2385P Long-term survival upon anti-PD-(L)1 monotherapy in metastatic urothelial cancer (mUC): A multicenter retrospective study

Agents targeting programmed cell death (ligand) 1 (α-PD-(L)1) are approved as first- and second-line (1L, 2L) treatment options for mUC. Durable responses have been reported, but clinical trials were often closed before long-term follow-up (FU) could be assessed. C-reactive protein (CRP) and antibiotic (AB) use at start of α-PD-(L)1 have been suggested to be associated with progression. Here, we show ‘real-world’ long-term survival upon α-PD-(L)1 monotherapy for mUC and correlate outcome to several baseline clinical and laboratory parameters. We expect patients (pts) requiring AB around α-PD-(L)1 start to have poor survival outcomes. This is a retrospective, multicenter study, in which data were collected for mUC pts treated with α-PD-(L)1 monotherapy as 1L-4L between 2014-2023. Overall- and progression-free survival (OS, PFS) were estimated with the Kaplan-Meier method. Uni- and multivariate regression models were used to identify independent factors associated with progression, death, PFS and OS. We included 375 pts (median age 67 years (yr) (59-75); 75% male; 68% visceral metastasis; 43% 1L α-PD-(L)1). After a median FU of 55 months (mo), median OS and PFS for all lines combined were 9 (7.448-10.552) and 3 mo (2.525-3.475) respectively. OS and PFS were comparable between treatment lines. For pts who did not progress within 2 yr after α-PD-(L)1 start, PFS and OS were 53.2% and 62.4% respectively at 5 yr after treatment start. Results from the regression analyses are depicted in the table.Table: 2385PRegression analysesOSPFSDeathProgressionUnivariate (U)Multivariate (M)UMUMUMLymph node metastasis0.0000.0380.0000.1220.0000.7760.0000.179Visceral metastasis0.0000.0000.0000.001gamma-glutamyltransferase >ULN<0.0010.198<0.0010.1130.0180.8830.0040.386Lactate dehydrogenase >ULN0.0040.4290.0390.0160.2410.5270.1070.502CRP>75 percentile<0.0010.2640.0100.9190.2740.9850.4990.237AB use0.0940.0040.6180.0020.3240.2900.9450.182Steroid use0.1110.1780.3380.1990.5120.7870.4150.477Platinum fitness0.6760.2420.7190.1470.6940.4980.0870.120Metastasis at cancer diagnosis0.1820.0700.8240.0200.6300.1570.8650.998 Open table in a new tab Median OS and PFS observed in our cohort is in line with data from clinical trials. Our data suggest that of the patients without progression at 24 mo, half will still be progression-free and alive at 5 yr from treatment start. Our data indicate that AB use around start of α-PD-(L)1 is associated with inferior PFS and OS. We recognize the retrospective nature of our cohort as a limitation. More data will be available and presented at ESMO2023.