Trial of SMA Therapy RG7800 on Hold, but Roche, Partners Developing Another Compound

International pharmaceutical company Roche, with its SMA drug development collaboration partners PTC Therapeutics and the SMA Foundation, said a clinical study called Moonfish (NCT02240355) that was investigating a compound and investigational medicine known as RG7800 for people with spinal muscular atrophy (SMA) was placed on clinical hold in April 2015 after an unexpected eye finding in an animal study

Roche, PTC, and the SMA Foundation announced the hold in an update on the clinical development program of SMN2 splicing modifier drug development program for treating SMA.

However, the partners are developing another SMN2 splicing modifier compound called RG7916 that is still in early clinical stages.

Roche said that concentrations of RG7800 being tested in the animal study were higher than those received by any of the Moonfish study’s human participants, and the company says it can can confirm that no safety issues have been identified in any person who received RG7800 through their participation in the Moonfish study.

RG7800 is an investigational oral drug for the treatment of SMA, a genetic disorder caused by the mutation or deletion of the survival of motor neuron gene 1 (SMN1).

Roche and its partners believe RG7800 may have potential to target SMA’s underlying cause by increasing SMN protein levels in the nervous system, muscles, and other tissues through modifying SMN2 gene splicing to stimulate greater production of full-length SMN mRNA.

The SMN2 splicing modifier drug development program was originally launched by PTC Therapeutics in partnership with the SMA Foundation. The program was designed to utilize PTC’s Alternative Splicing technology platform to identify and develop new small-molecule therapeutics in treating and prevention of SMA.

In November 2011, Roche gained an exclusive license to the program, with clinical development of RG7800 being led by Roche with oversight provided by a steering committee with members representing Roche, PTC, and the SMA Foundation.

However, with further clinical development of RG7800 still on hold, in January 2016 the collaborators began a Phase 1 clinical trial in the Netherlands of another SMN2 splicing modifier compound called RG7916.

Based on information from that study, the partners hope to begin clinical trials of RG7916 in people with SMA Type 1 and SMA Type 2/3 by the end of this year. Clinical trial sites, enrollment information, and study timelines will be announced once regulatory feedback has been obtained in countries where the proposed trials will be conducted.

Moonfish study participants will be offered the opportunity to enroll in an open label study with RG7916 provided they meet study criteria. These patients will be contacted by their clinical trial administrator to update them on the new developments.

For more information about updates on the RG7800 and RG7916 studies, visit https://www.clinicaltrialsregister.eu or https://clinicaltrials.gov, or contact the Genentech Trial Information Support Line at 888-662-6728.

The partners say details of the upcoming RG7916 studies will be posted on these websites soon. They note that public participation in clinical trials is critical to the process of advancing scientific understanding of SMA.

According to the research and support organization CureSMA, the disease affects approximately 1 in 10,000 babies, and is the No. 1 genetic cause of death in infants, with about 1 in every 50 Americans a genetic carrier. There is currently no cure for SMA, with treatment consisting of managing the symptoms and preventing complications.