Sage Therapeutics has announced that its Phase 2 DIMENSION study of dalzanemdor (SAGE-718) did not meet its primary endpoint in treating cognitive impairment associated with Huntington's Disease (HD). The 12-week, double-blind, placebo-controlled study, which involved 189 participants, failed to demonstrate a statistically significant difference versus placebo in the change from baseline on the Symbol Digit Modalities Test (SDMT) at Day 84.
The DIMENSION study aimed to evaluate the effects of dalzanemdor on cognitive function in individuals with HD. Despite the drug being generally well-tolerated with no new safety signals, analyses of secondary endpoints also did not reveal statistically significant or clinically meaningful differences compared to the placebo group. The majority of treatment-emergent adverse events were mild to moderate in severity.
Discontinuation of Dalzanemdor Development
Based on the disappointing results from the DIMENSION study, Sage Therapeutics has decided to halt further development of dalzanemdor. This decision also includes the closure of the ongoing PURVIEW study, an open-label safety study of dalzanemdor in participants with Huntington's Disease.
"We are disappointed by the results of the DIMENSION Study, especially for the individuals and families affected by Huntington’s Disease who have long awaited new treatment options," said Barry Greene, Chief Executive Officer of Sage Therapeutics. He also expressed gratitude to the participants, investigators, and the Huntington’s Disease community for their commitment to the research effort.
Huntington's Disease and Cognitive Impairment
Huntington's Disease is a progressive neurodegenerative disorder characterized by motor, cognitive, and psychiatric symptoms. Cognitive impairment is a significant aspect of the disease, affecting memory, attention, and executive functions, which significantly impacts patients' quality of life. There remains a high unmet need for effective treatments that can address the cognitive deficits associated with HD.
Study Design and Outcomes
The Phase 2 DIMENSION study was designed as a 12-week, double-blind, placebo-controlled trial. Participants were randomized to receive either dalzanemdor or a placebo. The primary endpoint was the change from baseline on the SDMT, a widely used measure of cognitive function, at Day 84. Secondary endpoints included other cognitive assessments and measures of functional capacity. While dalzanemdor was generally well-tolerated, the study did not demonstrate any statistically significant benefit on the primary or secondary endpoints.
