FDA’s Commitment Letter, available at www.fda.gov/gdufa, explains that:
Products to respond to current and anticipated public health
emergencies, products under special review programs, such as the
President’s Emergency Plan for AIDS Relief (PEPFAR), products for
which a nationwide shortage has been identified, and first generic
products for which there are no blocking patents or exclusivities on the
reference listed drug currently may qualify for expedited review. For
ANDAs in the year 1 and 2 cohorts, FDA will expedite review of
Paragraph IV6 applications that are submitted on the first day that any
valid Paragraph IV application for the drug in question is submitted.