Sac-TMT plus pembrolizumab improves PFS in PD-L1-negative NSCLC

Extending an earlier win into PD-L1-negative disease

Sac-TMT, also known as SKB264/MK-2870, is an antibody-drug conjugate paired here with the checkpoint inhibitor pembrolizumab. Caicun Zhou, the trial’s national lead principal investigator at Shanghai East Hospital, Tongji University, said in the announcement that for patients with driver-gene-negative and PD-L1-negative NSCLC, immunotherapy combined with chemotherapy remains the current first-line standard of care, and has improved outcomes only to a limited degree, with long-term survival benefit still constrained. OptiTROP-Lung06 tested whether replacing the chemotherapy component with sac-TMT would improve outcomes, in a randomised, open-label, multicentre design conducted at sites in China, comparing the two regimens head-to-head.

The trial follows OptiTROP-Lung05, a related Phase 3 study of the same combination in PD-L1-positive NSCLC, which also met its primary endpoint; those results were presented at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting and published in The Lancet.

A significant PFS gain, exact numbers not yet disclosed

At the interim analysis, sac-TMT plus pembrolizumab produced a statistically significant and clinically meaningful improvement in progression-free survival over pembrolizumab plus chemotherapy, with a positive trend also seen in overall survival, Kelun-Biotech said. The announcement did not include the specific survival figures, hazard ratios, or p-values typically reported alongside a trial result. The company said the safety profile was consistent with previous studies of the combination, with no new safety signals identified. Unlike OptiTROP-Lung05, whose results were presented at ASCO and published in The Lancet, this announcement does not reference a medical-meeting presentation or publication.

A likely first for this combination, and what comes next

Kelun-Biotech characterised the result as the first Phase 3 trial of an antibody-drug conjugate combined with a checkpoint inhibitor to meet its primary endpoint in first-line, driver-gene-negative and PD-L1-negative non-squamous NSCLC; that characterisation comes from the company, not an independent analysis. Zhou set the result against the limits of the current standard of care:

“The achievement of positive results in the Phase III OptiTROP-Lung06 study represents an important breakthrough in the first-line treatment of PD-L1-negative NSCLC.”Caicun Zhou, National Lead Principal Investigator, Shanghai East Hospital, Tongji University

Kelun-Biotech said it plans to discuss the results with China’s National Medical Products Administration. Sac-TMT is being evaluated in ten registrational studies in lung cancer, the company said, including five trials in China and five global multicentre Phase 3 studies.