Voyager Therapeutics is halting development of its SOD1 ALS gene therapy, VY9323, after three-month primate data revealed an off-target effect and a narrow therapeutic window. The company will explore alternative payloads for the treatment, while retaining its novel TRACER capsid, which performed well in other preclinical studies. This decision extends Voyager’s cash runway into mid-2027, excluding potential milestone payments.
This setback for VY9323 is important for the ALS community because SOD1 mutations are a known genetic driver of the disease, and gene therapies offer a potentially powerful approach to address the underlying cause. While other therapeutic strategies exist, they largely focus on symptom management rather than modifying disease progression. The pursuit of an effective SOD1-targeted therapy remains a critical area of research, and Voyager’s shift in strategy represents a lost opportunity, at least in the near term.
Voyager’s decision to explore alternative payloads suggests that the siRNA component of VY9323 is the root cause of the observed issues. The company’s confidence in the TRACER capsid, demonstrated by its successful performance in other programs, allows them to focus on optimizing the therapeutic payload. This approach could potentially accelerate the identification of a viable clinical candidate in the future. Financially, the extended cash runway provides Voyager with the resources to pursue these alternative strategies without immediate funding pressures. The continued development of other pipeline programs targeting GBA1 Parkinson’s disease, Friedreich’s ataxia, and tau-related pathologies remains unaffected.
The future of Voyager’s SOD1 program now hinges on its ability to identify and validate a suitable replacement payload. This will require additional preclinical research and likely push back any potential clinical trials. While this represents a delay in the development of a much-needed treatment for SOD1 ALS, Voyager’s decision demonstrates a commitment to developing a safe and effective therapy. The coming months will be crucial in determining whether a viable path forward for the SOD1 program can be identified, and whether the company can capitalize on the promise of its TRACER capsid technology.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
