The Absolute Effect / Oncology Evidence / Evidence Index
KEYNOTE-042
In untreated advanced NSCLC with PD-L1 TPS ≥1% and no EGFR/ALK alteration, does pembrolizumab monotherapy improve overall survival over platinum chemotherapy?
Registry: NCT02220894 · Evidence reviewed 9 November 2026 · Aliases and follow-up publications consolidated.
Phase III open-label randomized; n=1,274.Primary-source evidence summaryStudy design, population and eligibility
Phase III open-label randomized; n=1,274.
Untreated locally advanced/metastatic NSCLC, PD-L1 TPS ≥1%, EGFR/ALK wild-type.
Treatment and comparator
Intervention: Pembrolizumab monotherapy.
Comparator: Platinum chemotherapy.
Endpoints
OS tested hierarchically in TPS ≥50%, ≥20%, then ≥1%.
Key efficacy and clinical outcomes
At 61.1-mo follow-up, OS HR 0.68 (TPS≥50%), 0.75 (≥20%), 0.79 (≥1%); 5-y OS estimates 21.9%, 19.4%, 16.6% respectively.
Source-reported outcome visualization
Values are reproduced from the cited report; bars are scaled within this figure. First-line locally advanced/metastatic NSCLC · PD-L1 TPS ≥1%
Median survival and hazard ratios are not fixed-time event risks; NNT is not inferred from them.
Toxicity and treatment burden
Immune-mediated AEs; risk of early progression with monotherapy must be considered.
Absolute effect and NNT/NNH
The broad ≥1% group contains the ≥50% group; modest overall benefit does not make monotherapy best for every patient.
NNT/NNH is not calculated unless a directly reported, comparable fixed-time risk difference supports it. Median survival and hazard ratios alone do not provide an NNT.
Critical interpretation and limitations
The broad ≥1% group contains the ≥50% group; modest overall benefit does not make monotherapy best for every patient.
This page is an evidence summary, not a substitute for multidisciplinary assessment or patient-specific decision-making.
Current-practice context
Review date: 9 November 2026. Primary publication and selected follow-up sources were reviewed. Full disease-specific guideline, regulatory-label and sequencing audit remains pending; verify current local recommendations and biomarker eligibility before clinical application.