A phase 2 study of sacituzumab govitecan with or without atezolizumab in rare genitourinary tumors (SMART) - design and rationale.

Sacituzumab govitecan (SG) is a TROP2-directed antibody-drug conjugate with a payload of SN-38, a topoisomerase inhibitor. SG monotherapy has demonstrated activity in multiple solid tumors, including metastatic breast and bladder cancer. Rare tumors of the genitourinary tract often exhibit aggressive clinical behavior yet lack effective treatment options. This article describes the design and rationale for an open-label, non-randomized, phase 2 trial of SG monotherapy or concomitant SG plus atezolizumab in locally advanced/metastatic bladder/urinary tract adenocarcinoma/urachal adenocarcinoma, squamous cell carcinoma, or high-grade neuroendocrine carcinoma; renal medullary carcinoma; and penile squamous cell carcinoma.Clinical Trial Registration: NCT06161532 (ClinicalTrials.gov).