Safety Data Favorable For Trial Of DNA Vaccine Against CMV
An independent data safety monitoring board (DSMB) found no safety issues and recommended continuation of Vical Incorporated's Phase 2 trial of a DNA vaccine against cytomegalovirus (CMV). The DSMB completed an interim evaluation of safety data after the two-month follow-up visits for the first 20 hematopoietic stem cell transplant (HCT) recipients enrolled in the study.
Because most HCT recipients are expected to face a natural viral challenge as pre-existing CMV infection reactivates under immunosuppression, the primary efficacy endpoint in the double-blind, placebo-controlled Phase 2 trial is the occurrence rate of clinically significant CMV levels in HCT patients receiving vaccine compared with patients receiving placebo. Other important endpoints include immune responses against the specific CMV features targeted by the vaccine. The trial also is comparing safety of the vaccine against placebo in up to 80 matched, related HCT donors and recipients, and up to 80 additional HCT recipients. The DSMB evaluated safety data only in the interim analysis.
CMV is a herpes virus that infects more than half of all adults in the United States by age 40, and is even more widespread in developing countries. While a healthy immune system typically protects an infected person against CMV disease, it rarely succeeds in completely eliminating the infection, and those whose immune systems are not fully functional are at high risk of CMV proliferation, potentially leading to severe illness or death. These include transplant patients who take immunosuppressive drugs, and fetuses and newborns of mothers who first become infected during pregnancy.
CMV infection affects 30 to 60 percent of the patients undergoing various transplant procedures, causing transplant rejection, serious illness and even death if untreated. Expensive antiviral drug therapy is used to control the disease, but does not eliminate the infection. Congenital CMV infection affects one out of every hundred infants, and causes severe consequences in about 3,600 infants and death in about 400 each year in the United States.
There is no approved vaccine against CMV. Vaccine approaches that result in predominantly antibody responses to CMV have not proven highly effective in transplant patients. Vaccine approaches using live, attenuated viruses can induce both antibody and cellular immune responses, but pose a potential safety concern, particularly for immunocompromised patients, of causing the disease they are intended to prevent. Vical's novel DNA vaccine approach is designed to induce both antibody and cellular immune responses against specific features of the CMV virus without the risk of causing CMV disease. Vical's vaccine has received orphan drug designation for hematopoietic stem cell transplant and solid organ transplant patients.
Vical researches and develops biopharmaceutical products based on its patented DNA delivery technologies for the prevention and treatment of serious or life-threatening diseases. Potential applications of the company's DNA delivery technology include DNA vaccines for infectious diseases or cancer, in which the expressed protein is an immunogen; cancer immunotherapeutics, in which the expressed protein is an immune system stimulant; and cardiovascular therapies, in which the expressed protein is an angiogenic growth factor. The company is developing certain infectious disease vaccines and cancer therapeutics internally. In addition, the company collaborates with major pharmaceutical companies and biotechnology companies that give it access to complementary technologies or greater resources. These strategic partnerships provide the company with mutually beneficial opportunities to expand its product pipeline and address significant unmet medical needs.