CMV DNA Vaccine Candidate Fails to Meet Endpoints in Phase 3 Trial

Astellas Pharma Inc. and Vical Incorporated recently announced that the phase 3 HELIOS clinical trial studying a DNA vaccine did not meet the desired endpoints. The vaccine candidate is ASP0113, which was in development to treat and prevent cytomegalovirus (CMV) in hematopoietic stem cell transplant (HSCT) recipients. ASP0113 was developed in its beginning stages by Vical before Astellas joined as a partner in the development.

CMV is a widespread herpes virus that is estimated to infect nearly half of US adults by the age of 50. The immune system typically protects against the disease, but individuals with weakened immune systems have a greater risk for CMV reactivation, which in severe cases may result in death. High-risk individuals include HCT recipients and solid-organ transplant recipients.

The trial was a randomized, double-blind, placebo control study that included 514 participants who were all CMV-seropositive and undergoing allogeneic stem cell transplants. The trial’s objectives were to evaluate the vaccine in comparison with placebo. Results from the study indicated that the primary endpoints which were mortality and CMV end-organ disease occurring within a year after a transplant, were not met. Secondary endpoints, consisted of, “time to first protocol-defined CMV viremia and time to first use of adjudicated CMV-specific antiviral therapy” and also were not met in phase 3, according to a press release.

“The Phase 3 trial outcome is disappointing,” said Vijay Samant, Vical’s chief executive officer in the release. “Astellas and Vical employees, the investigators and study site personnel did an outstanding job conducting this study, but unfortunately, the vaccine was unable to provide protection against all-cause mortality in this very difficult-to-treat patient population.”

For more information about the ASP0113 clinical trial, visit www.clinicaltrials.gov.