The age of participants at baseline was reported.

Analysis set included all participants who were enrolled in the study and received maintenance avelumab treatment between 24 February 2021 and 30 November 2021, participants meeting all the inclusion criteria were analyzed.

Number of Participants With Advanced and Metastatic UC by sex was reported.

Analysis set included all participants who were enrolled in the study and received maintenance avelumab treatment between 24 February 2021 and 30 November 2021, participants meeting all the inclusion criteria were analyzed.

The primary tumor site is divided into the following categories: "upper urinary tract" for renal pelvis or ureter "lower urinary tract" for bladder and urethra.

Analysis set included all participants who were enrolled in the study and received maintenance avelumab treatment between 24 February 2021 and 30 November 2021, participants meeting all the inclusion criteria were analyzed.

The subtype of urothelial carcinoma included micropapillary, microcystic, nested, lymphoepithelioma-like, plasmacytoid, sarcomatoid, giant cell, poorly differentiated, lipid rich, clear cell. number of participants with presence of UC subtype was reported.

Analysis set included all participants who were enrolled in the study and received maintenance avelumab treatment between 24 February 2021 and 30 November 2021, participants meeting all the inclusion criteria were analyzed.

Number of participants with metastatic sites at start of First Line Chemotherapy was reported.

Analysis set included all participants who were enrolled in the study and received maintenance avelumab treatment between 24 February 2021 and 30 November 2021, participants meeting all the inclusion criteria were analyzed.

ECOG PS measured on-therapy (time between first dose and last dose date) assessed participant's performance status on 5 point scale: 0 is equal to (=) fully active/able to carry on all pre-disease activities without restriction; 1=restricted in physically strenuous activity, ambulatory/able to carry out light or sedentary work; 2=ambulatory (greater than [>] 50% of waking hours [hrs]), capable of all self care, unable to carry out any work activities; 3=capable of only limited self care, confined to bed/chair >50% of waking hrs; 4=completely disabled, cannot carry on any self care, totally confined to bed/chair; 5=dead.

Analysis set included all participants who were enrolled in the study and received maintenance avelumab treatment between 24 February 2021 and 30 November 2021, participants meeting all the inclusion criteria were analyzed.

Chemotherapies were categorized as: 1.Gemcitabine + Cisplatin 2. Gemcitabine + Carboplatin 3. Dose-dense methotrexate, vinblastine, doxorubicin, cisplatin 4. Other.

Analysis set included all participants who were enrolled in the study and received maintenance avelumab treatment between 24 February 2021 and 30 November 2021, participants meeting all the inclusion criteria were analyzed.

Number of Firstline Chemotherapy Cycles in participants at baseline was reported.

Analysis set included all participants who were enrolled in the study and received maintenance avelumab treatment between 24 February 2021 and 30 November 2021, participants meeting all the inclusion criteria were analyzed.

Determination of the best overall response to first-line chemotherapy is categorized as following: "Objective response" when "Complete Response" or "Partial Response." "Non-objective response" when "Stable Disease" of "Progressive Disease"

Analysis set included all participants who were enrolled in the study and received maintenance avelumab treatment between 24 February 2021 and 30 November 2021, participants meeting all the inclusion criteria were analyzed.

Number of participants with presence or absence of variant histology was reported.

Analysis set included all participants who were enrolled in the study and received maintenance avelumab treatment between 24 February 2021 and 30 November 2021, participants meeting all the inclusion criteria were analyzed.

Treatment free-interval is defined as the time from the end date of first-line chemotherapy to the start date of avelumab administration. Treatment-free interval divided into the following categories. <4 weeks/4 to 10 weeks/>10 weeks.

Analysis set included all participants who were enrolled in the study and received maintenance avelumab treatment between 24 February 2021 and 30 November 2021, participants meeting all the inclusion criteria were analyzed.

Second-Line Therapies were categorized as: 1. Platinum Chemotherapy, 2. Enfortumab Vedotin, Gem, Gemcitabine, 3.immune checkpoint inhibitor.

Analysis set included all participants who were enrolled in the study and received maintenance avelumab treatment between 24 February 2021 and 30 November 2021, participants meeting all the inclusion criteria were analyzed.

TTF was defined as the time from start of avelumab maintenance therapy to the date of end of treatment due to any cause including death. If there is no record of the end of treatment, it be discontinued on the last visit date during the study period.

Analysis set included all participants who were enrolled in the study and received maintenance avelumab treatment between 24 February 2021 and 30 November 2021, participants meeting all the inclusion criteria were analyzed.

rwPFS is defined as: The time from start of avelumab maintenance therapy to date of first disease progression (as clinically assessed by local investigator based on radiology, laboratory evidence, pathology, or other assessments) or death due to any cause, whichever occurred first. If there were no clinical records of death or disease progression, they will be censored at the date of initiation of the next line of therapy for the participants undertaking 2 or more lines of therapy (subsequent therapy after avelumab maintenance therapy) based on the record, or at their last visit date during the study period for the participants undertaking only 1 line of therapy (only avelumab maintenance therapy) based on the record.

Analysis set included all participants who were enrolled in the study and received maintenance avelumab treatment between 24 February 2021 and 30 November 2021, participants meeting all the inclusion criteria were analyzed.

The Best ORR was defined as the percentage of participants having achieved complete response (CR) or partial response (PR) according to RECIST version 1.1 as determined by the IRC. CR: defined as disappearance of all target and all non-target lesions and no new lesions. PR: defined as at least a 30% decrease in sum of diameters of target lesions, taking as reference the baseline sum diameters, no progression of non-target lesions and no new lesions.

Analysis set included all participants who were enrolled in the study and received maintenance avelumab treatment between 24 February 2021 and 30 November 2021, participants meeting all the inclusion criteria were analyzed.

rwPFS-c is defined as the following: The time from start of first-line Chemotherapy to date of first disease progression (as clinically assessed by local investigator based on radiology, laboratory evidence, pathology, or other assessments) or death due to any cause during avelumab treatment, whichever occurred first. If there were no clinical records of death or disease progression, they will be censored at the date of initiation of the next line of therapy for the participants undertaking 2 or more lines of therapy (subsequent therapy after avelumab maintenance therapy) based on the record, or at their last visit date during the study period for the participants undertaking only 1 line of therapy (only avelumab maintenance therapy) based on the record.

According to protocol, only participants whose best overall response to chemotherapy was assessed as CR, PR,orSD received avelumab treatment,and their PFS was evaluated.However,for participants whose best overall response to chemotherapy was assessed as Progressive Disease,data on subsequent treatment regimens and PFS were not collected. Due to this selective data collection,the data would not be representative of the rwPFS-c for the patient population.For these reasons data was not collected.