What are the inclusion criteria for priority review?

The FDA's priority review process is designed to expedite the development and review of new drugs. A Priority Review designation will direct overall attention and resources to the evaluation of applications for drugs that, if approved, would be significant improvements in the safety or effectiveness of the treatment, diagnosis, or prevention of serious conditions when compared to standard applications. 
Significant improvement may be demonstrated by the following examples:
evidence of increased effectiveness in treatment, prevention, or diagnosis of condition;
elimination or substantial reduction of a treatment-limiting drug reaction;
documented enhancement of patient compliance that is expected to lead to an improvement in serious outcomes; or
evidence of safety and effectiveness in a new subpopulation.
If a drug does not meet the inclusion criteria for a priority application, it may still be eligible for priority review. Applicants can use priority review vouchers when applying for marketing, and even if the drug itself does not meet the conditions for priority application inclusion, it will still be granted priority review designation.