KEYNOTE-177
Does first-line pembrolizumab improve outcomes versus chemotherapy in MSI-H/dMMR metastatic colorectal cancer?
Trial design and population
Population: 307 patients with previously untreated MSI-H/dMMR metastatic colorectal cancer.
Treatment vs comparator: Pembrolizumab 200 mg IV every 3 weeks vs mFOLFOX6 or FOLFIRI ± bevacizumab/cetuximab.
Registry: NCT02563002
Key results
Median PFS 16.5 vs 8.2 months (HR 0.60, 95% CI 0.45–0.79). Five-year OS 54.8% vs 44.2% (HR 0.73, 95% CI 0.53–0.99). Grade 3–5 treatment-related adverse events 22% vs 67%; subsequent immunotherapy in control arm complicates OS.
Median progression-free survival · Final PFS analysis
Bars are scaled to the larger reported value. Median survival differences are not NNTs.
Absolute effect
Endpoint/time horizon: Median progression-free survival · Final PFS analysis. NNT is not calculated from median survival or hazard ratios; use fixed-time absolute risks only. NNH not calculated without a defensible fixed-time excess-harm risk difference.
Safety, burden and QoL
Grade 3–5 treatment-related adverse events 22% vs 67%. Immune toxicities can be prolonged; chemotherapy carries greater acute cytotoxic burden, neuropathy, diarrhoea and cytopenias.
QoL and discontinuation percentages are not asserted without full source-table verification; source-level QoL/toxicity audit remains a QC item.
Subgroups, maturity and limitations
MSI-H/dMMR status is required. Subsequent immunotherapy in the control arm complicates OS; do not derive NNT from median PFS.
Distinguish prespecified from exploratory subgroup analyses and mature from immature endpoints. Verify current guideline context before applying historical trial findings.
Current-practice context · 21 October 2026
Confirm current guidelines, regulatory status, biomarkers, prior treatment, comorbidities and patient goals. Full clinical freshness and source-level QoL audit remain pending.