Vical and Astellas Pharma said today that their ASP0113 failed a Phase II trial comparing the cytomegalovirus (CMV) vaccine candidate to placebo in kidney transplant patients receiving an organ from a CMV-seropositive donor.
ASP0113 did not meet the study’s primary endpoint—the proportion of patients having CMV viremia, defined as a plasma viral load of ≥1000 IU/mL by central laboratory assay through 1 year after first injection of the vaccine.
The trial’s secondary endpoints of CMV-associated disease and CMV-specific antiviral therapy were similar in both treatment groups, on the basis of an evaluation by an independent, blinded Adjudication Committee.
While the safety profiles were generally similar between treatment groups, local injection site reactions were more common in the ASP0113 treatment group, the companies acknowledged, adding that additional detailed data from the trial “is expected to be disclosed at an upcoming scientific congress.”
The Phase II study was a randomized, double-blind, placebo-controlled trial designed to evaluate the safety and efficacy of ASP0113 in CMV-seronegative kidney transplant recipients receiving an organ from a CMV-seropositive donor (D+/R–). Enrollment included 150 kidney transplant recipients across approximately 80 centers in North America, Europe, and Australia. Participants were randomized to receive either ASP0113 or placebo, in addition to valganciclovir or ganciclovir prophylaxis for 100 days after kidney transplant.
“Although we had hoped for a different outcome, we look forward to further analyzing these data in hopes of contributing knowledge to the future development programs in this patient population,” Bernhardt G. Zeiher, M.D., Astellas’ president, development, said in a statement.
ASP0113 is designed to prevent CMV disease and associated complications in solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients. The bivalent DNA vaccine is designed to work by encoding CMV phosphoprotein 65 and glycoprotein B antigens for induction of both cellular and humoral immune responses, formulated with a proprietary poloxamer-based delivery system.
Initially developed by Vical, ASP0113 is now being developed and commercialized in partnership with Astellas. ASP0113 has received Orphan Drug designation in the U.S. and Europe for prevention of CMV disease in SOT and HCT recipients.
ASP0113 is the subject of an ongoing Phase III trial of in HCT recipients—the first time a CMV vaccine or a DNA vaccine has entered pivotal phase testing in a registrational trial.
“We continue to focus on execution of our Phase III study in hematopoietic cell transplant (HCT) recipients and are pleased to announce that we have met our target enrollment,” Dr. Zeiher added.
Results from the Phase III study are expected during the fourth quarter of 2017, added Vijay Samant, Vical’s president and CEO.