U.S. FDA has granted accelerated approval to the drug called Vyondys 53 (golodirsen) for treating cases of Duchenne muscular dystrophy. This drug is available in an injectable form. It is specially designed for patients suffering from DMD with a confirmed mutation of the gene dystrophin. This mutation in the gene is amenable to exon 53 skipping. According to an estimation, around 8% of the patients have this mutation with DMD.
DMD, a rare genetic disorder that is characterized by the slow degradation of the muscles and weakness. Duchenne Muscular dystrophy is the most common type of muscular dystrophy. It is caused by the absence of the gene and mutation in the gene dystrophin.
It is a protein that keeps the muscle intact and maintains its shape. The first symptom usually appears between the age of three to five years and become severe with time. The occurrence of the disease is usually seen in people without a known history of the family about this condition.
Boys are more affected by this disease and only rare cases include girls. The prevalence rate is 1 in 3600 male infants across the world.
According to the words of Billy Dunn, the director of the office of Neurosciences in the FDA Center for Drug Evaluation and Research that for serious neurological disorders, there is a need for developing the new medical treatment.
For this reason, the center has a long-standing commitment to work with researchers, patients, and drug companies. This would be done to assist the development and approval of drugs for treating rare diseases. Today’s accelerated approval will facilitate the patients by treating the Duchenne muscular dystrophy having confirmed mutation of the dystrophin gene.
This approval will make an easy way for the viability of Vyondys 53 to the patients and still we aimed at finding the more benefits of the drug through ongoing clinical trials.
Patients who suffer from DMD lose their ability to independently perform daily activities. They require a wheelchair in their early teenage. With the progression of the disease, severe heart and respiratory disease may occur. The patient usually succumbs to the disease between 20 and 30 years. The severity of disease and expectancy of life vary in every patient.
Under the accelerated approval pathway, Vyondys 53 approved. This approval is for the drug to treat the serious disease that life-threatening. The drug approval usually based on the results that are extracted from the clinical tails study to predict the benefits of the drug in treating the patients.
The approval also provides easy and early access to the new drugs while the company is engaged in conducting the clinical trials.
The accelerated approval given to the drug was based on the surrogate endpoint. When the patients are treated with the drug, it increases the production of dystrophin in the skeletal muscles. This proves the clinical benefit of the drug in the patients with DMD who have confirmed mutation in the gene amenable to exon 53 skipping. The improvement of motor function has not been observed. This indicated the potential risk associated with the drug.
A two-part clinical study evaluated Vyondys 53. In the first part, 12 DMD patients were included. Eight patients were receiving Vyondys 53 and four were administrated with placebo. The second part was open-label including the 12 patients from the first part and 13 new patients. The results of the study showed that the level of dystrophin increased from 0.10% to 1.02% of normal after giving the drugs to patients for 48 weeks or longer.
Another set of clinical trials are designed to confirm the clinical benefits of the drug. The study is designed to find whether the motor function of patients with DMD improves. If the trials will not succeed in verifying the clinical benefits, proceedings to withdraw approval may initiate by FDA
The most common side effect observed in the patients who received Vyondys 53 during the clinical studies were fever, headache, cough, abdominal pain, vomiting, cold and nausea. Also, patients may suffer from hypersensitivity reactions, itching, rash, fever, skin irritation, and skin peeling. Animals who are administrated with the golodirsen show the renal toxicity, but this was not seen in the patients who received Vyondys 53.
Fast Track and Priority Review designation were imparted to this application by the FDA. For providing the incentives to assist and appreciate the synthesis of the drug to treat a rare disease, Vyondys 53 received Orphan Drug designation. The FDA rare pediatric disease priority review voucher is given to the manufacturer to encourage the effort in making the drug for preventing the rare disease.