VCL-CB01, an injectable bivalent plasmid DNA vaccine for potential protection against CMV disease and infection.

Vaccines for the prevention of human CMV (hCMV) infection and disease are a major public health priority. Immunization with DNA vaccines encoding key proteins involved in the immune response to hCMV has emerged as a major focus of hcmv vaccine research. Validation of the protective effect of DNA vaccination in animal models has provided support for clinical trials. VCL-CB01, under development by Vical Inc for the prevention of hCMV infection and disease, is a poloxamer-formulated, bivalent DNA vaccine that contains plasmids encoding hCMV tegument phosphoprotein 65 and the major hCMV surface glycoprotein B. In a phase I trial in healthy adults, VCL-CB01 was well tolerated. In interim results from a phase II trial in hCMV-seropositive hematopoietic cell transplant recipients, VCL-CB01 increased T-cell responses compared with placebo. The final results from the phase II trial will be of value for developing strategies to prevent hCMV disease in hCMV-seropositive transplant recipients, and may lead to other trials of VCL-CB01 or related vaccines for the prevention of congenital hCMV infection.