Duchenne muscular dystrophy (DMD) is a genetic disease that causes progressive muscle weakness. DMD commonly affects boys, where symptoms are seen in early childhood. There is no cure for DMD. Health care providers manage symptoms with steroids, physical therapy, and assistive devices (like braces, wheelchairs). New medicines are being studied to help slow the progression of DMD by targeting the abnormal gene. Elevidys is a new gene therapy medicine for DMD that helps keep muscles strong.
How Does Elevidys Work?
Muscles in the body need a protein called dystrophin to work correctly and stay strong. DMD is caused by a genetic mutation that causes the body to make this protein wrong. A mutation is a mistake in the instructions the body uses to make things. Without enough dystrophin, muscles weaken over time. The weakness starts in the legs and pelvis. This makes it hard to run, climb stairs, or get up off the floor. As time goes on, DMD can affect your arms, heart, and lungs.
DMD is a progressive disease that is usually diagnosed in young children. This means that the symptoms are more noticeable as the child gets older. Since there is no cure for DMD, health care providers manage the symptoms with medicines and physical therapy to help keep muscles strong.
New medicines have been approved to target specific areas of these genetic mistakes or to provide a similar dystrophin protein directly to the muscle cells. This allows the body to start making a similar dystrophin protein. With more dystrophin, the muscles can stay strong longer.
Elevidys is one of these medicines, also called gene therapy. Elevidys uses a special virus, called a vector, to get a version of the dystrophin protein to the muscle cells. It helps the body produce a shortened version of the dystrophin protein, potentially slowing the progression of the disease.
How Should I Use This Medicine?
Elevidys is a single, one-time treatment. It is given as an infusion by a health care provider, which means it is delivered directly into the bloodstream through a vein. The infusion is given at a hospital so that you can be monitored closely. The infusion process can take a few hours. Before the infusion, your health care provider may do blood tests to make sure you are ready for the infusion. (See the Monitoring section below.)
Your health care provider will start a medicine known as a corticosteroid to help prevent infusion-related side effects. Your vaccines should be up-to-date before starting Elevydis. (See the Interaction section below.) Your health care provider will tell you how to take the medicine and when to stop taking it.
How Was It Studied for DMD?
Three studies have been done to look at the safety and efficacy of Elevidys for the treatment of DMD. Two studies (study 1 and study 3) were placebo-controlled, which helps researchers see differences in benefit or harm of a medicine when compared with no treatment. People in the study had a diagnosis of DMD with specific gene mutations. The following information was similar for all the studies.
- Patients were male (100%) and were 4 to 8 years of age, with an average age of 6 years and average weight of 50 pounds.
- Most people receiving Elevidys in the studies were White (76%), with 12% who identified as Asian, 7% as other, 2% as African American or Black, 2% as "not reported," and 1% as multiple races. All people in the study took a corticosteroid medicine before getting the infusion and had antibody levels below the level determined to be safer for Elevidys infusion.
Study 1 had two phases, where people received one infusion of either Elevidys or placebo. The placebo infusion did not have active medicine. The people were monitored for improvements and side effects for 48 weeks. After the first 48 weeks, people in the study switched to receiving either Elevidys or placebo, the opposite of what they received in the first phase. (See the table below.) All of the people in the study were ambulatory, meaning they were able to walk without assistance.
Study Group | Phase 1: 48 Weeks | Phase 2: 48 Weeks |
Group 1 | Elevidys | Placebo |
Group 2 | Placebo | Elevidys |
In study 2, all people in the study received Elevidys. There was no placebo. A small number of people (17%) were non-ambulatory, meaning they were no longer able to walk independently.
In study 3, people in the study received either an Elevidys or placebo infusion.
The effectiveness of Elevidys in the studies was based on changes in the North Star Ambulatory Assessment (NSAA) score and/or changes in the amount of micro-dystrophin proteins in the skeletal muscles. NSAA is a test that measures how well someone with DMD can move and do their everyday activities. The maximum score is 34. A lower score shows that a person has limited mobility or poor muscle health. The average NSAA score in all studies was 21-23, which means that the person had some limitations in their movement, but they were still able to do most daily activities. Other results looked at the ability to move by timing events like walking/running a distance, climbing four stairs, and standing from lying down.
What Benefits Were Seen in the Studies?
People who received Elevidys in the studies saw improvements in NSAA scores, increases in the amount of dystrophin in their muscles, and positive changes in their timed movements. This means that their muscles were a little stronger and they had more ability to move compared to the people who received a placebo.
Change in NSAA scores. At the end of the studies, people who received Elevidys had an average improvement in their NSAA scores by 2 points compared with a small decrease in scores for the people who received placebo. This means that Elevidys strengthened their muscles, allowing easier movement in their daily activities. The change in scores were greater in younger children who received Elevidys (ages 4-7).
Change in dystrophin proteins. Elevidys delivers a version of the dystrophin protein, which causes the body to start making natural dystrophin. In two studies, the amount of dystrophin in the muscle cells increased. The levels were like what is expected for normal muscles. This could mean that having more dystrophin in the muscle cells could protect the muscles from further damage. Further studies are needed to see how long this effect would last.
Ability to move. In the studies, the mobility of each person was timed when they were doing the following three activities.
- Time to rise, which is the time it takes the person to move from lying down to standing
- Time to walk/run 10 meters and 100 meters
- Time to climb four stairs
The studies showed that people who received Elevidys had improvements in the timing of these activities compared with the people who received placebo. Patients receiving Elevidys were able to complete these movements slightly faster. Further studies are needed to see how long this effect would last.
Your results may differ from what was seen in clinical studies. You and your health care provider should determine if the benefits outweigh any potential risks.
When Will the Medicine Start Working?
It may take up to a few years to see the benefits from Elevidys. As the body starts to make its own dystrophin for muscles, the muscles may slowly start to become stronger. You may see slight improvements in movement, like walking, climbing stairs, or getting up off the floor. It is important to track your progress and review it with your health care provider. Contact your health care provider if you don’t see improvements.
Are There Reasons This Medicine Should Not Be Used?
Elevidys should not be used if you have specific types of genetic mutations, including any deletion of exon 8 or exon 9 in the DMD gene. Your health care provider may test for these specific genetic mutations before giving you Elevidys.
People with a high amount of a specific antibody (Elevidys vector AAVrh74) may not be able to use Elevidys. These antibodies can block the way Elevidys gets to the muscle cells and can cause serious side effects. (See the Side Effects section below.) Your health care provider may do a blood test to check the number of antibodies before starting the infusion. If the number of antibodies is too high, Elevidys should not be used.
The corticosteroid taken before and after Elevidys infusions can cause serious side effects if you have an active infection, like the common cold, flu, stomach flu, ear infection, or respiratory infection. The corticosteroid medicine and Elevidys infusion should not be started if you have an active infection. Tell your health care provider if you have any of the following symptoms of infection:
- Fever or chills
- Body aches
- Coughing or trouble breathing
- Tiredness
- Sneezing
- Runny nose
- Sore throat
How Can I Prevent and Manage Side Effects?
The most common side effects of Elevidys are nausea and vomiting, which are usually experienced in the first few weeks. Tell your health care provider if you have nausea or vomiting. They may give you medicine for nausea and suggest changes to your diet to ease the symptoms. Make sure that you stay hydrated by drinking plenty of water.
Other common side effects include fever and low platelet levels (thrombocytopenia). Contact your health care provider if you have a fever, as that could be a sign of infection. Platelets help to form blood clots. Having a low level of platelets may increase your risk of bleeding. Tell your health care provider if you have any of the following symptoms of low platelet levels:
- Easy bruising or bleeding
- Bleeding that does not stop
- Nosebleeds
These are not all of the possible side effects. Talk with your health care provider if you are having symptoms that bother you. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.
What Monitoring or Blood Tests Might I Need?
Your health care provider may perform lab tests to monitor your health before the infusion and assess how your body responds to the medicine. The following are key pieces to that monitoring.
Gene tests. Your health care provider may do a blood test to see if you have the dystrophin gene before starting Elevidys. They will also see if you have specific mutations to see if Elevidys should not be used.
Antibodies to Elevidys vector. Your health care provider may do a blood test to check the number of antibodies to the Elevidys vector (AAVrh74) in the blood. This helps prescribe the right dose and see if there may be safety concerns. (See the Adverse Effects section below.)
Infections. Elevidys should not be started if you have an active infection. Complete blood count (CBC) is a blood test that can check for infections or other blood disorders.
Liver health. If you have active liver disease or if your skin or the whites of your eyes appear yellowish (a sign of liver problems), your health care provider may wait to start Elevidys until the liver problems are resolved. A liver function test (LFT) looks for liver damage. After the infusion, your health care provider will check these tests again to look for liver side effects.
Heart muscle health. DMD can cause inflammation that can damage heart muscle cells. When the heart muscle cells are damaged, they release a protein called troponin into your bloodstream. Your health care provider may monitor the health of your heart muscle by checking troponin levels before giving Elevidys and after the infusion. Contact your health care provider if you have chest pain or shortness of breath, as these may be symptoms of inflammation in your heart.
Platelet levels. Elevidys may cause a decrease in your platelet levels. Your health care provider may check platelets before giving Elevidys and after the infusion.
What Types of Interactions Can Happen?
Before starting the corticosteroid medicine before the Elevidys infusion, your health care provider will review your vaccine history. Corticosteroids weaken the immune system, which can potentially affect the response to a vaccine. Any vaccine needed should be given at least 4 weeks before starting the corticosteroid medicine.
This is not a complete list of medicines that may interact with Elevidys. Tell your pharmacist or health care provider about all the prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, or other supplements you take or have recently taken. This will help them determine if there are any interactions or if you need a dosage adjustment.
Getting Your Medicine: What to Expect
Elevidys is given by a health care provider at a hospital or clinic. It requires a different process than picking up a prescription at your local pharmacy. The manufacturer has a program to help support the process for you and your health care provider. You can find out more at www.elevidys.com or by calling 888-727-3782.
Here are some differences that you may expect:
Insurance approval. Your insurance may require approval for using this medicine, also called a prior authorization. The insurance company reviews the prescription from your health care provider to make sure it is covered and determines the process that needs to be followed.
Using an Elevidys treatment center. Elevidys infusions are given at select hospitals and clinics in the United States. This ensures that the treatment center has health care providers with experience using gene therapies like Elevidys.
Financial assistance. There is a financial assistance program from the manufacturer. Whether you are eligible depends on whether you have prescription insurance and what type of insurance you have.