Sac-TMT extends survival over chemotherapy in EGFR-mutant lung cancer

Overview

Updated 1 hour ago

Patients with EGFR-mutant lung cancer who progressed on TKI therapy gained 8.5 months of median survival on sac-TMT versus platinum-doublet chemo: 25.9 months to 17.4. The figure comes from the final analysis of the Phase III OptiTROP-Lung04 trial, presented at the 2026 ESMO Congress in Madrid. It makes sac-TMT the first TROP2-targeting antibody-drug conjugate to show a survival benefit over chemotherapy in this patient group.

The death-risk reduction of 31% held after 32.3 months of median follow-up, with 54.1% of sac-TMT patients alive at two years versus 37.2% on chemo. Whether this becomes a global standard now rests with MSD, which holds rights outside Greater China and is running 18 Phase III studies of the drug.

Why it matters

Patients who progress on EGFR-TKI therapy have had chemotherapy as the default; a TROP2 antibody-drug conjugate now beats it on survival.

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Key Indicators

8.5 months

Median overall survival gain with sac-TMT

25.9 months for sac-TMT versus 17.4 months for platinum-based doublet chemotherapy.

31%

Reduction in risk of death

Hazard ratio 0.69 (95% CI 0.54–0.89) versus chemotherapy.

54.1%

Two-year overall survival rate with sac-TMT

Versus 37.2% for chemotherapy, a 16.9-point improvement.

376

Patients randomized in OptiTROP-Lung04

Split 1:1 between sac-TMT monotherapy and platinum-based doublet chemotherapy.

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People Involved

Wenfeng Fang

Professor of oncology, Sun Yat-sen University Cancer Center

Presented the OptiTROP-Lung04 final OS analysis at ESMO 2026

Organizations Involved

Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd.

Biopharmaceutical company

Developer of sac-TMT; holds commercialization rights in Greater China

Developed sacituzumab tirumotecan (sac-TMT, also known as SKB264/MK-2870), the first TROP2-targeting antibody-drug conjugate approved for lung cancer.

MSD (Merck & Co.)

Pharmaceutical company

Global partner holding ex-Greater-China rights to sac-TMT

Licensed sac-TMT for markets outside Greater China and is running 18 global Phase III studies of the drug.

Timeline

2025 October 2026

4 events Latest: Today

Tap a bar to jump to that date

October 2026
Final OS results presented at ESMO 2026
Today Conference

Final analysis confirmed sustained survival benefit: 31% death-risk reduction, 8.5-month median OS gain.
Today
August 2026
Data cutoff for final OS analysis
Data

Final overall survival analysis locked at 32.3 months median follow-up.
August 6th, 2026
September 2025
NMPA approves sac-TMT for EGFR-mutant NSCLC
Approval

China's National Medical Products Administration approved sac-TMT for EGFR-mutant NSCLC after progression on EGFR-TKI therapy.
September 2025
2025
Phase III PFS and interim OS results published in NEJM
Publication

Final PFS analysis showed a 51% reduction in progression or death risk; interim OS favored sac-TMT.
2025

Scenarios

Sac-TMT wins its first approval outside China

Possible Resolves by Q2 2028

Discussed by: MSD's global Phase III program; analysts at AllMind note a China trial alone does not establish global efficacy or regulatory acceptance

MSD runs 18 global Phase III studies of sac-TMT, alone or with pembrolizumab. Positive survival data from those trials, and approvals from the FDA or the European Medicines Agency, would confirm the Chinese results generalize. This is the main test of whether sac-TMT becomes a global standard rather than a China-only option.

Rival TROP2 antibody-drug conjugate outflanks sac-TMT

Possible Resolves by End of 2028

Discussed by: Competing antibody-drug conjugate development programs, including datopotamab deruxtecan

Other TROP2-targeting antibody-drug conjugates are in late-stage NSCLC development. If a rival posts comparable or better survival data in the post-TKI EGFR-mutant setting, or wins approval there first, it would cap sac-TMT's market share and undercut its commercial value.

Sac-TMT wins first-line approval in combination with pembrolizumab

Likely Resolves by Q2 2027

Discussed by: NMPA, which has accepted the filing and placed it under priority review

Sac-TMT plus pembrolizumab is under priority review in China as first-line therapy for NSCLC with PD-L1 TPS ≥1% in EGFR-negative, ALK-negative disease. Approval would expand the drug from the post-TKI salvage setting to the front line, a much larger market.

Historical Context

2 moments from history that rhyme with this story — and how they unfolded.

2017

Osimertinib transforms post-TKI EGFR-mutant NSCLC (AURA3, 2017)

The AURA3 trial randomized 419 patients with EGFR T790M-mutant NSCLC whose tumors had progressed on first-line TKI therapy to osimertinib or platinum-pemetrexed chemotherapy. Osimertinib roughly doubled median progression-free survival, 10.1 versus 4.4 months, and became the standard of care.

Then

Chemotherapy was relegated to later lines for T790M-positive disease.

Now

Set the precedent that a targeted agent can displace chemo in post-TKI NSCLC, though the randomized comparison never showed a clean overall survival benefit due to heavy crossover.

Why this matters now

The same crossover dynamic shaped OptiTROP-Lung04, where 22.6% of chemotherapy patients later received an ADC, requiring an adjusted analysis to isolate the true survival effect.

2021-2022

Trastuzumab deruxtecan displaces an established standard (DESTINY-Breast03, 2021)

DESTINY-Breast03 randomized 524 patients with HER2-positive metastatic breast cancer to trastuzumab deruxtecan or ado-trastuzumab emtansine. The antibody-drug conjugate cut the risk of progression or death by 72% and became the global second-line standard.

Then

Trastuzumab deruxtecan replaced ado-trastuzumab emtansine as the reference second-line therapy within about a year.

Now

Demonstrated that an antibody-drug conjugate can displace an established targeted standard on the strength of a single randomized trial.

Why this matters now

sac-TMT faces a similar test on a larger stage: whether its Chinese-trial survival benefit holds in MSD's global Phase III program before it can displace chemotherapy beyond China.