Merck and Kelun-Biotech’s antibody-drug conjugate significantly improved progression-free and overall survival in a pivotal endometrial cancer study, though the companies have yet to specify when they plan to file for approval.
Merck has notched a late-stage endometrial cancer victory for an investigational antibody-drug conjugate that the pharma secured from its $1.4 billion agreement with Kelun-Biotech back in 2022.
Without revealing specific data, the pharma on Monday said that the Phase 3 TroFuse-005 study hit its primary endpoint at an interim analysis, demonstrating significantly better overall survival (OS) and progression-free survival (PFS) in patients treated with sacituzumab tirumotecan (sac-TMT).
“There has been growing investor interest in sac-TMT’s potential over the past several months, and we expect today’s positive news to only increase that enthusiasm further,” analysts at Guggenheim Securities told investors in a note on Monday morning. The pharma has promised to present more detailed findings from the trial at an upcoming medical congress, which Guggenheim expects will happen at the European Society for Medical Oncology congress in October.
TroFuse-005 focused on patients with advanced or recurrent endometrial cancer who had undergone prior platinum-based and anti-PD-1 therapies. For the control, the study used a physician’s choice of intervention.
This outcome makes TroFuse-005 the “first global Phase 3 trial to demonstrate statistically significant improvement in both OS and PFS compared to chemotherapy” in this patient population, Merck said. Aside from the survival benefits, sac-TMT also hit the trial’s secondary endpoint of objective response rate.
TroFuse-005 was designed as a pivotal trial to serve as a basis for sac-TMT’s regulatory application, but Merck on Monday did not provide a specific timeline for plans to file for the asset’s approval. If approved, however, sac-TMTM “has the potential to become a cornerstone in the treatment of certain patients with advanced endometrial cancer,” Dean Li, president of Merck Research Laboratories, said in a prepared statement.
Sac-TMT is an investigational ADC that works by targeting the TROP2 marker, a protein highly expressed in many cancers and has been linked with the survival and rapid growth of tumors as well as their invasion into surrounding tissues and metastasis to distant locations. Sac-TMT carries a belotecan-derived topoisomerase I inhibitor that triggers cell death.
What sets sac-TMT apart from other ADCs, however, is a proprietary linker that according to Merck maximizes the delivery of its payload to the target cancer cells while also minimizing off-target effects.
Merck got a hold of sac-TMT in mid-2022, when it put up to $1.4 billion on the line to partner with China’s Kelun-Biotech, according to a Chinese-language release at the time. Soon after, the pharma made a much bigger bet on Kelun, pledging up to $9.3 billion for seven investigational ADCs for cancer.
The companies have since launched a broad late-stage program for sac-TMT, consisting of 17 studies overall, testing the asset in a variety of oncology indications including ovarian, cervical, breast and lung cancers.
