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Approved

Tofersen

Also known as Qalsody, BIIB067, IONIS-SOD1Rx

Bottom line

Strongly lowers the toxic protein and a nerve-damage marker. Its only placebo-controlled trial missed its six-month goal; longer open-label follow-up and small real-world studies suggest slower decline, mainly when started early, but without a placebo group.

Tofersen is a genetic medicine for people whose ALS is caused by a mutation in the SOD1 gene, a small share of all ALS. It lowers the harmful SOD1 protein and a marker of nerve damage (neurofilament), and is approved in the USA, EU, Japan and other countries. Its main trial missed its goal at six months, but longer follow-up suggested people who started earlier declined less. A large study (ATLAS) is testing whether starting it before symptoms can delay ALS.

Information checked 5 Nov 2026

Evidence: Hints only

Studies: 1 for · 2 mixed

Controlled trials missed their main goal. Some measures or subgroups looked better, which needs confirming.

Missed 6-month goal; less decline with early start

1.2 points less decline over 28 weeks (not significant); 3.6 points less over 148 weeks with early start (open-label)

How we decide the overall verdict: How to read this site.

Regulators' decisions for ALS

At a glance

CompanyBiogen (with Ionis Pharmaceuticals)Explanation and sources

Tofersen was discovered by Ionis Pharmaceuticals and licensed to Biogen, which ran the clinical trials and sells it as Qalsody. Biogen is a large US company focused on neurology medicines.

Sources

  1. FDA Grants Accelerated Approval for QALSODY (tofersen) for SOD1-ALSBiogen · 25 Apr 2023 · Company press release
  2. FDA approves QALSODY (tofersen), first treatment targeting a genetic cause of ALSIonis Pharmaceuticals · 25 Apr 2023 · Company press release
How it worksSilences the faulty SOD1 gene so less toxic protein is madeSOD1 mRNA (antisense oligonucleotide)Explanation and sources

Some people have ALS because a mutation in the SOD1 gene makes a toxic form of the SOD1 protein. Tofersen is an antisense oligonucleotide, a short strand of genetic material that sticks to the SOD1 message (mRNA) and causes it to be broken down, so less SOD1 protein is made. It only makes sense for people with a SOD1 mutation, which a genetic test can find.

Sources

  1. FDA approves treatment of amyotrophic lateral sclerosis associated with a mutation in the SOD1 geneUS FDA · 25 Apr 2023 · Regulator
  2. Trial of Antisense Oligonucleotide Tofersen for SOD1 ALSNew England Journal of Medicine · 21 Sept 2022 · Peer-reviewed paper
StageApprovedApproved for SOD1-ALS in USA, EU, Japan, China, Canada, UK, AustraliaExplanation and sources

The FDA gave accelerated approval on April 25, 2023, based on the drop in neurofilament light (NfL), a blood marker of nerve damage, which means a clinical benefit still has to be confirmed. The EU approved it under exceptional circumstances on May 29, 2024, and Japan approved it on December 27, 2024. Canada gave approval with conditions on February 28, 2025, pending confirmation of benefit. China, the UK and Australia have also approved it.

Sources

  1. FDA approves treatment of amyotrophic lateral sclerosis associated with a mutation in the SOD1 geneUS FDA · 25 Apr 2023 · Regulator
  2. Commission implementing decision granting marketing authorisation for QalsodyEuropean Commission · 29 May 2024 · Regulator
  3. Qalsody approval in Japan for SOD1-ALS (Japanese)Biogen Japan · 27 Dec 2024 · Company press release
  4. Summary Basis of Decision for QalsodyHealth Canada · 8 May 2025 · Regulator
  5. Qalsody listed on the PBS for SOD1-ALSBiogen Australia · 11 Sept 2026 · Company press release
  6. SOD1-targeted therapies and trialsALS/MND Association (als-mnd.org) · Patient organisation
Best reported effectMissed 6-month goal; less decline with early start1.2 points less decline over 28 weeks (not significant); 3.6 points less over 148 weeks with early start (open-label)Explanation and sources

In the VALOR trial (108 people), the main goal was missed: after 28 weeks, the faster-progressing group on tofersen declined 6.98 ALSFRS-R points versus 8.14 on placebo, a difference that could be chance. Tofersen did cut SOD1 protein in spinal fluid by 35% and NfL in blood by 55%. In the open-label extension, people who started early had lost 9.9 points after 148 weeks versus 13.5 for those who started six months later; this was not tested as a formal goal, and by then everyone was on the drug. About 7% had serious nervous system side effects, including spinal cord inflammation (myelitis).

This is the most favourable result reported. See all key studies for the full picture.

Sources

  1. Trial of Antisense Oligonucleotide Tofersen for SOD1 ALSNew England Journal of Medicine · 21 Sept 2022 · Peer-reviewed paper
  2. Biogen Announces Topline Results from the Tofersen Phase 3 Study and its Open-Label Extension in SOD1-ALSBiogen · 17 Oct 2021 · Company press release
  3. FDA approves treatment of amyotrophic lateral sclerosis associated with a mutation in the SOD1 geneUS FDA · 25 Apr 2023 · Regulator
  4. Long-Term Tofersen in SOD1 Amyotrophic Lateral SclerosisJAMA Neurology · 22 Dec 2025 · Peer-reviewed paper
Who it's forAdults with ALS caused by a SOD1 gene mutationSOD1 · Spinal injection, monthlyExplanation and sources

Tofersen is only for people with a confirmed SOD1 mutation; about 330 people in the USA and fewer than 1,000 in Europe have SOD1-ALS. It is given by lumbar puncture (an injection into the fluid around the spine): three starting doses two weeks apart, then one dose every four weeks.

Sources

  1. FDA approves treatment of amyotrophic lateral sclerosis associated with a mutation in the SOD1 geneUS FDA · 25 Apr 2023 · Regulator
  2. Biogen Receives European Commission Approval for QALSODY (tofersen)Biogen · 30 May 2024 · Company press release
  3. Qalsody approval in Japan for SOD1-ALS (Japanese)Biogen Japan · 27 Dec 2024 · Company press release
What's nextATLAS presymptomatic trial main results (primary completion Aug 2027)Expected August 2027Explanation and sources

ATLAS is testing tofersen in about 150 people who carry a SOD1 mutation but do not yet have symptoms. Treatment starts when their NfL level begins to rise, and the main question is how many develop clinical ALS within 24 months. The registry lists primary completion as August 2027 and full completion as May 2028.

Sources

  1. A Study of BIIB067 (Tofersen) Initiated in Clinically Presymptomatic Adults With a Confirmed SOD1 Mutation (ATLAS)ClinicalTrials.gov · Trial registry
  2. Tofersen (Qalsody)The ALS Association · Patient organisation
How to get itPrescription where approved; small trials in non-SOD1 ALS recruitingRecruiting nowExplanation and sources

Where approved, tofersen is prescribed by a neurologist after a genetic test confirms a SOD1 mutation. Biogen's expanded access programme is now listed as "approved for marketing" rather than open. In Australia it has been subsidised on the PBS since October 1, 2026, and in France the health authority upgraded its rating in April 2026 pending more data. ATLAS is no longer recruiting; a small Phase 2 study is testing tofersen in people without a SOD1 mutation.

Sources

  1. Expanded Access Program for Tofersen (BIIB067)ClinicalTrials.gov · Trial registry
  2. Qalsody listed on the PBS for SOD1-ALSBiogen Australia · 11 Sept 2026 · Company press release
  3. Qalsody : de nouvelles données ont permis une réévaluation par la HASHaute Autorité de Santé · 21 Apr 2026 · Regulator
  4. A Study of BIIB067 (Tofersen) Initiated in Clinically Presymptomatic Adults With a Confirmed SOD1 Mutation (ATLAS)ClinicalTrials.gov · Trial registry
  5. Tofersen in non-SOD1 ALSClinicalTrials.gov · Trial registry
  6. Long-term safety study of tofersen (observational)ClinicalTrials.gov · Trial registry

Timeline

10 events, newest first. Company updates are marked; independent news and regulator decisions are shown too.

2026

  1. Press releaseFrom the companyBiogen Australia

    Qalsody to be subsidised in Australia

    Biogen Australia announced that tofersen would be listed on the Pharmaceutical Benefits Scheme from October 1, 2026.

  2. RegulatoryHaute Autorité de Santé

    French health authority upgrades its rating

    After new data, France's HAS raised tofersen's medical benefit rating to "low", conditional on further data and a new review within a year.

2024

  1. Press releaseFrom the companyBiogen Japan

    Qalsody approved in Japan

    Biogen Japan announced approval of tofersen for SOD1-ALS in Japan.

  2. Press releaseFrom the companyBiogen

    Biogen announces EU approval

    Biogen said fewer than 1,000 people in Europe live with SOD1-ALS.

  3. RegulatoryEuropean Commission

    European Commission approves Qalsody

    The EU approved tofersen for SOD1-ALS under exceptional circumstances, a route used when full data are hard to collect for very rare diseases.

2023

  1. RegulatoryUS FDA

    FDA grants accelerated approval to Qalsody

    The FDA approved tofersen for SOD1-ALS based on lower neurofilament levels, a marker considered reasonably likely to predict benefit.

  2. Press releaseFrom the companyBiogen

    Biogen announces US approval

    Biogen announced the accelerated approval, which rests on a 55% drop in blood neurofilament levels rather than a proven clinical benefit.

2022

  1. PublicationNew England Journal of Medicine

    VALOR results published in NEJM

    The paper reported the missed main goal, a 52-week signal favouring early start that was not formally adjusted, and serious nervous system side effects in 7% of people.

2021

  1. Press releaseFrom the companyBiogen

    VALOR misses its main goal

    Biogen reported that tofersen did not significantly slow decline on the ALSFRS-R at six months, though it lowered SOD1 and neurofilament levels. Biogen said it would expand early access.

  2. Trial registryClinicalTrials.gov

    ATLAS presymptomatic trial starts

    Biogen began testing tofersen in people with a SOD1 mutation who do not yet have ALS symptoms, starting treatment when a blood marker of nerve damage rises.

All sources for this page

  1. Biogen Announces Topline Results from the Tofersen Phase 3 Study and its Open-Label Extension in SOD1-ALSBiogen · 17 Oct 2021 · Company press release
  2. Trial of Antisense Oligonucleotide Tofersen for SOD1 ALSNew England Journal of Medicine · 21 Sept 2022 · Peer-reviewed paper
  3. FDA approves treatment of amyotrophic lateral sclerosis associated with a mutation in the SOD1 geneUS FDA · 25 Apr 2023 · Regulator
  4. FDA Grants Accelerated Approval for QALSODY (tofersen) for SOD1-ALSBiogen · 25 Apr 2023 · Company press release
  5. FDA approves QALSODY (tofersen), first treatment targeting a genetic cause of ALSIonis Pharmaceuticals · 25 Apr 2023 · Company press release
  6. US FDA approves Biogen's ALS drugReuters · 25 Apr 2023 · News
  7. Commission implementing decision granting marketing authorisation for QalsodyEuropean Commission · 29 May 2024 · Regulator
  8. Biogen Receives European Commission Approval for QALSODY (tofersen)Biogen · 30 May 2024 · Company press release
  9. Qalsody approval in Japan for SOD1-ALS (Japanese)Biogen Japan · 27 Dec 2024 · Company press release
  10. Qalsody review report (Japanese)PMDA · Regulator
  11. Qalsody : de nouvelles données ont permis une réévaluation par la HASHaute Autorité de Santé · 21 Apr 2026 · Regulator
  12. Qalsody listed on the PBS for SOD1-ALSBiogen Australia · 11 Sept 2026 · Company press release
  13. SOD1-targeted therapies and trialsALS/MND Association (als-mnd.org) · Patient organisation
  14. Tofersen (Qalsody)The ALS Association · Patient organisation
  15. A Study of BIIB067 (Tofersen) Initiated in Clinically Presymptomatic Adults With a Confirmed SOD1 Mutation (ATLAS)ClinicalTrials.gov · Trial registry
  16. Expanded Access Program for Tofersen (BIIB067)ClinicalTrials.gov · Trial registry
  17. Tofersen in non-SOD1 ALSClinicalTrials.gov · Trial registry
  18. Long-term safety study of tofersen (observational)ClinicalTrials.gov · Trial registry
  19. Long-Term Tofersen in SOD1 Amyotrophic Lateral SclerosisJAMA Neurology · 22 Dec 2025 · Peer-reviewed paper
  20. JAMA Neurology Publishes Long Term Results from the QALSODY Phase 3 VALOR Study and its Open-Label ExtensionBiogen · 22 Dec 2025 · Company press release
  21. Effects of tofersen treatment in patients with SOD1-ALS in a real-world setting: a 12-month multicenter cohort study from the German early access programeClinicalMedicine (The Lancet) · 15 Feb 2024 · Peer-reviewed paper
  22. Tofersen for SOD-1-associated amyotrophic lateral sclerosisThe Lancet Neurology · Peer-reviewed paper
  23. Summary Basis of Decision for QalsodyHealth Canada · 8 May 2025 · Regulator
  24. Biogen's targeted ALS treatment is reversing decline in some patients. Can more be helped?BioSpace · News