MRK: Initial Positive Phase 3 Data for sac-TMT Likely to Further Increase Enthusiasm for the Program Heading Into ASCO

Research evidence excerpt

MRK: Initial Positive Phase 3 Data for sac-TMT Likely to Further Increase Enthusiasm for the Program Heading Into ASCO

FLASH NOTE

May 18, 2026

Vamil Divan, M.D. vamil.divan@guggenheimpartners.com MRK: Initial Positive Phase 3 Data for sac-TMT Likely

212 823 6543 to Further Increase Enthusiasm for the Program

Seamus Fernandez

seamus.fernandez@guggenheimpartners.com Heading Into ASCO

617 859 4637

Daniel Krizay, Ph.D. Key Message: Merck has announced positive data from the Phase 3 TroFuse-005

daniel.krizay@guggenheimpartners.com trial for its TROP2-directed ADC sacituzumab tirumotecan (sac-TMT) in patients with 212 823 6561

advanced or recurrent endometrial cancer, with sac-TMT showing a benefit on both

Edouard Mullarky, Ph.D. progression-free survival (PFS) and overall survival (OS) at an interim analysis.

edouard.mullarky@guggenheimpartners.com Importantly, TroFuse-005 is one of 17 ongoing Phase 3 trials for sac-TMT across a

212 518 9579 wide range of tumor types (link; Table 1). There has been growing investor interest

Arseniy Shabashvili in sac-TMT's potential over the past several months, and we expect today's positive

arseniy.shabashvili@guggenheimpartners.com news to only increase that enthusiasm further. The full data for TroFuse-005 will be

212 699 1971 released at an upcoming medical meeting (we estimate it may be at ESMO in October)

but sac-TMT will also be in focus at ASCO later this month given Kelun-Biotech (6990-

HK), Merck's collaborator on sac-TMT, will be releasing full data from the open-label

MRK OptiTROPLung05TMT plus pembrolizumabtrial of sac-TMTshowed ain benefit1L NSCLCon PFSthatandwasarunpositivein Chinatrendandin whereOS. Mercksac-

Merck & Co. Inc. will also be hosting its annual Investor Event at ASCO on June 1, where we expect sac-