Muscular dystrophy is a group of diseases that make muscles weaker and less flexible over time. It is caused by a problem in the genes that control how the body keeps muscles healthy. Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy. DMD mainly affects boys, and symptoms usually start between the ages of 3 and 5 years. DMD slowly gets worse over time and affects muscles used for movement, breathing, and heart function.
Health care providers can prescribe Amondys 45 (casimersen) for people with DMD who have a gene mutation that can be treated by skipping a certain section of genetic code called exon 45. Amondys 45 is the first targeted treatment for this type of mutation and has been shown to help increase the production of a muscle protein called dystrophin.
How Does Amondys 45 Work?
People with DMD have a change (mutation) in their genes that affects a muscle protein called dystrophin. Without the right amount of functioning dystrophin, muscles are unable to repair themselves as they should. Amondys 45 is a treatment for some people with DMD whose genetic testing shows a mutation that is suitable for this specific medicine. Amondys 45 uses a process called “exon skipping,” which helps the body make a shorter but working dystrophin protein.
Is Amondys 45 Right for Me?
Your health care provider will perform a test to make sure that Amondys 45 is right for you. Amondys 45 may be a good choice for you if you have DMD caused by a gene mutation that can be treated by skipping a certain section of genetic code called exon 45.
How Is Amondys 45 Given?
Amondys 45 is typically given once weekly as an intravenous (IV) infusion into your vein by your health care provider. Each infusion takes about 35-60 minutes to complete. The dose of Amondys 45 is based on your weight.
How Was Amondys 45 Studied?
Amondys 45 was evaluated in a study that included boys with DMD who had a confirmed DMD gene mutation that could be treated with exon skipping. To join the study, boys must have been taking a stable dose of oral corticosteroids for at least 24 weeks. Boys in the study were randomly assigned to receive weekly IV infusions of either Amondys 45 or a placebo containing no medicine. Neither the boys in the study nor the study personnel knew which treatment each person was getting.
At the beginning of the study, boys in the study were between the ages of 7 and 20 years, with an average age of about 9 years. Most boys were White (88%), and 9% were Asian.
The main purpose of this study was to measure the amount of dystrophin in the muscles before and after treatment with Amondys 45, and compare it to dystrophin levels in boys who received a placebo. To find out how much dystrophin was in the muscles, each participant had a small muscle sample taken for a muscle biopsy. The sample was then tested in a laboratory test to measure the amount of dystrophin it contained. The researchers compared the results to the amounts normally found in healthy muscle and reported it as a percentage of “normal” dystrophin levels for each person.
What Did the Study Show?
Preliminary study results are available for 43 boys. Of these, 27 received Amondys 45 and 16 received a placebo. After 48 weeks of treatment, the boys who received Amondys 45 had a significantly greater increase in dystrophin levels compared to boys who received a placebo.
At the start of the study, dystrophin levels were very low in both groups (less than 1% of normal). After 48 weeks, boys who received Amondys 45 had an average dystrophin level of 1.74%, while those who received a placebo had a level of 0.76%. This means the Amondys 45 group had an average increase of 0.81%, compared to only 0.22% in the placebo group.
Your results may differ from what was seen in clinical studies.
How Strong Is the Evidence for Amondys 45?
Amondys 45 was approved by the FDA through a special process called “accelerated approval.” This means the FDA approved the medicine based on early promising results showing that it increases the amount of dystrophin that is made by the muscle. Additional studies are needed to confirm the benefits of Amondys 45.
What Can I Do to Manage Side Effects?
The most common side effects with Amondys 45 include upper respiratory infections (like a common cold), cough, and fever. Regular hand washing is your best strategy to keep from getting sick. You should also minimize contact with people who have colds. If you are looking for relief from the symptoms of a cold, fever, or the flu, there are many over-the-counter (OTC) options at your local pharmacy. Two common types of pain relievers are acetaminophen (Tylenol) and nonsteroidal anti-inflammatory drugs (NSAIDs). Most OTC pain relief medicines contain one or the other. A health care provider can recommend OTC options that are safe for you.
The Amondys 45 infusion may cause some discomfort where the IV is placed. Your health care provider may apply a numbing cream to the area before the infusion to help reduce pain.
Amondys 45 may cause damage to your kidneys. Your health care provider will check your kidney function regularly. This is usually done by testing your urine (pee) before the infusion or a few days after the infusion.
Is There Any Cost Assistance Available?
Yes. There is a Co-Pay Assistance Program offered by the drugmaker. Whether you are eligible depends on whether you have prescription insurance and what type of insurance you have. You can find out more information at www.amondys45.com/getting-support/how-we-can-help or by calling 888-727-3782.