Genentech and PTC Therapeutics announced that the U.S. Food and Drug Administration (FDA) has granted priority review for the New Drug Application (NDA) for risdiplam (RG7916) for the treatment of spinal muscular atrophy (SMA). The Prescription Drug User Fee Act (PDUFA) goal date for a decision by the FDA is May 24, 2020.
The NDA submission was based on 12-month data from the dose-finding Part 1 sections of the FIREFISH and SUNFISH pivotal studies, as well as data from the confirmatory Part 2 of SUNFISH.
FIREFISH is an open-label, two-part seamless pivotal clinical trial in infants with Type 1 SMA. Part 1 was a dose-escalation study in 21 infants aged 1-7 months. The primary objective of Part 1 was to assess the safety profile of risdiplam in this age group and determine the dose for Part 2, designed as a pivotal, single-arm trial evaluating risdiplam in 41 infants with Type 1 SMA for 24 months, followed by an open-label extension. Data from the dose-finding Part 1 portion of the FIREFISH trial showed the infants achieved key motor milestones after one year of treatment with risdiplam, and the treatment was deemed safe.
SUNFISH is a two-part, double-blind, placebo-controlled pivotal clinical trial in children and young adults (2-25 years old) with Type 2 or 3 SMA. Part 1 determined the dose for the confirmatory Part 2 and evaluated efficacy as an exploratory endpoint. SUNFISH Part 2 is a large placebo-controlled trial evaluating treatment for people with Type 2 or 3 SMA. SUNFISH Part 2 met its primary endpoint of change from baseline in the Motor Function Measure 32 (MFM-32) scale.
Priority Review designation is granted to medicines that the FDA considers having the potential to provide significant improvements in the safety and effectiveness of the treatment, prevention or diagnosis of a serious disease.
The FDA granted Orphan Drug Designation for risdiplam in January 2017, followed by Fast Track Designation in April 2017.
Risdiplam is an orally administered liquid survival motor neuron-2 (SMN-2) splicing modifier for SMA. It is designed to increase and sustain SMN protein levels both throughout the central nervous system and peripheral tissues of the body. It is being evaluated for its potential ability to help the SMN-2 gene produce more functional SMN protein throughout the body.
Roche, PTC Therapeutics and the SMA Foundation signed a licensing agreement in November of 2011, granting Roche an exclusive worldwide license to PTC’s SMA program.
About Spinal muscular atrophy
Spinal muscular atrophy is a severe, inherited, progressive neuromuscular disease that causes devastating muscle atrophy and disease-related complications. It is the most common genetic cause of infant mortality and one of the most common rare diseases, affecting approximately one in 11,000 babies. SMA leads to the progressive loss of nerve cells in the spinal cord that control muscle movement. Depending on the type of SMA, an individual’s physical strength and their ability to walk, eat or breathe can be significantly diminished or lost.
SMA is caused by a mutation in the survival motor neuron-1 (SMN-1) gene that results in a deficiency of SMN protein. SMN protein is found throughout the body and increasing evidence suggests SMA is a multi-system disorder and the loss of SMN protein may affect many tissues and cells, which can stop the body from functioning.