Clinical Trials

A clinical trial, or interventional study, tests new drugs and treatments for spinal muscular atrophy (SMA) in a controlled setting using protocols, or plans, that will likely provide conclusive results.

Cure SMA’s Approach

The process of conducting clinical trials can be long, complicated, and difficult. On average, only ten percent of drugs in clinical development get approved by the U.S. Food and Drug Administration (FDA). Through the SMA Industry Collaboration, we fund research to ensure that effective, safe treatments for SMA can progress through clinical trials quickly and gain approval from the FDA and international regulators. Our research also ensures these treatments address the unmet needs of the SMA community, and that the community’s priorities and goals are incorporated into the development, review, and approval of therapies.


See below for spinal muscular atrophy (SMA) clinical trials currently recruiting for participants.

Clinical trials often include an extended post-study follow-up period ranging anywhere from months to years to assess the long-term impact of the treatment. Long-term follow-up (LTFU) studies are conducted to address the needs of the scientific community and regulators, and they may help to inform clinical decision making. Some LTFU studies may only be open to participants of prior clinical trials testing that drug. Others may be open to anyone currently taking the drug and meeting certain criteria. Below is a list of LTFU studies for participants with SMA:

See additional SMA clinical trials that are recruiting here.

How Clinical Trials Work

The following is a summary of the clinical trial process. For a more detailed description, download our care series booklet, Learning About Clinical Trials.

Clinical Trial Phases

A drug must pass each individual phase of a clinical trial before advancing. The number of participants in each phase can vary. The numbers given below are typical of trials for an orphan disease, such as SMA. For additional information on major drug programs in development, visit the SMA Drug Pipeline.

  • Phase 1

    Tests safety and dosage levels, usually ten to 20 individuals. Sometimes, these volunteers are healthy individuals. However, for an orphan disease like SMA, some or all may be patients with the condition being studied.

  • Phase 2

    Tests a slightly larger group, usually twenty to 40 individuals, all of whom have the condition being studied.

  • Phase 3

    Increases the number of people tested — up to 100-200, including the control or placebo group. A drug that passes these three phases can be approved and marketed to the general public.

  • Phase 4

    Primarily involves ongoing evaluation and monitoring, even after a drug is approved for the general public.

Regulating Clinical Trials

Clinical trials are regulated before they begin and while in progress.

FDA Approval. Clinical trials are usually conducted in multiple cities/states to ensure the most comprehensive, accurate results. The FDA must approve a drug for use in a clinical trial so the drug can be distributed across state lines. To get FDA approval for the trial, clinical trial sponsors submit an Investigational New Drug (IND) application. Once approved, the IND allows them to distribute the drug for the duration of the trial

IRB Review. Clinical trials are approved by an Institutional Review Board (IRB). This independent committee ensures that a trial is conducted ethically, potential benefits justify any risks, and the rights of participants are protected. The IRB reviews the trial as it progresses

Informed Consent. Trial participants must receive all facts about a trial before it starts and sign an informed consent document. Informed consent is not a contract. Participants can still withdraw from the trial

The SMA Industry Collaboration strives to engage the FDA and other regulatory agencies to bring the priorities of the community to the drug development and assessment process. Learn more about the collaboration’s regulatory engagements to date.

Clinical Trial Protocols

Protocols are a study plan for clinical trials and cover important details.

Who Can Participate. These rules, called “inclusion and exclusion criteria,” typically include age, stage, or type of disease, previous treatment history, and other medical conditions

Study Expectations. This includes what procedures, medications, and dosages will be given to each participant, and how often

Timing Details. This involves working with participants on when they must see a study doctor and what tests or measurements the doctor will use to evaluate them

Control Group (if applicable). Participants in the control group will receive a placebo—an inactive pill, liquid, or powder—or the current standard treatment. The other group is given the experimental treatment. Participants are often not told which group they are in, and the researchers may not know either. This “double-blind” format keeps participant or researcher bias from affecting results

Clinical Trials for Combination Therapy

In the SMA community there is increasing interest in understanding the safety and efficacy of combination therapy. The concept of combining treatments stems from the potential to see added or synergistic benefit by addressing multiple aspects of the disease at the same time to improve outcomes. Clinical trials provide an opportunity to explore the safety and efficacy of combination therapy in a controlled setting using testing protocols and inclusion criteria most likely to yield conclusive results. Protocols will often compare outcomes from combined treatments to the use of a single treatment alone.

Learn more about potential benefit and risk considerations of combination therapy.

There are multiple approaches being explored to treat SMA. “SMN dependent” methods increase the amount of survival motor neuron protein (SMN) in the body; this may be achieved by replacing or correcting the faulty SMN1 gene or modulating the low-functioning SMN2 “back-up gene”. A second approach, commonly called “SMN independent,” aims to target other pathways, systems, and processes within the body.

SMN Dependent Therapeutic Strategies

Gene therapy: Replaces the missing SMN1 gene via a viral vector

SMN2 promoter activation: Causes the SMN2 gene to be “on” more, generating more fully functional protein

SMN2 splicing modulation: Redirects splicing of SMN2 to make more full-length transcripts containing exon 7

SMN Independent Therapeutic Strategies

Neuroprotection: Protects against neuronal injury or degradation

Muscle enhancement: Prevents and restores loss of motor function

Neuronal function: Enhances neuronal transmission

Motor Neuron


There are many factors you should consider when deciding whether or not to enroll in a clinical trial. It’s important to understand how the process works and what your family should expect before you begin.

Finding a Trial

The FDA website,, is the best way to get more details about a particular trial or to see the progress of trials that are in stages other than recruitment. Other sources include Clinical Trial and Study Opportunities page and Cure SMA Latest News, through which we regularly announce new trials and trial updates. Your healthcare provider may also have information on trials that are recruiting participants.

Information About Trial Participation

There are many things to consider when choosing to participate in a clinical trial. For more detailed information on clinical trial participation, download our care series booklet, Learning About Clinical Trials.

Benefits and Risks

A well-designed and well-executed trial offers many benefits:

Advance knowledge about SMA, contribute to the development of a potential treatment, and help others with SMA in the future

Potentially receive access to an investigational drug

Offer appointments with an SMA study team

Receive trial-related care, monitoring, and assessments

There are also possible risks to consider:

There may be unpleasant, serious, or even life-threatening side effects to experimental drugs

The experimental drug might not be effective

The protocol may require more of your time and attention than a standard course of treatment, including trips to the study site, more drugs, hospital stays, or complex dosage requirements

Often, though not always, you must forgo taking an approved therapy while you are in the clinical trial

Questions to Ask

When deciding to participate, learn as much as possible about the clinical trial, the care expected, the cost, and the team that will be conducting the trial. We recommend you write down a list of questions to ask before meeting with the study doctors. Here are some potential questions you might ask:

What is being studied?

If researchers are studying an investigational drug, why do they believe it may be effective for SMA?

How long will participation last?

How often will I have to visit the hospital or clinic? Will any of these visits require an overnight stay?

Is there a chance of receiving a placebo?

What types of tests and medical procedures will be performed?

What are the possible risks and benefits of participation?

Who will oversee my healthcare while participating?

Will the results of the clinical trial be available to participants?

Who will pay the costs associated with participation?

Will I be reimbursed for other expenses?

Is travel support included?

Is there a planned extension trial?

You should also discuss your decision with your primary physician, family members, and, if needed, a counselor, therapist, or spiritual advisor.


During the Trial

Follow all instructions given by the study team

Tell the principal investigator of any new health-related problems. Even if you don’t consider them to be caused by the clinical trial or the investigational drug, any small change is very important to report

Complete questionnaires about your health status (or your family member’s health status) between visits

Attend all scheduled visits

Tell the principal investigator about any new medications or changes in the doses or frequency of medication

Be mindful about discussing the clinical trial with other participants, including whether you think you or your family member may be receiving a placebo

Clinical Trial Webinars

There is a lot of information to consider when deciding to participate in a clinical trial. We have made some of our previous webinars on Clinical Trials for SMA available to you to help give you some of the information you need to make an informed decision.

SMA Clinical Trials: What You Need To Know - Click Here to Watch

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