- PTC Therapeutics and its partner Roche announced positive preliminary data from part one of the Phase 2 SUNFISH trial in patients with type 2/3 spinal muscular atrophy (SMA) at the Cure SMA meeting in Orlando this weekend.
- The trial is testing RG7916, a small molecule modifier of Survival Motor Neuron 2 (SMN2) splicing, in patients with the rare genetic disorder. The study is also being supported by the SMA Foundation.
- Early results from the study demonstrated that RG7916 showed a dose-dependent increase in the SMN2 full length/Δ7 mRNA ratio of approximately 400%. Patients with SMA are usually lacking the SMN1 gene, resulting in reduced SMN protein.
Despite setbacks in some of its other programs, PTC is moving forward with its SMA program. While the data presented this weekend was still early mid-stage information from 43 patients, it was an indicator that the oral compound could perform well in later stage trials.
Currently, the only approved treatment for SMA is Biogen’s Spinraza (nusinersen), which was green lit by the Food and Drug Administration in late-December. The drug has been slow to launch, though, and some insurers have indicated apprehension about covering it, limiting use of the medication to the sickest patients.
RG7916, on the other hand, is an oral compound that could turn out to be a major competitor to the injectable Spinraza.
The development of the drug began with a partnership between PTC and the SMA Foundation. Roche signed on to help develop it in 2011 for $30 million upfront, as well as the potential for $460 million in milestone payments.
In 2015, Roche ditched another compound, RG7800, that was part of the agreement due to safety concerns. The companies then switched gears to RG7916, which, so far, has not shown any safety issues.
The partners are currently running two other Phase 2 trials of RG7916. The FIREFISH trial and the second part of SUNFISH are expected to report out before the end of the year.