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Stopped

Zilucoplan

Also known as Zilbrysq, RA101495

Bottom line

One placebo-controlled trial was stopped early because zilucoplan was not slowing ALS, and no group of patients looked likely to benefit. It is used for myasthenia gravis, not ALS.

Zilucoplan is a daily injection under the skin that blocks part of the immune system called complement. It was tested in ALS in the HEALEY ALS Platform Trial, but that arm was stopped early in 2022 because it was not working. It is approved for a different disease, generalised myasthenia gravis, not for ALS.

Information checked 5 Nov 2026

Evidence: Not shown to work

Studies: 1 against

Controlled trials found no benefit.

No benefit vs placebo

Slightly faster decline than placebo, 1.11 vs 1.03 points a month on the 48-point ALSFRS-R

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

At a glance

CompanyUCBExplanation and sources

UCB is a Belgian pharmaceutical company focused on immune and neurological diseases. It provided zilucoplan to the HEALEY ALS Platform Trial, run by Massachusetts General Hospital, and sells it as Zilbrysq for myasthenia gravis.

Sources

  1. UCB announces US FDA approval of Zilbrysq (zilucoplan) for generalized myasthenia gravisUCB · 17 Oct 2023 · Company press release
  2. HEALEY ALS Platform Trial Update: Zilucoplan arm stopped early for futilityMassachusetts General Hospital · 1 Mar 2022 · Company press release
How it worksBlocks complement C5, part of the immune systemComplement component 5 (C5) inhibitorExplanation and sources

Complement is a group of immune proteins that can attack and inflame tissue. Some research suggested complement activation may harm motor neurons and the junctions between nerves and muscles in ALS. Zilucoplan blocks C5, a key step in this process.

Sources

  1. Zilucoplan in ALS - HEALEY ALS Platform Trial results (Regimen A)JAMA Network Open · 17 Feb 2025 · Peer-reviewed paper
  2. HEALEY ALS Platform Trial Update: Zilucoplan arm stopped early for futilityMassachusetts General Hospital · 1 Mar 2022 · Company press release
StageDiscontinuedHEALEY Platform Trial arm stopped early for futility (2022)Explanation and sources

Zilucoplan was Regimen A of the HEALEY ALS Platform Trial. In March 2022 the trial's leaders announced that this arm was stopped early because it was very unlikely to show a benefit. Zilucoplan is still sold for myasthenia gravis, which is unrelated to this result.

Sources

  1. HEALEY ALS Platform Trial Update: Zilucoplan arm stopped early for futilityMassachusetts General Hospital · 1 Mar 2022 · Company press release
  2. UCB announces US FDA approval of Zilbrysq (zilucoplan) for generalized myasthenia gravisUCB · 17 Oct 2023 · Company press release
What happenedHEALEY Platform Trial arm stopped early for futility1 Mar 2022Explanation and sources

Massachusetts General Hospital announced that the zilucoplan arm had been stopped after an interim review showed it was unlikely to work. The full results, published in 2025, confirmed no benefit.

Sources

  1. HEALEY ALS Platform Trial Update: Zilucoplan arm stopped early for futilityMassachusetts General Hospital · 1 Mar 2022 · Company press release
  2. Zilucoplan in ALS - HEALEY ALS Platform Trial results (Regimen A)JAMA Network Open · 17 Feb 2025 · Peer-reviewed paper
Best reported effectNo benefit vs placeboSlightly faster decline than placebo, 1.11 vs 1.03 points a month on the 48-point ALSFRS-RExplanation and sources

In the published results, 122 people on zilucoplan were compared with 164 on placebo. Decline was, if anything, slightly faster on zilucoplan (disease rate ratio 1.08, where 1.0 means no difference), and the range of likely values included no effect. There was no sign it slows ALS, even though blood tests showed the drug did block complement.

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

Sources

  1. Zilucoplan in ALS - HEALEY ALS Platform Trial results (Regimen A)JAMA Network Open · 17 Feb 2025 · Peer-reviewed paper
  2. ALS trials fail to meet key endpoints, but it's still a winMedscape · News
Who it's forAdults with ALSAll ALS · Injection under the skin, dailyExplanation and sources

The HEALEY trial enrolled adults with ALS at sites across the USA. In this arm, people injected zilucoplan (0.3 mg per kg) or placebo under the skin every day for 24 weeks.

Sources

  1. HEALEY ALS Platform Trial - Regimen A ZilucoplanClinicalTrials.gov · Trial registry
  2. HEALEY platform trialMND Association · Patient organisation
Can I join?Not available for ALSExplanation and sources

Zilucoplan is not approved for ALS and no ALS trials are recruiting. It can be prescribed for generalised myasthenia gravis, but there is no evidence it helps ALS.

Sources

  1. UCB announces US FDA approval of Zilbrysq (zilucoplan) for generalized myasthenia gravisUCB · 17 Oct 2023 · Company press release
  2. Zilucoplan in ALS - HEALEY ALS Platform Trial results (Regimen A)JAMA Network Open · 17 Feb 2025 · Peer-reviewed paper

Timeline

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

2025

  1. PublicationJAMA Network Open

    Full results published in JAMA Network Open

    Peer-reviewed results confirmed zilucoplan did not slow ALS progression.

2023

  1. Press releaseFrom the companyUCB

    FDA approves zilucoplan for myasthenia gravis

    UCB announced US approval of Zilbrysq for generalised myasthenia gravis, a different neuromuscular disease. This does not apply to ALS.

2022

  1. Trial registryClinicalTrials.gov

    Zilucoplan regimen completed

    The registry records completion of the 162-person zilucoplan regimen.

  2. NewsALS News Today

    Patient news reports the stop

    ALS News Today reported that the zilucoplan arm ended early for lack of effect.

  3. Press releaseMassachusetts General Hospital

    Zilucoplan arm stopped early for futility

    Massachusetts General Hospital announced that the zilucoplan arm was stopped because it was very unlikely to show a benefit.

2020

  1. Trial registryClinicalTrials.gov

    Zilucoplan arm of HEALEY Platform Trial starts

    Zilucoplan began testing as Regimen A, one of the first drugs in the HEALEY ALS Platform Trial.

All sources for this page

  1. HEALEY ALS Platform Trial Update: Zilucoplan arm stopped early for futilityMassachusetts General Hospital · 1 Mar 2022 · Company press release
  2. UCB stops zilucoplan arm early in HEALEY trial for ALSALS News Today · 7 Mar 2022 · News
  3. Zilucoplan in ALS - HEALEY ALS Platform Trial results (Regimen A)JAMA Network Open · 17 Feb 2025 · Peer-reviewed paper
  4. ALS trials fail to meet key endpoints, but it's still a winMedscape · News
  5. HEALEY ALS Platform Trial - Regimen A ZilucoplanClinicalTrials.gov · Trial registry
  6. UCB announces US FDA approval of Zilbrysq (zilucoplan) for generalized myasthenia gravisUCB · 17 Oct 2023 · Company press release
  7. HEALEY platform trialMND Association · Patient organisation
  8. HEALEY ALS Platform Trial - Master ProtocolClinicalTrials.gov · Trial registry