- Design
- Partitioned survival cost-effectiveness model
- Population
- Simulated KEYNOTE-689 cohort with locally advanced HNSCC, by PD-L1 CPS
- Primary outcome
- Incremental cost-effectiveness ratio
- Effect
- CPS >10: ICER $134,700/QALY; CPS 1–10: ICER about $2.18 million/QALY
The KEYNOTE-689 trial showed improved event-free survival when perioperative pembrolizumab was added to standard care for locally advanced head and neck squamous cell carcinoma. A JAMA Otolaryngology economic evaluation modelled its cost-effectiveness using US costs, splitting patients by PD-L1 combined positive score.
For CPS above 10, pembrolizumab added about 1.35 quality-adjusted life-years at an extra $181,900, an ICER of $134,700 per QALY, with a 57% chance of being cost-effective at $150,000. For CPS 1 to 10, it added only about 0.08 QALYs for $166,500, an ICER of about $2.2 million, with an 11% chance of being cost-effective.
The CPS 1 to 10 estimates were derived indirectly from published subgroups and rest on digitised survival curves, so they are uncertain. The direction is clear, though: almost all of the value sits in patients with high PD-L1 expression. Drug prices differ widely outside the US, so the absolute figures will not transfer, but the relative message will.
- Check the PD-L1 combined positive score before discussing perioperative pembrolizumab.
- Most of the modelled benefit was in patients with CPS above 10.
- In CPS 1 to 10, the modelled gain was small relative to cost.
- US cost figures do not transfer directly to other health systems, but the CPS gradient likely does.
Why it matters
Biomarker selection may decide whether a costly perioperative immunotherapy is worth offering.
Don't overread it
This is a model built on trial subgroup data; the CPS 1 to 10 estimate was reconstructed indirectly.
The statistics, in plain English
An ICER is the extra cost for each extra year of healthy life gained. $134,700 is near common US thresholds; $2.2 million is far above any.
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