Singh, Parminder Pal

639 Background: Immunotherapy combined with chemotherapy (IO/C) as the first-line management of locally advanced or metastatic urothelial carcinoma (LA/mUC) has been investigated in multiple trials with conflicting outcomes. Therefore, we conducted a meta-analysis of available trials to compare objective response rates (ORR) of this combination regimen, both in overall and in cisplatin-ineligible populations. Methods: EMABSE and MEDLINE were searched from 2000 through July 20th, 2023, to identify phase II and III clinical trials assessing IO, C or both in LA/mUC. Main outcome of interest was objective response rates (ORR) as defined in the included trials. An inverse variance random-effects meta-analysis was performed to estimate pooled ORR using the restricted maximum likelihood estimation method. Subgroup differences were assessed among IO/C, IO alone, and C alone. The threshold for statistical significance was established at 0.1. Results: Of 5975 citations identified, a total of 26 trials with a total of 4,628 participants were included in this systematic review. In the overall group, the ORR in IO/C trials (5 trials, 1,236 patients) was 44.70% (95% CI: 21.88%- 70.0%). In IO trials (7 trials, 2,189 patients), ORR was 23.68% (19.55%- 28.36%) and in C trials (26 trials, 4,628 patients) was 43.46% (37.43%-49.68%]). In the cisplatin-ineligible group, the ORR in IO/C trials (2 trials, 240 patients) was 60.06% (33.38%-81.86%), in IO trials (6 trials, 1,103 patients) was 26.15% (23.01%; 29.56%), and in C trials (8 trials, 767 patients) was 42.45% (35.67%-49.52%). In terms of subgroup differences, the difference in ORR was statistically significant between IO/C and IO trials (p= 0.0844) and between IO and chemotherapy trials (p< 0.0001) in the overall population. Similarly, we found a statistically significant difference in ORR between IO/C and IO (p= 0.0108) and between IO and chemotherapy trials (p< 0.0001) in the cisplatin-ineligible population. No statistically significant differences were observed between IO/C and C alone. Conclusions: First-line IO/C may achieve a better objective response compared to IO alone in patients diagnosed with locally advanced/metastatic UC. Although, there appears to be a trend of greater benefit with IO/C compared to C alone, the difference was not statistically significant. The results will be updated as soon data from new trials (CheckMate 901 and EV 302) becomes available which could offer new insights. [Table: see text]

627 Background: Enfortumab vedotin (EV) is an antibody-drug conjugate recently approved to treat locally advanced or metastatic bladder cancer (la/mUC). Initial trials have shown promising response to EV in advanced urothelial cancers (UC), where prognosis is currently poor. Here, we report real-world experience using EV at a tertiary center. Methods: This study reports treatment details and outcomes in 92 patients (pts) that received at least one complete cycle of EV monotherapy in treatment of la/mUC. Treatment details include intent of cycle duration, 21 days (treatment on days 1 and 8) or 28 days (treatment on days 1, 8 and 15), dose reductions, and median number of cycles completed. Interruptions in treatment are reported as intentional (i.e. holding EV after achieving positive response) or unintentional (i.e. secondary to drug toxicity or other delay). Image-based best clinical response consists of progressive disease (PD), stable (SD), partial (PR), complete response (CR), and not evaluable (NE). Clinical benefit rate (CBR) is defined as either SD, PR, and CR outcomes. The Kaplan-Meier method was used to estimate overall survival (OS) and progression-free survival (PFS). Results: Patients mean age was 71.1 years (IQR: 66.8 - 78), 72 (79.2%) are male and 20 (20.8%) female, 89 (96.7%) pts received EV in the setting of metastatic UC, 3 (3.3%) in locally advanced UC. 13 (13.5%) pts were previously chemotherapy exposed, 9 (9.8%) were immunotherapy exposed, 60 (65.2%) were both chemo and immunotherapy exposed, and 11 (12.0%) received EV first line. 46 (50%) pts underwent 21-day treatment cycles, and 46 underwent 28-day treatment cycles. The median number of EV cycles was 3 (range 1-16) in the overall cohort, 3 in the 21-day cycle group, and 4 in the 28-day cycle group. 50 (54.3%) pts required dose reductions secondary to toxicity. 11 (12.0%) pts had planned interruptions, and 33 (35.9%) had unplanned interruptions. Best clinical response consisted of 24 (26.0%) pts with PD, 12 (13.0%) with SD, 25 (27.2%) with PR, 17 (18.5%) with CR, and 14 (15.2%) NE. CBR was 54 (58.7%) in the overall sample. CBR in the 21-day and 28-day cycle groups was identical at 27 (29.3%). EV therapy was discontinued most for cancer progression (34, 37.0%), therapy toxicity (18, 19.6%), and pt death (12, 13.0%). In 13 (14.1%) pts therapy is still ongoing. 73 (76.0%) pts had mild to moderate toxicities, and 19 (19.7%) reported severe toxicities that required hospitalization. Median OS in the total cohort was 11.01 months (95% CI: 8.51-14.6). Median PFS is 5.49 months (95% CI: 4.60-8.19). Conclusions: Real-world utilization of EV showed significant heterogeneity in administration patterns (21 days vs 28 days) and across a range of settings (first line, chemo exposed, IO exposed, chemo and IO exposed). Although EV has high response rates, more than 3/4th of patients suffered mild to moderate toxicities and 1/5th required hospitalization.

601 Background: Neuroendocrine carcinomas (NEC) of the genitourinary (GU) tract, including small cell (SC) NEC and large cell (LC) NEC, are rare aggressive malignancies. Although highly sensitive to cisplatin-based chemotherapy, GU metastatic NEC (mNEC) have limited data to support next therapies. Lurbinectedin, a marine-derived alkylating drug and a selective inhibitor of oncogenic transcription and DNA repair pathways, is FDA-approved for small cell lung cancer (SCLC) after progression on frontline platinum-based therapy, with a disease control rate (DCR) of 68.6%. It is unknown whether DCR is similar in SCLC and GU mNEC. Methods: We report the first multi-institutional series (n=14) of lurbinectedin in GU mNEC. Imaging-based best overall responses (BOR) were noted as complete (CR), partial (PR), stable (SD), progressive (PD) or non-evaluable (NE). DCR includes CR, PR, and SD. We use the Kaplan-Meier method for overall survival (OS) and progression-free survival (PFS) from lurbinectedin start date. We define duration of response (DoR) from response date to progression or last contact date for patients (pts) with CR or PR. Results: Most pts had a median age at metastasis of 70.5 years (ICR: 64-74.5) [Table]. Primary locations were bladder (7/14, 50%), prostate (5/14, 35.7%) and ureter (2/14, 12.3%). Histology at diagnosis mostly consisted of mixed or pure SCNEC, with one exception of LCNEC. Most pts had visceral disease, prior immunotherapy and at least 2 prior lines of therapy for mNEC before lurbinectedin (8/14, 57.1%). DCR was 6/14 (42.8%), including 5 bladder pts and 1 prostate pt. Among bladder pts, BOR included one CR (1/7, 14.3%) for the LCNEC case, 2 PR (2/7, 28.6%), 2 SD (2/7, 28.6%) and 2 PD (2/7, 28.6%). Most prostate and ureteral pts either progressed on lurbinectedin or were NE (Prostate: 1 PR, 2 PD, and 2 NE; Ureteral: 1 PD and 1 NE). For all 14 pts, median OS was 11.47 months (95% CI: 2.17-13.63) and median PFS was 2.8 mo (1.4-10.9). Median DoR was 7.38 mo (2.3-9.53) for 4 responding pts (CR or PR). Treatment was stopped due to progression (9/14, 64.3%), three adverse events [thrombocytopenia, electrolyte abnormalities, cerebrovascular accident] (3/14, 21.4%), and pt preference (1/14, 7.1%). Conclusions: Lurbinectedin offers encouraging responses (DCR: 5/7, 71.4%) close to those in SCLC, in previously treated bladder mNEC. One CR was noted for a bladder pt with LCNEC. Responses were less appreciated in prostate and ureteral mNEC due to NE responses and limited number. Larger cohorts are needed to confirm survival benefit and genetic analyses are warranted to identify characteristics of responders. [Table: see text]

529 Background: Radical cystectomy is recommended for patients with BCG-unresponsive (BU) non-muscle invasive bladder cancer (NMIBC) due to high risk of progression. Improved methods for assessing these risks would greatly facilitate the potential for bladder preservation. Here, we tested the capacity of the urinary comprehensive genomic profile (uCGP) to predict event-free survival (EFS) in patients with BU-NMIBC treated with atezolizumab in the single arm phase 2 trial SWOG S1605. Methods: Urine was collected from patients with BU NMIBC (CIS, Ta, T1) treated with at least one dose of intravenous atezolizumab at baseline and before the 5th cycle of therapy (3 months). The uCGP was assessed using UroAmp (Convergent Genomics). Risk scores for recurrence at baseline and at 3 months were calculated by a prespecified machine learning algorithm incorporating alterations in 60 genes and low pass whole genome sequencing, and categorized as high versus low. Molecular response was classified based on change in uCGP between the two time points. Risk scores and molecular response were submitted to SWOG for clinical correlation with EFS using a Cox model, adjusting for CIS status. Time to event was calculated from date of study entry (baseline risk) or from the 2nd collection time (3-month risk) to first high grade (HG) recurrence or persistent CIS at 3 months. Death unrelated to bladder cancer and patients last known to be alive without HG recurrence were censored at date of last visit. Results: Samples were provided at baseline in 89 patients and before the 5th cycle in 77; 68 had both samples available for paired analysis. The risk score at baseline was classified as high in 69% of samples (73% for CIS ±Ta/T1 and 62% for Ta/T1). At 12 and 18 months the EFS probabilities were 26% and 23% for high-risk and 67% and 51% for low-risk patients, respectively, with a HR of 2.82 (95% CI: 1.58, 5.03; p<0.001). The risk score at the 3-month timepoint was classified as high in 81% of samples, and the EFS probabilities at 12 and 18 months after urine collection were 26% and 22% for high-risk and 80% and 72% for low-risk patients, respectively, with a HR of 3.39 (95% CI: 1.41, 8.13; p<0.006). Molecular response to treatment was classified as complete (CR) in 8%, partial (PR) in 14%, stable (SD) in 25% and progression (PD) in 46%, with 7% having no detectable genomic abnormalities at both time points. Clinical recurrence was observed by 18 months in 0/6 patients with CR, 7/9 (78%) with PR, 11/14 (79%) with SD and 25/33 (76%) with PD by genomic profile. Conclusions: This study suggests that uCGP at baseline and after 4 cycles of treatment can identify genomic patterns associated with an increased risk of HG persistence, recurrence or progression in BU NMIBC treated with immune checkpoint inhibition. Future studies will determine if this can be used to guide early treatment intensification.

412 Background: Previously we have reported comparative effectiveness data regarding survival of first line (1L) treatment options in mRCC. However, it is not known how the life-prolonging frontline combinations compare to patient-reported outcomes. Methods: Electronic databases including MEDLINE and EMBASE were searched from each database’s inception through July 1st 2023. Phase III randomized controlled trials (RCTs) assessing 1L immune-checkpoint inhibitor (ICI) combination therapies for mRCC and reporting HrQoL were included. Small sample size adjusted standardized mean differences (SMD; Hedges’ g) with 95% confidence intervals (CI) were computed for global, physical, functional, and emotional QoL. Positive SMD indicated an improvement. A network meta-analysis was conducted to assess the comparative HrQoL across different treatment options. P-scores were computed to assess relative treatment rankings. Results: Of 5770 citations identified, five trials (nine references) were included in this analysis. Patient-reported outcomes have not been reported in the JAVELIN Renal 101 or COSMIC-313 trials yet. Global QoL was significantly improved with cabozantinib-nivolumab (CaboNivo) as compared to Nivo-ipilimumab (SMD 2.74, 95% CI 2.54; 2.93), lenvatinib-pembrolizumab (LenPem; 2.79, 2.53; 3.06), sunitinib (2.87, 2.72; 3.03), Pem-axitinib (PemAxi; 3.09, 2.89; 3.30) and atezolizumab-bevacizumab (AteBev; 3.24, 3.04; 3.45). Global QoL improvement was also observed with NivoIpi compared to sunitinib (0.14, 0.02; 0.25), PemAxi (0.36, 0.18; 0.54) and AteBev (0.51, 0.33; 0.68). Physical QoL improvement were consistent with CaboNivo. Likewise, LenPem significantly improved QoL compared to sunitinib (0.26, 0.04; 0.47), PemAxi (0.38, 0.13; 0.64) and NivoIpi (0.51, 0.27; 0.76). Significant functional QoL benefits were only observed with CaboNivo (0.32, 0.17; 0.48) and NivoIpi (0.19, 0.08; 0.31) compared to sunitinib. No significant mixed treatment comparisons were observed for emotional QoL, however, currently available data suggests that LenPem (rank 1) may potentially improve QoL (Table). Conclusions: CaboNivo and NivoIpi as 1L therapy may offer an improved overall HrQoL compared to other contemporary treatment options in mRCC. [Table: see text]

230 Background: Elevated suicide risk is established in cancer patients compared with the general population. We aim to investigate the risk of SRD among individuals diagnosed with mGU cancers. Methods: Surveillance, Epidemiology, and End Results (SEER) database (2004-2020) was queried to obtain data on suicide death in adults (>20 years of age) diagnosed with mGU cancers including bladder cancer (BC), kidney cancer (KC), and prostate cancer (PC). Standardized mortality ratios (SMRs) with 95% confidence interval (CI) were computed overall and by latency period of <1, 1-5, and >5 years (y) after the initial diagnosis of mGU cancers. SMR >1 indicated increased while <1 indicated decreased SRD. Stratification was done by age (<50y, 50-70y, >70y), race (White, Black, Asian, Native American), ethnicity (Hispanic, non-Hispanic), chemotherapy, radiotherapy, surgery, and marital. Results: This analysis included 87,357 mGU patients. In overall population, the risk of suicide-related deaths was highest <1y after diagnosis (SMR: 3.29, 95% CI: 2.47-4.29) followed by 1-5y (2.61, 2.0-3.35) and >5y (1.27, 0.61-2.34) after diagnosis. With respect to race, SRD was significantly higher in Whites (3.31, 2.46-4.36) but not in Blacks (2.58, 0.31-9.33), and Asians (2.03 (0.05-11.3). In ethnic subgroups, non-Hispanics were observed to have increased SRD (3.71, 2.77-4.86) but not Hispanics (0.83, 0.1-3.0). Patients who received chemotherapy (3.74, 2.10-6.18) or those who did not receive radiotherapy (3.66, 2.68-4.89) were more likely to die from suicide. In terms of marital status, single patients had a higher SRD (4.39, 2.94-6.30) compared to those who were married (2.54, 1.65-3.76). Detailed results are outlined in the Table. Conclusions: Patients with GU malignancies are at increased risk of SRD. Targeted and timely interventions in highest risk subgroups such as Non-Hispanic patients with a recent cancer diagnosis with no partner support, may reduce the risk of SRD in patients diagnosed with mGU cancers. [Table: see text]

229 Background: We aim to investigate non-cancer cause of death in adults within 2 years after initial diagnosis of mGU cancers including bladder cancer (BC), kidney cancer (KC), and prostate cancer (PC). Methods: Surveillance, Epidemiology, and End Results (SEER) database (2004-2020) was searched to obtain data on death caused by cardiovascular diseases (CVD), kidney diseases (KD), respiratory diseases (RD), liver diseases (LD), diabetes mellitus (DM), and sepsis in adults (>20y of age) diagnosed with mGU cancers. Standardized mortality ratios (SMRs) with 95% confidence interval (CI) were calculated within 2y of initial diagnosis. SMR was defined as the observed deaths from each category divided by the expected number of deaths in the age-matched US population for the same period. SMR >1 indicated increased while <1 indicated decreased mortality. Stratification factors included age (<50y, 50-70y, >70y), race (White, Black, Asian/Pacific Islander), ethnicity (Hispanic, non-Hispanic), chemotherapy, and radiotherapy. Results: This study including 77,246 mGU cancer patients showed that the greatest risk of early death was observed to be caused by sepsis (SMR: 4.21, 95% CI: 3.64-4.84) followed by CVD (1.70, 1.62-1.80), KD (1.58, 1.31-1.90), LD (1.58, 1.16-2.09), DM (1.56, 1.32-1.82), and RD (1.38, 1.22-1.56). Patients aged <50y observed the highest risk of mortality caused by sepsis (61.76, 30.83-110.5) followed by KD (28.06, 9.11-65.48) and CVD (5.63, 3.60- 8.84). However, patients aged 50-70y were more likely to die by RD (2.47, 1.94-3.09) and LD (2.01, 1.38-2.82). The results were consistent for Black patients; sepsis (6.59, 5.04-8.46) followed by RD (2.01, 1.41-2.78) and KD (1.64, 1.04-2.46). Asian/Pacific Islanders were more likely to die from CVD (2.52, 2.13- 3.00) and DM (2.21, 1.21-3.71). Hispanics were more likely to die from LD (3.11, 1.66-5.32) and non-Hispanics from sepsis (4.28, 3.68-4.96). This risk of death due to sepsis was increased with chemotherapy (7.06, 5.22-9.33) and radiotherapy (4.92, 3.58-6.61). Detailed results are available in Table. Conclusions: Sepsis remained the leading cause of early non-cancer-deaths in mGU cancers consistently across all subgroups. Younger adults were more likely to die from CVD and KD, Black patients from RD, and Hispanics from LD. [Table: see text]

173 Background: The data for combining PARPi and ARPi in mCRPC have shown conflicting results. Here, we report a quantitative summary of benefits by clinically meaningful subgroups (HRR mutation status, BRCA mutation status) to guide the use of PARPi and ARPi combination in mCRPC setting. Methods: MEDLINE, EMBASE, and CENTRAL were systematically searched from each database’s inception through September 7, 2023. Phase III studies comparing PARPi + ARPi with ARPi + placebo in mCRPC were included. Radiographic progression-free survival (rPFS) and overall survival (OS) in patient subgroups based on HRR and BRCA mutation status were assessed. Hazard ratios for rPFS and OS with 95% CI were collected at the level of each trial, and a random-effects meta-analysis was conducted using an inverse variance approach. Subgroup differences were assessed and p-value of interaction <0.1 was considered statistically significant. Results: The literature search identified 4976 studies from which 3 trials (11 references) – TALAPRO2, PROpel and MAGNITUDE met the inclusion criteria. A total of 2254 participants were eligible for analysis. PARPi + ARPi prolonged rPFS in patients with HRR mutations (HR: 0.55, 95%CI: 0.38-0.78) as well as in patients without HRR mutations (HR: 0.74, 95%CI: 0.63-0.88). There is no evidence of treatment interaction by HRR mutation status (p = 0.14). In patients harboring HRR mutations, improved rPFS was observed in those with BRCA mutations (HR: 0.28, 95%CI: 0.13-0.62) as well as those without BRCA mutations (HR: 0.72, 95%CI: 0.59-0.87). However, there is evidence that patients with BRCA mutations derived greater rPFS benefit as compared to patients without BRCA mutations (p =0.02). PARPi + ARPi showed no significant improvement in overall survival either in patients with HRR mutations (HR: 0.79, 95%CI: 0.59-1.05) or in patients without HRR mutations (HR: 0.92, 95%CI: 0.74-1.14). Conclusions: Genomic testing for HRR genes is mandatory to guide clinical decision making in mCRPC patients. Patients harboring BRCA mutations are most likely to derive clinically meaningful benefit from combination PARPi + ARPi treatment. [Table: see text]

171 Background: Treatment effects vary by volume of disease and timing of metastatic presentation in patients with mCSPC. Therefore, we updated the existing body of evidence to assess the comparative efficacy of systemic therapy in mCSPC by prognostic subgroups to inform clinical practice guidelines. Methods: This living systematic review was conducted using the living interactive evidence (LIvE) synthesis framework. Phase III clinical trials assessing contemporary systemic therapy in mCSPC and reporting overall survival (OS) by four prognostic subgroups were included. Prognostic subgroups included synchronous high volume (SHV), synchronous low volume (SLV), metachronous high volume (MHV), and metachronous low volume (MLV) disease. Mixed treatment comparisons were made using a network-meta-analytic approach in each subgroup. P-scores were used to assess relative treatment rankings in congruency with pairwise estimates. Higher scores indicated better efficacy. Results: This study included a total of nine trials with eight unique treatment options. In patients with SHV disease, darolutamide+docetaxel+ADT (DARO+D+ADT) significantly improved OS when compared to D+ADT (HR: 0.69; 0.57-0.85), enzalutamide (E)+ADT (HR: 0.67; 95% CI: 0.46-0.99), and apalutamide (APA)+ADT (HR: 0.65; 95% CI: 0.43-0.96). In patients with SLV disease, E+ADT (HR: 0.62; 95% CI: 0.42-0.91) and AAP+ADT (HR: 0.66; 95% CI: 0.49-0.89) significantly improved OS when compared to ADT. Although E+D+ADT trended toward improvement compared to other treatments, the results were not statistically significant. In patients withMHV disease, no statistically significant differences were observed among mixed treatment comparisons. However, OS with DARO+D+ADT trended toward improvement when compared to D+ADT (HR: 0.69; 95% CI: 0.39-1.23), APA+ADT (HR: 0.72; 95% CI: 0.23-2.33), E+ADT (HR: 0.67; 95% CI: 0.24-1.86), and E+D+ADT (HR: 0.59; 95% CI: 0.26-1.34). In patients with MLV disease, E+ADT significantly improved OS compared to ADT (HR: 0.51; 95% CI: 0.32-0.79), and D+ADT (HR: 0.48; 95% CI: 0.27-0.85). APA+ADT significant improved OS compared to ADT (HR: 0.22; 95% CI: 0.09-0.54), and D+ADT (HR: 0.21; 95% CI: 0.08-0.55). No other statistically significant differences were observed among mixed treatment comparisons. Conclusions: Current evidence suggests that triplet systemic therapy may be preferred in SHV, E systemic triplet and E hormonal doublet in SLV, DARO systemic triplet and APA hormonal doublet in MHV, and APA or E hormonal doublets in MLV mCSPC. [Table: see text]

111 Background: Comparative evidence of quality of life (QoL) outcomes regarding life-prolonging treatments for the management of first-line treatment of metastatic castration sensitive prostate cancer (mCSPC) is not known. Methods: This systematic review uses the living interactive evidence synthesis framework (PMID: 36862387). Phase III randomized controlled trials assessing contemporary systemic treatments in mCSPC were included. Small sample size adjusted standardized mean differences (SMD; Hedges’ g) with 95% confidence intervals (CI) were computed for global QoL at 3, 6, 12, and 24 mo. Positive SMD indicated better health-related QoL, with zero indicating a null effect. Mixed treatment comparisons were made using a network meta-analysis. P-scores were computed; a higher score indicated better QoL. Results: Of 10 clinical trials initially included, eight trials (15 references) reported QoL. At 3mo global QoL was improved with abiraterone (AAP)+ADT compared to D+ADT (SMD: 0.26; 95% CI: 0.13-0.39), enzalutamide (E)+ADT (0.18; 0.03-0.33), and ADT (0.14; 0.02-0.27). At 6mo, AAP+ADT significantly improved global QoL compared to D+ADT (0.74; 0.62-0.87), E+ADT (1.74; 1.56-1.92), and ADT (1.79; 1.65-1.93). D+ADT also improved global QoL at 6mo compared to ADT (1.05; 0.93-1.16) but not when compared to E+ADT. At 12mo, AAP+ADT improved global QoL compared to E+ADT (0.20; 0.05-0.34) and ADT (0.19; 0.07-0.31) but not compared to D+ADT (0.05; -0.07-0.17). D+ADT also improved global QoL at 12mo compared to ADT (0.14; 0.03-0.24) (Table). Global QoL has not been reported for ARASENS trial at this time. These results are available on the Living interactive website. Conclusions: The totality of evidence suggests improved global QoL with androgen-pathway inhibitors (API) doublet therapy. D+ADT may offer better QoL at longer 6 and 12 months of follow-up. QoL data for triplet therapy is still emerging and will be incorporated in the living review as soon as it becomes available. [Table: see text]