A feasibility study of preoperative pembrolizumab before radical nephroureterectomy in patients with high-risk, upper tract urothelial carcinoma: PURE-02.

Introduction: Advances in neoadjuvant therapy for patients with localized, nonmetastatic, upper tract urothelial carcinoma (UTUC) is needed.

Patients And Methods: PURE-02 was a feasibility study enrolling individuals with UTUC, at clinical stage N0M0, with high-risk features according to the modified European Association of Urology definition, based on the presence of either: high-grade disease, multifocality, tumor size ≥2 cm, and/or hydronephrosis. The treatment consisted of 3 courses of 200 mg pembrolizumab, intravenously, every 3 weeks, followed by radical nephroureterectomy (RNU). The endpoints were to assess the safety, pathological responses, and biomarkers.

Results: Ten patients were enrolled between August 2018 and November 2020, 9 (90%) completed the neoadjuvant course. One treatment-related death occurred as a complication of severe myocarditis, myasthenia gravis, hepatitis and myositis. One (14.3%) patient achieved a clinical complete response and refused to undergo RNU. Two (20%) had disease progression and received subsequent chemotherapy, prior to RNU. Overall, 7 patients underwent RNU: one (14.3%) achieved an ypT1N0 response, although this patient was reported to have a cT1 tumor at baseline imaging. The remaining patients were nonresponders. Circulating tumor DNA assay did not identify patients likely to achieve a complete pathologic response.

Conclusion: Single-agent neoadjuvant pembrolizumab did not appear to be a promising treatment strategy for patients with biomarker-unselected, high-risk localized UTUC.