Today, new data was presented demonstrating the ongoing benefit of risdiplam (RG7916) for the treatment of all types of spinal muscular atrophy (SMA). The data was presented at the 24th International Annual Congress of the World Muscle Society. Presentations include data from the FIREFISH, SUNFISH, and JEWELFISH clinical trials. The SMA program is a collaboration between PTC, the SMA Foundation, and Roche/Genentech.

Data from Part 1 of the FIREFISH clinical trial demonstrated that after 16 months of treatment, 82% (14/17) of high-dose patients had a CHOP-INTEND score ≥40. 86% (18/21) of all infants were event-free after receiving risdiplam for 16 months. No infant has required tracheostomy or reached permanent ventilation. The primary objective of FIREFISH Part 1 was to assess the safety profile of risdiplam in infants and determine the dose for Part 2.

In patients in Part 1 of the SUNFISH clinical trial, risdiplam treatment led to a median two-fold increase in blood SMN protein levels after four weeks of treatment, sustained for at least 12 months. In the natural history cohort, patients did not experience any change in SMN protein levels over the same period. Patients receiving risdiplam in SUNFISH Part 1 showed a clinically meaningful increase in total MFM32 score including a broad range of ages and functional status at baseline compared with natural history, independent of age and disease severity. SUNFISH Part 1 is focused on the safety, tolerability, pharmacokinetics, pharmacodynamics and exploratory efficacy in patients with type 2 or 3 SMA between 2 and 25 years old.

Data from 45 patients in the JEWELFISH trial demonstrated a sustained, greater than two-fold increase in median SMN protein versus baseline over 12 months of treatment. Patients in the JEWELFISH study have previously been treated with nusinersen or other therapies.

In August, the first patient was enrolled in the RAINBOWFISH trial, an open-label, single-arm, international, multi-center clinical study to investigate the efficacy, safety, pharmacokinetics and pharmacodynamics of risdiplam in infants with genetically diagnosed SMA who are not yet presenting symptoms.

Risdiplam has been well tolerated at all dose levels and in all clinical studies. To date, there have been no drug-related safety findings leading to withdrawal from any study.

History of Risdiplam

Risdiplam is an investigational, oral medicine that is systemically distributed and designed to increase SMN protein levels in the central nervous system (CNS) and throughout the body. It is designed to help the SMN2 gene produce more functional SMN protein, to better support motor neurons and muscle function. Roche and Genentech are leading the clinical development of risdiplam in collaboration with the SMA Foundation and PTC Therapeutics. Risdiplam is currently being evaluated in three multicenter trials in people with SMA.