A Pilot Trial of an Accelerated Immunization Schedule With ALVAC-pp65 (vCP260) for Inducing CMV-Specific Immunity in Stem Cell Allotransplant Donors and Healthy Volunteers

Detailed Summary

This study will evaluate the safety and effectiveness of a new vaccine, ALVAC-pp65, in boosting immunity to cytomegalovirus (CMV) infection in stem cell transplant donors. CMV is a member of the herpesvirus group, which includes herpes simplex virus types 1 and 2, varicella-zoster virus (which causes chickenpox), and Epstein-Barr virus (which causes infectious mononucleosis). Most adults are infected with CMV, but a healthy immune system keeps the virus in check, so that it does not cause harm. In people with a weakened immune system, such as transplant recipients, the virus can become reactivated. Medications for treating the infection may cause low blood counts and kidney damage, and, in some cases, the virus may cause death. The ALVAC-pp65 vaccine is intended to improve immunity against CMV in stem cell donors and thereby prevent its reactivation in recipients. It is made from a virus that ordinarily infects canaries. The virus is weakened so that it cannot infect the person who receives it, and it is modified to carry a copy of a CMV gene called pp65. This gene instructs cells to make CMV proteins that the vaccine recipient's immune system can produce antibodies to, thus conferring immunity to the disease. Persons 18 years of age or older who are scheduled to donate stem cells for a patient in an NIH protocol and who are not allergic to eggs, egg products, or other vaccines, may be eligible for this study. Candidates are screened with a medical history, physical examination, and blood tests. Participants receive three vaccinations one week apart beginning at least 3 weeks before the scheduled stem cell donation. They are observed for 30 minutes after each vaccination to look for any immediate side effects of the vaccine. Approximately 3 tablespoons of blood are drawn before each vaccination and 1 week after the last vaccination to evaluate vaccine safety. Blood samples are also collected at the screening evaluation, 3 weeks after the start of vaccination, and 3 months after the last vaccination to check for CMV immunity. Participants keep a diary, recording any reactions to the vaccine and any change in medications. They are contacted by telephone for follow-up 3 months after the last vaccination to report any additional symptoms.

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