Merck drug extends survival in endometrial cancer trial, wins US priority review

Oct 26 — The US health regulator has accepted Merck's experimental targeted drug for a priority review ​based on data from a late-stage trial where it extended survival in women with an advanced form of endometrial cancer.

The drug, sacituzumab ‌tirumotecan, also known as sac-TMT, delivers a cancer-killing payload to cells that carry a protein called TROP2, ⁠which is common in endometrial tumors.

The ​trial enrolled 776 patients whose cancer ⁠had returned or progressed after earlier treatment. Patients were randomly assigned to ‌sac-TMT or to ‌a chemotherapy their doctor chose, either doxorubicin or paclitaxel.

Results showed sac-TMT ⁠reduced the risk of death by 32%, ⁠with patients living a median of 19 months compared with 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 with 3.9 months on chemotherapy. In addition, about 35% ‌of sac-TMT patients saw their tumors shrink, compared ​with 17% on chemotherapy.

A regulatory decision is expected by June 2027, Merck said. The trial data was presented at the ESMO medical congress.

"Based on discussions with the FDA, the company is hopeful for an approval before the PDUFA date to bring sac-TMT to patients as quickly as possible," said Dean Y. Li, president, Merck Research Laboratories.

Severe treatment-related side effects were ​more frequent with sac-TMT, affecting about 54% of patients compared with 41% on ‌chemotherapy. About 3% of ‌patients ⁠stopped treatment due to side effects.

About 68,000 cases of endometrial cancer are expected to be diagnosed in the United States in 2026, with over 14,000 deaths, according to the American Cancer Society.

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 with Chinese ​biotech firm Kelun-Biotech, which discovered the therapy.

(Reporting by Kamal Choudhury in Bengaluru; Editing by ​Devika Syamnath)

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