Good practice violations at the Speke facility noted following a US Food and Drug Administration (FDA) inspection earlier this year have now been addressed says MedImmune, with the company promising to continue working closely with the agency on the "implementation and ongoing execution of all quality and compliance commitments."
Back in May the company was issued with a warning letter from the US regulators, highlighting concerns relating to a series of contamination problems at the facility.
The deviations in good manufacturing practice (GMP) stemmed from a lack of aseptic practices by personnel, deficiencies in cleaning, validation and disinfection practices at the vaccine manufacturing plant.
The warning letter and the associated violations also led the FDA to withhold final decisions on MedImmune's prior supplemental biologics licence application (sBLA), through which the company hopes to extend the age indication for FluMist to children under five years of age.
Despite a vote by an FDA advisory committee in favour of expanding the population able to use FluMist to the younger age group only weeks before the warning letter was issued, the agency still chose to reserve final judgement on the application until the compliance problems at the Liverpool site had been addressed.
Although the company responded to the FDA's concerns following the original inspection in March this year, the agency deemed the firm's reply wanting, failing to provide "sufficient detail to fully assess the adequacy of the corrective actions" undertaken by the company.
Just over five months later the problems at the site appear to have been rectified, allowing the company to pursue approval of the sBLA and move ahead with manufacturing at the site to gear up for the 2007/2008 flu season.
MedImmune's FluMist has had its fair share of stumbling blocks since its approval by the FDA in 2003.
Originally manufactured as a frozen formulation, the vaccine was soon found to be impractical, posing storage problems for providers and limiting usage of the inhalable product.
In January this year the company gained approval of a new formulation of the inhalable flu vaccine that can be refrigerated rather than frozen, which should help improve access to the drug and make it a more attractive option for prescribers during the next flu season.
However, with the manufacturing glitches and violations spotted by the FDA just a few months later, MedImmune (and new owner AstraZeneca) had yet another obstacle to deal with.
The facility itself is less than two years old, the result of a major investment by the company to vastly increase capacity at the Speke site.
The new facility was 10 times larger than the original Speke plant, with capacity for 15 million bulk doses of FluMist per month, or around 90 million per influenza manufacturing season.
The plant was approved by the FDA at the very end of 2005.
With all the problems encountered by the FluMist vaccine so far now seemingly dealt with, MedImmune hopes to push forward with its sBLA as well as focusing on the upcoming flu season.
The company is still intending to provide doses of FluMist for the impending flu season, and says it is currently working with the FDA on the standard annual lot release process so that shipping can begin in time for this year's flu bout.