SUNFISH: Risdiplam Meets Primary Endpoint in SMA

An investigational drug called risdiplam (Genentech/Roche) has shown promise in the pivotal part 2 of the SUNFISH trial in people with type 2 or 3 spinal muscular atrophy (SMA).

"The study met its primary endpoint of change from baseline in the Motor Function Measure 32 (MFM-32) scale after 1 year of treatment with risdiplam, compared to placebo," the companies said in separate news releases announcing topline results of the trial.

The safety of risdiplam was consistent with its known safety profile, and no new safety signals were identified, they said.

This agent was developed by Roche and Genentech as part of a collaboration with the SMA Foundation and PTC Therapeutics, the statement notes. "Data from the SUNFISH study will be presented at an upcoming medical congress."

SMA, which affects about 1 in 11,000 babies, is caused by a mutation in the survival motor neuron 1 (SMN1) gene. The gene encodes the SMN protein, which is critical for the maintenance and function of motor neurons.

Risdiplam (formerly RG7916) is an orally administered, centrally and peripherally distributed small molecule that modulates survival motor neuron 2 (SMN2) premessenger RNA splicing to increase SMN protein levels.

The SUNFISH trial is a two-part, double-blind, placebo-controlled pivotal study involving people aged 2 to 25 years with type 2 or 3 SMA. Part 1 of the trial, which had 51 participants, determined the dose for the confirmatory phase of the study.

Part 2 of the trial, which had 180 participants, evaluated motor function using total MFM-32 score at 12 months. MFM-32 is a validated scale used to evaluate fine and gross motor function in people with neurologic disorders, including SMA.

"The positive outcome of this trial is an important milestone for people with type 2 or 3 SMA, too many of whom remain untreated," Levi Garraway, MD, PhD, Roche's chief medical officer and head of global product development, said in the news release.

"SUNFISH is the largest placebo-controlled study ever undertaken in type 2 or 3 SMA patients. We thank the SMA community for their partnership and look forward to sharing these results with regulators and bringing risdiplam to people living with this condition," Garraway added.

The mechanism of action of risdiplam is similar to that of another drug, nusinersen (Spinraza, Ionis Pharmaceuticals/Biogen), which was approved by the US Food and Drug Administration (FDA) for SMA in 2016.

Last spring, the FDA approved onasemnogene abeparvovec-xioi (Zolgensma, AveXis Inc, a Novartis company), the first gene therapy for children younger than 2 years who have SMA, as reported by Medscape Medical News.

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Cite this: SUNFISH: Risdiplam Meets Primary Endpoint in SMA - Medscape - Nov 13, 2019.

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