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Fast Track & Breakthrough Therapy Toolkit

Application process, strategic benefits, and practical guidance for FDA expedited development and review designations

Updated Q4 2025  |  BioPharmaWire Editors  |  Based on FDA guidance documents, 21 CFR Parts 312 and 314, and FDASIA Section 902

The FDA offers four principal expedited programs for drugs and biologics targeting serious conditions: Fast Track Designation, Breakthrough Therapy Designation, Accelerated Approval, and Priority Review. These are distinct programs with different eligibility criteria, different benefits, and different points of application — and they can be stacked. A single drug can simultaneously hold Fast Track, Breakthrough Therapy, and Accelerated Approval status while also receiving Priority Review of its NDA or BLA. Understanding which programs apply, when to apply, and how to use them strategically can meaningfully compress development timelines and reduce regulatory risk.

The Four Programs at a Glance

Before diving into each program individually, the table below maps all four across the dimensions that matter most for strategic planning.

Feature	Fast Track	Breakthrough Therapy	Accelerated Approval	Priority Review
Primary benefit	Frequent FDA interaction; rolling review eligibility	Intensive FDA guidance; cross-disciplinary review team; rolling review	Approval on surrogate/intermediate endpoint with post-market confirmatory trial requirement	6-month review vs standard 12-month PDUFA clock
Eligibility — disease	Serious or life-threatening condition	Serious or life-threatening condition	Serious or life-threatening condition	Any condition; no disease severity requirement
Eligibility — drug	Drug must have potential to address unmet medical need	Preliminary clinical evidence showing substantial improvement over available therapy on a clinically significant endpoint	Drug must have an effect on a surrogate or intermediate clinical endpoint reasonably likely to predict clinical benefit	Drug must offer major advance in treatment OR provide therapy where none exists
When to apply	Pre-IND or any time after IND filing. Earlier is better — enables rolling review from the start	After Phase 1 data available showing preliminary clinical evidence. Must be before NDA/BLA submission	At NDA/BLA submission or during pre-NDA/BLA meetings. Strategy should be agreed with FDA in advance	Requested with NDA/BLA submission. FDA grants or denies within 60 days of receipt
Rolling review	Yes — sponsor can submit completed NDA/BLA sections as they are finalised	Yes — same rolling review benefit as Fast Track	No formal rolling review; standard submission format	No — full NDA/BLA submitted at once; priority clock applies to review only
FDA meeting access	More frequent meetings; written responses within 30 days of requests	Intensive guidance including cross-disciplinary teams; senior FDA leadership involvement	Standard Type A/B/C meeting access; no additional meetings above standard	Standard meeting access; no additional meetings
Post-approval obligations	None specific to Fast Track; standard pharmacovigilance applies	None specific to BTD; standard pharmacovigilance applies	Mandatory post-market confirmatory trial to verify clinical benefit. FDA can withdraw approval if confirmatory trial fails	None specific to Priority Review; standard pharmacovigilance applies
Can be combined with	BTD, Accelerated Approval, Priority Review, ODD, RMAT	Fast Track, Accelerated Approval, Priority Review, ODD, RMAT	Fast Track, BTD, Priority Review, ODD	Fast Track, BTD, Accelerated Approval, ODD
Recent grant rate	~75-80% of requests granted. FDA rarely denies well-supported Fast Track requests	~50-60% of requests granted. Higher bar than Fast Track; requires preliminary clinical evidence	Sponsor-driven strategy agreed with FDA in advance; formal ‘grant’ is built into NDA/BLA filing	~60-65% of NDA/BLA submissions receive Priority Review designation
CFR/statutory basis	21 CFR 312.80-312.88; FDAMA Section 112	FDASIA Section 902; 21 CFR 312.300-312.320	21 CFR 314.500-314.560 (drugs); 21 CFR 601.40-601.46 (biologics)	PDUFA; 21 CFR 312.80-312.88

Fast Track Designation

What It Actually Gets You

Fast Track is the most widely granted of the four designations — and, because of that, the most frequently misunderstood. It does not speed up the FDA review clock on its own. What it does is create a framework for more frequent, more structured dialogue with FDA throughout development, and — critically — it enables rolling review, which allows sponsors to submit completed NDA or BLA sections to FDA before the full dossier is ready. For a complex program, rolling review alone can compress time-to-approval by 6-12 months by the time formal review is initiated.

The second major benefit is access. Fast Track sponsors are entitled to written FDA responses within 30 days of submitting meeting requests, versus the standard 30-day scheduling window plus the meeting itself. For a program in active Phase 2 or Phase 3 development, this accelerated interaction cadence allows sponsors to resolve questions and course-correct faster than in a standard development program.

What It Does Not Get You

Fast Track designation does not guarantee approval, does not reduce the evidentiary standard for approval, and does not shorten the formal review clock. A Fast Track product still requires the same quality, safety, and efficacy evidence as any other NDA or BLA. The designation is about development efficiency, not a lower bar. Sponsors who apply for Fast Track expecting automatic priority review or a faster FDA decision are frequently disappointed.

Fast Track: Step-by-Step Application Process

#	Step	Detail
1	Confirm eligibility	Verify the condition qualifies as ‘serious or life-threatening’ under FDA’s definitions. FDA interprets ‘serious’ broadly: conditions substantially affecting daily functioning or likely to cause death, hospitalisation, or significant disability if left untreated. The drug must have the potential to address an unmet medical need — meaning no available therapy, or existing therapy is inadequate.
2	Time the request strategically	Fast Track can be requested at pre-IND or any time after IND filing. Requesting before IND submission allows rolling review from Phase 1 onward. Earlier requests maximise the duration of FDA engagement and rolling review benefit. Do not wait until Phase 3 — by then, the primary value of Fast Track has already been missed.
3	Prepare the Fast Track request	Submit as an amendment to the IND (or as part of the pre-IND package). Include: description of the serious condition, explanation of the unmet medical need, description of the drug and proposed indication, available nonclinical and clinical data supporting the potential to address the unmet need. The request should be concise — 3-5 pages is sufficient. FDA does not require extensive data for Fast Track.
4	Submit to the appropriate FDA division	Fast Track requests are submitted to the FDA review division responsible for the therapeutic area. Address to the Division Director. Include in the cover letter: IND number, drug name, proposed indication, and statement that this is a Fast Track Designation Request.
5	Receive FDA decision (60 days)	FDA must respond within 60 days of receiving the request. If granted, FDA sends a designation letter. If denied, FDA provides written reasons — the sponsor may resubmit with additional data or request a meeting to discuss the denial.
6	Activate rolling review	Once Fast Track is granted, notify the FDA division that you wish to activate rolling review. Submit completed NDA/BLA sections (CMC, nonclinical, clinical pharmacology, individual study reports) as they are finalised. FDA begins reviewing each completed section immediately rather than waiting for the full submission.
7	Utilise increased meeting access	Fast Track sponsors are entitled to more frequent Type B meetings and written FDA responses within 30 days. Use this access deliberately: agree on Phase 2 design and endpoints before enrolment, confirm Phase 3 design and statistical assumptions at end-of-Phase-2 meeting, and address CMC questions early.

Breakthrough Therapy Designation

The Most Valuable Designation in Drug Development

Breakthrough Therapy Designation (BTD) is the most operationally powerful of the four expedited programs. It was created by Congress in 2012 following recognition that Fast Track, while useful, did not provide sufficient FDA engagement intensity for the most promising drugs. BTD delivers everything Fast Track offers — rolling review, frequent meetings, written responses — plus a cross-disciplinary project team at FDA, intensive senior leadership involvement, and the ability to use more flexible trial designs supported by active FDA input.

In practice, the most valuable element of BTD is the CDPT — the cross-disciplinary project team assigned to the program. This team includes senior FDA reviewers across clinical, clinical pharmacology, statistics, and CMC who are actively engaged throughout development. For a sponsor navigating a novel mechanism of action, a first-in-class molecule, or a complex patient population, having a dedicated FDA team available for rapid consultation is a material competitive advantage.

The Evidence Hurdle

The key distinction between Fast Track and BTD at the application stage is evidence. Fast Track can be granted on a compelling nonclinical package and mechanism-of-action argument. BTD requires preliminary clinical evidence of substantial improvement over available therapy on a clinically significant endpoint. This typically means Phase 1 data — but Phase 1 data that shows something striking. Response rates dramatically higher than historical controls, biomarker-defined patient populations with durable responses, or safety profiles materially better than standard of care are the kinds of signals that support a BTD request.

Breakthrough Therapy: Step-by-Step Application Process

#	Step	Detail
1	Establish preliminary clinical evidence	BTD requires actual clinical data showing substantial improvement over available therapy — unlike Fast Track, which can be granted on nonclinical data alone. The evidence threshold is described as ‘preliminary’ but must be clinical. Phase 1 data showing striking efficacy signals or a strong biomarker-driven response in a well-defined patient population is the typical basis for a BTD request.
2	Define ‘substantial improvement’ precisely	FDA evaluates improvement over available therapy on a clinically significant endpoint. ‘Substantial improvement’ means more than a modest incremental benefit — FDA is looking for early evidence of a step-change in efficacy, a dramatically improved safety profile, or efficacy in a population that does not respond to existing therapies. Document this comparison explicitly in the BTD request.
3	Prepare the BTD request	Submit as an IND amendment. BTD requests require more substance than Fast Track: include a full description of the preliminary clinical evidence (with data tables or figures), a comparison to available therapies with specific metrics, a description of the proposed indication and patient population, and a proposed development plan. Plan for 10-20 pages plus supporting data. FDA expects a compelling scientific narrative, not just a checklist.
4	Submit and await FDA decision (60 days)	Same 60-day response timeline as Fast Track. BTD denial rates are higher than Fast Track — approximately 40-50% of requests are denied. Common denial reasons: clinical evidence not yet available (nonclinical data submitted instead), improvement over available therapy not well-characterised, or condition does not meet ‘serious’ threshold.
5	Engage FDA’s cross-disciplinary team	BTD triggers assignment of a cross-disciplinary project team (CDPT) at FDA including senior representatives from clinical, clinical pharmacology, statistics, and CMC. This team is your accelerated development partner. Request a kick-off meeting with the CDPT immediately after BTD is granted — use it to align on the full development and approval strategy.
6	Use adaptive trial designs	FDA actively supports adaptive designs for BTD programs. Consider seamless Phase 2/3 designs that allow dose selection and population enrichment at interim analyses without resetting the regulatory clock. Discuss adaptive design plans with the CDPT early — FDA’s Office of Biostatistics engages deeply on adaptive designs for BTD products.
7	Agree on surrogate endpoints early	BTD programs frequently use Accelerated Approval in conjunction. If pursuing AA, align with FDA on the surrogate or intermediate endpoint before Phase 3 enrolment. FDA can grant BTD without Accelerated Approval and vice versa — but the two are often used together for maximum development efficiency.
8	Prepare for intensive review	BTD applications receive intensive review with senior FDA involvement. Expect the review to move faster than standard but with more detailed questions. Prepare for rapid-turnaround FDA requests during the review period and ensure your regulatory team has capacity to respond within the compressed timelines.

Accelerated Approval

Approval Before Definitive Clinical Benefit is Proven

Accelerated Approval (AA) allows FDA to approve a drug based on a surrogate endpoint — a biomarker or intermediate clinical endpoint that is reasonably likely to predict clinical benefit — rather than waiting for definitive evidence of improved survival, reduced hospitalisations, or other hard clinical outcomes. The approval is conditional: the sponsor must complete a post-market confirmatory trial demonstrating actual clinical benefit, and FDA can withdraw approval if the confirmatory trial fails or the sponsor does not pursue it diligently.

AA has been transformative in oncology and rare disease, where hard clinical endpoints like overall survival require large, long-duration trials that may take years longer than surrogate-based trials. The most common surrogate endpoints used in AA: overall response rate (ORR) and duration of response in oncology; CD4 count and viral load in HIV; forced expiratory volume (FEV1) in respiratory disease; haemoglobin levels in haematologic conditions.

The Confirmatory Trial Obligation

The 2022 FDORA legislation tightened FDA’s post-market enforcement authority for AA products. FDA now has clearer authority to require that confirmatory trials be underway at the time of AA approval — not just ‘planned’ — and to initiate withdrawal proceedings more quickly if confirmatory trials are discontinued or fail. Sponsors pursuing AA should plan the confirmatory trial in detail before the AA submission and be prepared to demonstrate active enrolment at the time of approval.

Surrogate Endpoint Strategy

Selecting the right surrogate endpoint is the most consequential strategic decision in an AA program. The endpoint must be: reasonably likely to predict clinical benefit (FDA will not approve on a marker with no biological plausibility for the clinical outcome); measurable in a reasonable trial timeframe; and capable of being assessed in a blinded, randomised design if feasible. Discuss surrogate endpoint selection with FDA’s clinical division and the Office of Biostatistics before Phase 2 design is finalised.

Priority Review

A Faster Clock, Not a Different Bar

Priority Review designation shortens the PDUFA review clock from 12 months to 6 months. It does not change the evidentiary standard for approval, does not provide additional FDA interaction during development, and does not affect the rolling review process. It is a review-stage benefit, not a development-stage benefit.

Priority Review is granted for drugs that offer a major advance in treatment or provide a therapy where none exists for a serious condition. It is requested at the time of NDA or BLA submission (not during development) and FDA grants or denies it within 60 days of receipt. The majority of NDA and BLA submissions that qualify for Priority Review have already received Fast Track or BTD during development, as the eligibility criteria substantially overlap.

Note:  Priority Review vouchers (PRVs) are a separate mechanism — a tradable asset granted to sponsors of certain rare pediatric or neglected tropical disease products. PRVs can be sold to other sponsors who then redeem them for Priority Review on any NDA/BLA. PRV values have ranged from $67M to $350M in recent years. If your program qualifies for a Rare Pediatric Disease designation, PRV eligibility is worth evaluating as a standalone financial asset.

RMAT: A Fifth Designation Worth Knowing

The Regenerative Medicine Advanced Therapy (RMAT) designation, created by the 21st Century Cures Act in 2016, is the cell and gene therapy equivalent of BTD. Eligibility: the product must be a regenerative medicine therapy (cell therapy, therapeutic tissue engineering, human cell/tissue product, or combination product using such therapies) intended to treat a serious condition with preliminary clinical evidence of potential to address unmet medical need.

RMAT provides all BTD benefits plus early interactions with FDA to discuss potential surrogate endpoints and post-approval studies, and expedited interactions to facilitate efficient development. For any cell therapy, gene therapy, or ATMP program, RMAT designation should be evaluated in parallel with BTD. The two designations serve similar purposes, but RMAT is specific to regenerative medicine and has a slightly different eligibility framework.

Strategic Stacking: Which Designations to Pursue Together

Most well-positioned development programs in serious conditions should pursue multiple designations simultaneously. The typical optimal stack:

Pre-IND / IND filing:  Apply for Fast Track immediately. Also apply for Orphan Drug Designation if prevalence criteria are met. If cell/gene therapy, apply for RMAT.

After Phase 1 clinical data:  If preliminary evidence of substantial improvement exists, apply for BTD. BTD supersedes Fast Track in practice but keep Fast Track in place as a fallback if BTD is denied.

End of Phase 2:  Discuss Accelerated Approval eligibility and surrogate endpoint strategy at end-of-Phase-2 meeting. Agree on Phase 3 design that supports both traditional and accelerated approval pathways if possible.

NDA/BLA submission:  Request Priority Review at submission. If pursuing AA, submit the AA NDA/BLA with confirmatory trial enrolled.

Common Strategic Mistakes

Watch out:  Applying for BTD without clinical data. FDA denies approximately 40-50% of BTD requests, most frequently because the sponsor submitted nonclinical evidence only. Wait until Phase 1 data is available before applying.

Watch out:  Treating Fast Track as a guarantee of faster approval. The designation has no effect on the review clock without rolling review activation. Make sure rolling review is actually activated and utilised.

Watch out:  Agreeing to surrogate endpoints without FDA alignment. Sponsors who select surrogate endpoints for Accelerated Approval without formal FDA agreement risk having AA denied at NDA/BLA submission, or having the endpoint rejected during review.

Tip:  Use the BTD cross-disciplinary team meeting agenda strategically. Request topics in advance and come prepared with specific questions. FDA CDPT meetings are among the most valuable regulatory interactions available — do not treat them as status updates.

Tip:  Track the confirmatory trial timeline from day one of AA approval. FDORA 2022 gave FDA new enforcement tools. Sponsors who are not actively enroling confirmatory trials face higher withdrawal risk than at any previous point.

Tip:  For RMAT programs, request early CBER interaction even before RMAT designation. CBER has a dedicated office for regenerative medicine — engaging before IND filing can prevent significant late-stage surprises.

Key FDA Guidance Documents

Expedited Programs for Serious Conditions — Drugs and Biologics (May 2014) — the primary guidance covering all four programs

Breakthrough Therapy Designation (December 2018 update) — specific guidance on BTD eligibility and process

Accelerated Approval of Oncology Products: A Compendium of Policies (2023) — FDA’s updated post-FDORA AA framework

Adaptive Designs for Clinical Trials of Drugs and Biologics (2019) — relevant for BTD programs considering adaptive Phase 2/3 designs

Regenerative Medicine Advanced Therapy Designation (February 2019) — RMAT eligibility and process

This toolkit is an editorial product of BioPharmaWire based on publicly available FDA guidance and legislative sources as of Q4 2025. Regulatory requirements and procedures are subject to change. This document does not constitute regulatory or legal advice. Sponsors should consult qualified regulatory affairs professionals and refer to current FDA guidance before submitting designation requests.