Background The current prognostic models for patients with advanced urinary tract cancers were developed and validated in the chemotherapy setting. As immunotherapy has become the backbone of novel treatments, updated prognostic scores are needed. Methods A comprehensive analysis of inflammatory indexes from peripheral blood and clinical factors was planned on the entire real-world cohort of pretreated patients with advanced urinary tract carcinoma receiving atezolizumab in the prospective, single-arm, phase IIIb SAUL study. Univariable and multivariable analyses with overall survival as the primary endpoint, bootstrap internal validation, Schneeweiss scoring system and calibration test were performed to develop a novel immunotherapy prognostic score. Results Thirteen clinical variables from 1001 patients were analysed. The following eight prognostic factors were included in a model: ECOG PS, liver and bone metastases, histology, pre-treatment steroids, systemic immune-inflammatory index (i.e., neutrophils-to-lymphocytes ratio times platelets count), haemoglobin and lactate dehydrogenase. The prognostic model was able to stratify patients into five risk groups with significantly different (p < 0.001) median overall survival of NR, 18.0, 8.7, 4.6 and 2.4 months, respectively. The c-index for OS was higher than the Bellmunt score one (0.702 vs 0.672). Conclusions A novel 5-class prognostic model contemporary to immunotherapy provides robust prognostic discrimination of patients with advanced urinary tract carcinoma homogeneously treated with immunotherapy through baseline affordable and reproducible clinical and laboratory factors. It couls be quickly adopted in clinical practice to inform patients about prognosis with immunotherapy and assess the benefit of novel immunotherapy combinations in clinical trials.

Dr Rebuzzi received honoraria as speaker at scientific events and travel accomodation from Amgen, GSK, BMS, MSD and Janssen. Dr Banna reports personal fees from AstraZeneca, Astellas, and non-financial support from Janssen. Dr Fornarini services advisory boards for Astellas, Janssen, Pfizer, Bayer, MSD, Merck and received travel accomodation from Astellas, Janssen, Bayer. Dr Buti received honoraria as speaker at scientific events and advisory role by BMS, Pfizer, MSD, Ipsen, Roche, AstraZeneca, Pierre-Fabre, Novartis. Dr Rescigno services advisory boards/consultingfor services advisory boards/consulting for MSD, AstraZeneca, Janssen. The other authors have no conflicts of interest to disclose.

NCT02928406

The SAUL study was sponsored and funded by F. Hoffmann-La Roche. This subanalyses did not receive any additional funding.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The study used previously collected data from the SAUL study. Data were available after request from Vivli database.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.

Yes

Data availability is subject to a written request to Roche.