# SWOG S1801

Source: https://onco.cc/trials/swog-s1801/  
OnCo record `swog-s1801` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Simply moving three doses of the same drug to before surgery improved outcomes, a result that changed how the field thinks about timing.

## Summary

2-year EFS 72% vs 49% (HR 0.58), NEJM 2023. Same total drug exposure in both arms; the difference is attributed to priming the immune response while the tumour and its draining nodes are still present. Three-year follow-up presented at ESMO 2025 sustained the benefit. Together with NADINA it established neoadjuvant immunotherapy as standard for resectable stage III disease.

## Fields

- Kind: Trial
- Status: positive
- Last checked: 2026-09-07
- Registry id: NCT03698019
- Phase: 2
- Setting: Resectable stage IIIB-IV melanoma: three doses of pembrolizumab before surgery then 15 after, vs 18 doses after surgery
- Sponsor: SWOG / NCI
- Enrolled: 313
- Result: 2-year EFS 72% vs 49%; HR 0.58.
- Outcomes: Event-free survival at 2 years: Neoadjuvant + adjuvant pembrolizumab 72% vs Adjuvant pembrolizumab 49%, HR 0.58
- Replication: Replicated in principle by NADINA with a different regimen.

## Sources

- ClinicalTrials.gov NCT03698019: https://clinicaltrials.gov/study/NCT03698019
- NEJM 2023: https://www.nejm.org/doi/full/10.1056/NEJMoa2211437

## Connected records

- cancers: [Melanoma](https://onco.cc/cancers/melanoma/), [Stage III melanoma (after surgery)](https://onco.cc/cancers/stage-iii-melanoma/)
- technologies: [Immune checkpoint inhibitors](https://onco.cc/technologies/checkpoint-inhibitor/)
- targets: [PD-1](https://onco.cc/targets/pd1/)
- drugs: [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/)
- companies: [SWOG Cancer Research Network](https://onco.cc/companies/swog/)
- terms: [Neoadjuvant / adjuvant / perioperative](https://onco.cc/terms/neoadjuvant-adjuvant/)
- people: [Sapna P. Patel](https://onco.cc/people/sapna-patel/)
- key papers: [Neoadjuvant-Adjuvant or Adjuvant-Only Pembrolizumab in Advanced Melanoma](https://onco.cc/key-papers/paper-swog-s1801-n-engl-j-med-2023/)
- pairings: [Neoadjuvant immunotherapy → response-adapted adjuvant](https://onco.cc/pairings/neoadjuvant-io-response-adapted/)
- roadmaps: [Surgery roadmap: radical operations → less surgery → no surgery when a drug has done the work](https://onco.cc/roadmaps/surgery-roadmap/)

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