Merck Highlights Phase III Cancer Wins, Eyes 2027 Oncology Pipeline Catalysts

Key Points

• Sac-TMT delivered positive phase III results in previously treated endometrial cancer, reducing the risk of progression or death by 41% and death by 32% versus chemotherapy. Merck expects a potential FDA decision by June 15.
• In lung cancer, sac-TMT plus KEYTRUDA cut the risk of progression or death by 51% in a phase II study, while Merck plans to begin phase III development of MK-2010 combinations in the first half of 2027.
• Merck and Moderna’s individualized neoantigen therapy, intismeran autogene, plus KEYTRUDA reduced recurrence or death by 42% in a phase III melanoma trial, supporting further regulatory discussions and studies across additional cancers.

Merck & Co., Inc. NYSE: MRK outlined new oncology data and development plans at the European Society for Medical Oncology annual meeting, highlighting phase III results for its sacituzumab tirumotecan, or sac-TMT, antibody-drug conjugate in endometrial cancer and its individualized neoantigen therapy, intismeran autogene, in melanoma.

Eliav Barr, Merck’s senior vice president, head of global clinical development and chief medical officer, said the company’s oncology strategy remains focused on extending KEYTRUDA into earlier disease settings while building a diversified pipeline across immuno-oncology, precision molecular targeting and tissue-targeting therapies.

“The data presented at ESMO reflect meaningful progress on several of the programs we believe will help define the next chapter in our oncology portfolio,” Barr said.

Sac-TMT Shows Phase III Benefit in Endometrial Cancer

Marjorie Green, senior vice president and head of oncology global clinical development, presented results from the phase III TroFuse-005 study of sac-TMT in certain patients with recurrent or advanced endometrial cancer who had previously received platinum-based chemotherapy and a PD-1 or PD-L1 therapy.

According to Green, sac-TMT demonstrated statistically significant improvements in progression-free survival, overall survival and objective response rate compared with physician’s-choice single-agent chemotherapy. The treatment reduced the risk of disease progression or death by 41% and reduced the risk of death by 32%.

• Median progression-free survival increased to 7.2 months from 3.9 months.
• Overall response rate rose to 35% from 17.3%.
• Duration of response was 11.1 months.
• Discontinuation rates were 3.1% for sac-TMT and 4.9% for physician’s-choice treatment.

Green said the results represent the first positive global phase III data for a TROP2-directed antibody-drug conjugate, or any ADC, in endometrial cancer. She added that no new safety signals were identified and that quality of life was maintained over time.

Barr said the Food and Drug Administration has assigned a June 15 PDUFA date for sac-TMT. He said Merck expects sac-TMT could be one of two potential oncology approvals next year.

Lung Cancer Program and MK-2010 Plans

Merck also discussed data presented by partner Kelun-Biotech from the OptiTROP-Lung06 study in China. The study evaluated sac-TMT plus pembrolizumab in first-line advanced nonsquamous non-small cell lung cancer with PD-L1 tumor proportion scores below 1%.

Green said the combination reduced the risk of progression or death by 51% compared with pembrolizumab plus chemotherapy. Median progression-free survival increased to 15 months from 5.7 months, while overall survival data remained immature but showed a favorable trend, with a hazard ratio of 0.58.

Merck’s TroFuse program includes 18 ongoing global phase III studies of sac-TMT across cancers including endometrial, ovarian, cervical, breast, lung, bladder and gastric cancer. The company said it is pursuing broad biomarker plans across the program, though it has not disclosed where it may use biomarker-enriched study designs.

The company also plans to initiate phase III development of MK-2010, including combinations with sac-TMT in first-line non-small cell lung cancer, during the first half of 2027. Green said multiple phase II combination studies are underway involving MK-2010, sac-TMT, WELIREG and other assets. Merck has held what executives described as productive discussions with the FDA regarding its phase III plans.

Individualized Neoantigen Therapy in Melanoma

Merck and Moderna presented phase III results from INTerpath-001, which evaluated intismeran autogene plus KEYTRUDA in certain patients with high-risk resected melanoma. Intismeran is designed using a patient’s tumor sample to create an mRNA-based therapy encoding up to 34 neoantigens specific to that individual’s cancer.

Green said the study was the first positive phase III trial of an individualized neoantigen therapy and the first positive phase III trial of an mRNA-based cancer therapy in melanoma.

• The combination reduced the risk of recurrence or death by 42% compared with KEYTRUDA alone.
• It reduced the risk of distant metastasis or death by 38%.
• No new safety signals were identified.

Green said the recurrence-free survival and distant metastasis-free survival curves overlapped during the first six months before separating, which she said was biologically consistent with the time needed to prime and boost an immune response. In a prespecified sensitivity analysis, hazard ratios after six months were 0.42 for recurrence-free survival and 0.50 for distant metastasis-free survival.

During the question-and-answer session, executives said they are engaging with regulatory authorities on intismeran based on the melanoma data. Merck is also studying the therapy across melanoma, lung cancer, bladder cancer and renal cell carcinoma, including in both earlier-stage and metastatic settings.

Barr said the company views the melanoma results as a proof point for the platform but cautioned that the role of individualized neoantigen therapy across additional tumor types remains to be defined. He said Merck expects further data and studies in 2027 to help determine the optimal direction for the program.

About Merck & Co., Inc. (NYSE:MRK)

Merck & Co, Inc is a global healthcare company that develops, manufactures and markets prescription medicines, vaccines and animal-health products. Its pharmaceutical business focuses on oncology, infectious diseases, cardiology, immunology and other areas of significant medical need. The company serves patients, healthcare providers and institutions in markets worldwide.

Merck's principal products include Keytruda, an immunotherapy used to treat a range of cancers; Gardasil and Gardasil 9, vaccines that help protect against human papillomavirus; and Januvia and Janumet, medicines used to manage type 2 diabetes.

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