Drugs Currently Being Tested in Clinical Trials
Drugs Currently Being Tested in Clinical Trials
The currently available SMA treatments (Nusinersen, Zolgensma and Risdiplam) aim to increase the amount of survival motor neuron (SMN) in the body. They are referred to as ‘SMN-targeted therapies‘.
Some of the drugs currently in clinical trials are being tested as ‘combination therapies’.
Combining an SMN-targeted therapy with a second approach that targets muscles may result in a complementary or added benefit. The idea is that this combined approach treat both the underlying cause of SMA and the symptoms of the condition.
We are often asked about access to clinical trials.
ClinicalTrials.gov > is a place to learn about clinical studies from around the world. SMA Europe has also set up a Global Clinical Trials Finder > SMA UK has no input into either of these website and cannot guarantee they are up to date and accurate.
If you are thinking about applying to join a clinical trial, we suggest you talk with:
Your clinical team about:
- What they know about the trial and any results so far
- How they think it might help you / your child
- Any health or other risks of travel for the trial
- How close you need to be to the trial centre and for how long. For follow up and in case of complications from the treatment
- Any risks there might be having a treatment provided in one place and ongoing care in another.
The trial Principal Investigator about all of the above, plus:
- The eligibility criteria and referral process
- How they would assess you / your child
- How often you would need to attend
- How long the trial is for
- What follow up is needed at the trial centre
- Where you would stay during and after treatment
- What costs would be covered by the trial and what would you need to fund:
- the treatment
- the travel
- accommodation
Your family and supporters about:
- Managing the commitment practically, emotionally and financially
- If overseas – travel insurance to cover your / your child’s health and other needs.
- If overseas – travel insurance for anyone other than the patient.
Adimanebart (ARGX-119) is a muscle directed therapy which aims to reduce the muscle fatigue and weakness experienced by SMA patients. This drug is an antibody that has been designed to target the protein muscle-specific kinase (MuSK). MuSK is a protein that is important for facilitating communication between the nerve and the muscle, at the site called the neuromuscular junction. Good communication at the neuromuscular junction is essential for muscles to move and function normally.
In SMA, we know that the neuromuscular junction does not work as it should, which contributes to the muscle weakness and fatigue that SMA patients experience. This drug aims to improve communication between the nerves and muscles which could help with muscle function. This drug would be given to SMA patients in conjunction with an SMN replacement therapy such as nusinersen, risdiplam or zolgensma.
Sparkle Study
The Sparkle study is testing adimanebart (ARGX-119), a drug that targets muscle fatigue and weakness. It is a randomised, double-blind Phase 2 clinical trial, aiming to recruit approximately 60 patients across 7 sites in the UK and also in the USA. The trial opened in December 2025.
- What is the purpose of this study? To find the correct dose of ARGX-119, determine its safety, how well it works, how it moves through the body and how the immune system responds to it.
- Who can take part? Patients with 5q-SMA are eligible if they are between 5-18 years old, able to walk at least 50 metres without walking aids, and already on stable SMA treatment (either nusinersen or risdiplam) and/or have already received gene therapy treatment.
- How does the trial work? ARGX-119 is given by injection into the blood (intravenously). Patients will be assigned to 1 of 3 groups by chance:
(1) usual treatment for SMA + high dose of ARGX-119
(2) usual treatment for SMA + low dose of ARGX-119
(3) usual treatment for SMA + placebo.
After an initial 4-week screening period, the main study will be 24 weeks. After this time, there will be an extension of around 2 years where all participants will receive ARGX-119. The safety follow up period will be 20 weeks after the last dose of ARGX-119 is given. Overall, the trial will run for approximately 3 years.
f you wnat to find more about this trial ask your clinician and see visit the government clinical trial website
Salanersen is similar to Spinraza (nusinersen) in that it is an “antisense oligonucleotide” (ASO). This is a small snippet of synthetic genetic material. Like Spinraza (nusinersen), salanersen is designed to target the SMN2 gene to increase the amount of SMN protein that it produces. It is a once a year injection. A Phase 1 clinical trial of Salanersen in healthy volunteers was initiated in late 2022. This showed the drug was safe and well-tolerated. Part B of this trial is with people who had previously been treated with Zolgensma, but had a suboptimal response to the gene therapy.
This is a randomised, double-blind, sham-controlled Phase 3 study with a primary objective to evaluate the clinical efficacy, safety, and tolerability of a one-time intrathecal (IT) dose of Zolgensma in treatment naïve children and young people with Type 2 SMA who are between 2 and 18 years of age, able to sit, but have never walked.
See:
SRK-015 / Apitegromab is a muscle-directed therapy that aims to reverse or restrict the muscle atrophy and weakness experienced by SMA patients. The drug is an antibody that very specifically targets an important protein called myostatin. Myostatin is naturally present in our muscles, where it plays an important role in limiting muscle growth. By inhibiting myostatin function, Apitegromab can potentially release the breaks on muscle cell growth leading to an increase in muscle size and function. If this is successful, this could benefit people who have SMA.
Read more about trials and any updates, including information about access in the UK >
GYM329 / Emugrobart was an investigational anti-myostatin antibody designed to target skeletal muscles (i.e., those used for voluntary movement), potentially increasing their size and growth. It was tested in Phase 1 and 2 clinical trials. Roche ended trials in March 2026 as the treatment did not consistently deliver the improvements they hoped for.
NMD670 is an orally-bioavailable, small molecule that specifically targets a protein called ClC-1 that is found almost exclusively on the surface of muscles cells. The function of ClC-1 is to dampen the excitability of muscles and prevent them from becoming overstimulated. By inhibiting ClC-1 function, NMD670 can increase and improve the passage of signals from motor neurons to muscles, which can increase how easily muscles are able to contract.
Trials are still active, with an expected completion date of May 2026.