Clinical Trial Program Testing RG6206 in DMD Boys Has Been Discontinued

The clinical program evaluating the safety, tolerability, and efficacy of RG6206 in boys with Duchenne muscular dystrophy (DMD) has been discontinued, according to a letter to the DMD community by Roche and Genentech.

“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,” Eydith Comenencia Ortiz and Elena Zhuravleva said on behalf of the Roche and Genentech (part of Roche) Global Duchenne Team.

The program included two clinical trials, the open-label extension of the Phase 1b/2 THUNDERJET trial (NCT02515669) and the global Phase 2/3 SPITFIRE study (NCT03039686). Both studies were investigating the effects of RG6206 in young boys with DMD.

RG6206, formerly known as BMS-986089, is a myostatin inhibitor originally developed by Bristol-Myers Squibb and later licensed to Roche. As myostatin is a protein that suppresses muscle growth, blocking it with RG6206 could be beneficial for people with DMD.

However, a preliminary analysis of SPITFIRE suggested that RG6206 was unlikely to lead to significant motor improvements (measured by the North Star Ambulatory Assessment or NSAA) in children with DMD who were able to walk without assistance (ambulant).

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According to the analysis, SPITFIRE’s primary endpoint, or goal — to assess changes in the NSAA total scores from the beginning of the study until the end of a 48-week treatment period — would most likely not have been met with RG6206.

The safety profile of RG6206 was consistent with data from previous trials. No new safety concerns were reported in this analysis.

“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,” the letter stated.

Roche has informed all clinical sites involved in the studies. Trial investigators are currently getting in touch with participants and their families to notify them about the decision. To speed up this process, Roche also hosted two global webinars.

Study participants and family members are encouraged to contact their physicians for more information and next steps. Genentech can be contacted via email at [email protected] or by phone at (888) 662-6728.

“We thank the community for supporting our efforts to develop RG6206 and are especially grateful to the individuals and families who participated in our clinical studies for RG6206. We sincerely thank you for your time, your partnership, and your unwavering commitment to research,” the letter said.

The company is planning to present full data from this early analysis of SPITFIRE at upcoming meetings. Also, it expects to share additional results of RG6206 with patient communities and with consortia, including the Trajectory Analysis Project consortium, to help develop new therapies for people living with DMD.

In the meantime, the company said it will continue to collaborate with the Duchenne community on multiple projects, including the World Duchenne Organization on its Psychosocial Program and data-sharing initiative.