Benchmarking Maintenance Therapy Survival in First-Line Platinum-Based Chemotherapy-Treated Patients with Advanced...

First-line (1L) maintenance avelumab prolonged overall survival (OS) in patients with advanced urothelial carcinoma (aUC) in JAVELIN Bladder 100. OS was measured from maintenance initiation in patients with disease control following 1L platinum-based therapy (PBT). The OS impact of maintenance for the 1L PBT-treated population is unknown since it was not measured from 1L initiation, nor can it be benchmarked with other 1L therapies. To characterize the OS impact of maintenance avelumab, we used an oncology simulation model to estimate the OS of maintenance-eligible and -ineligible patients with aUC from 1L PBT initiation.

We developed a simulated cohort of 1L PBT-treated patients with aUC, including those who did and did not receive maintenance avelumab. Eligibility was assessed at 5.6 months post 1L PBT initiation based on the JAVELIN trial design. Among the 1L-treated population, 58% (95% credible interval [CrI] 49-67%) were projected to be eligible (calculated from contemporary phase 3 trials); of those, 85% were assumed to receive maintenance. The model estimated median OS (mOS) among a maintenance-ineligible simulated cohort which when combined with the maintenance-eligible cohort yielded an estimated OS in the overall maintenance- intended population from 1L PBT initiation.

Approximately half of the modeled 1L PBT-treated population received maintenance. Estimated mOS was 10.1 months (95% CrI 7.5-13.5) for the maintenance-ineligible cohort, 29.3 months (95% CrI 24.8-33.9) for the maintenance-eligible, received maintenance cohort, and 15.9 months (95% CrI 13.2-19.1) in the overall maintenance-intended, 1L PBT-treated population, including those eligible and ineligible for maintenance.

The model shows that maintenance avelumab has a modest impact on OS in the overall 1L PBT-treated population of patients with aUC. While maintenance avelumab improves OS for eligible patients, a large proportion of the maintenance-intended population may not receive maintenance due to ineligibility or physician/patient choice.