Roche Terminates Myostatin Inhibitor for DMD One Year After Pfizer Did the Same

A little more than one year after Pfizer terminated its studies of PF-06252616 as a potential treatment for Duchene Muscular Dystrophy, Swiss pharma giant Roche is following suit. The company terminated the development of RG6206 an investigational anti-myostatin adnectin protein, in ambulatory boys with DMD.

In a letter to the Duchene Muscular Dystrophy community this week, Roche announced the news about its clinical development program. Roche said its decision to terminate the DMD programs impacts both the Phase Ib/II THUNDERJET study, as well as the Phase II/III SPITFIRE study. The decision to terminate the studies was based on a pre-planned analysis of the SPITFIRE data. That analysis, Roche said, indicated that RG6206 was highly unlikely to demonstrate clinical benefit as defined by meeting the primary endpoint when compared with placebo. The primary endpoint was a change from baseline in the North Star Ambulatory Assessment. The assessment is a rating scale used to measure functional motor abilities in ambulant children with DMD. There were no safety concerns in the study, Roche said.

Roche intends to hold two global meetings with members of the DMD community to provide the stakeholders with as much information as possible.

“We recognize this news is deeply disappointing for the Duchenne community, especially in view of the historical challenges in DMD drug development and the ongoing need for new treatment options to treat this devastating disease. While the science and large body of research gave us hope that RG6206 would have offered people living with DMD and their families a safe and effective treatment option, the results of the SPITFIRE study at this time led us to the difficult conclusion that this approach will not be successful,” Roche said in its letter.

Last year, when Pfizer terminated its DMD studies of domagrozumab, which like RG2606 was also a monoclonal anti-myostatin antibody, Roche posted a letter addressing concerns that Pfizer’s decision would impact Roche’s DMD program. At the time, Roche said its work would continue and reminded members of the DMD community that clinical studies are designed in ways that are specific to the molecule being studied, which meant it wasn’t possible to draw conclusions.

Duchenne muscular dystrophy is the most common and severe form of muscular dystrophy that primarily affects boys. The genetic disease causes a progressive loss of muscle strength attributable to a loss of a protein called dystrophin, which normally protects muscle fibers from breaking down. Approximately 15,000 U.S. patients are affected with Duchenne, with a total of 300,000 patients worldwide.

Data from the interim analysis of the Phase II/III SPITFIRE study will be presented at an upcoming study, the company said. Additionally, Roche is making plans to share additional data about RG6206 “in order to contribute to the broader community’s efforts to develop new treatment options for people with this condition.” Roche also said it and its subsidiary Genentech will continue to partner with the global Duchenne community on ongoing projects, including with World Duchenne Organization on its Psychosocial Program as well as its data-sharing initiative.