The 1992 Prescription Drug User Fee Act (PDUFA) established a two-tiered system – Standard Review and Priority Review.
Standard Review is applied to a drug that offers at most, only minor improvement over existing marketed therapies. The 2002 amendments to PDUFA set a 10 month goal for a standard review.
Priority Review designation is given to drugs that offer major advances in treatment, or provide a treatment where none existed. The goal for completing a Priority Review is six months.