Roche's experimental drug risdiplam hits main goal of study in infants with Type 1 spinal muscular atrophy

Roche announced Thursday that the pivotal part of the FIREFISH study investigating risdiplam in infants aged one to seven months with Type 1 spinal muscular atrophy (SMA) met its primary endpoint. "We are very encouraged by these results and we look forward to sharing them with regulators," remarked chief medical officer Levi Garraway.

The first part of the trial assessed the safety profile of risdiplam in 21 patients with Type 1 SMA and determined the dose for the second portion. Roche noted that the second part of the study evaluated efficacy in 41 patients as measured by the proportion of infants sitting without support after 12 months of treatment, and longer, based on the Gross Motor Scale of the Bayley Scales of Infant and Toddler Development Third Edition (BSID-III).

According to top-line results, the safety of risdiplam in the FIREFISH study was consistent with its known safety profile and no new safety signals were identified. Roche added that data from the trial will be presented at an upcoming medical meeting. "This large, global trial confirms the efficacy of risdiplam in an advanced and difficult-to-treat population, including many infants whose disease had already progressed significantly before starting treatment," commented Garraway.

In November last year, the FDA granted priority review to a filing seeking approval of risdiplam for patients with SMA, with the regulator expected to make a decision on the application by May 24. The filing included data from the FIREFISH study, as well as findings from the SUNFISH trial, which Roche recently announced met its primary endpoint, with risdiplam demonstrating significant improvements in motor function using total score of Motor Function Measure 32 (MFM-32) versus placebo in patients aged two to 25 years with type 2 or 3 SMA.

Following the latest results, Zuercher Kantonalbank analyst Michael Nawrath said "we're almost certain of its approval," predicting that risdiplam could become the standard treatment for patients with less-acute forms of SMA that emerge months after birth. Nawrath estimates the drug will generate peak sales of around CHF 2 billion ($2.1 billion).

Risdiplam is an experimental SMN2 splicing modifier being developed by Roche as part of a collaboration with the SMA Foundation and PTC Therapeutics. The orally administered liquid, also known as RG7916, is being studied in a broad clinical trial programme, with patients ranging from birth to 60 years old, and includes patients previously treated with SMA-targeting therapies.

For related analysis, see ViewPoints: Experts' enthusiasm for Roche's risdiplam grows as FDA grants priority review.

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