Antibody-drug conjugate combination outperforms chemo-immunotherapy in PD-L1-negative lung cancer

Overview

Updated 1 hour ago

A trial pairing an antibody-drug conjugate with the immunotherapy pembrolizumab cut the risk of disease progression or death by 51% in patients with PD-L1-negative advanced lung cancer. The OptiTROP-Lung06 results were presented at the 2026 European Society for Medical Oncology (ESMO) congress in Madrid and published the same day in the New England Journal of Medicine.

The experimental arm replaces the platinum chemotherapy backbone of the current standard — pembrolizumab plus chemo — with sacituzumab tirumotecan (sac-TMT), a conjugate that targets the TROP2 protein on tumor cells. Median progression-free survival nearly tripled, from 5.7 months to 15.0 months, in a population that responds least well to immunotherapy alone.

Why it matters

If approved, this regimen replaces chemotherapy as pembrolizumab's partner for first-line PD-L1-negative lung cancer, giving these patients a more effective immunotherapy-based option.

Questions about this story

Free account needed to ask — your question is kept and asked for you right after sign-up. Answers are public.

No questions yet — be the first to ask.

Key Indicators

0.49

Progression-free survival hazard ratio

Risk of disease progression or death reduced by 51% versus chemo-immunotherapy (95% CI 0.36–0.65; P<0.0001)

15.0 vs 5.7 months

Median progression-free survival

sac-TMT plus pembrolizumab versus pembrolizumab plus platinum-based chemotherapy, per blinded independent review

455

Patients enrolled

Randomized 1:1 in the Phase III OptiTROP-Lung06 study across 9.7 months median follow-up

77.6% vs 66.4%

Estimated 1-year overall survival rate

Overall survival data immature (20% of events); hazard ratio 0.58 shows a favorable trend

13.6 vs 6.8 months

Median duration of response

Responses lasted twice as long in the sac-TMT arm (hazard ratio 0.47; 95% CI 0.29–0.77)

Voices

Curated perspectives — historical figures and your fellow readers.

Ever wondered what historical figures would say about today's headlines?

People Involved

Caicun Zhou

Professor and lead investigator, Shanghai East Hospital, Tongji University

Presented OptiTROP-Lung06 results at ESMO 2026 (LBA66)

Dean Y. Li

President, Merck Research Laboratories (head of R&D)

Signaled intent to redesign KEYNOTE-189 with sac-TMT replacing chemo

Organizations Involved

Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd.

Biopharmaceutical company

Sponsor of OptiTROP-Lung06 and developer of sac-TMT

Chengdu-based developer of sac-TMT (SKB264/MK-2870), marketed in China as 佳泰莱®.

Merck & Co.

Pharmaceutical company

Co-developer of sac-TMT; manufacturer of pembrolizumab (KEYTRUDA®)

Supplies pembrolizumab used in the trial and co-develops sac-TMT with Kelun-Biotech across nearly 20 global Phase III studies.

Timeline

May 2026 October 2026

4 events Latest: Today

Tap a bar to jump to that date

October 2026
OptiTROP-Lung06 results presented at ESMO and published in NEJM
Today Presentation

Phase III data show sac-TMT plus pembrolizumab cuts progression risk by 51% versus chemo-immunotherapy in PD-L1-negative non-squamous NSCLC.
Today
August 2026
Merck signals sac-TMT will replace chemo in first-line lung cancer
Strategy

R&D chief Dean Li tells investors the company will rethink KEYNOTE-189 using sac-TMT as a 'next-gen chemo'.
August 2026
June 2026
OptiTROP-Lung06 interim analysis data locked
Trial milestone

Data cutoff for the interim analysis with median follow-up of 9.7 months across 455 patients.
June 9th, 2026
May 2026
Kelun-Biotech reports positive sac-TMT combination results
Announcement

Hong Kong Stock Exchange filing shows significantly improved progression-free survival for sac-TMT plus pembrolizumab in a comparator trial.
May 22nd, 2026

Scenarios

FDA approves sac-TMT plus pembrolizumab for first-line PD-L1-negative NSCLC

Likely Resolves by End of 2028

Discussed by: Fierce Pharma notes Merck appears positioned to seek approval in this setting after the PFS win; Kelun-Biotech characterized the result as a first-in-class Phase III success for an ADC plus checkpoint inhibitor.

Kelun-Biotech and Merck file for regulatory approval based on the demonstrated progression-free survival benefit. Approval would expand sac-TMT beyond its current use into first-line therapy for the roughly one-third of non-squamous NSCLC patients with PD-L1-negative tumors. The immature overall survival data could slow the review.

Merck launches pivotal trial replacing chemo with sac-TMT across the PD-L1 spectrum

Likely Resolves by End of 2027

Discussed by: Dean Li on Merck's Q2 2026 earnings call; Fierce Pharma reporting that Merck appears willing to close the gap in PD-L1-low and -negative settings.

Merck redesigns the KEYNOTE-189 regimen, testing sac-TMT plus pembrolizumab without platinum chemotherapy in a broader first-line non-squamous NSCLC population that includes PD-L1-positive patients. A new randomized Phase III trial would confirm whether the ADC can serve as the chemotherapy replacement across the full PD-L1 spectrum.

Mature OS data confirm or weaken the sac-TMT survival benefit

Uncertain Resolves by Q2 2028

Discussed by: Study authors noted overall survival was immature at the interim analysis, with 20% of events and a hazard ratio of 0.58.

With only 20% of patients deceased at the data cutoff, the overall survival advantage could strengthen with longer follow-up or fade toward the null. A mature analysis at a future congress or journal publication will determine whether the progression-free survival win translates into a statistically significant survival benefit.

Historical Context

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

October 2016

KEYNOTE-024 (2016)

The phase III KEYNOTE-024 trial showed pembrolizumab monotherapy beat platinum-based chemotherapy in first-line NSCLC patients with PD-L1 expression on at least half their tumor cells. It was published in NEJM that November.

Then

Pembrolizumab became the first checkpoint inhibitor approved as first-line monotherapy for a subset of lung cancer patients.

Now

It established PD-L1 expression as the biomarker guiding first-line immunotherapy selection, a framework the field still uses.

Why this matters now

KEYNOTE-024 proved checkpoint inhibitors could replace chemotherapy in first-line NSCLC. OptiTROP-Lung06 extends that logic: it tests whether an ADC can replace chemo as the partner for pembrolizumab in patients who don't respond to immunotherapy alone.

April 2018

KEYNOTE-189 (2018)

KEYNOTE-189 randomized 616 patients with non-squamous NSCLC to pembrolizumab plus pemetrexed and platinum chemo or placebo plus the same chemo. The pembrolizumab arm showed superior overall survival regardless of PD-L1 expression.

Then

Pembrolizumab plus pemetrexed/platinum chemo became the global standard of care for first-line non-squamous NSCLC, including PD-L1-negative patients.

Now

The KEKEYNOTE-189 regimen is the control arm OptiTROP-Lung06 tested against, making this the direct successor challenge to that paradigm.

Why this matters now

OptiTROP-Lung06's control arm is essentially KEYNOTE-189's regimen. The new study asks whether swapping chemotherapy for an ADC improves on the standard KEYNOTE-189 established eight years earlier.