Good news for patients with Mucopolysaccharidosis Type VII (MPS VII)!
In mid-November, the FDA approved a new drug for treatment of this rare disorder. The drug can be used for both adult and pediatric patients.
MPS VII, also called Sly syndrome, is an enzymatic disorder that only affects about 150 patients in the world. It’s one type of lysosomal storage disorder, resulting from a shortage of beta-glucuronidase enzyme. This deficiency leads to an accumulation of toxic substances in cells.
While this disorder may be uncommon, its effects are severe. The exact symptoms change from one patient to the next, but they generally include skeletal abnormalities, accumulation of fluid in the brain, and a larger tongue. Patients also may develop enlarged an spleen and liver, problems in their heart valves, and respiratory issues. Life expectancy varies between patients, based off of their symptoms. Some patients will not live to reach adolescence. To learn more about MPS VII, click here.
If you or someone you love has MPS VII, you know how badly patients need a treatment. The U.S. FDA saw this need. A little while back, it gave Mepsevii (vestronidase alfa-vjbk), a drug made to treat MPSVII, both the Fast Track Designation and the Orphan Drug Designation. This meant the drug’s approval process was sped up, since the research was promising, and financial incentives were put in place to help the development of the much-needed drug. The drug also is assisted by the Rare Pediatric Disease Priority Review Voucher, which encourages development of treatments for rare diseases affecting children.
On November 15th, the whole process came to fruition when Mepsevii was approved for treatment.
The approval followed rigorous clinical trials, which studied 23 participants with the disease, who ranged from 5-month-old babies to 25-year-old patients. 23 patients may not sound like very many, but when you consider that there are fewer than 150 patients in the world with this diagnosis, it’s a significant portion of the MPS VII population. The patients were administered a dose of the drug once every two weeks, over 164 weeks overall. The researchers measured the effectiveness through a six minute walk test. After 24 weeks, the difference between the treated group and placebo group was significant. There was a 18 meter walking disparity. A follow up study, which tracked patients for another 120 weeks, showed that the treatment continued to benefit patients. Two of the participants also demonstrated significantly better pulmonary function while under treatment, which would be very surprising without the drug.
There are, unfortunately, some side effect– the necessary evil of groundbreaking treatments. Some patients experienced reactions at the infusion site, rash, diarrhea, and anaphylaxis. Although the drug is deemed safe for treatment, the manufacturer is still required to conduct a post-marketing long-term safety evaluation.
Overall, this is a big leap forward for the patients with MPS VII and the people who love them.
Read the FDA Press Release about the new MPS VII treatment here.
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