Nomogram to Assess the Survival Benefit of New Salvage Agents for Metastatic Urothelial Carcinoma in the Era of Immunotherapy.

INTRODUCTION

Optimal end points in phase 2 trials evaluating salvage therapy for metastatic urothelial carcinoma are necessary to identify promising drugs, particularly immunotherapeutics, where response and progression-free survival may be unreliable. We developed a nomogram using data from phase 2 trials of historical agents to estimate the 12-month overall survival (OS) for patients to which observed survival of nonrandomized data sets receiving immunotherapies could be compared.

PATIENTS AND METHODS

Survival and data for major prognostic factors were obtained from phase 2 trials: hemoglobin, performance status, liver metastasis, treatment-free interval, and albumin. A nomogram was developed to estimate 12-month OS. Patients were randomly allotted to discovery:validation data sets in a 2:1 ratio. Calibration plots were constructed in the validation data set and data bootstrapped to assess performance. The nomogram was tested on external nonrandomized cohorts of patients receiving pemetrexed and atezolizumab.

RESULTS

Data were available from 340 patients receiving sunitinib, everolimus, docetaxel + vandetanib, docetaxel + placebo, pazopanib, paclitaxel, or docetaxel. Calibration and prognostic ability were acceptable (c index = 0.634; 95% confidence interval [CI], 0.596-0.652). Observed 12-month survival for patients receiving pemetrexed (n = 127, 23.5%; 95% CI, 16.2-31.7) was similar to nomogram-predicted survival (19%; 95% CI, 16.5-21.5; P > .05), while observed results with atezolizumab (n = 403, 39.0%; 95% CI, 34.1-43.9) exceeded predicted results (24.6%; 95% CI, 23.4-25.8; P < .001).

CONCLUSION

This nomogram may be a useful tool to interpret results of nonrandomized phase 2 trials of salvage therapy for metastatic urothelial carcinoma by assessing the OS contributions of drug intervention independent of prognostic variables.