ASP-0113

Cytomegalovirus (CMV) is a latent infection in most infected individuals, but can be pathogenic in immunocompromised kidney transplant recipients. ASP0113 is a DNA-based vaccine for the prevention of CMV-related mortality and end-organ disease in transplant recipients. The efficacy, safety, and immunogenicity of ASP0113 was assessed in a phase 2, double-blind, placebo-controlled study in CMV-seronegative kidney transplant recipients receiving a kidney from a CMV-seropositive donor. Transplant recipients were randomized (1:1) to receive 5 doses of ASP0113 (5 mg; n = 75) or placebo (n = 74) on Days 30/60/90/120/180 posttransplant, and they received prophylactic valganciclovir/ganciclovir 10-100 days posttransplant. The primary endpoint was the proportion of transplant recipients with CMV viremia ≥1000 IU/mL from Day 100 through to 1 year after the first study vaccine injection. There was no statistically significant difference in the primary endpoint between the ASP0113 and placebo groups (odds ratio 0.79, 95% confidence interval 0.43-1.47; P = .307). There were similar numbers of transplant recipients with treatment-emergent adverse events between groups; however, more transplant recipients reported injection site pain in the ASP0113 group compared with placebo. ASP0113 did not demonstrate efficacy in the prevention of CMV viremia in this CMV-seronegative kidney transplant population, but demonstrated a safety profile similar to placebo. ClinicalTrials.gov registration number: NCT01974206.

Cytomegalovirus (CMV) infection/reactivation is a serious complication after hematopoietic cell transplantation (HCT). The DNA vaccine ASP0113 contains two plasmids encoding CMV antigens (glycoprotein B and tegument phosphoprotein 65) that stimulate humoral and cellular immunity. Between June 2013 and February 2014, Astellas conducted a phase 2, open-label, uncontrolled, three-center trial to investigate the safety and tolerability of ASP0113 in Japanese patients undergoing HCT for hematologic disorders. Ten patients aged 22-61 years were enrolled; nine received at least one dose of ASP0113. Six patients received all five doses of ASP0113 5 mg at intervals before and after HCT. Pre-emptive antiviral therapy was allowed. One patient died following relapse of primary disease. All patients had serious adverse events deemed unrelated to ASP0113. CMV viremia (assessed by CMV antigenemia) occurred in seven patients, who then received anti-CMV therapy. No patients developed CMV end-organ disease. Adverse events associated with ASP0113 injection included pyrexia (three patients), skin reactions [injection site pain, injection site tenderness, and erythema (two patients each); and rash, injection site erythema, injection site induration, and injection site swelling (one patient each)], and hyperuricemia (one patient). ASP0113 was well tolerated in Japanese HCT recipients. Further studies should evaluate its efficacy and safety. ClinicalTrials.gov Identifier: NCT01903928.