Vaishampayan, Ulka

4559 Background: Baseline QOL has been linked to survival in mRCC therapy clinical trials (Cella, 2024); however, there is a paucity of prospectively collected real-world QOL data across front-line management strategies. We used data from ODYSSEY to examine the relationship between baseline QOL and early death. Methods: ODYSSEY is a multi-site, prospective observational study of 468 US pts with mRCC. Pts must have mRCC (any histology); have no prior systemic therapy (ST) or be within 3 months of starting ST; and follow up at a PCORnet study site. Exclusion criteria include treatment for cancer except mRCC. The primary objective is to determine patterns of change in QOL and symptom burden of pts with mRCC. Early death was defined as death within 12 months post-enrollment. All pts with non-missing FKSI-19 or FKSI-DRS at enrollment were included. Cumulative event probabilities as a function of time were stratified by either < or ≥ median QoL value and plotted as a step function vs time since enrollment to create cumulative event curves. To determine association between QoL at enrollment and early death, separate Cox proportional hazards models (unadjusted and adjusted) for time-to-first-event as a function of baseline QoL were fit. The adjusted model controlled for the following baseline covariates: IMDC risk (favorable vs intermediate or poor), histology (clear cell vs non). Results: As of 1/5/26, 468 pts were enrolled; 425 had non-missing FKSI-19 or FKSI-DRS at enrollment (329 immediate ST, 96 deferred ST [DST]). ST included 129 IO-IO, 108 IO-TKI, 92 Other. DST included 57 Active Surveillance, 22 Local Therapy Planned, 17 Other/Missing. 209 and 190 pts have < median FKSI-19 (score = 59) and FKSI-DRS (score = 29), respectively; 216 and 235 pts have ≥ median FKSI-19 and FKSI-DRS, respectively. Those below the median have lower rates of nephrectomy, worse IMDC risk and KPS, shorter time since RCC diagnosis, and higher rates of bone metastasis (all p<0.05). Cumulative event probabilities for death at 12 months are 21% and 7% in those < and ≥ median baseline FKSI-19, respectively; and 21% and 7% in those < and ≥ median baseline FKSI-DRS, respectively. For FKSI-19, the unadjusted hazard ratio (HR) for early death is 0.55 (95% CI: 0.43 – 0.70; p<0.001) and adjusted HR is 0.65 (0.49 – 0.85; p = 0.002) per 1 SD higher score. For FKSI-DRS, the unadjusted HR for early death is 0.57 (95% CI: 0.46 – 0.71; p<0.001) and adjusted HR is 0.66 (0.51 – 0.86; p =0.002) per 1 SD higher score (higher score indicates better QOL). Conclusions: Across management strategies in our ODYSSEY cohort of systemic therapy naïve mRCC patients, better baseline QOL was associated with better survival. This is to our knowledge the largest reported real world mRCC cohort with prospectively collected PROs. Future analyses will focus on association of outcomes with longitudinal PROs. Clinical trial information: NCT04919122 .

476 Background: Lack of standardized reporting and collection of patient-reported outcomes (PROs) limits cross-trial comparisons of first-line IO-based regimens for mRCC. Prospectively collected real world data may fill this important knowledge gap. Pts with stable/improved QoL at 3 mo versus baseline have longer median OS than pts with worse/unobserved HRQoL versus baseline (Cella, 2024). Methods: ODYSSEY is a multi-site, prospective observational study of 468 US pts with mRCC. Pts must have mRCC (any histology), no prior systemic therapy (ST), and follow up at a PCORnet study site. Exclusion criteria include treatment for cancer except mRCC. Descriptive statistics are used to show PRO score changes from baseline. We evaluate longitudinal change from baseline in PRO scores using least squares mean (LSM). Minimally important differences (MID) are 3 points for FKSI-19 total score, 1 point for the FKSI-Disease Related Symptoms (DRS) subscale and 7 points for FACT-G. Higher score indicates better QOL. The primary objective is to determine patterns of change in QOL and symptom burden of pts with mRCC. Results: As of 10/1/25, 360 pts were managed with ST, including 266 pts on IO-based combinations: 35 cabozantinib + nivolumab (C+N), 49 lenvatinib + pembrolizumab (L+P), 40 axitinib + pembrolizumab (A+P), and 142 ipilimumab + nivolumab (I+N). Overall median follow-up is 12.1 mos (IQR 6, 24). Age, sex and race were similar across regimens. Prior nephrectomy (50%) was lower than in trials. C+N and L+P pts had less clear cell (56 and 65%) versus A+P and I+N pts (94 and 82%). A+P pts had more favorable IMDC risk (19%) and less poor risk (14%). Baseline QOL was variable across regimens, with L+P generally the lowest. Absolute changes in PROs from enrollment to mo 3 (early change) by regimen are shown in the Table. LSM change from baseline in FKSI-19 and FKSI-DRS favored IO-IO versus IO-TKI at 3 mos but not at 6 mos (not shown). Conclusions: While early change in PROs did not meet the MID threshold between the IO-TKI and I+N cohorts, different patterns of early change are apparent among specific IO-TKI regimens. IO-TKI regimens exhibited higher variation in early PRO change vs I+N. As the data matures, we will associate baseline PROs and early PRO changes with early death and other outcomes. Clinical trial information: NCT04919122 . 3 month change. Instrument C+N (N=35) L+P (N=49) A+P (N=40) All IO-TKI(N=124) I+N(N=142) FKSI-19, N (%) 26 (74) 33 (67) 33 (83) 92 (74) 104 (73) Mean (SD) -0.3 (11) 2.8 (13) -3.2 (12) -0.2 (12) 0.7 (10) Median (IQR) 1.4 (-7, 6) 5.0 (-7, 11) -1.0 (-14, 5) 1.4 (-10, 8) -0.3 (-5, 6) FKSI-DRS, N (%) 26 (74) 33 (67) 33 (83) 92 (74) 104 (73) Mean (SD) -0.8 (5) 1.5 (7) -1.8 (6) -0.3 (6) 0.8 (5) Median (IQR) -0.5 (-5, 3) 2.0 (-5, 5) -1.0 (-5, 3) 0.0 (-5, 4) 0.0 (-2, 4) FACT-G, N (%) 27 (77) 32 (65) 29 (73) 88 (71) 102 (72) Mean (SD) 2.1 (14) 5.2 (16) -3.5 (15) 1.4 (15) 0.3 (13) Median (IQR) 4.0 (-4, 10) 1.2 (-6, 13) -6.4 (-11, 4) 1.6 (-8, 10) 1.6 (-7, 8)

Abstract Purpose: Prostate-specific membrane antigen (PSMA)–directed therapies provide meaningful clinical benefit in metastatic castration-resistant prostate cancer (mCRPC), yet responses remain limited, underscoring the need for additional biomarkers of PSMA expression heterogeneity. In this study, we explored the relationship between PSMA imaging and PSMA expression on circulating tumor cells (CTC) in our early-phase trial using a PSMA-targeted small molecule. Experimental Design: This phase I study investigated EC1169, a small molecule conjugated to a tubulysin analog warhead, and 99mTc–EC0652, a PSMA imaging agent. Part A (dose escalation) identified the recommended phase II dose. Part B (dose expansion) assessed radiographic progression-free survival (rPFS) as its primary endpoint. We enrolled and treated 103 patients with mCRPC. Most part B patients underwent 99mTc–EC0652 PSMA imaging. A CTC assay assessed PSMA-positive CTCs and their association with response and PSMA imaging. Results: 99mTc–EC0652 single-photon emission computed tomography (SPECT) imaging demonstrated increased sensitivity for detecting bone lesions compared with standard scans (computed tomography/bone scans). Using an optimized CTC assay, we observed that patients with a decrease in PSMA+ CTCs at baseline versus C3D1 displayed a longer rPFS (8 vs. 2.9 months; P = 0.04). Importantly, patients with predominantly PSMA-positive disease on 99mTc–EC0652 imaging also harbored PSMA-negative CTCs, with a subset displaying neuroendocrine prostate cancer–like morphology. Conclusions: Although EC1169 showed limited activity, CTC and imaging analyses showed significant heterogeneity in PSMA expression on CTCs in patients with predominantly PSMA-positive lesions on SPECT. Our study highlights the importance of assessing both PSMA-based CTC and imaging assays in future validation trials.

PURPOSE Preclinical studies suggest the combination of the poly(adenosine diphosphate[ADP]-ribose) polymerase (PARP) inhibitor olaparib and the ataxia telangiectasia–mutated and Rad3-related (ATR) inhibitor ceralasertib has synergistic antitumor activity in homologous recombination proficient (HRP) and homologous recombination repair gene mutation (HRRm) patients. This study aims to determine the efficacy of olaparib plus ceralasertib in metastatic castration-resistant prostate cancer (mCRPC) with and without HRRm. PATIENTS AND METHODS Thirty-five HRP and 12 HRRm PARP inhibitor–naïve patients with mCRPC progressing on ≥1 line of therapy or previous androgen receptor pathway inhibitor were enrolled. Patients received olaparib (300 mg twice daily) and ceralasertib (160 mg once daily, days 1-7) in 28-day cycles. HRRm was defined as biallelic inactivation of BRCA2 or BRCA1 , monoallelic inactivation of ATM , or germline inactivation of any of these genes. The primary end point was disease response rate (dRR; confirmed prostate-specific antigen decline ≥50% and/or complete/partial radiographic response by RECIST v1.1) in HRP patients. Secondary end points included dRR in HRRm patients, progression-free survival (PFS), and safety/toxicity. Two-stage designs were used. RESULTS Four of 35 (11%; 95% CI, 3.2 to 26.7) HRP and four of 12 HRRm patients responded. Median PFS was 8.2 months (95% CI, 5.3 to not reached) for HRP patients. Thirty-six percent of patients had ≥grade 3 toxicity, most commonly from anemia. Limitations include small, single-arm, nonrandomized trial design. CONCLUSION Combining ceralasertib with olaparib had limited activity in patients with HRP mCRPC. HRRm response rate was not greater than previous single-agent PARP inhibitor clinical trials.

4516 Background: Ipilimumab/nivolumab (ipi/nivo) is a standard of care first-line treatment (tx) for patients (pts) with mccRCC; however, ideal timing of subsequent immunotherapy txs are not well defined. We performed an analysis of patients initially treated with ipi/nivo and subsequent cohort assignments on PDIGREE (A031704). Methods: The PDIGREE trial treated pts with IMDC intermediate/poor risk mccRCC with first-line ipi/nivo (Step 1) at NCTN sites (categorized as academic (A), academic regional (R), and community (C)). Subsequent management was based on iRECIST responses at 12 weeks: pts with complete response (CR) received 1-year nivo maintenance; pts with progressive disease (PD) received cabozantinib (cabo) monotherapy, pts with non-CR/non-PD were randomized to nivo with or without cabo (for primary endpoint of overall survival [OS], target sample size was 1175). Enrollment was held when the randomized sample target was reached. Pts with unresolved toxicity at week 22 were managed off protocol. Step 1 pt demographics, assignments into Step 2, and adverse event (AE) data are presented. Descriptive statistics were used, and cohorts were compared using a chi-square test. These data were released with DSMB approval and do not inform the primary OS endpoint (1EP). Results: From May 2019 to May 2024, 1111 pts were enrolled and treated with ipi/nivo. Pt characteristics included median age 64.0 years (range 29.0-86.0); 819 (73.7%) males; White (85.1%), Hispanic (10.4%), Black (4.2%), and American Indian/Native Hawaiian (1.3%); 849 (76.8%) intermediate risk/257 (23.2%) poor risk; 458 (41.2%) at Academic, 113 (10.2%) at Regional, and 540 (48.6%) at Community centers; and 603 (54.3%) with de novo metastases. 364 pts (33%) stopped tx in Step 1: 160 (44%) for AEs, 46 (13%) for PD/clinical PD/suspected PD, 42 (12%) withdrawals, 39 (11%) alternative txs, 37 (10%) deaths on the study, 12 (3%) other complicating disease, 8 (2%) MD decision and 19 (5%) other reasons. Of the 37 deaths, 15 (1.4%) grade 5 SAEs were reported, 6 of which were due to PD. Of 747 (67%) pts registered to Step 2 at 3 months, 9 (1.2%) achieved CR, and 141 (18.9%) pts were assigned to the PD cohort. 597 pts (80%) were randomized for the 1EP, notable with fewer pts with poor risk [(21 vs 27%, p = 0.01] and bone metastases [24.5% vs 34.2%, p = 0.0007] compared to Step 1 pts who discontinued tx. Gr 3/4 tx-related AEs in 314/1093 (29%) evaluable pts included diarrhea/colitis (8%), transaminase elevation (3%), rash (2%), adrenal insufficiency (2%), fatigue (2%), and hypophysitis (1%). Conclusions: The PDIGREE trial enrolled a representative US-based population with mccRCC. Step 1 pt characteristics and associated outcomes with induction ipi/nivo reveal new insights into the tolerability and tx response of 1L ipi/nivo. Clinical trial information: NCT03793166 .

PURPOSE The COSMIC-021 study assessed the safety and efficacy of cabozantinib plus atezolizumab in advanced solid tumors. Presented here are results from the expansion cohorts with advanced urothelial carcinoma (UC). METHODS This phase Ib study (ClinicalTrials.gov identifier: NCT03170960 ) enrolled patients with inoperable locally advanced/metastatic UC into four tumor cohorts: first-line cisplatin-eligible (cis-eligible), first-line cisplatin-ineligible (cis-ineligible), previous platinum-containing chemotherapy (previous chemotherapy-treated), and previous immune checkpoint inhibitor (ICI)–treated. Patients received oral cabozantinib 40 mg once daily and intravenous atezolizumab 1,200 mg once every 3 weeks. The primary end point was objective response rate (ORR), as assessed by the investigator per RECIST v1.1 every 6 weeks for 12 months and every 12 weeks thereafter; the secondary end point was safety. RESULTS A total of 121 patients (previous ICI-treated cohort, n = 31, and each of the other cohorts, n = 30) received study treatment from March 2018 to November 2021. The ORR (95% CI) was 30% (15 to 49) for cis-eligible, 20% (8 to 39) for cis-ineligible, 27% (12 to 46) for previous chemotherapy-treated, and 10% (2 to 26) for previous ICI-treated cohorts. The median progression-free survival (95% CI) was 5.5 (1.6 to 11.6), 5.6 (3.1 to 11.1), 5.4 (1.6 to 7.6), and 3.0 (1.8 to 5.5) months, respectively. Grade 3 or 4 treatment-related adverse events (TRAEs) were experienced by 43%, 67%, 57%, and 45% of patients, respectively. TRAEs led to discontinuation of all treatment components in 17%, 13%, 3%, and 19%, respectively. No grade 5 TRAEs were reported in any cohort. CONCLUSION The novel combination of cabozantinib plus atezolizumab exhibited clinical activity in advanced UC that is cis-eligible, cis-ineligible, or previously treated with platinum-containing chemotherapy; clinical activity in previous ICI-treated UC was modest. The toxicity profile was consistent with that previously reported for the combination.

Birt-Hogg-Dubé (BHD) syndrome is associated with an increased risk of multifocal renal tumors, including hybrid oncocytic tumor (HOT) and chromophobe renal cell carcinoma (chRCC). HOT exhibits heterogenous histologic features overlapping with chRCC and benign renal oncocytoma, posing challenges in diagnosis of HOT and renal tumor entities resembling HOT. In this study, we performed integrative analysis of bulk and single-cell RNA sequencing data from renal tumors and normal kidney tissues, and nominated candidate biomarkers of HOT, L1CAM, and LINC01187, which are also lineage-specific markers labeling the principal cell and intercalated cell lineages of the distal nephron, respectively. Our findings indicate the principal cell lineage marker L1CAM and intercalated cell lineage marker LINC01187 to be expressed mutually exclusively in a unique checkered pattern in BHD-associated HOTs, and these 2 lineage markers collectively capture the 2 distinct tumor epithelial populations seen to co-exist morphologically in HOTs. We further confirmed that the unique checkered expression pattern of L1CAM and LINC01187 distinguished HOT from chRCC, renal oncocytoma, and other major and rare renal cell carcinoma subtypes. We also characterized the histopathologic features and immunophenotypic features of oncocytosis in the background kidney of patients with BHD, as well as the intertumor and intratumor heterogeneity seen within HOT. We suggest that L1CAM and LINC01187 can serve as stand-alone diagnostic markers or as a panel for the diagnosis of HOT. These lineage markers will inform future studies on the evolution and interaction between the 2 transcriptionally distinct tumor epithelial populations in such tumors.

684 Background: In the COSMIC-021 phase 1b study (NCT03170960) evaluating cabozantinib plus atezolizumab in advanced solid tumors, this combination therapy demonstrated encouraging clinical activity in patients with advanced non-clear cell renal cell carcinoma (nccRCC) with a median follow-up of 13 mo (Pal. JCO 2021). Results after extended follow-up in nccRCC are presented. Methods: Patients with advanced nccRCC and ECOG PS 0/1 who had ≤1 prior VEGFR-targeting tyrosine kinase inhibitor (TKI) were eligible. Prior treatment with TKIs targeting MET or immune checkpoint inhibitors was not allowed. Patients received cabozantinib 40 mg PO QD plus atezolizumab 1200 mg IV Q3W until unacceptable toxicity or progression; dose reductions of cabozantinib (40 mg QD to 20 mg QD, then to 20 mg QOD) were permitted to manage adverse events. The primary endpoint was objective response rate (ORR) per RECIST v1.1 by the investigator; other endpoints included safety, duration of response (DOR), PFS, and OS. Results: The study enrolled 32 patients with nccRCC (2 from dose escalation phase, and 30 from expansion phase of the study): median age, 62 y; male, 81%; ECOG PS 0/1, 75%/25%; histology, papillary/chromophobe/clear cell/other, 47%/28%/3%/22%; sarcomatoid feature, 13%; IMDC risk favorable/intermediate/poor, 50%/41%/9%; ≥3 tumor sites, 56%; tumor sites, lung/kidney/bone/liver, 50%/25%/16%/16%; prior nephrectomy, 63%; prior VEGFR TKI, 22%; 0/1 lines of prior therapy (locally advanced/metastatic setting), 81%/19%. As of July 21, 2022, median follow-up was 37.2 mo (range 32.1–58.5) with 5 (16%) patients remaining on study treatment. ORR by investigator was 31% (all PRs) and disease control rate was 94% (Table); median DOR was 8.1 mo. Median PFS was 9.3 mo (95% CI 5.5–12.3), and median OS was not reached (95% CI 23.0–NE). PFS and OS estimates at 12 mo were 34% and 84%, respectively; 24-mo estimates were 6% and 70%. Treatment-related AEs occurred in 97% (grade 3/4, 53%); the most common AEs included diarrhea (69%), palmar-plantar erythrodysesthesia (50%), fatigue (44%), dysgeusia (41%), hypertension (31%) and nausea (31%). One grade 5 treatment-related AE of pulmonary hemorrhage occurred. Treatment-related AEs leading to discontinuation of both study treatments occurred in 13% of patients. Conclusions: Extended 3-year follow-up reinforces the encouraging clinical activity of cabozantinib plus atezolizumab in advanced nccRCC with a manageable safety profile. Clinical trial information: NCT03170960 . [Table: see text]

Introduction. Chromophobe renal cell carcinoma (chromophobe RCC) is the third major subcategory of renal tumors after clear cell RCC and papillary RCC, accounting for approximately 5% of all RCC subtypes. Other oncocytic neoplasms seen commonly in surgical pathology practice include the eosinophilic variant of chromophobe RCC, renal oncocytoma, and low-grade oncocytic unclassified RCC. Methods. In our recent next-generation sequencing based study, we nominated a lineage-specific novel biomarker LINC01187 (long intergenic non-protein coding RNA 1187) which was found to be enriched in chromophobe RCC. Like KIT (cluster of differentiation 117; CD117), a clinically utilized chromophobe RCC related biomarker, LINC01187 is expressed in intercalated cells of the nephron. In this follow-up study, we performed KIT immunohistochemistry and LINC01187 RNA in situ hybridization (RNA-ISH) on a cohort of chromophobe RCC and other renal neoplasms, characterized the expression patterns, and quantified the expression signals of the two biomarkers in both primary and metastatic settings. Results. LINC01187, in comparison to KIT, exhibits stronger and more uniform expression within tumors while maintaining temporal and spatial consistency. LINC01187 also is devoid of intra-tumoral heterogeneous expression pattern, a phenomenon commonly noted with KIT. Conclusions. LINC01187 expression can augment the currently utilized KIT assay and help facilitate easy microscopic analyses in routine surgical pathology practice.

4504 Background: C, a multitargeted receptor tyrosine kinase inhibitor (TKI), promotes an immune-permissive environment that may enhance response to immune checkpoint inhibitors (ICIs). COSMIC-021, a multicenter phase 1b study, is evaluating C + A (anti‒PD-L1 therapy) in various solid tumors (NCT03170960). C + A demonstrated encouraging clinical activity in cohort 2 of COSMIC-021 in patients (pts) with UC previously treated with platinum-containing chemotherapy (chemo) (Pal S et al. ASCO 2020. Abstract 5013). Outcomes of C + A from 3 other UC cohorts (C3, C4, C5) are presented. Methods: Pts with inoperable locally advanced/metastatic UC with transitional cell histology and ECOG PS 0‒1 were eligible. Pts enrolled in C3 and C4 had no prior therapy and were cisplatin-based chemo ineligible (C3) or eligible (C4). C5 enrolled pts with one prior ICI and no prior VEGFR-TKI therapy. Pts received C 40 mg PO QD and A 1200 mg IV Q3W. CT/MRI scans were performed Q6W for first year and Q12W thereafter. The primary endpoint is objective response rate (ORR) per RECIST v1.1 by investigator. Other endpoints: safety, duration of response (DOR), PFS, and OS. Results: Thirty pts each were enrolled in C3 and C4, and 31 in C5. Baseline characteristics for C3, C4, and C5, respectively: median age, 74 y, 66 y, 68 y; male, 67%, 73%, 55%; ECOG PS 1, 63%, 57%, 74%; lung/liver metastasis; 33%/17%, 40%/20%, 58%/23%; ≥3 tumor sites, 30%, 43%, 45%; bladder as primary site, 67%, 70%, 71%. As of Nov 30, 2021, the median follow-up for C3, C4, and C5 was 27.9, 19.1, and 32.9 mo, respectively, with 1, 6, and 1 pts on treatment. C + A demonstrated clinical benefit across all cohorts (Table). Most common treatment-related adverse events (TRAEs) of any grade across C3, C4, and C5, respectively, were diarrhea (43%, 33%, 35%), nausea (27%, 17%, 26%), fatigue (27%, 27%, 48%), and decreased appetite (33%, 27%, 39%); grade 3/4 TRAEs occurred in 63%, 43%, and 45%, and there was no grade 5 TRAE. Conclusions: C + A demonstrated encouraging clinical activity with manageable toxicity in inoperable locally advanced/metastatic UC as first-line systemic therapy in cisplatin-based chemo eligible/ineligible pts and as second- or later line in pts who received prior ICI. Clinical trial information: NCT03170960. [Table: see text]