PTC Therapeutics Press Release - Risdiplam (RG7916)
07 October 2019
Data presented at the Annual Congress of the World Muscle Society, demonstrated the ongoing benefit of risdiplam (RG7916) for the treatment of all Types of SMA. Risdiplam is a small molecule drug taken orally, which targets and encourages the SMN2 ‘back-up’ gene to produce a greater amount of functional SMN protein.
The data presented were from four trials of risdiplam:
- FIREFISH is a two-part trial of risdiplam in 21 infants with SMA Type 1.
- SUNFISH is a two-part trial of risdiplam in 51 people with SMA aged from 2 to 25 years.
- JEWELFISH is a trial for people who have previously participated in a trial with SMN2-targeting therapies, or olesoxime, or who received previously treatment with nusinersen.
- RAINBOWFISH is a trial of risdiplam in infants with genetically diagnosed SMA who are not yet presenting symptoms.
Data from Part 1 of the FIREFISH clinical trial demonstrated that after 16 months of treatment:
- 82% of high-dose patients had a score of ≥40 on the CHOP-INTEND motor function scale, which is higher than untreated patients, indicating improved muscle function.
- 86% (18/21) of all infants were event-free after receiving risdiplam for 16 months.
- No infant has required tracheostomy or reached permanent ventilation.
In patients in Part 1 of the SUNFISH clinical trial, risdiplam treatment led to:
- A 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.
- A clinically meaningful increase in motor function, including a broad range of ages and functional status at baseline compared with natural history, independent of age and disease severity.
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-centre clinical study to investigate the efficacy, safety, pharmacokinetics and pharmacodynamics of risdiplam in infants with genetically diagnosed SMA who are not yet presenting symptoms (similar in nature to the NURTURE trial of SpinrazaTM).
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.