Safety Study to Evaluate FluMist in Immunocompromised Children

This study is a randomized, double-blind Phase 1 study of FluMist vs. placebo in mild to moderately immunocompromised children 5 to 17 years of age with cancer. The primary objective of this study is to describe the safety of FluMist compared with placebo in mild to moderately immunocompromised children with cancer. The secondary objectives of this study are to describe the immune responses following vaccination with FluMist and to determine the incidence and duration of viral replication following vaccination with FluMist. The standard 0.5 mL dose of vaccine or placebo was administered intranasally. Patients were evaluated at four visits scheduled between days 3-5, days 7-10, days 14-28, and days 35-42 for viral shedding via nasal swabs. Safety outcomes were collected at study clinic visits or by telephone contact through 42 days post dose. Serious adverse events and significant new medical conditions were collected through 180 days after receipt of investigational product. Immune responses were measured by detection of influenza-specific antibodies as measured by the standard hemagglutination inhibition (HAI) assay. Influenza-specific serum antibody isotype levels were determined and nasal swab specimens were analyzed for the expression of influenza-specific immunoglobulin A (IgA). Serum was analyzed for its ability to neutralize viral particles from infecting Madin-Darby canine kidney cells (microneutralization). Baseline immunosuppression as measured by expression of T- and B-lymphocyte subsets was compared to immunosuppression at time points after vaccination. The duration of viral replication and the titers of live-attenuated influenza virus shed was evaluated from nasal swab specimens collected at scheduled time points after administration of FluMist.