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RAG-17

Also known as RAG17

Bottom line

It clearly lowers SOD1 and a nerve-damage marker in a handful of people. Whether that slows ALS is unknown: the only clinical data come from 6 people with no comparison group and a trial that is still blinded.

RAG-17 is a gene-silencing drug (an siRNA) for people with ALS caused by a faulty SOD1 gene. It is injected into the spinal fluid and lowers the amount of SOD1 protein, the same target as the approved drug tofersen. Early studies in China showed large drops in SOD1 and in a nerve-damage marker, but they were tiny, and the placebo-controlled results are still blinded, so it is not yet known whether it slows ALS. A placebo-controlled Phase 2 part finished enrolling in August 2026.

Information checked 5 Nov 2026

Evidence: Early signal only

Studies: 1 mixed · 2 running

Only small, open-label or historical-comparison studies so far. Promising at best; not proof.

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

At a glance

CompanyRactigen TherapeuticsExplanation and sources

Ractigen is a Chinese biotech based in Jiangsu province that makes RNA-based medicines using its own delivery technology. RAG-17 is being tested in China, with Beijing Tiantan Hospital as the lead site. The drug has FDA orphan drug designation and a cleared US trial application, but no US trial has been announced.

Sources

  1. Ractigen Therapeutics Announces First Patient Dosed in Phase I Clinical Trial for RAG-17 in SOD1-ALSRactigen Therapeutics · 24 Dec 2024 · Company press release
  2. Ractigen's RAG-17 ALS Data Shines at AAN 2025, Earns Top Award, Phase I AdvancesRactigen Therapeutics · 9 Apr 2025 · Company press release
  3. RAG-17 Phase 1/2 trial in SOD1-ALS (NCT06556394)ClinicalTrials.gov · Trial registry
How it workssiRNA that silences the SOD1 gene to lower toxic SOD1 proteinSOD1 messenger RNAExplanation and sources

In SOD1-ALS, a faulty gene makes a harmful form of the SOD1 protein that damages motor neurons. RAG-17 is a small piece of RNA that tells cells to destroy the SOD1 gene's message before it is turned into protein. This is the same goal as tofersen, which works through a different kind of molecule. Ractigen adds a helper molecule designed to get the drug into nerve cells.

Sources

  1. RAG-17 preclinical efficacy and first-in-human study in SOD1-ALSNature Medicine · 15 Jul 2026 · Peer-reviewed paper
  2. Ractigen Therapeutics Announces Landmark Publication in Nature Medicine on RAG-17 in SOD1-ALSRactigen Therapeutics · 15 Jul 2026 · Company press release
StagePhase 1/2Phase 1/2 in China; Phase 2 part fully enrolledExplanation and sources

After a six-person study led by doctors, Ractigen ran a single-dose Phase 1 part with 20 people in China, which began in December 2024. A multiple-dose, placebo-controlled Phase 2 part started dosing in January 2026 and finished enrolling in August 2026. The registry record still lists the trial as Phase 1 and recruiting, which is out of date.

Sources

  1. Ractigen Therapeutics Announces First Patient Dosed in Phase I Clinical Trial for RAG-17 in SOD1-ALSRactigen Therapeutics · 24 Dec 2024 · Company press release
  2. Ractigen Therapeutics Announces First Patient Dosed in Phase II Clinical Trial of RAG-17 for SOD1-ALSRactigen Therapeutics · 13 Jan 2026 · Company press release
  3. Ractigen Therapeutics Announces Completion of Enrollment and First Dosing in Phase II Clinical Trial of RAG-17 for SOD1-ALSRactigen Therapeutics · 6 Aug 2026 · Company press release
  4. RAG-17 Phase 1/2 trial in SOD1-ALS (NCT06556394)ClinicalTrials.gov · Trial registry
Best reported effectBiomarkers fell; effect on ALS not yet knownCSF SOD1, blood NfL, ALSFRS-RExplanation and sources

In the six-person open-label study published in Nature Medicine, spinal-fluid SOD1 fell by 56-69% and the nerve-damage marker NfL by 52-62%. Function declined more slowly after treatment than before (0.30 vs 0.43 ALSFRS-R points per month), but the "before" rate was estimated looking back, there was no control group, and the three people with milder disease declined faster on average after treatment than before. In the Phase 1 single-dose part, results were reported blinded, mixing people on placebo with those on the drug (1 in 4 got placebo), so the "81% NfL drop" cannot be compared with placebo yet.

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

Sources

  1. RAG-17 preclinical efficacy and first-in-human study in SOD1-ALSNature Medicine · 15 Jul 2026 · Peer-reviewed paper
  2. Ractigen Therapeutics Presents Positive Phase I Data for RAG-17 in SOD1-ALS at the 2026 AAN Annual MeetingRactigen Therapeutics · 21 Apr 2026 · Company press release
  3. RAG-17 Phase I single-dose results (AAN 2026 abstract)Neurology · Conference presentation
Who it's forAdults with ALS caused by SOD1 gene changesSOD1 · Injection into spinal fluidExplanation and sources

RAG-17 is only for people with a confirmed SOD1 gene change, a small share of all ALS. It is given by lumbar puncture (an injection into the lower back). No serious side effects linked to the drug were reported in the early studies.

Sources

  1. RAG-17 Phase 1/2 trial in SOD1-ALS (NCT06556394)ClinicalTrials.gov · Trial registry
  2. RAG-17 preclinical efficacy and first-in-human study in SOD1-ALSNature Medicine · 15 Jul 2026 · Peer-reviewed paper
  3. Ractigen Therapeutics Presents Positive Phase I Data for RAG-17 in SOD1-ALS at the 2026 AAN Annual MeetingRactigen Therapeutics · 21 Apr 2026 · Company press release
What's nextResults from the placebo-controlled Phase 2 partExplanation and sources

All patients in the Phase 2 part were enrolled and dosed by August 2026. Ractigen has not said when results will be released.

Sources

  1. Ractigen Therapeutics Announces Completion of Enrollment and First Dosing in Phase II Clinical Trial of RAG-17 for SOD1-ALSRactigen Therapeutics · 6 Aug 2026 · Company press release
Can I join?Phase 2 fully enrolled; China onlyExplanation and sources

Ractigen announced in August 2026 that the Phase 2 part was fully enrolled, so new people cannot join, even though the registry still says recruiting. The trial is only in China. We found no expanded access programme.

Sources

  1. Ractigen Therapeutics Announces Completion of Enrollment and First Dosing in Phase II Clinical Trial of RAG-17 for SOD1-ALSRactigen Therapeutics · 6 Aug 2026 · Company press release
  2. RAG-17 Phase 1/2 trial in SOD1-ALS (NCT06556394)ClinicalTrials.gov · Trial registry

Signal: Steady

Signal measures how often, and how reliably, Ractigen Therapeutics tells the public about this drug. It says nothing about whether the drug works. A quiet company isn't necessarily a bad sign, but regular, on-time updates help patients plan.

Last company update6 Aug 2026 (3 months ago)12 / 40
Company updates in the last 12 months423 / 35
Promises keptNot enough history yet (neutral score)12.5 / 25
Signal score48 / 100 · Steady

70 or more is Active, 45 or more is Steady, 20 or more is Quiet, below 20 is Silent. Full method.

Timeline

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

2026

  1. Press releaseFrom the companyRactigen Therapeutics

    Phase 2 part fully enrolled and dosed

    Ractigen said all patients in the Phase 2 part had been enrolled and had received their first dose.

  2. PublicationNature Medicine

    First-in-human results published in Nature Medicine

    The six-person study and lab results were published in Nature Medicine, showing large drops in SOD1 and NfL, without a control group.

  3. Press releaseFrom the companyRactigen Therapeutics

    Ractigen announces the Nature Medicine paper

    Ractigen issued a press release on the Nature Medicine publication.

  4. ConferenceFrom the companyRactigen Therapeutics

    Phase 1 single-dose results at AAN 2026

    Ractigen reported no serious side effects in 20 people, spinal-fluid SOD1 down by up to 58%, and NfL down by 81% at the highest dose. Results are still blinded to which patients got placebo.

  5. Press releaseFrom the companyRactigen Therapeutics

    First patient dosed in Phase 2 part

    Ractigen began the multiple-dose, placebo-controlled Phase 2 part of the trial in China.

2025

  1. Press releaseFrom the companyRactigen Therapeutics

    Early patient data presented at AAN 2025

    Ractigen presented results from the six-person doctor-led study at the American Academy of Neurology meeting, where the abstract won an award.

2024

  1. Press releaseFrom the companyRactigen Therapeutics

    First patient dosed in Phase 1 trial

    Ractigen dosed the first patient in the single-dose Phase 1 part of its RAG-17 trial in people with SOD1-ALS in China.

All sources for this page

  1. Ractigen Announces Positive Clinical Data for RAG-17 in ALS-SOD1 Treatment from Investigator-Initiated TrialRactigen Therapeutics · 10 Sept 2024 · Company press release
  2. Ractigen Therapeutics Announces First Patient Dosed in Phase I Clinical Trial for RAG-17 in SOD1-ALSRactigen Therapeutics · 24 Dec 2024 · Company press release
  3. Ractigen's RAG-17 ALS Data Shines at AAN 2025, Earns Top Award, Phase I AdvancesRactigen Therapeutics · 9 Apr 2025 · Company press release
  4. Ractigen Therapeutics Announces First Patient Dosed in Phase II Clinical Trial of RAG-17 for SOD1-ALSRactigen Therapeutics · 13 Jan 2026 · Company press release
  5. Ractigen Therapeutics Presents Positive Phase I Data for RAG-17 in SOD1-ALS at the 2026 AAN Annual MeetingRactigen Therapeutics · 21 Apr 2026 · Company press release
  6. RAG-17 Phase I single-dose results (AAN 2026 abstract)Neurology · Conference presentation
  7. RAG-17 preclinical efficacy and first-in-human study in SOD1-ALSNature Medicine · 15 Jul 2026 · Peer-reviewed paper
  8. Ractigen Therapeutics Announces Landmark Publication in Nature Medicine on RAG-17 in SOD1-ALSRactigen Therapeutics · 15 Jul 2026 · Company press release
  9. Ractigen Therapeutics Announces Completion of Enrollment and First Dosing in Phase II Clinical Trial of RAG-17 for SOD1-ALSRactigen Therapeutics · 6 Aug 2026 · Company press release
  10. RAG-17 Phase 1/2 trial in SOD1-ALS (NCT06556394)ClinicalTrials.gov · Trial registry
  11. RAG-17 safe, shows early signs of efficacy as SOD1-ALS treatmentALS News Today · News
  12. Ractigen doses first patient in Phase I ALS trialClinical Trials Arena · News