SAUL, a single-arm study of atezolizumab for chemotherapy-pretreated locally advanced or metastatic carcinoma of the urinary tract: outcomes by key baseline factors, PD-L1 expression and prior platinum therapy.

Abstract

BACKGROUND:

The impact of pretreatment factors on immune checkpoint inhibition in platinum-refractory advanced urothelial cancer (aUC) deserves further evaluation. The aim was to study the association of Bellmunt risk factors, time from last chemotherapy (TFLC), previous therapy and PD-L1 expression with atezolizumab efficacy in platinum-refractory aUC.

PATIENTS AND METHODS:

This was a post-hoc analysis of patients who had received prior cisplatin or carboplatin in the prospective, single-arm, phase IIIb SAUL study (NCT02928406). Patients were treated with 3-weekly atezolizumab 1200 mg intravenously. The primary outcome was overall survival (OS). Relationships were analysed using Cox regression and long-rank test.

RESULTS:

Of 997 patients in SAUL, 969 were eligible for this analysis. The number of Bellmunt risk factors was associated with OS (P < 0.001); median OS (mOS) for 0, 1 and 2-3 risk factors was 17.9, 8.9 and 3.3 months, respectively. Significant associations were also observed between OS and TFLC (P < 0.001), programmed death-ligand 1 (PD-L1) expression (P = 0.002), and prior perioperative chemotherapy (P = 0.013); mOS was 6.97 versus 11.63 months for TFLC ≤6 versus >6 months, 7.75 versus 11.6 months for PD-L1 expression on <1% of tumour-infiltrating immune cells (ICs) (IC0)/expression on 1% to <5% of tumour-infiltrating ICs (IC1) versus expression on ≥5% of tumour-infiltrating ICs (IC2/3) and 10.2 versus 7.8 months for prior versus no prior perioperative chemotherapy, respectively. The type of platinum compound and number of previous treatment lines were not associated with outcomes.

CONCLUSIONS:

Post-platinum atezolizumab is active in aUC, irrespective of previous platinum compound and lines of therapy. Bellmunt risk stratification, PD-L1 expression, TFLC and perioperative chemotherapy were identified as prognostic factors for OS with second-line atezolizumab, indicating the need for novel prognostic signatures for immunotherapy-treated patients with aUC.

• Authors: A Bamias, A S Merseburger, Y Loriot, N James, E Choy, D Castellano, F Lopez-Rios, F Calabrò, M Kramer, G de Velasco, R Zakopoulou, K Tzannis, C N Sternberg
• Journal: ESMO open (ESMO Open) Vol. 6 Issue 3 Pg. 100152 (06 2021) ISSN: 2059-7029 [Electronic] England
• PMID: 33984672 (Publication Type: Clinical Trial, Phase III, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.

Chemical References

• Antibodies, Monoclonal, Humanized
• B7-H1 Antigen
• Platinum
• atezolizumab

Topics

• Antibodies, Monoclonal, Humanized
• B7-H1 Antigen
• Carcinoma, Transitional Cell (drug therapy)
• Humans
• Platinum (therapeutic use)
• Prospective Studies
• Urinary Tract