MedImmune initiates clinical trial comparing intranasal influenza vaccine with injectable flu vaccine

MedImmune announced that it has initiated a pivotal head-to-head Phase 3 clinical trial designed to compare its next-generation, refrigerator- stable intranasal influenza vaccine (CAIV-T: cold adapted intranasal influenza vaccine, trivalent) with the injectable flu shot (TIV: trivalent influenza vaccine).

The company also announced that it has completed enrollment in a bridging study designed to establish that CAIV-T, the refrigerator-stable form of its live, attenuated intranasal influenza technology, is equivalent to its currently marketed frozen formulation, FluMist (Influenza Virus Vaccine Live, Intranasal).

"With the advancement of these studies, we remain on course with our influenza vaccine development program," said Edward M. Connor, M.D., executive vice president of clinical development and chief medical officer at MedImmune, Inc. "These trials will provide pivotal data regarding the safety and relative efficacy of our intranasal vaccine compared to TIV, as well as data regarding the comparative safety and immune responses for the frozen and the refrigerator-stable formulations of FluMist. MedImmune remains hopeful that it will deliver an improved option for the prevention of influenza disease, particularly for children."

The Phase 3 head-to-head trial is a randomized, double-blind study that will compare the safety and relative efficacy of CAIV-T to TIV during the 2004/2005 influenza season. The study will be conducted at approximately 300 sites in the Northern Hemisphere. Approximately 7,000 children across 18 countries between the ages of 6 months through 59 months will be randomized one-to-one in this study to receive either CAIV-T or TIV. All participants will receive both an intranasal mist and an intramuscular injection to preserve the double-blind design of the study.

MedImmune's bridging study is a double-blind, randomized trial designed to establish the equivalent immunogenicity and safety of MedImmune's two live, attenuated intranasal formulations (refrigerator-stable and frozen). The study is being conducted at 31 sites in the United States. In this study, 977 healthy participants between the ages of 5 and 49 years have been randomized one-to-one to receive either CAIV-T or FluMist. Participants 5 through 8 years of age will receive two doses of study vaccine, while those 9 through 49 years of age have received one dose of study vaccine.

To date, the safety, tolerability and efficacy of CAIV-T has been studied in a number of trials involving populations between the ages of 6 weeks and 98 years, including healthy persons and persons at high-risk of complications due to influenza. Data from several of these trials showing that the vaccine was safe and effective in reducing the incidence of community acquired influenza in the populations studied were presented in October 2003 at the Fifth Annual Options for the Control of Influenza Conference. Further, data from two Phase 3 trials involving a total of 4,400 children with a history of respiratory illness or asthma were presented in May 2004 at the Pediatric Academic Societies' annual meeting, showing that CAIV-T provided superior protection with a similar safety profile to the injectable flu vaccine.

To collect additional safety and efficacy on its currently marketed live, attenuated intranasal influenza vaccine, MedImmune is advancing a Phase 1 placebo-controlled trial in 20 immunocompromised children with cancer, as well as a Phase 1/2 trial comparing FluMist to TIV in 300 HIV-infected children. The HIV trial is being conducted in collaboration with the Pediatrics AIDS Clinical Trials Group (PACTG).

A number of post-marketing studies for FluMist are also underway, including: several trials in elementary schools in Washington, Texas, Maryland and Minnesota to determine the direct and indirect impact of FluMist immunization among school-aged children and their families; a Phase 4, open- label, single-arm trial to assess the shedding, immunogenicity and safety of FluMist in healthy individuals 5 to 49 years of age; a large safety surveillance trial that will enroll at least 60,000 individuals between 5 and 49 years of age over multiple influenza seasons at participating Kaiser Permanente centers in Northern California and Colorado; and a community-based, non-randomized, open-label trial to assess safety and herd immunity in approximately 5,000 healthy children between 5 and 17 years of age in Central Texas.