MedImmune Advances Vaccine Program

MedImmune, Inc. (Gaitherburg, MD, www.medimmune.com) reports that the US Food andDrug Administration (Rockville, MD, www.fda.gov) approved the company'ssupplemental biologics license application to use reverse geneticstechnology to construct new vaccine strains to produce seasonalinfluenza vaccines, including "FluMist" (influenza virus vaccine live,intranasal) and the next-generation, refrigerator-stable formulation,CAIV-T (cold adapted intranasal vaccine-trivalent).

Creation of new vaccine strains is the first step (and often aproduction-limiting one) in the influenza vaccine manufacturingprocess, noted MedImmune in a press release. Use of reverse genetics(also known as "plasmid rescue") technology enhances the safety,specificity, reliability, and efficiency with which new vaccine strainscan be produced, said the company.

"Reverse genetics represents an important breakthrough incommercial influenza vaccine processes by improving the efficiency ofproducing new influenza vaccine strains on an annual basis," saidGeorge W. Kemble, PhD, vice-president of research and development,vaccines, in a company release. "This technology enables scientists toreplace cumbersome seasonal vaccine strain development methods thatwere created in the 1960s with modern techniques, which should allow usto accelerate the availability of influenza vaccines to the public.

"For producing pandemic influenza vaccine seeds, reverse geneticshas the added benefit of allowing scientists to remove potentiallypathogenic portions of the virus, thereby creating a safer productionprocess for the vaccines," Kemble commented further.

Toward this end, MedImmune has already begun applying its plasmidrescue technology to pandemic research efforts. Last month, theNational Institutes of Health (NIH) began enrolling participants in aPhase I study of an intranasal H5N1 influenza vaccine candidate basedon MedImmune's live, attenuated vaccine technology, which also usedreverse genetics technology.

Investigators at MedImmune and Johns Hopkins Bloomberg School of PublicHealth Center for Immunization Research, where the study is beingconducted, are hopeful that a live, attenuated intranasal influenzavaccine would be as effective against potential pandemic A strains asit has been shown to be against seasonal matched and mismatched Astrains of influenza.

Most influenza vaccine manufacturing companies and governmentalagencies are now using reverse genetics technology in their developmentof pandemic vaccine candidates because it allows them to avoid workingdirectly with the infectious, circulating pandemic strains, saidMedImmne. MedImmne holds key patent estates for use of the reversegenetics technology in human influenza vaccines. The company hasoffered other influenza vaccine manufacturers nonexclusive licenses tothis intellectual property estate for use in manufacturing seasonal orpandemic vaccines.

MedImmune also recently received a $170-million contract from the USHealth and Human Services Department to expedite the development ofcell culture-based production of its influenza vaccine. The companyalso recently submitted its first lots of commercial FluMist for the2006-2007 influenza season to the FDA for approval and release. Thecompany expects to have all lots approved and released for commercialsale by the first week in September. Should all things continue ontrack, MedImmune anticipates shipping its first doses of FluMist forthe upcoming season to customers by the end of July 2006.