Reviews/Perioperative Immunotherapy Solid Tumours/Adjuvant pembrolizumab disease-free survival in non-small cell lung cancer
Nsclc · PERIO-NSCLC-03 · v2
Borderline: within 4 points of the Established/Likely boundary, so a re-grade could land either side.
One large, well-designed randomised trial tested adding pembrolizumab after lung-cancer surgery and chemotherapy, and found patients lived longer without the cancer returning [6][7][8]. The benefit was clearest in exactly the group the claim describes, people who had received chemotherapy after their operation [6][7]. A separate trial of a drug in the same family pointed the same way, which adds reassurance that this is a real class effect rather than a fluke [21]. The main caution is that all the direct evidence comes from a single trial, so there is no second study to confirm it, and one of the trial's two headline analyses, in patients with high PD-L1, did not reach statistical significance [8]. The trial also enrolled a slightly narrower range of patients than the claim's stated stage range. The panel treated the result as strong and directly on point but not yet confirmed by a second independent trial.
A triple-blind phase 3 randomised trial, KEYNOTE-091, reported across [6][7][8], showed adjuvant pembrolizumab significantly improved disease-free survival versus placebo in completely resected stage IB (T greater than or equal to 4 cm) to IIIA NSCLC, with ITT HR 0.76 (95% CI 0.63-0.91, P=0.0014) [6][8]. The effect was concentrated in the 1010 patients who received adjuvant chemotherapy, HR 0.73 (95% CI 0.60-0.89), the population matching the claim's wording [6][7]. Adjuvant atezolizumab in [21] (IMpower010), a different PD-L1 agent in the same resected setting, corroborates a class-level DFS benefit. No second independent trial of adjuvant pembrolizumab in NSCLC appears in this corpus. The contested point: The evidence divides on uniformity and independence: in the PD-L1 TPS greater than or equal to 50% population significance was not achieved, HR 0.82 (95% CI 0.57-1.18, P=0.14) [8], and in patients who received no adjuvant chemotherapy the direction reversed, HR 1.25 (95% CI 0.76-2.05) [6]. All direct evidence traces to a single trial [6][7][8], so the result is strong and on point but unreplicated.
All 27 papers behind this claim with their DOIs and what each does to it, the panel’s arbitration, the evidence gap map and the open research questions. Free, and sent to your inbox.
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One reviewer's only job is to attack the finding. The challenges below were weighed before the grade was set.
The exact-claim evidence is a single trial (KEYNOTE-091, NCT02504372) reported three times in [6][7][8]; there is no independent replication of adjuvant pembrolizumab in NSCLC within the corpus.
Scope overreach: the claim states stage IB-III, but the trial enrolled only stage IB (T≥4cm) to IIIA per AJCC v7 — IIIB and small IB tumours are not covered by the evidence.
Where it remains uncertain. The benefit is conditional and not uniform: no significance in the PD-L1 greater than or equal to 50% population, HR 0.82, P=0.14 [8], and a reversed point estimate in patients without adjuvant chemotherapy, HR 1.25 [6].
Aleatory
Small subgroups such as the 167 patients without adjuvant chemotherapy carry wide intervals (HR 1.25, 95% CI 0.76-2.05) that straddle no effect [6].
The load-bearing papers from a corpus of 27, each classified by what it does to the claim. Every DOI is taken from the corpus the claim was graded on.
Primary direct evidence: significant adjuvant-pembrolizumab DFS benefit in completely resected IB-IIIA NSCLC.
“pembrolizumab significantly improved DFS compared with placebo in patients (pts) with completely resected stage IB (T ≥4 cm) to IIIA NSCLC per AJCC v7, regardless of PD-L1 expression (N = 1177, HR 0.76, 95% CI 0.63-0.91, P = 0.0014)”
Panel auditInternal validity: high · scope of inference: Adjuvant pembrolizumab vs placebo DFS in completely resected stage IB (T≥4cm)-IIIA NSCLC by surgery, node, size and chemo subgroups.Key limitations: conference abstract · stage IIIB not covered (trial IB-IIIA) · no-chemo subgroup HR 1.25 and pN2 HR 1.00
Supports the exact 'following complete resection and chemotherapy' population — DFS benefit in the adjuvant-chemo subgroup.
“Median (95% CI) DFS was 58.7 mo (39.2 mo–not reached [NR]) in the pembro arm vs 34.9 mo (28.6 mo–NR) in the pbo arm (HR, 0.73 [95% CI, 0.60–0.89])”
Panel auditInternal validity: high · scope of inference: Adjuvant pembrolizumab vs placebo DFS in stage IB (T2a≥4cm), II or IIIA NSCLC completely resected and given adjuvant platinum chemo.Key limitations: conference abstract · no alpha assigned to subgroup · stage IIIB not covered · PD-L1≥50% subgroup CI crosses 1 (HR 0.80, 0.54-1.20)
Confirms significant ITT DFS benefit while flagging the unmet PD-L1≥50% dual-primary endpoint.
“pembrolizumab (pembro) as adjuvant therapy significantly improved DFS vs placebo (pbo) in the ITT population (HR, 0.76; 95% CI, 0.63–0.91; P = 0.0014); significance was not achieved in the PD-L1 TPS ≥50% population (0.82; 95% CI, 0.57–1.18; P = 0.14)”
Panel auditInternal validity: high · scope of inference: Adjuvant pembrolizumab vs placebo DFS in completely resected stage IB-IIIA NSCLC (ITT, with or without chemo).Key limitations: brief abstract, N not stated · ITT includes patients without adjuvant chemo · PD-L1≥50% not significant (HR 0.82, 0.57-1.18) · stage IIIB not covered
3 of 27 papers shown. The full review lists all of them, with the panel’s arbitration →
Claims are graded at each quarterly release, and re-graded between releases only when a pivotal trial lands. Every change is a new version of the claim.
A single significant phase 3 DFS result with concordant class evidence strongly supports the claim but does not reach Established given low independence and subgroup heterogeneity.
Release 2026-q4 re-graded every claim from its corpus under protocol v0.19. An earlier release's grade is shown for the record; it came from an earlier protocol and is not a movement.
Assumptions that carry weight but are not themselves established.
The panel records the gap that would most move the claim, and the study that would close it.
Independent replication of adjuvant pembrolizumab. The exact claim rests on one trial reported three times [6][7][8]; a second independent trial would move the evidence from single-trial to replicated. The panel rates this the highest-importance open gap for the claim, and names the study design that would close it: An independent randomised placebo-controlled adjuvant-pembrolizumab trial in completely resected NSCLC with a DFS primary endpoint.
Open question: Does an independent trial confirm the adjuvant-pembrolizumab DFS benefit seen in KEYNOTE-091? Why it is still open: All direct corpus evidence is a single trial reported across [6][7][8] with no second study.
Priors is a sceptical first reader, not peer review, and not medical advice.
Release 2026-q4 · graded 21 Oct 2026 · protocol v0.19