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.
Open the tabs to read about current clinical trials
We are often asked about access to clinical trials.
Your clinical team will know of any UK clinical trials you or your child might qualify for. Please be aware recruitment is often global with are a very limited number of places.
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.
The ASCEND trial will evaluate whether treatment with a higher dose of nusinersen has the potential to improve clinical outcomes and address unmet medical needs in people with later-onset SMA who were previously treated with risdiplam. Up to 135 later-onset, non-ambulatory people with SMA aged 5-39 years will be enrolled. All participants must have been treated with the maximum dose of 5 mg of risdiplam before joining the study and be willing and able to change their treatment regimen to a higher dose of nusinersen.
Read more about trials of nusinersen and any updates, including information about access in the UK in our Nusinersen section >
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 was with people who had previously been treated with Zolgensma, but had a suboptimal response to the gene therapy. Interim results were published in July 2025
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.
Read more about trials of zolgensma and any updates, including information about access in the UK in our Zolgensma section >
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 is an investigational anti-myostatin antibody that is designed to target skeletal muscles (i.e., those used for voluntary movement), potentially increasing their size and growth. Myostatin plays an important role in the regulation of skeletal muscle size by controlling growth. Inhibiting myostatin may help muscles grow in size and strength. GYM329 / Emugrobart in combination with risdiplam, which is designed to increase the amount of SMN protein throughout the body, has the potential to further improve motor function and outcomes for people living with SMA Type 2.
Taldefgrobep alfa is a protein designed to bind to and inhibit the function of myostatin. Myostatin is naturally present in our muscles, where it plays an important role in limiting muscle growth. By inhibiting myostatin function, taldefgrobep alfa 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.
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.
NMD670 is being tested in a phase 2, randomised, double-blind, placebo-controlled study in 50 ambulatory participants with SMA Type 3 that is estimated to be completed in late 2024.