A study to find out if enfortumab vedotin given with pembrolizumab helps people with muscle-invasive bladder cancer keep their bladder.

Prior treatment

• Participant has received prior therapy with an anti-PD-1, anti-PD-L1, or anti-PD-L2 agent or with an agent directed to another stimulatory or coinhibitory T-cell receptor (e.g., CTLA-4, OX-40, CD137).
• Participant has received prior systemic anti-cancer therapy for MIBC/NMIBC, or received prior systemic anti-cancer therapy including investigational agents (including enfortumab vedotin or other MMAE-based ADCs) within 3 years prior to screening
• Participant has received a partial cystectomy of the bladder to remove any NMIBC or MIBC.
• Participant has received any prior radiotherapy to the bladder.
• Participant has a second malignancy diagnosed within 3 years before first dose of study intervention, or any evidence of residual disease from a previously diagnosed malignancy. Participant with non-melanoma skin cancer, localized prostate cancer treated with curative intent with no evidence of progression, low-risk or very low-risk (per standard guidelines) localized prostate cancer under active surveillance/watchful waiting without intent to treat, or carcinoma in situ of any type (if complete resection was performed) are allowed.
• Participant has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days prior the first dose of study intervention. Inhaled or topical steroids are permitted in the absence of active autoimmune disease. Physiologic replacement doses of corticosteroids are permitted for participants with adrenal insufficiency."

Other illness

• Participant has ≥ N2 disease or metastatic disease (M1) as identified by imaging.
• Participant has known active keratitis or corneal ulcerations. Participant with superficial punctate keratitis is allowed if the disorder is being adequately treated in the opinion of the investigator
• Participant has a history of (non-infectious) pneumonitis/ILD that required steroids or has current pneumonitis/ILD.
• Participant has a history of idiopathic pulmonary fibrosis, organizing pneumonia, drug-induced pneumonitis, idiopathic pneumonitis, or evidence of active pneumonitis on screening chest CT scan.
• Participant has active autoimmune disease that has required systemic treatment in past 2 years (i.e., with use of disease modifying agents, corticosteroids or immunosuppressive drugs).

Lab values

• Participant has a history of uncontrolled diabetes mellitus within 3 months prior to screening. Uncontrolled diabetes (within 3 months before first dose) is defined as HbA1c ≥ 8% or HbA1c between 7% and < 8% with associated diabetes symptoms (polyuria or polydipsia) that are not otherwise explained. The lowest HbA1c during the screening period will be used to determine eligibility.

Other

• Participant has preexisting sensory or motor neuropathy Grade ≥ 2

• Participant is ≥ 18 years of age at the time of signing the ICF.
• Participant has histologically-confirmed MIBC, stage cT2–T4aN0M0 or T1-T4aN1M0.
• Participant has predominant UC histology (≥ 50%).
• Participant is deemed eligible for RC and PLND by a urologist and/or oncologist.
• Participant has accessible archival tumor tissue from the primary tumor, for which source and availability have been confirmed prior to study intervention. If no archival tumor tissue is available, the participant will have a biopsy to obtain tumor tissue prior to study intervention.
• Participant has ECOG performance status of 0 to 2.
• Have a TUR of a bladder tumor within 60 days (+14 days) prior to screening (from the date of ICF signature).