Roche and PTC Therapeutics Announce FDA Priority Review for Evrysdi (risdiplam) sNDA to Treat Pre-Symptomatic Infants with Spinal Muscular Atrophy

Recently, Roche and PTC Therapeutics announced that the U.S. FDA has granted priority review status to the supplemental New Drug Application (sNDA) for Evrysdi (risdiplam), an oral SMN2 splicing modifier, to expand its use to include spinal muscular atrophy (SMA) infants under 2 months of age who have not yet shown symptoms. The press release noted that once approved, Evrysdi will become the first drug that can be administered at home to treat symptom-free SMA infants. This medication has also been approved for marketing by China's National Medical Products Administration (NMPA) under the trade name Evrysdi (risdiplam oral solution granules) for the treatment of SMA patients aged two months and above.

SMA is a severe progressive neuromuscular disease, affecting approximately 1 in every 10,000 infants. The disease is typically caused by the absence or dysfunction of the survival motor neuron (SMN) protein, impacting the patient’s movement, breathing, swallowing, and multiple organs including the spleen, heart, and pancreas, even posing a threat to life. The SMN protein is crucial for maintaining healthy motor neurons and enabling movement. In the human body, the SMN1 and SMN2 genes produce SMN proteins, with the SMN1 gene playing a dominant role while the SMN2 gene accounts for about 10% of SMN protein production.

Evrysdi is an RNA splicing modifier targeting SMN2. The SMN2 gene in the human body can also express SMN protein, but due to mRNA splicing errors, the level of normal SMN protein expressed is very low and cannot compensate for the lack of SMN protein caused by SMN1 gene mutations. Evrysdi improves the level of functional SMN protein by modulating the mRNA splicing of the SMN2 gene. After taking this medication, it is evenly distributed to all parts of the body, including the central nervous system (CNS). Patients can take it daily at home in liquid form via oral or feeding tube administration.

This application is based on the interim positive results obtained from an ongoing pivotal Phase 2 clinical trial. The currently available data indicates that 80% of SMA infants who have not yet shown symptoms achieved motor milestones, such as sitting without support, rolling over, crawling, standing without assistance, and walking independently, after receiving Evrysdi treatment for at least 12 months.

References:

[1] FDA Grants Evrysdi® Priority Review Based on Results From Treating Pre-Symptomatic Infants with Spinal Muscular Atrophy. Retrieved January 25, 2022, from https://ir.ptcbio.com/news-releases/news-release-details/fda-grants-evrysdir-priority-review-based-results-treating-pre

(Original text has been abridged)

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