this, participants will be randomly assigned to receive either Tofersen or a placebo, which is a solution that looks like the treatment but does not contain the active substance. This part of the study will help researchers understand the effects of Tofersen compared to no active treatment. Participants will be monitored over time to see if they develop symptoms of ALS and to assess any changes in their health status.

Following the initial phase, there will be an open-label extension, where all participants will have the opportunity to receive Tofersen. Throughout the study, researchers will collect information on various health measures, including changes in physical abilities and breathing function. The study aims to provide valuable insights into the potential benefits of Tofersen for individuals at risk of developing ALS due to the SOD1 mutation.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, participation is confirmed for individuals who are clinically presymptomatic for amyotrophic lateral sclerosis (ALS) with a confirmed superoxide dismutase 1 (SOD1) mutation.

    Eligibility is determined by specific criteria, including a rapidly progressive SOD1 mutation and plasma neurofilament light chain (NfL) levels below a certain threshold.

  2. Step 2

    Initial assessment

    An initial assessment is conducted to establish baseline measurements. This includes evaluating functional abilities using the ALS Functional Rating Scale, which assesses respiratory, bulbar function, gross motor skills, and fine motor skills.

    Baseline measurements of slow vital capacity (SVC) and plasma NfL concentrations are also taken.

  3. Step 3

    Treatment phase

    Participants receive the study medication, BIIB067 (tofersen), administered as a solution for injection via intrathecal use. This involves injecting the medication into the space around the spinal cord.

    The treatment phase is divided into several parts, with the primary objective of evaluating the efficacy of tofersen in delaying the onset of clinically manifest ALS.

  4. Step 4

    Monitoring and follow-up

    Participants are monitored for the emergence of clinically manifest ALS over a period of up to 24 months from the baseline of Part B.

    Secondary outcomes include changes in ALS functional scores, SVC, and plasma NfL concentrations, as well as the occurrence of adverse events and serious adverse events.

  5. Step 5

    Long-term evaluation

    The study includes a long-term follow-up period, extending up to 5.6 years, to assess the time to emergence of clinically manifest ALS and other long-term outcomes.

    Participants are evaluated for changes in cerebrospinal fluid (CSF) SOD1 concentrations and other health indicators.

  6. Step 6

    Completion of study

    The study is estimated to conclude by October 18, 2027, with all data collected and analyzed to determine the efficacy and safety of tofersen in delaying the onset of ALS symptoms in presymptomatic individuals with a SOD1 mutation.

Who can join the trial?

6 criteria

  • Participants must have a specific type of genetic change called a **SOD1 mutation**. This mutation should be confirmed by a central reader or approved by a special committee.
  • Participants should have a **plasma NfL level** below a certain threshold. **Plasma NfL** is a substance in the blood that can indicate nerve cell damage.
  • Participants must not show any symptoms of **ALS**. This means they should not have any signs of the disease yet.
  • Participants can be of any gender.
  • Participants must be adults, which means they should be 18 years or older.
  • Other specific criteria defined in the study protocol may also apply.

Who cannot join the trial?

5 criteria

  • Individuals who do not have the specific genetic mutation related to **Amyotrophic Lateral Sclerosis (ALS)**. This is a condition that affects nerve cells in the brain and spinal cord.
  • Individuals who are not carriers of the **SOD1 gene mutation**. This is a specific change in a gene that can be linked to ALS.
  • Individuals who do not have elevated levels of **neurofilament (NF)**. Neurofilament is a type of protein found in nerve cells, and higher levels can indicate nerve damage.
  • Individuals who are not adults. The study is only for adults, which means people who are 18 years or older.
  • Individuals who already show symptoms of ALS. The study is for those who do not yet have symptoms.
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

We usually reply within a few days

Verified sites

All sites with verified contact details – recruitment status may not be available; ask directly

Trial locations

Where you can join this trial

Countries are shaded by recruitment status. Click a recruiting country to ask about joining there.

Not recruiting
Not finding your country?

Not sure what to do next?

Joining a clinical trial can seem overwhelming. We guide you step by step, so you know exactly what to expect and how we support you through the process.

See the full process and FAQ

Investigated drugs

Tofersen is a medication being studied for its effectiveness in adults who carry a specific genetic mutation known as superoxide dismutase 1 (SOD1). This mutation is linked to certain neurological conditions. The trial aims to see if tofersen can help these individuals before they show any symptoms. The study focuses on people with elevated levels of a protein called neurofilament, which can be a sign of nerve damage.

What is already known about the treatment

Tofersen – Tofersen is administered through an injection into the spinal canal, a method known as intrathecal administration. It is currently being studied in clinical trials, particularly for its potential to treat Amyotrophic Lateral Sclerosis (ALS) associated with a mutation in the SOD1 gene. The medication works by targeting and reducing the production of the SOD1 protein, which is believed to contribute to the progression of ALS. Tofersen is classified as an antisense oligonucleotide, a type of drug designed to interfere with the genetic instructions for producing specific proteins.

Investigated diseases

Amyotrophic Lateral Sclerosis (ALS) associated with SOD1 gene mutation – This is a rare neurodegenerative disease that affects nerve cells in the brain and spinal cord, leading to the progressive loss of muscle control. It is specifically linked to mutations in the SOD1 gene, which can cause the abnormal accumulation of proteins that damage motor neurons. As the disease progresses, individuals may experience muscle weakness, twitching, and eventually, the inability to move, speak, swallow, or breathe independently. The progression of symptoms can vary, but it typically leads to significant physical disability over time. The condition is characterized by the gradual degeneration of motor neurons, which are responsible for transmitting signals from the brain to the muscles.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-505641-12-00Protocol code233AS303Estimated enrolment150 patientsSponsorBiogen Idec Research Limited

sourced from the EU Clinical Trials Register and site verification

Want to learn more about this trial or check if you can participate?

Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

ClinicalTrials.eu

Every clinical trial in Europe, in plain language.

Explore the full ecosystem of clinical research in Europe.

Search trials

Legal notice · Published by CTIN POLAND sp. z o.o., ul. rtm. Witolda Pileckiego 67/109, 02-781 Warsaw, Poland · KRS 0001111334 · REGON 528919042 · NIP 9512598637

© 2026 Clinical Trials EU – European Clinical Trials Information Network

GDPR compliance, ISO 9001 and ISO 27001 certified (LL-C Certification)

On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).