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OptiTROP-Lung05 — Sac-TMT (TROP2 ADC) + pembrolizumab vs pembrolizumab, first-line PD-L1+ advanced NSCLC

Abstract: 8506 · Session: Lung Cancer — Metastatic Non-Small Cell (Oral), Fri May 29, 2026 · Presenter: Caicun Zhou, Shanghai East Hospital, Tongji University · Embargo: May 29, 2026

At a glance

  • Sponsor: Sichuan Kelun-Biotech Biopharmaceutical Co. (developer); Merck/MSD (collaborator, exclusive rights outside Greater China)
  • PI / presenter: Caicun Zhou (Shanghai East Hospital, Tongji University)
  • NCT ID: not confirmed in trade press / ASCO abstract surfaced — omitted to avoid error
  • Phase: 3
  • Design: Randomized, open-label, multicenter; 1:1 randomization
  • N: 413
  • Primary endpoint(s): PFS by blinded independent central review (BICR)
  • Comparator: Pembrolizumab monotherapy
  • Indication: Locally advanced or metastatic NSCLC, PD-L1 TPS ≥1%, without EGFR/ALK alterations
  • Line: First-line (treatment-naïve)

Headline result

At interim analysis (data cutoff Sep 29, 2025; median follow-up 10.5 mo), sac-TMT + pembrolizumab significantly prolonged PFS vs pembrolizumab alone: median PFS by BICR not reached vs 5.7 months (HR 0.35; 95% CI 0.26–0.47; p<0.0001) — a 65% reduction in risk of progression or death; 12-month PFS 62.4% vs 29.0%. ORR was 70.2% vs 42.0% and deep response rate 49.0% vs 25.9%; 12-month DoR 77.7% vs 59.4%. Overall survival, immature at interim, trended in favor of the combination: median NR vs 14.5 months (HR 0.55; 95% CI 0.36–0.85), a ~45% reduction in risk of death; 12-month OS 80.4% vs 68.9%. Grade ≥3 treatment-emergent AEs were higher with the combination (primarily hematologic); no sac-TMT-related deaths and no new safety signals. Simultaneously published in The Lancet.

Mechanism / class

Sacituzumab tirumotecan (sac-TMT, SKB264/MK-2870) is a TROP2-directed antibody-drug conjugate carrying a belotecan-derivative topoisomerase-I inhibitor payload via a hydrolyzable linker. Pembrolizumab is an anti–PD-1 checkpoint inhibitor. This is the first randomized phase 3 trial to show a PFS benefit for an ADC + checkpoint inhibitor combination over checkpoint inhibitor alone in first-line PD-L1–positive advanced NSCLC.

Practice-changing?

Pending. The PFS benefit is large and consistent with maturing OS, ORR, and depth-of-response signals, positioning the combination as a potential new 1L standard for PD-L1–positive NSCLC without driver alterations. Confirmation awaits mature OS, regulatory review, and the China-heavy trial population's generalizability.

  • Other ASCO 2026 trials: ./ — see other lung / ADC abstracts in this trials folder
  • JPM 2026: ../../jpm-2026/index.md — Kelun-Biotech / Merck sac-TMT collaboration

Sources

  • ASCO Meeting Library (Abstr 8506): https://www.asco.org/abstracts-presentations/259330
  • The Lancet (interim analysis): https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(26)00968-2/abstract
  • PR Newswire (Kelun-Biotech press release): https://www.prnewswire.com/news-releases/the-results-of-phase-iii-optitrop-lung05-study-of-sacituzumab-tirumotecan-sac-tmt-presented-as-an-asco-oral-presentation-and-simultaneously-published-in-the-lancet-302786204.html
  • OncLive: https://www.onclive.com/view/optitrop-lung05-shows-pfs-benefit-with-first-line-sac-tmt-plus-pembrolizumab-in-pd-l1-nsclc
  • Targeted Oncology: https://www.targetedonc.com/view/sacituzumab-tirumotecan-plus-pembrolizumab-improves-pfs-in-nsclc
  • OncoDaily: https://oncodaily.com/oncolibrary/lung-oncology/optitrop-lung05