FDA Priority Review: Eligibility, Six-Month Clock, and Vouchers

FDA Priority Review is a designation that shortens the agency’s target action time on a drug or biologic application from ten months to six. To qualify, the product must treat a serious condition and, if approved, offer a significant improvement in safety or effectiveness over therapies already available. The designation speeds up the administrative clock. It does not lower the scientific bar for approval, and it does not guarantee the drug will be approved.¹

The six-month and ten-month figures are performance goals FDA commits to under the Prescription Drug User Fee Act, currently covering fiscal years 2023 through 2027. They are targets, not statutory deadlines: the agency aims to meet them for 90 percent of applications in each category.²

Who Qualifies

Two conditions must both be met. Meeting one without the other is not enough.

A Serious Condition

The drug has to target a serious condition, meaning a disease or health state that substantially affects a patient’s ability to function day to day. Cancer, heart failure, HIV, and treatment-resistant depression are straightforward examples. Life-threatening illness is not required; persistent, debilitating symptoms that impair daily life can meet the threshold, and the agency evaluates seriousness case by case.³

Significant Improvement Over Existing Therapies

The application also has to show that approval would be a meaningful step forward compared to what patients can already get. FDA guidance describes several ways to make that showing:³

Greater effectiveness, shown through clinical trial data such as higher response rates, longer survival, or better disease control than current treatments.
Fewer serious side effects, by eliminating or substantially reducing a reaction that limits how a current therapy can be used.
Better compliance leading to better outcomes. A dosing change, such as moving from daily injections to a once-monthly oral dose, counts only when the sponsor provides data showing improved compliance produces superior clinical results.
Effectiveness in a subpopulation that has no adequate therapy, such as a pediatric group or patients with a specific genetic marker.

This is where most requests succeed or fail. A drug that is merely equivalent to existing options, even one that works through a novel mechanism, will not qualify. Comparative data is what carries the request, not standalone efficacy numbers.

Which Applications Are Eligible

Three types of submissions can receive Priority Review: original New Drug Applications, original Biologics License Applications, and efficacy supplements for already-approved products that include new clinical data.³ Generic drug applications filed under the abbreviated pathway are not eligible, because they rest on bioequivalence to a reference product rather than new clinical evidence of a therapeutic advance.

The PDUFA user fee applies either way. For fiscal year 2026, an application requiring clinical data carries a fee of $4,682,003, whether it receives Standard or Priority Review.⁴

How to Request It

Priority Review is not automatic. The sponsor asks for it when submitting the application. FDA guidance instructs sponsors to identify the submission as a “REQUEST FOR PRIORITY REVIEW DESIGNATION” in bold, uppercase letters in the cover letter, and the agency does not expect requests to arrive after the application has already been filed.³

The request itself should summarize the clinical evidence supporting the significant-improvement claim and lay it out side by side with currently available therapies. Every referenced safety and effectiveness data point needs to cite specific volumes and pages in the larger application so reviewers can find it quickly. A general assertion that the drug is “better” will not move the needle. The request has to walk reviewers through the trial results that show the advantage.

How the Six-Month Clock Actually Runs

The timeline does not start the day the application arrives. When FDA receives an application, a 60-day filing review period begins, during which the agency confirms the submission is complete enough for substantive review. The priority review determination happens in this window, and the review division notifies the sponsor in writing by Day 60. A denial comes with a written explanation.⁵

For new molecular entity NDAs and original BLAs, the PDUFA review clock then starts at the end of that 60-day filing period, so the six-month Priority Review goal date falls roughly eight months after original receipt. For non-new-molecular-entity original NDAs, the clock starts on the date of receipt.²

The six-month target can slide. A major amendment during the review cycle, such as a significant new safety study or a substantial risk management plan, can extend the goal date by three months. Only one extension is allowed per cycle, and the agency generally reserves it for situations where reviewing the new information could resolve outstanding deficiencies and lead to approval in the current cycle. A manufacturing facility not properly identified in the original submission can also trigger a three-month extension.²

Priority Review Is Not Approval

This is the point sponsors and patients most often misread. Priority Review shortens the timeline for a decision. The decision itself can still go either way. FDA has stated explicitly that designating a drug as priority “does not alter the scientific/medical standard for approval or the quality of evidence necessary.”¹

At the end of the review the agency either issues an approval letter, meaning the drug can be marketed, or a complete response letter, meaning it found deficiencies that must be resolved before approval. Resolving them can involve additional clinical trials, manufacturing changes, or labeling revisions. Complete response letters after a priority review are not rare, and sponsors sometimes go through multiple cycles before clearing all of the agency’s concerns.

Priority Review Vouchers: A Separate Route

A sponsor can also obtain Priority Review by redeeming a Priority Review Voucher, which sits outside the standard eligibility criteria. Congress created these vouchers to encourage development of treatments for diseases that lack commercial appeal. A voucher is earned by gaining FDA approval for a qualifying product in one of three categories:

Tropical diseases. Established in 2007, this program covers tuberculosis, malaria, cholera, and roughly two dozen other infectious diseases that disproportionately affect populations in developing nations.⁶
Rare pediatric diseases. Created in 2012 and recently extended, this program will sunset after September 30, 2029, with no vouchers awarded under it after that date.⁷
Medical countermeasures. Created in 2016, this covers drugs intended to prevent or treat harm from biological, chemical, radiological, or nuclear threats identified as material threats to national security.⁸

The company that earns a voucher does not have to use it. Vouchers can be sold or transferred, with no limit on how many times a voucher changes hands before redemption.⁹ Sale prices have historically ranged from roughly $20 million to $350 million, depending on market conditions and voucher supply.

Redemption carries its own cost. For fiscal year 2026, the sponsor pays an additional user fee of $1,962,472 on top of the standard PDUFA application fee.¹⁰ A voucher covers one application, and the transfer has to be documented with letters from both the original holder and the new owner submitted with the application.

How Priority Review Fits with Other Expedited Programs

Priority Review is one of four FDA expedited programs for serious conditions, alongside Fast Track, Breakthrough Therapy, and Accelerated Approval. Those three operate during drug development or shape the evidentiary basis for approval; Priority Review operates on the application itself once it is filed. A single drug can hold more than one designation, and Breakthrough Therapy status does not automatically confer Priority Review, though many breakthrough-designated drugs receive it based on their clinical data.¹¹

If FDA Denies the Request

A denial is not the last word. The agency’s formal dispute resolution process lets sponsors escalate scientific and medical disagreements above the review division to the office or center level within the relevant review center.¹² In practice, sponsors first try to resolve the disagreement informally with the review division before invoking the formal process. A successful appeal results in the designation being granted and the review timeline adjusted accordingly.

1
U.S. Food and Drug Administration. Priority Review
2
U.S. Food and Drug Administration. PDUFA Reauthorization Performance Goals and Procedures Fiscal Years 2023 Through 2027
3
U.S. Food and Drug Administration. Expedited Programs for Serious Conditions – Drugs and Biologics
4
Federal Register. Prescription Drug User Fee Rates for Fiscal Year 2026
5
U.S. Food and Drug Administration. Review Designation Policy – Priority (P) and Standard (S)
6
Office of the Law Revision Counsel. 21 USC 360n – Priority Review to Encourage Treatments for Tropical Diseases
7
U.S. Food and Drug Administration. Rare Pediatric Disease Designation and Priority Review Voucher Programs
8
Office of the Law Revision Counsel. 21 USC 360bbb-4a – Priority Review to Encourage Treatments for Agents That Present National Security Threats
9
U.S. Food and Drug Administration. Tropical Disease Priority Review Vouchers – Guidance for Industry
10
Federal Register. Fee Rate for Using a Priority Review Voucher in Fiscal Year 2026
11
U.S. Food and Drug Administration. Breakthrough Therapy
12
U.S. Food and Drug Administration. Formal Dispute Resolution – Sponsor Appeals Above the Division Level Guidance for Industry and Review Staff