Merck's experimental drug sacituzumab tirumotecan, also known as sac-TMT, has shown promising results in treating advanced endometrial cancer. The drug, which targets cells carrying the TROP2 protein, significantly extended survival rates in a late-stage trial presented at the ESMO medical congress. The US health regulator has accepted the drug for priority review, with a decision expected by June 2027.
The trial involved 776 patients whose cancer had returned or progressed after earlier treatment. Participants were randomly assigned to receive sac-TMT or a standard chemotherapy option. Results indicated that sac-TMT reduced the risk of death by 32%, with patients living a median of 19 months compared to 12.1 months on standard chemotherapy. The treatment also reduced the risk of cancer progression or death by 41%, with patients remaining progression-free for a median of 7.2 months compared to 3.9 months on chemotherapy.
About 35% of sac-TMT patients saw their tumors shrink, compared to 17% on chemotherapy. However, severe treatment-related side effects were more frequent with sac-TMT, affecting about 54% of patients compared to 41% on chemotherapy. Approximately 3% of patients stopped treatment due to side effects.
Jefferies analysts project peak sales of roughly $900 million in endometrial cancer for the drug and $9 billion across all potential indications. Merck is developing the drug in collaboration with Chinese biotech firm Kelun-Biotech, which discovered the therapy.