Spinal Muscular Atrophy (SMA) is a rare genetic disease that affects the motor nerve cells in the spinal cord and is the leading genetic cause of infant mortality. It is caused by an inherited faulty SMN1 gene. The SMN1 gene helps provide instructions to cells on how to produce the SMN (survival motor neuron) protein. If there isn’t enough correct SMN protein produced, it leads to degeneration, meaning decline or deterioration, of motor neurons. This creates problems with a person’s physical strength, often taking away the ability to walk, eat or even breathe. Gene therapy is a fitting approach for diseases caused by a single gene mutation, like SMA. It targets the cause of disease by delivering a working fully functioning copy of the gene into motor neuron cells. Let’s learn more about how it works.
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Treatments
There are a few approved gene therapy treatment options available that can help manage symptoms of SMA, along with slowing or stopping disease progression. There are also active preclinical research studies and clinical trials for SMA, including those studying to expand existing treatments for more ages or investigating dual treatments. Clinical trials are a required part of the research process that aim to help researchers understand the way a drug or treatment will interact with the human body and whether it is safe and effective. Preclinical studies are an even earlier stage of research to confirm the safety and effectiveness of a treatment in animal or cell-based models before proceeding with a human clinical trial.
To stay up to date on open clinical trials in the U.S. or globally, visit the ASGCT Clinical Trials Finder and search Spinal Muscle Atrophy using the "diagnosis" filter.
Zolgensma
The FDA approved Zolgensma is a gene therapy developed by Novartis Gene Therapies for clinical use in the United States with children under two years of age with all types of SMA.
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For clinical trials treating SMA type 1, researchers described improvements in respiratory and movement function meaning patients were able to breathe better, feed themselves, and sit unassisted. These improvements lead to fewer and less lengthy hospitalizations compared to what patients traditionally face. These reductions in hospitalizations can help improve both the child’s and caregiver’s quality of life.
Spinraza
There’s an FDA-approved treatment called Spinraza that helps to counter the effects of SMA. Spinraza helps increase the production of the SMN protein by using a backup gene called SMN2. With Spinraza’s help, enough SMN protein is produced. If you think this treatment might be an option for you or your child, make an appointment with your healthcare provider to learn more and help determine eligibility.
Challenges & Benefits
One-Time Treatment and Expansion
The aim for SMA gene therapy is to only need one administration by targeting the cause of the disease. Typically this should only take about an hour. This is in comparison to other treatments that may require a series of doses, multiple times throughout the patient’s life. Once a therapy is approved, then researchers begin to work on expanding it to reach patients that have other Types of SMA or that may be older than the current inclusion age.
Early Diagnosis: Newborn Screenings
The symptoms of SMA Type 1—the most common and severe form of the disease—show up within the first six months of a child’s life. These symptoms can cause irreversible damage to a patient within this period, so early diagnosis is key to receiving an effective gene therapy treatment.
Early diagnosis can be completed through standard newborn screenings. Although progress has been made, there are still many states that do not include SMA as a part of standard screening completed for newborns. As mentioned above, it is highly important for this disease to be diagnosed as early as possible. You can help advocate for SMA to be added to the panel of newborn screenings in your state.
Screening Before or During Pregnancy
Parents who are planning a pregnancy can learn if they are carrying genes for inherited disorders by analyzing small samples of blood or body tissues gathered from a cheek swab or blood draw. Expecting parents can also consider genetic testing during pregnancy, where pregnant women can undergo amniocentesis or chorionic villus sampling to screen for disorders. Genetic testing can also be done soon after birth.
Eligibility and Access
If you are considering participation in a clinical trial for yourself or your child, remember that it is difficult to know if and when a clinical trials can be stopped, delayed or approved. Because of this, it can be risky to avoid other forms of care or approved treatments while waiting for a new treatment approval. It is also important to know that certain eligibility criteria is in place, which may include age or weight, and having a certain type of SMA. It is best to speak with your healthcare provider or neurologist to understand and maneuver this difficult decision-making process.
Patient and Family Support
Patient advocacy organizations work hard to provide support, advice and information for getting involved. They are a great way to connect with other families affected by SMA. Although the disease may be rare, you’re not alone. For more resources and support networks, check out:
You can also watch this series of webinars from NORD, Obtaining Support and Ongoing Care for Children with Spinal Muscular Atrophy (SMA) After Gene Replacement Therapy, a six-part educational program intended for caregivers and patients affected by SMA. You'll hear from experts who will discuss the benefits of gene replacement therapy and methods to maintain respiratory health, improve motor function, and optimize nutritional health for patients with SMA.
Cure vs. Control
While pursuing existing or future SMA gene therapy treatments, it is important to note that gene therapy is not a cure and instead helps to control the progression of the disease. It’s impossible to restore already damaged neurons in a patient. However, gene therapy can help slow or stop the effects of the disease, greatly increasing the quality of life for the child as they grow older.