Sacituzumab Tirumotecan (MK-2870) in Post Platinum and Post Immunotherapy Endometrial Cancer (MK-2870-005)

The main inclusion and exclusion criteria include but are not limited to the following:

Inclusion Criteria:

• Has a histologically-confirmed diagnosis of endometrial carcinoma or carcinosarcoma.

• Has radiographically evaluable disease, either measurable or nonmeasurable perresponse evaluation criteria in solid tumors (RECIST 1.1), as assessed by blindedindependent central review (BICR).

• Has received prior platinum-based chemotherapy and anti-programmed cell death 1protein (PD-1)/anti- programmed cell death ligand 1 (PD-L1) therapy, eitherseparately or in combination.

Exclusion Criteria:

• Has neuroendocrine tumors or endometrial sarcoma, including stromal sarcoma,leiomyosarcoma, adenosarcoma, or other types of pure sarcomas

• Has a history of documented severe dry eye syndrome, severe Meibomian gland diseaseand/or blepharitis, or severe corneal disease that prevents/delays corneal healing

• Has active inflammatory bowel disease requiring immunosuppressive medication orprevious history of inflammatory bowel disease

• Has had a recurrence of endometrial carcinoma or carcinosarcoma more than >12 monthsafter completing platinum-based therapy administered in the curative-intent settingwithout any additional platinum-based therapy received in the recurrent setting.Note: 1) If Immunotherapy-based treatment is administered in the recurrent setting,then platinum rechallenge is not required, regardless of the duration of theplatinum-free interval from time of adjuvant therapy 2) For Stage IVb disease,treatment that includes gynecological surgery followed by a platinum-based regimenis NOT considered curative-intent per protocol and does not require platinumrechallenge in the recurrent setting, regardless of the duration of theplatinum-free interval

• Has received more than 3 prior lines of therapy for endometrial carcinoma orcarcinosarcoma

• Has history of (noninfectious) pneumonitis/interstitial lung disease that requiredsteroids or has current pneumonitis/interstitial lung disease

• Has received prior treatment with single-agent nonplatinum based chemotherapy in thethird-line setting

• Has received prior treatment with a trophoblast cell surface antigen 2 (TROP2)-targeted antibody drug conjugate (ADC) (eg, sacituzumab govitecan)

• Has received prior treatment with a topoisomerase I inhibitor-containing ADC (eg,sacituzumab govitecan or fam-trastuzumab deruxtecan-nxki)

• Has previously received both single-agent paclitaxel and single-agent doxorubicin inany setting for prior treatment of endometrial cancer

• Requires recurrent drainage of effusions (e.g., pleural, ascitic, etc.) within 6weeks before randomization