On Saturday, PTC Therapeutics, Inc. announced the presentation of updated interim clinical data from Part 1 of the FIREFISH study investigating risdiplam (RG7916) in babies with Type 1 Spinal Muscular Atrophy (SMA), at the 22nd Annual SMA Researcher Meeting. The data presented by Dr. Baranello demonstrated that at Day 182, over 90% of the babies achieved a greater than 4-point increase in CHOP-INTEND score compared to baseline. The CHOP-INTEND data were further supported by video footage presented by Dr Baranello demonstrating antigravity movements, the ability to control their head, roll, or sit in babies participating in FIREFISH. Part 2 of the pivotal FIREFISH study is ongoing. The SMA program is a collaboration between PTC, Roche, and the SMA Foundation.

“We are delighted that up to 6.5-fold increase of protein production has translated into clinical impact for these babies in the FIREFISH study,” said Stuart W. Peltz, Ph.D. Chief Executive Officer of PTC Therapeutics. “The survival data and CHOP-INTEND scores are very promising, since babies with Type 1 SMA typically do not experience functional motor milestone improvement based on natural history. We look forward to sharing updates for the programs as the data further develop at upcoming medical meetings.”

Risdiplam is an investigational splicing modifier targeting the survival motor neuron 2 (SMN2) RNA, restoring a functional transcript. Risdiplam is taken orally, crosses the blood brain barrier, and shows systemic distribution to the organs that are affected by low levels of SMN protein.

Other presentations included an analysis of data from Part 1 of the SUNFISH study which demonstrated that risdiplam administration resulted in a dose-dependent increase in SMN protein levels up to 3.5-fold; pharmacodynamic data from the JEWELFISH trial; and preclinical data demonstrating SMN protein production and distribution, as well as the development of the SMA Independence Scale (SMAIS).

About RG7916

The SMA program was initially developed by PTC Therapeutics in partnership with the SMA Foundation in 2006. In November 2011, Roche gained an exclusive worldwide license to the PTC/SMA Foundation SMN2 alternative splicing program. The development of risdiplam RG7916 is being executed globally by Roche, including in the US through Genentech, a member of the Roche group. The SMA program is overseen by a Joint Steering Committee with members from PTC, Roche, and the SMA Foundation.

In late 2016, Genentech/Roche first announced plans to begin Phase 2 trials of RG7916, in response to favorable results from a Phase 1 study in healthy volunteers. 

FIREFISH (NCT02913482) assesses RG7916 in babies with Type 1 SMA aged 1 to 7 months. FIREFISH has two parts: Part 1 explored two dose levels of RG7916; Part 2 will evaluate efficacy of the most appropriate dose of RG7916. FIREFISH is open-label, i.e. there is no placebo in this study.

This compound is also being tested in two additional pivotal trials: SUNFISH and JEWELFISH.

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