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Health · North America

FDA raises Keytruda’s tumor-mutation threshold to 13 per megabase

The FDA granted traditional approval to pembrolizumab for advanced solid tumors with at least 13 mutations per megabase, as measured by an FDA-authorized test. The indication applies to patients whose tumors progressed after prior treatment and who have no satisfactory alternative options.

AI-assisted synthesis · Based on 4 outlets' reporting · Article text read from 3 of 4 outlets · 1 article captured only in partHow it's made

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4 outletsLatest reporting 3 min read
Coverage: Center OnlyL 0 · C 4 · R 0
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Photo: The U.S. Food and Drug Administration / Wikimedia Commons (Public domain)

What happened

Key facts

  • An FDA-authorized test must determine that a tumor has at least 13 mutations per megabase to meet the threshold (per curetoday.com, oncnursingnews.com).
  • The approval covers adults and children whose tumors progressed after prior treatment and who have no satisfactory alternative treatment options (per curetoday.com).
  • The prior threshold was 10 mutations per megabase; the revised cutoff is 13 (per curetoday.com, oncnursingnews.com).
  • Efficacy supporting traditional approval was not confirmed for patients whose tumors had 10 to fewer than 13 mutations per megabase (per curetoday.com, oncnursingnews.com).
  • Of the 220 patients in the analysis, 145 were enrolled in Cohort M, which prospectively included patients with TMB-H tumors that were not MSI-H (per curetoday.com).

The brief

The FDA granted traditional approval to pembrolizumab for advanced solid tumors classified as TMB-H, setting the cutoff at 13 or more mutations per megabase. The decision applies to adults and children whose tumors have progressed after prior treatment and who lack satisfactory alternative options, with the mutation count established by an FDA-authorized test.

The new cutoff replaces the 10-mutation-per-megabase threshold used for the earlier accelerated approval. The FDA did not confirm efficacy sufficient to support traditional approval for patients whose tumors measured from 10 to fewer than 13 mutations per megabase.

The revised eligibility line therefore narrows which tumors meet the approved TMB-H definition; it does not change the threshold for patients whose results are 13 or higher. The FDA assessed evidence from KEYNOTE-158, a study of patients with previously treated, unresectable or metastatic solid tumors.

The analysis included 220 patients whose tumors had at least 13 mutations per megabase. Of those, 145 were in Cohort M, which prospectively enrolled patients with TMB-H tumors that were not microsatellite instability-high.

OncLive describes KEYNOTE-158 as an open-label, nonrandomized study and says it enrolled adults with advanced solid tumors confirmed by histology or cytology. The coverage also distinguishes the treatment forms: the approval includes intravenous and subcutaneous pembrolizumab.

CureToday identifies the products as Keytruda and Keytruda Qlex, while the other accounts describe the drug by its generic name, pembrolizumab. Tumor mutational burden measures mutations in a tumor’s DNA.

CureToday notes that a high burden may help identify cancers that could respond to immunotherapies such as Keytruda; the threshold itself is an eligibility criterion, not a guarantee that an individual patient will benefit.

The safety information cited by OncLive lists fatigue, musculoskeletal pain, rash, diarrhea, fever, cough, reduced appetite, itching, shortness of breath, constipation, pain, abdominal pain, nausea and hypothyroidism among adverse effects reported in at least 20% of patients receiving pembrolizumab alone.

The approval accounts also warn that treatment can cause serious side effects. The central practical change is the cutoff: patients below 13 mutations per megabase no longer meet this TMB-H threshold, while those at or above it may qualify if they also meet the treatment-history and alternative-option conditions.

The reported evidence and eligibility rules frame the decision; the cited material does not provide an individual patient’s expected response or a comparison of outcomes across treatment options.

Why it matters

  • Adults and children with previously treated advanced solid tumors face a narrower biomarker-based eligibility threshold: at least 13 mutations per megabase, rather than 10.
  • Patients whose tumors measure 10 to fewer than 13 mutations per megabase are outside the revised TMB-H cutoff because efficacy supporting traditional approval was not confirmed for that range.
  • The decision covers intravenous and subcutaneous pembrolizumab, while eligibility also requires progression after prior treatment and no satisfactory alternative options.
  • The cited KEYNOTE-158 analysis included 220 patients at or above the new cutoff, including 145 in Cohort M with TMB-H tumors that were not MSI-H.

What to watch next

  • Whether clinicians and patients apply the 13-mutations-per-megabase cutoff using an FDA-authorized test.
  • How the revised threshold affects eligibility for patients whose tumor results fall between 10 and fewer than 13 mutations per megabase.
  • How the intravenous and subcutaneous pembrolizumab formulations are used within the stated eligibility conditions.
  • How safety information, including adverse effects reported in at least 20% of patients treated with pembrolizumab alone, informs treatment discussions.

How it's being covered

Coverage analysisShow details
4 source articles · 4 unique outlets
Outlet political mix: Center Only· 4 Center
Where the outlets are based: US/Canada 75% · Unknown 25%
Outlet political mix
Center Only
Left
Center
Right
0 outlets
4 outlets
0 outlets
The marker shows coverage balance: each unique outlet counts once.
Geography
Where the outlets covering this story are based.
4 unique outletsDominant coverage: US/Canada
Coverage imbalance
  • Coverage is currently concentrated among Center-rated outlets (4 of 4 rated sources); comparatively few Left or Right-rated outlets have published on the event.
  • Coverage is currently concentrated among outlets based in US/Canada (3 of 4 geographically-identified sources).
How we measure coverage

How outlets' accounts compare

1 framing difference · 2 uncorroborated claims · 1 information gap
The reports repeat the same account with different emphasis; its central claims are not independently confirmed in the reporting Updat3 read.Compared across 3 reports whose article text Updat3 read; 1 other outlet was checked by headline only.
Framing / emphasis differences
Sources emphasise different angles, actors or consequences of the same reporting.
  • CureToday names the branded products Keytruda and Keytruda Qlex and emphasizes the adult-and-child eligibility conditions; Oncology Nursing News highlights the intravenous and subcutaneous formulations and the threshold change; OncLive uses the generic name pembrolizumab and describes the trial and adverse effects.
Updat3: These are differences of emphasis, not disputes about what is reported. They do not show that the reported claims are true.
One-sided or uncorroborated claims
Claims that come from one party or one source family and are not independently corroborated.
  • CureToday says the confirmatory data did not establish sufficient efficacy for tumors with 10 to fewer than 13 mutations per megabase.
  • OncLive lists adverse effects reported in at least 20% of patients receiving pembrolizumab monotherapy.
Updat3: Not independently corroborated yet — treat as a claim, not an established fact.
Not established by the reporting
Information the available reporting does not contain or confirm. This is a gap, not a disagreement.
  • The sources do not provide patient-level response rates or duration-of-response results for the 220 patients in the analysis.
Updat3: Updat3 cannot conclude anything about this from the current sources.

Timeline

Developments from this story's sources, dated background we compiled and fact-checked, and our earlier coverage. Each row says which.
  1. President Franklin D. Roosevelt signed the Federal Food, Drug, and Cosmetic Act, expanding federal oversight of food, drugs and cosmetics.
    Background · compiled and fact-checked by Updat3
  2. President John F. Kennedy signed the Kefauver-Harris Amendments, requiring evidence of drug effectiveness as well as safety.
    Background · compiled and fact-checked by Updat3
  3. The FDA’s accelerated-approval pathway, established in 1992, permits earlier approval for serious diseases based on a surrogate endpoint or an intermediate clinical outcome, with confirmatory evidence expected afterward.
    Background · from our historical context
  4. Pembrolizumab had first received FDA approval in 2014, for advanced melanoma.
    Background · from our historical context
  5. The FDA approved pembrolizumab for certain cancers selected by MSI-H or dMMR biomarkers, regardless of tumor location.
    Background · compiled and fact-checked by Updat3
  6. The FDA granted accelerated approval to pembrolizumab for advanced solid tumors with at least 10 mutations per megabase.
    Background · compiled and fact-checked by Updat3

How we got here

On June 16, 2020, the FDA granted pembrolizumab (Keytruda) accelerated approval for adults and children with unresectable or metastatic solid tumors classified as tumor mutational burden-high (TMB-H), after prior treatment and when no satisfactory alternatives remained.

The indication used a cutoff of at least 10 mutations per megabase, measured by an FDA-authorized test, and relied on response data from the KEYNOTE-158 study. That trial included patients with several tumor types; the FDA’s analysis found an overall response rate of 29% among patients whose tumors met the TMB-H cutoff.

Original sources

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