The US Food and Drug Administration (FDA) and other National Regulatory Authorities (NRAs) have been developing new criteria
for evaluating vaccines against pandemic influenza strains for licensure. Even with aggressive and successful efforts to strengthen
and optimize US inter-pandemic production, manufacturing capacity in the United States is currently inadequate for a widespread
pandemic. To prepare for the emergence of an influenza pandemic, new approaches and technologies must be evaluated ahead of
time. Technologies for developing new influenza vaccines such as cell culture-based and reverse genetics have significantly
advanced during the past decade. These technological advances present significant challenges and opportunities to the NRAs
because regulatory agencies must develop new scientific criteria to evaluate these vaccines for safety and efficacy and final
standards for any vaccine are relevant to the technology used to produce it. New influenza vaccine candidates must be evaluated
using a blend of knowledge from the past and the best of current science in assessing their risks and benefits. FDA is actively
developing needed pathways and using current regulatory processes, such as accelerated approval, to speed the availability
of vaccines against pandemic influenza.
The US FDA's Center for Biologics Evaluation and Research (CBER) regulates vaccines for use in the US and is responsible for
their safety and effectiveness. Ensuring an adequate, safe, and effective supply of influenza vaccine each year is one of
FDA's highest priorities. Vaccine development and commercialization are complex processes. However, a single set of basic
regulatory evaluation criteria applies to vaccines, regardless of the technology used to produce them. Licensure of a new
vaccine is based on the demonstration of safety and effectiveness, and the ability to manufacture in a consistent manner.
The agency facilitates the development and evaluation of new vaccines by anticipating and addressing the regulatory issues
involved. General regulatory issues—such as detection of adventitious agents, and improved test methods that are reliable
and sensitive—are applicable to many products and product classes including vaccines. Vaccine-specific issues and challenges,
however, include determining correlates of protection necessary for evaluating efficacy, improving assays for potency, or
finding animal models that can be used for the evaluation of efficacy when human clinical trials are infeasible or unethical.
Accelerated Approval Regulatory Pathways
FDA has developed mechanisms for advancing new therapies and vaccines through the review process. These mechanisms include
fast-track development, accelerated approval, and priority review of marketing applications.
The FDA's fast-track programs are designed to facilitate the development and review of new drugs and biologics that are intended
to treat serious or life-threatening conditions, and that demonstrate the potential to address unmet medical needs. The fast
track adds to existing programs the possibility of a "rolling submission" for a marketing application. A "rolling submission"
allows the applicant to submit portions of a marketing application for review (upon agreement with the FDA) before submitting
the complete biologics license application (BLA). An important feature of fast track is that it emphasizes the critical nature
of frequent and early communication between the FDA and sponsors to improve the efficiency of product development.