Real-World Treatment Patterns and Clinical Outcomes in Patients With Locally Advanced or Metastatic Urothelial Carcinoma by Eligibility for Maintenance Avelumab.

Introduction: 1L PBC has historically been recommended for patients with la/mUC. Maintenance avelumab is recommended for patients without disease progression following 1L PBC. Real-world data on the proportion of patients eligible for maintenance avelumab are limited, and outcomes among patients ineligible for maintenance avelumab are uncertain. This study assessed the proportion of patients with la/mUC initiating 1L PBC who were maintenance-avelumab eligible and real-world outcomes following 1L PBC by maintenance-avelumab eligibility.

Methods: A retrospective, observational study was conducted using a longitudinal electronic health record-derived database comprising de-identified patient-level structured and unstructured data including adults with Ia/mUC who received ≥1 dose of 1L PBC (April 2020-January 2022). The proportion of patients eligible for maintenance avelumab (real-world stable disease, partial response, or complete response following 1L PBC) was estimated and median overall survival (mOS) assessed for maintenance avelumab-eligible and -ineligible patients.

Results: Of 336 patients with Ia/mUC treated with 1L PBC (55.4% received cisplatin-based treatment 44.6% carboplatin-based treatment); 181 (54%) were maintenance-avelumab eligible; and 138 (41%) maintenance-avelumab ineligible (17 [5%] were nonevaluable). Of 181 maintenance-avelumab-eligible patients, 67 (37.0%; 19.9% of all 1L PBC-treated patients) received maintenance avelumab. mOS (95% CI) among all 1L PBC-treated patients was 15.0 (12.2-19.6) months and among maintenance-avelumab-ineligible patients was 8.0 (6.7-10.3) months; whereas among maintenance-avelumab-eligible patients (including 37% who received maintenance avelumab), mOS was 27.6 (23.4-not reached) months.

Conclusions: In this study, approximately half of 1L PBC-treated patients were maintenance-avelumab eligible, and one-fifth received it. Real-world OS remains short for the overall 1L PBC-treated population. These results support the use of treatment-guideline preferred 1L treatment options that demonstrate survival benefit for all patients with la/mUC, and are available to patients irrespective of their eligibility for cisplatin, or response to PBC.