Phase 3 data for Merck’s Kelun-Biotech-partnered TROP2-directed antibody-drug conjugate have increased analyst expectations for a key part of the company’s post-Keytruda strategy. The results, presented at the American Society for Clinical Oncology annual meeting, suggest that Merck’s candidate, sacituzumab tirumotecan (sac-TMT), may distinguish itself in first-line treatment of non-small cell lung cancer.
Kelun provided overall survival results from a Phase 3 trial studying sac-TMT as a first-line treatment for non-small cell lung cancer in Chinese patients. After 12 months, the overall survival rate was 80.4% in patients who received sac-TMT plus Keytruda compared to 68.9% with Keytruda alone. BMO Capital Markets said in a note to investors that sac-TMT plus Keytruda “demonstrated a clear advantage” over single-agent checkpoint inhibitor therapy.
Median overall survival on Keytruda monotherapy appeared slightly lower than expected from global studies at 14.5 months, according to analysts, but they said, “the clear separation” from monotherapy is supportive of broader expected efficacy as Merck transitions to global studies.
The ASCO presentation also expanded on progression-free survival data previously reported by Kelun. Sac-TMT cut the risk of tumor progression by 65%, and this result was consistent across blinded independent central review and investigator-assessed measures, yielding hazard ratios of 0.35 and 0.38, respectively.
Trodelvy by Gilead Sciences and Datroway by AstraZeneca and Daiichi Sankyo have not yet reached the market as first-line treatments for non-small cell lung cancer but are targeting this indication with ongoing trials expected to report later this year. Merck’s global Phase 3 trial has an estimated primary completion date of January 2028.
BMO analysts said, “While investors have started to acknowledge the potentially differentiated efficacy of sac-TMT across tumor types, today’s results likely reinforce this, demonstrating clear consistency in PFS endpoints across BICR and investigator assessed measures with more promising overall survival analysis.” They also indicated confidence in Merck's long-term opportunity to defend its position in non-small cell lung cancer.
