Identification of patients with metastatic urothelial cancer not able to receive maintenance avelumab.

Abstract

702 Background: Maintenance avelumab following frontline platinum-based chemotherapy for metastatic urothelial cancer (mUC) is associated with survival benefit. Eligibility to receive avelumab maintenance requires receiving 4-6 cycles chemotherapy without disease progression. Not all patients complete 6 cycles of chemotherapy or meet eligibility to receive avelumab and these patients may need to have alternative therapies. Here we present real world data to assess whether baseline characteristics can be used to identify patients unable to complete 6 cycles of chemotherapy and whom may not be eligible for maintenance avelumab. Methods: This retrospective audit was performed at Barts Cancer Centre for consecutive patients from January 2010 until August 2023. Patients who received frontline gemcitabine and cisplatin/carboplatin chemotherapy for advanced mUC were included. Eligibility for avelumab is defined as completing 4-6 cycles of chemotherapy without disease progression (PD). Characteristics of patients completing 6 cycles of chemotherapy, versus those who do not were described. Chi-squared tests were conducted to compare characteristic between the two groups, using SPSS v28. Results: 265 patients receiving frontline systemic therapy were identified over a 13-year period. 242 (91%) received Gem/Cis or Gem/Carbo chemotherapy. 151 (63%) patients were eligible to receive maintenance avelumab. 91 (38%) patients were not eligible due to receiving less than 4 cycles chemotherapy (68%) or due to PD (75%), or both. 91 (38%) patients completed 6 cycles of chemotherapy. Having a low baseline Hb <100g/dl was the only baseline characteristic associated with receiving less than 6 cycles chemotherapy (p=0.002). 33% of patients who completed less than 6 cycles chemotherapy had a Hb <100g/dl, compared to 10% of the patients who completed chemotherapy (p=0.002). Any dose delays was associated with a lower likelihood of being eligible to receive avelumab (32% and 18% dose delays in avelumab eligible vs ineligible cohorts, respectively (p<0.001). Patients with any dose delays had more frequently received carboplatin (65% vs 39%, p=0.012) and had visceral metastases including liver metastases (63% vs 39%, p=0.014), compared to those without dose delays. Conclusions: Specific baseline factors predispose to an inability to deliver 6 cycles of chemotherapy without complications or progression. These patients are less likely to receive maintenance avelumab. These data help the optimise number of cycles offered to patients in mUC.