FDA Grants Priority Review to Genentech’s Risdiplam for Spinal Muscular Atrophy

Monday, November 25, 2019

Genentech, a member of the Roche Group, today announced that the U.S. Food and Drug Administration (FDA) has accepted the New Drug Application (NDA) and granted Priority Review for risdiplam, an investigational survival motor neuron-2 (SMN-2) splicing modifier for spinal muscular atrophy (SMA). Risdiplam is designed to increase and sustain SMN protein levels both throughout the central nervous system and peripheral tissues of the body. The FDA is expected to make a decision on approval by May 24, 2020.

“The FIREFISH and SUNFISH trials were designed to represent the real world spectrum of people living with SMA and include many people previously underrepresented in clinical trials,” said Levi Garraway, M.D., Ph.D., chief medical officer and head of Global Product Development. “We look forward to working closely with the FDA to explore broad access to risdiplam for all individuals in the community who might benefit.”

The risdiplam NDA submission incorporates 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, which evaluated efficacy as an exploratory endpoint, was to assess the safety profile of risdiplam in infants and determine the dose for Part 2, which is a pivotal, single-arm trial evaluating risdiplam in 41 infants with Type 1 SMA for 24 months, followed by an open-label extension.

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 recently met its primary endpoint of change from baseline in the Motor Function Measure 32 (MFM-32) scale.* No treatment-related safety findings leading to study withdrawal have been seen in any risdiplam trial to date. Safety for risdiplam was consistent with its known safety profile and no new safety signals were identified. Results will be presented at an upcoming medical congress.

If approved, risdiplam, an orally administered liquid, would be the first at-home administered medicine for people living with SMA. In addition to the studies included in the NDA submission, risdiplam is being studied in a broad clinical trial program in SMA, with patients ranging from newborns to 60 years old, and includes patients previously treated with SMA therapies.

Genentech leads the clinical development of risdiplam as part of a collaboration with the SMA Foundation and PTC Therapeutics, and would commercialize the medicine in the United States if approved.

Priority Review designation is granted to medicines that the FDA considers to have the potential to provide significant improvements in the safety and effectiveness of the treatment, prevention or diagnosis of a serious disease. Previously, the FDA also granted Orphan Drug Designation for risdiplam in January 2017, followed by Fast Track Designation in April 2017.

*MFM-32 is a validated scale used to evaluate fine and gross motor function in people with neurological disorders, including SMA.