RG7916 (RO7034067) is a code name for an oral drug being developed as a treatment for SMA by Roche, PTC Pharmaceuticals, and SMA Foundation. The RG7916 molecule modifies alternative splicing of the SMN2 gene in such a way that the gene starts producing only the SMN protein, which is deficient in all those with SMA.
RG7916 is a successor to RG7800, an earlier molecule that was trialled in patients in a study called Moonfish but whose development was stopped in 2015 after animal toxicity was observed.
RG7916 was tested for safety in healthy adult volunteers in early 2016 and in October 2016 phase 2–3 clinical trials in SMA patients started. The drug’s properties are being tested in three trials:
- Firefish – a clinical trial for babies 1–7 months old diagnosed with SMA type 1. This is an open-label trial where all participants receive the active substance for 24 months. The trial consists of two parts: The ongoing Part I tries to establish the optimum dose and safety, but also efficacy. Part II, which is yet to start, will primarily measure the compound’s efficacy. Firefish Part I is open in Belgium, France, Germany, Italy, Switzerland, Turkey and United States. UK babies may be enrolled in the Firefish trial in those centres and Roche will bear most of the cost. Hopes are there, too, that Firefish will open in two UK hospitals in 2018.
- Sunfish – a clinical trial for children and young adults aged 2–25 who have SMA type 2 or 3 and are unable to walk unsupported. Like Firefish, this trial consists of two parts: the recently completed Part I which established the safety and optimal dose and the ongoing Part II which is to test for the molecule’s efficacy. It is expected that at least one UK hospital will participate in the Sunfish trial starting in 1st half of 2018.
- Jewelfish – a clinical trial for participants aged 12–60 who have a history of receiving RG7800 or, possibly, nusinersen.