In oncology, waiting matters profoundly. The standard FDA approval pathway — requiring evidence of clinical benefit, typically an improvement in overall survival — can take years of randomized controlled trial data to generate. For patients with life-threatening cancers and limited treatment options, that timeline is often unacceptable. The accelerated approval pathway, established in 1992 in response to the AIDS epidemic and formalized in the 21st Century Cures Act, allows the FDA to approve drugs based on surrogate endpoints "reasonably likely to predict" clinical benefit — enabling patients to access promising treatments years earlier than conventional pathways would allow.
Oncology has become the dominant domain for accelerated approval: more than 60% of all accelerated approvals across all therapeutic areas have been in cancer. As of 2026, over 80 oncology drugs currently hold or have received accelerated approval — including transformative agents like pembrolizumab in microsatellite instability-high cancers, nivolumab in tumor mutational burden-high cancers, and dozens of targeted therapies in molecularly defined subpopulations. This article explains the mechanics of the pathway, the surrogate endpoints used, the controversies around confirmatory trial requirements, and what the 2022–2023 reforms have changed.
What Makes a Surrogate Endpoint "Reasonably Likely to Predict" Benefit?
The FDA's standard for accelerated approval requires a surrogate endpoint that is "reasonably likely to predict" an improvement in survival or patient wellbeing — a deliberately lower bar than the "valid surrogate" standard, which would require statistical evidence that changes in the surrogate reliably translate to changes in the true clinical outcome. In practice, the most commonly used surrogate endpoints in oncology accelerated approvals are objective response rate (ORR) and progression-free survival (PFS).
ORR — the proportion of patients whose tumors shrink by at least 30% (partial response) or disappear entirely (complete response) by standard RECIST criteria — is particularly attractive for accelerated approval because it can be measured in single-arm Phase 2 trials in weeks to months, without the need for a control arm or the long follow-up required to observe survival differences. The logical case for ORR as a surrogate is straightforward: a drug that shrinks tumors is doing something to halt cancer biology, and response is biologically plausible as an intermediate step toward prolonged survival.
However, the correlation between ORR and overall survival (OS) is imperfect and context-dependent. In some settings — such as heavily pretreated hematologic malignancies where any disease control is associated with prolonged survival — the relationship is strong. In others, particularly solid tumor settings where responses can be short-lived or where shrinkage does not translate to survival benefit, the correlation is weaker. This fundamental limitation is the source of ongoing debate about how the pathway should be used.
The Mechanics: From Accelerated to Full Approval
Drugs granted accelerated approval are required to conduct confirmatory trials that verify clinical benefit — typically randomized trials demonstrating improvement in OS or PFS compared to an appropriate control. If the confirmatory trial succeeds, the drug converts to regular (full) approval. If the confirmatory trial fails to demonstrate benefit, the FDA can withdraw the accelerated approval — a process that has historically been slow and contentious but has been significantly accelerated by legislative reforms.
The 2022 Omnibus spending bill included provisions that streamlined the withdrawal process: the FDA can now rescind an accelerated approval through expedited proceedings if a manufacturer fails to conduct required confirmatory trials with due diligence, or if the confirmatory trial does not verify clinical benefit. This addressed a significant criticism of the pathway — that some manufacturers had delayed or abandoned confirmatory trials for years without regulatory consequence while continuing to sell drugs under accelerated approval.
The 2022–2023 oncology accelerated approval review: Following increased Congressional scrutiny, the FDA conducted a voluntary review of oncology drugs with outstanding confirmatory trial requirements. Several high-profile withdrawals resulted — including pembrolizumab in hepatocellular carcinoma, accelerated approvals for atezolizumab in triple-negative breast cancer and urothelial cancer, and several others — not because the drugs were ineffective, but because confirmatory trials failed to demonstrate OS or PFS benefit over standard of care. This represented the most significant correction of the accelerated approval program in its history.
Other FDA Expedited Pathways: A Comparison
Accelerated approval is one of four FDA expedited programs for serious conditions. Understanding how they differ clarifies when each is appropriate.
| Pathway | What it does | Evidence standard |
|---|---|---|
| Fast Track | More frequent FDA interactions; rolling review of application sections | Standard — clinical benefit required |
| Breakthrough Therapy | Intensive FDA guidance; cross-disciplinary review; may enable smaller trials | Standard — clinical benefit required; evidence of substantial improvement |
| Accelerated Approval | Approval based on surrogate endpoint; confirmatory trial required post-approval | Surrogate "reasonably likely to predict" benefit |
| Priority Review | FDA review target shortened from 12 to 6 months | Standard — clinical benefit required |
Many oncology drugs receive multiple designations simultaneously — for example, a drug might have Breakthrough Therapy designation (enabling intensive FDA collaboration during development), Fast Track designation (enabling rolling review), and ultimately receive Accelerated Approval (based on ORR) followed by a Priority Review timeline. The designations stack and complement each other.
Tissue-Agnostic Approvals: A New Model for Accelerated Approval
One of the most important evolutions in FDA approval strategy over the past decade is the tissue-agnostic approval — authorizing a drug for any tumor type sharing a specific molecular alteration, regardless of where in the body the cancer originated. These approvals represent both an extension of the accelerated approval concept and a reflection of precision medicine's shift from organ-based to biomarker-based oncology.
The first tissue-agnostic approvals were pembrolizumab for MSI-H/dMMR tumors (2017) and larotrectinib for NTRK fusion-positive tumors (2018). Both were based on ORR data pooled across multiple tumor histologies from basket trials — the first time the FDA had approved a drug based on a molecular alteration rather than anatomic site. Subsequent tissue-agnostic approvals include entrectinib (NTRK fusions), pembrolizumab (TMB-high, ≥10 mut/Mb), dostarlimab (dMMR), and selpercatinib (RET fusions). The TMB-high pembrolizumab approval has been somewhat controversial, as the correlation between TMB and pembrolizumab benefit varies substantially by tumor type.
What Accelerated Approval Status Means for Patients
For patients, accelerated approval has significant practical implications. From an insurance coverage perspective, most commercial payers and Medicare cover accelerated-approval drugs for their approved indications, though coverage for off-label use in related tumor types is less consistent. The existence of an FDA approval — even accelerated — greatly facilitates coverage versus a purely investigational drug.
From an evidence perspective, patients and clinicians should understand that accelerated approval represents a lower evidentiary bar than full approval. An approved ORR of 35% in a single-arm trial does not mean that 35% of all similar patients will respond — single-arm trials cannot assess comparative efficacy against other options, and selection bias in trial enrollment can inflate apparent response rates relative to real-world populations. Reading the fine print of the approval — including the specific indication, prior treatment requirements, and biomarker criteria — is essential for determining applicability to an individual patient.
From a drug withdrawal risk perspective, patients should be aware that drugs under accelerated approval can be withdrawn if confirmatory trials fail. While the FDA typically allows transition to alternative therapies with adequate notice, the 2022–2023 wave of withdrawals created some clinical disruption for patients who had achieved durable responses on drugs that were subsequently withdrawn — a nuanced situation where individual patient benefit and population-level evidence diverge.
Key takeaway: The accelerated approval pathway has enabled patients to access genuinely transformative therapies — including many of the most impactful targeted and immunotherapy drugs of the past decade — years earlier than traditional approval timelines would allow. Its strength is speed; its limitation is uncertainty. Understanding whether a drug you or a patient is taking holds full or accelerated approval, and what confirmatory evidence exists, is an important component of evidence-based oncology practice. On CancerDrugEvidence, approval status is clearly labeled on each drug page.