Second-line VEGF TKI after IO combination therapy: Results from the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC)

684

Background: Immuno-Oncology (IO) combinations are standard of care first-line treatment for metastatic renal cell carcinoma (mRCC). Data on therapy with vascular endothelial growth factor (VEGF) tyrosine kinase inhibitors (TKI) post-progression on IO-combination therapy are limited. Methods: Using the IMDC, a retrospective analysis was done on mRCC patients treated with second-line VEGF TKIs after receiving IO combination therapy. Patients received first-line ipilimumab+nivolumab (IOIO) or anti-PD(L)1+anti-VEGF (IOVE). Baseline variables and second-line IMDC risk factors were collected. Overall response rates (ORR), time to treatment failure (TTF) and overall survival (OS) were determined. Multivariable Cox regression analysis was performed. Results: 142 patients were included. 75 patients received IOIO and 67 received IOVE pretreatment. The ORR of 2nd line therapy was 17/46 (37%) and 7/57 (12%) in the IOIO and IOVE pretreated groups, respectively (p<0.01). 2nd-line TTF was 5.4 months (95% CI 4.1-8.3) for the IOIO- and 4.6 months (95% CI 3.7-5.8) for the IOVE-pretreated group (p=0.37). 2nd-line median OS was 17.2 months (95% CI 10.8-35.1) and 11.8 months (95% CI 9.9-21.3) for the prior IOIO and IOVE groups, respectively (p=0.13). The hazard ratio adjusted by IMDC for IOVE vs IOIO pretreatment was 1.22 (95% CI 0.73-2.07, p=0.45) for 2nd line TTF and 1.43 (95% CI 0.74-2.8, p=0.29) for 2nd line OS. Conclusions: VEGF TKIs show activity after combination IO therapy. Response rates are higher in patients treated with VEGF TKIs after first-line IOIO compared to after IOVE. In patients with VEGF TKI after IOIO or IOVE, no difference in OS and TTF was observed.[Table: see text]

PROSPER: Phase III randomized study comparing perioperative nivolumab versus observation in patients with renal cell carcinoma (RCC) undergoing nephrectomy (ECOG-ACRIN EA8143)

TPS765

Background: There is no standard adjuvant systemic therapy that increases overall survival (OS) over surgery alone for non-metastatic RCC. Anti-PD-1 nivolumab (nivo) improves OS in metastatic RCC and is well tolerated. In mouse models, priming the immune system prior to surgery with anti-PD-1 results in superior OS compared to adjuvant dosing. Remarkable pathologic responses have been seen with neoadjuvant PD-1 in multiple ph 2 studies in bladder, lung and breast cancers. Phase 2 neoadjuvant RCC trials of nivo show preliminary feasibility and safety with no surgical delays. PROSPER RCC seeks to improve clinical outcomes by priming the immune system with neoadjuvant nivo prior to nephrectomy followed by continued immune system engagement with adjuvant blockade in patients (pts) with high risk RCC compared to standard of care surgery alone. Methods: This global, unblinded, phase 3 National Clinical Trials Network study is accruing pts with clinical stage ≥T2 or TanyN+ RCC of any histology planned for radical or partial nephrectomy. Select oligometastatic disease is permitted if the pt can be rendered ‘no evidence of disease’ within 12 weeks of nephrectomy (≤3 metastases; no brain, bone or liver). In the investigational arm, nivo is administered 480mg IV q4 weeks with 1 dose prior to surgery followed by 9 adjuvant doses. The control arm is nephrectomy followed by standard of care surveillance. There is no placebo. Baseline tumor biopsy is required only in the nivo arm but encouraged in both. Randomized pts are stratified by clinical T stage, node positivity, and M stage. 805 pts provide 84.2% power to detect a 14.4% absolute benefit in recurrence-free survival at 5 years assuming the ASSURE historical control of ~56% to 70% (HR = 0.70). The study is powered to evaluate a significant increase in OS (HR 0.67). Critical perioperative therapy considerations such as safety, feasibility, and quality of life metrics are integrated. PROSPER RCC embeds a wealth of translational studies to examine the contribution of the baseline immune milieu and neoadjuvant priming with anti-PD-1 on clinical outcomes. As of October 18, 2019, 317 patients have been enrolled. Clinical trial information: NCT03055013.

Cabozantinib real-world effectiveness in the first through fourth-line settings for the treatment of metastatic renal cell carcinoma (mRCC): Results from the International mRCC Database Consortium (IMDC)

639

Background: Cabozantinib (Cabo) is approved for mRCC patients based on the METEOR and CABOSUN trials. The real-world effectiveness of Cabo in mRCC patients in the first- (1L), second- (2L), third- (3L) and fourth-line (4L) settings requires characterization. Methods: This retrospective analysis included mRCC patients who were treated with Cabo and stratified using IMDC risk groups. Overall response rate (ORR), time to treatment failure (TTF), and overall survival (OS) were calculated. Results: A total of 413 patients (82.6% with clear cell and 17.4% non-clear cell) were identified. The median age was 57 years. Overall, 63% of patients had a Karnofsky performance status score of >80 and 82.6% had prior nephrectomy. 23.1%, 75.4% and 88.3% of patients received immunotherapy as a prior line of treatment, before receiving Cabo in the 2L, 3L and 4L settings, respectively. For patients treated with 1L PD(L)1 combination or monotherapy (n=31), 2nd line Cabo had ORR of 20.8%, median TTF of 5.4 months and median OS of 17.4 months. When segregated into IMDC favorable, intermediate, and poor risk groups, the median OS was 34.8 months (95% CI 5.52-NR), 18.0 months (12.3-35.6) and 9.8 months (7.4-20.8), p=0.0088, respectively for 2L Cabo; and 31.5 months (23.6-39.3), 20.5 months (10.1-21.8), and 6.9 months (4.1-10.9), p=<0.0001), respectively for 3L Cabo. Conclusions: The ORR and TTF of Cabo were maintained from the 1L to the 4L therapy settings. In the 2L and 3L settings, the IMDC criteria appropriately stratified patients into favorable, intermediate and poor risk groups for OS. Cabo has activity after first line immunotherapy.[Table: see text]

Sites of metastasis and survival in metastatic renal cell carcinoma (mRCC): Results from the International mRCC Database Consortium (IMDC)

642

Background: Across a variety of malignancies, sites of metastatic involvement are known to be associated with differences in survival. We sought to characterize the frequency and survival of patients with different sites of metastases in mRCC. Methods: Patients with mRCC starting treatment between 2002-2019 were identified and sites of metastatic involvement at time of systemic therapy initiation were documented. The primary outcomes of interest were prevalence of metastatic site involvement and overall survival (OS). Multivariable Cox regression models were performed to adjust for imbalances in IMDC risk factors. Results: A total of 10,320 patients were included. Median age at diagnosis was 60, 73% were male, 87% had clear-cell histology and 80% underwent nephrectomy. The most common sites of metastases were: lung (71%), lymph nodes (49%), bone (36%), liver (21%), adrenal (9%), brain (9%), pancreas (5%), pleura (4%) and thyroid (0.6%). Survival by metastatic site and adjusted hazard ratios are presented in Table. Conclusions: Metastases to endocrine organs (pancreas, thyroid, adrenal) are infrequent but are associated with the longest median OS, whereas bone, liver, pleura and brain metastases are associated with median OS < 18 months. These benchmark values are useful for patient counseling and study design. Sites of metastatic involvement may reflect differences in underlying disease biology, and further work to investigate differences in immune, molecular and genetic profiles between metastatic sites is encouraged.[Table: see text]

Real-world evidence of cabozantinib in metastatic renal-cell carcinoma (mRCC): Results from the Canadian Kidney Cancer Information System (CKCis)

682

Background: Cabozantinib is a multitargeted tyrosine kinase inhibitor (TKI) that has demonstrated efficacy in mRCC randomized trials. Less is known about the activity of cabozantinib in patients (pts) exposed to immuno-oncology (IO) agents. We explored the real-world effectiveness of cabozantinib, including in pts who had progressed on IO therapy. Methods: Using CKCis, a prospective Canadian database, pts treated with cabozantinib monotherapy as second-line or later were identified. Baseline clinical and treatment characteristics were collected. Rates of partial response (PR), stable disease (SD), progressive disease (PD) and disease control (DCR, PR+SD) were determined along with median time to treatment failure (mTTF) and median overall survival (mOS). Results: A total of 156 pts were identified. Median age was 62 years (range 21-84), 74% of pts had clear-cell histology, and 54% had > 3 sites of metastases (12% in CNS, 47% in bone). At time of cabozantinib start, 34% had KPS score < 80. Outcomes are described below. Conclusions: The effectiveness of cabozantinib observed in this real-world population was consistent with results from clinical trials. Cabozantinib also appears to provide benefit to mRCC pts who have progressed on prior IO therapy, and should be incorporated into contemporary treatment algorithms. Further follow up is ongoing.[Table: see text]

Impact of early identification of brain metastases in metastatic renal cell carcinoma (mRCC)

620

Background: Up to one-third of patients with mRCC can present with asymptomatic brain metastases (BM). Timely identification of BM allows for the delivery of early local interventions, which may lead to improved patient outcomes. To investigate the potential utility of routine intra-cranial imaging, we compared the outcomes of mRCC patients with asymptomatic versus symptomatic BM. Methods: Using the Canadian Kidney Cancer information system (CKCis) database, we identified mRCC patients diagnosed with BM between 2011 and 2018. This cohort was divided into two groups dependent on the presence or absence of neurological symptoms. Baseline patient demographics, clinico-pathological disease characteristics and survival data were extracted. Statistical analysis was through chi-square tests, analysis of variance and Kaplan-Meier method to characterize survival outcomes. Results: 269 mRCC patients with BM were identified with the majority presenting with symptomatic disease (n=163; 61%). No significant differences in clinico-pathological disease characteristics were identified. Median overall survival (OS) from mRCC diagnosis for asymptomatic patients was 33.4 months (interquartile range, IQR 27.8-64.4) versus 34.5 months (20.4-43.4) for symptomatic patients (p=0.35). Median OS from time of BM diagnosis revealed a trend favoring asymptomatic, as compared to symptomatic, patients [24.5 (17.6-24.9) vs. 13.1 months (9.0-20.6), p=0.06]. Factors associated with worse OS from time of BM diagnosis included presentation with symptomatic BM [hazard ratio, HR (95% CI): 1.40 (1.03-1.90), p=0.034] and International Metastatic Renal Cell Carcinoma Consortium Database (IMDC)-characterized intermediate/poor risk disease [HR (95% CI): 1.47 (1.01-2.13), p=0.045]. Conclusions: Routine intra-cranial imaging may lead to earlier identification of BM in mRCC. However, further investigation as to whether this practice improves survival is warranted.

Cytoreductive nephrectomy (CN) for metastatic renal cell carcinoma (mRCC) treated with immune checkpoint inhibitors (ICI) or targeted therapy (TT): A propensity score-based analysis

608

Background: The role of CN for mRCC treated with ICI is not well defined. Our aim was to evaluate the role of CN for mRCC treated by ICI or TT using a propensity score-based analysis. Methods: We retrospectively assessed patients who were diagnosed with de novo mRCC and who had started first line systemic therapy (ICI or TT) between 2009 and 2019 using the International Metastatic RCC Database Consortium (IMDC). Overall Survival (OS) was compared between patients receiving CN and those treated by systemic therapies alone, using the Kaplan-Meier method and Cox regressions, in the TT and ICI arms separately. In order to account for treatment selection bias, inverse probability of treatment weighting (IPTW) of propensity scores, based on 14 confounding variables, was used and variables were considered balanced if standardized mean difference (SMD) < 0.1. For variables with SMD≥0.1, residual confounding was adjusted for using multivariable models. Results: 3856 patients had been treated by TT (2470 CN+ & 1386 CN-) and 198 by ICI (143 CN+ & 55 CN-). Median follow-up was 38.5 months. After IPTW, baseline characteristics were largely balanced between the CN+ and CN- arms, in the TT and ICI groups (14/14 and 12/14 with SMD < 0.1, respectively). CN was associated with significantly improved OS in both the ICI (Hazard Ratio [HR] = 0.39 [0.19-0.83]) and TT (HR = 0.56 [0.51-0.62]) groups. The interaction term between CN and therapy type (ICI vs TT) was not statistically significant (p = 0.43). The point estimates of the HRs were consistent in sensitivity analyses using multivariable models. Conclusions: In a propensity score-based analysis, CN was found to be associated with a significant OS benefit in patients treated by either ICI or TT. While this study is not a substitute for randomized controlled trials (e.g. CARMENA), the results suggest that CN may still play a role in selected patients in the ICI era.[Table: see text]

Real-world utilization and safety of ipilimumab plus nivolumab (I+N) in metastatic renal cell carcinoma (mRCC) patients: Results from the Canadian Kidney Cancer Information System (CKCis)

633

Background: I+N is now standard of care for first line treatment of intermediate/poor risk mRCC patients (pts). Real world data is vital to understand drug usage, toxicity and outcomes in non-trial pts. This project describes the amount and tolerability of treatment delivered including discontinuation rates, reasons for discontinuation and outcomes from the CKCis database. Methods: Pts in CKCis, a prospective Canadian database from 15 academic centers, who received first line I+N were included. The number of doses of I+N, number of pts who received single-agent nivolumab (N) and duration of single agent N were determined. Reasons for treatment discontinuation, including the rate, type, and grade of toxicities were identified. Efficacy outcomes included time to failure (TTF – time to progression, death, or second line therapy), overall response rate (ORR) and overall survival (OS). Results: The cohort consists of 182 pts. Median age was 63 yrs, 71% had clear cell histology, 11% were on a clinical trial, the IMDC risk distribution was 5% good, 63% intermediate, 32% poor. Median follow up was 8.8 m. All 4 I+N doses were received by 30% of pts of which 78% went on to receive single-agent N. Less than 4 doses of I+N were received by 70% of pts of which 28% went on to receive single-agent N. The median time on single agent N was 5.7 m. In the entire cohort, 21% of patients discontinued therapy due to toxicity. The most common toxicity events were colitis (56% of all events), pneumonitis (19%), and hepatitis (8%). There were no toxicity-related deaths. Median OS has not been reached (22 events to date). Median TTF was 12.4 m. ORR was 32% (5% complete responses). 26% of pts received second line treatment, the most common being sunitinib in 79%. Conclusions: In this real world cohort, the majority of mRCC pts did not receive all 4 doses of I+N, contrasting with clinical trial reporting, yet many of these pts went on to receive single agent N. Discontinuation rates due to toxicity were similar to those reported in CheckMate 214. Further follow up is ongoing and efficacy outcomes analyzed on the basis of treatment quantity/duration will be presented.

High-dose chemotherapy with autologous stem cell transplantation (HDC-ASCT) for relapsed metastatic germ cell tumors (mGCTs): The Alberta experience from 2001 to 2018

406

Background: HDC-ASCT is a standard therapy for patients (pts) with mGCTs whose disease progresses on or after conventional dose chemotherapy. We conducted a retrospective review of HDC-ASCT in pts with relapsed mCGT in Alberta over the past two decades. Methods: Pts with mGCTs who received HDC-ASCT at two provincial referral cancer centers in Alberta, Canada from 2001-2018 were identified. Baseline clinical and treatment characteristics were collected as well as overall survival (OS) and disease-free survival (DFS). Relevant prognostic variables were analyzed. Results: Forty three pts were identified. Median age was 28 years (range 19 – 56). Majority (95%) had non-seminoma histology and testis/retroperitoneal primary (84%). Twenty pts (47%) had poor risk disease as per IGCCC at start of first-line chemotherapy. HDC-ASCT was used as second-line therapy in 65% and 58% received tandem HDC-ASCT. Median follow-up from ASCT was 22 months (range 2 – 181). At last follow-up, 42% of pts are alive without disease, including 3/7 (43%) of pts with primary mediastinal disease. Two-year and 5-year DFS/OS were 44%/51% and 41%/43%, respectively. Median OS and DFS for all pts were 27.9 months (10.2 – NR) and 9.3 months (4.2 – 124), respectively. Conclusions: We found that HDC-ASCT is an effective salvage therapy in mGCT, consistent with existing literature. Pts appeared to benefit regardless of primary site. Though limited by small sample size, we found a numerical difference in DFS and OS between 2nd and 3rd line HDC-ASCT and single vs. tandem ASCT.[Table: see text]

First-line (1L) immuno-oncology (IO) combination therapies in metastatic renal-cell carcinoma (mRCC): Results from the international mRCC database consortium (IMDC)

4577

Background: In mRCC, ipilimumab and nivolumab (ipi-nivo) is a 1L treatment option. Recent data have also shown efficacy of 1L IO-VEGF (IOVE) inhibitor combinations. Comparative data between these two strategies are limited and the efficacy of subsequent therapies remains unknown. Methods: Using the IMDC dataset, patients (pts) treated with any 1L IOVE combination were compared to those treated with ipi-nivo. Multivariable Cox regression analysis was performed to control for imbalances in IMDC risk factors. Results: 188 pts received 1L IO combination therapy: 113 treated with IOVE combinations and 75 with ipi-nivo. Baseline characteristics and IMDC risk factors were comparable between groups. When comparing IOVE combinations vs ipi-nivo, 1L response rate (RR) was 33% vs 40% (p=0.39), time to treatment failure (TTF) was 14.3 (95% CI 9.2-16.1) vs 10.2 months (95% CI 6.7-15.1, p=0.23), and median overall survival (OS) was not reached (NR) (95% CI 22.3-NR) vs NR (95% CI 35.1-NR, p=0.17). When adjusted for IMDC risk factors, the hazard ratio (HR) for TTF was 0.71 (95% CI 0.46-1.12, p=0.14) and the HR for death was 1.74 (95% CI 0.82-3.68, p=0.14). Second-line (2L) treatments were varied. In pts receiving subsequent VEGF-based therapy, 2L RR was lower in the IOVE (n=20) versus ipi-nivo (n=20) cohort (15% vs 45%; p=0.04), though 2L TTF was not significantly different (3.7 vs 5.4 months, p=0.40, n=55). The use of IO post IOVE was uncommon and 3/5 pts had PD as best response; 2/5 had PR/SD but their 1L IOVE exposure was short at <3 months. Conclusions: There does not appear to be a superior 1L IO combination strategy in mRCC, as lOVE combinations and ipi-nivo have comparable 1L RR, TTF and OS. Most pts received VEGF-based therapy in the 2L. In this group, 2L RR was greater in pts who received ipi-nivo, though there was no difference in 2L TTF. [Table: see text]

Patient-reported experience of diagnosis, management, and burden of renal cell carcinomas: Results from a global patient survey in forty-three countries

e16091

Background: The International Kidney Cancer Coalition (IKCC) is a federation of 38 affiliated patient organizations representing 1.2 million patients worldwide that is committed to reduce the global burden of kidney cancer. A large-scale global survey of RCC patients to capture real world experiences (RWE) has never been undertaken. Methods: The 35-question survey was designed to identify geographic variations in patient education, experience and awareness, access to care, best practices, quality of life, involvement in clinical trials and to highlight unmet needs. The survey was conducted online or in paper form in Sept-Oct 2018 by kidney cancer patients and /or their caregivers identified by IKCC’s Affiliate Organizations and through social media in 14 languages. Results: 1,983 responses were recorded from 43 countries. Analysis revealed that at diagnosis, 43% of all respondents had no understanding of their RCC sub-type; patients with clear cell carcinoma (64%) had a notably poorer understanding of their RCC subtype than did patients with rarer RCC subtypes. While 96% of respondents reported psychosocial impacts, surprisingly, only 50% disclosed them to their healthcare team. Of the 70% of patients who were never asked to participate in a clinical trial, 89% responded they would have “fairly likely” done so if asked. RCC patients < 45 years old reported nearly twice as many barriers to treatment as patients > 45 at diagnosis. Females reported longer delays to diagnosis than males. Shared decision making remains aspirational across major cancer centers and community hospitals: globally 29% of all patients reported no involvement in their treatment decision, responding ‘my doctor decided for me’. Conclusions: This exploratory research sheds light on the unmet needs in the RCC patient experience and warrants further analysis. This first-ever global survey serves as a benchmark for longitudinal data collection. RWE indicates opportunities to improve communication about diagnosis, psychosocial impacts, and clinical trials. [Table: see text]

Active surveillance in metastatic renal cell carcinoma (mRCC): Results from the Canadian Kidney Cancer information system (CKCis)

4516

Background: Active surveillance (AS) is a commonly used strategy in patients (pts) with low tumor burden or slow growing disease. However, few studies have assessed AS for mRCC compared to immediate treatment. We aimed to assess the outcomes and safety of AS in comparison to immediate systemic treatment for mRCC pts. Methods: Using CKCis, mRCC pts diagnosed between January 1, 2011 and December 31, 2016 were identified. AS strategy was defined as: (1) start of systemic therapy ≥6 months after diagnosis of mRCC; or (2) never receiving systemic therapy for mRCC with an overall survival (OS) ≥1 yr (OS ≥ 1 yr a surrogate to exclude pts not started on treatment due to poor prognosis). Pts starting systemic treatment < 6 months after diagnosis of mRCC were defined as receiving immediate systemic treatment. OS and time until 1st line treatment failure (TTF) between the two cohorts were compared. Results: A total of 863 pts met criteria for AS (cohort A). Of these, 370 started treatment ≥ 6 months after their initial diagnosis (cohort A1) and 493 never received systemic treatment and were alive for ≥1 year (cohort A2). 848 pts received immediate systemic treatment (cohort B). Median age for pts in cohort A and B was 65.1 (19.0-91.5) vs. 62.2 yrs (23.1-87.1) (p < 0.0001). Sex distribution was not statistically different. Pts in cohort A had fewer sites of metastatic disease vs. cohort B ( < 0.0001) and 23% of pts in cohort A had metastasectomy vs. 5% in cohort B (P = < 0.0001). Five-year OS probability was significantly greater for cohort A than for cohort B (70.2% vs. 32.1%; P < 0.0001). After adjusting for IMDC risk criteria and age, both OS (HR 0.46, 0.38-0.56, P < 0.0001) and TTF (HR 0.79, 0.69-0.92, P = 0.0021) were greater in cohort A1 vs. B. For cohort A1 the median time on AS was 14.2 m (range 6 – 71). Conclusions: Based on the largest analysis of AS in mRCC to date, our data suggest that a subset of pts may be safely observed without immediate initiation of systemic therapy. Prospective validation is required in the contemporary immunotherapy era.

Efficacy of bone resorption inhibitors (BRI) + abiraterone acetate + prednisone (AA) vs. AA alone as first-line therapy for men with castration-resistant prostate cancer (CRPC) and bone metastases (BM) in an international multicenter hospital-based registry

e16508

Background: BM in patients (pts) with CRPC correlate with higher mortality and costs. BRI zoledronic acid and denosumab are frequently used for the prevention of skeletal-related events (SRE) in pts with CRPC and BM. AA is the most common 1st line treatment for men with metastatic CRPC. We sought to evaluate the impact of BRI on time to first SRE (ttSRE) and OS of pts receiving 1st line therapy AA for CRPC with BM. Methods: We identified a cohort of men starting AA as 1st line therapy for CRPC with BM between 2013-2015 from 7 hospitals’ IRB approved registries. Pts were grouped by use of concomitant BRI and subgrouped by volume of disease (per E3805 definition) at AA start. The endpoints were OS, defined as time from AA start to death or last follow-up visit, and ttSRE. Results: Of the 338 pts included, 256 (76%) received AA alone and 82 (24%) AA+BRI. ECOG PS (PS) was ≥1 for 178 pts (52.7%). No statistically significant difference in ttSRE was found between the 2 cohorts [see Table]. Median follow-up for OS was 25.6 months. Pts receiving concomitant BRI showed a significantly longer OS and a 36% decreased risk of death compared to AA alone (HR = 0.64; 95% CI, 0.64 0.46-0.91; p = 0.012). Notably, OS in the AA alone group was shorter than commonly described. The OS benefit with BRI was greater for men with high volume disease (HV) (HR = 0.42; 95% CI, 0.25-0.71; p = 0.001). On MVA, BRI vs. no BRI, low volume of disease vs. HV, PS 0 vs. ≥1, baseline VAS pain ≤3 vs. > 5, and baseline PSA are independently associated with longer OS. Conclusions: Using a multicenter database, the addition of BRI to 1st line AA for CRPC men with BM and poor prognostic factors did not improve prevention of SRE. However, concomitant use of BRI and AA was associated with a significantly improved OS, particularly in HV. Further research to determine the driving factors is needed. [Table: see text]

PROSPER: A phase III randomized study comparing perioperative nivolumab (nivo) versus observation in patients with renal cell carcinoma (RCC) undergoing nephrectomy (ECOG-ACRIN 8143)

TPS4597

Background: The anti-PD-1 antibody nivo improves overall survival (OS) in metastatic RCC and is well tolerated. There is no standard adjuvant (adjuv) systemic therapy that increases OS over surgery alone for non-metastatic RCC. Priming the immune system prior to surgery with anti-PD-1 has shown an OS benefit compared to a pure adjuv approach in mouse solid tumor models. Multiple ph 2 studies in bladder, lung and breast cancers have shown remarkable pathologic responses with neoadjuvant (neoadj) PD-1 blockade. Two ongoing ph 2 studies of perioperative nivo in M0 RCC patients are showing preliminary feasibility and safety with no surgical delays (NCT02575222; NCT02595918). PROSPER RCC (NCT03055013) aims to improve clinical outcomes by priming the immune system prior to nephrectomy with neoadj nivo and continued engagement with adjuv blockade in patients with high risk RCC compared to surgery alone. Methods: This global, unblinded, phase 3 National Clinical Trials Network study is currently accruing patients with clinical stage ≥T2 or TanyN+ RCC of any histology planned for nephrectomy. Oligometastases are permitted if can be rendered NED. We amended the study to enhance accrual and patient quality of life by changing nivo dosing to 480mg q4 wks and requiring baseline tumor biopsy only in the nivo arm. The investigational arm receives 1 dose of nivo prior to surgery followed by 9 adjuv doses. The control arm undergoes standard nephrectomy followed by observation. Randomized patients are stratified by clinical T stage, node positivity, and M stage. Accrual of 805 patients provides 84.2% power to detect a 14.4% absolute benefit in recurrence-free survival (RFS) at 5 years assuming the ASSURE historical control of ~56% to 70% (HR = 0.70). The study is powered to evaluate a significant increase in OS (HR 0.67). Critical perioperative therapy considerations such as safety, feasibility, and quality of life endpoints have been integrated. PROSPER RCC embeds a wealth of translational work aimed at investigating the impact of the baseline immune milieu, the changes induced by neoadjuvant anti-PD-1 priming, and how both may predict clinical outcomes. Clinical trial information: NCT03055013.

Deferred cytoreductive nephrectomy among patients with newly diagnosed metastatic renal cell carcinoma treated initially with sunitinib

4578

Background: While the CARMENA trial prompts more caution with upfront cytoreductive nephrectomy (CN) in patients with metastatic renal cell carcinoma (mRCC), 17% of patients in the sunitinib alone arm underwent deferred CN (dCN). Upfront systemic therapy has been proposed as a potential litmus test to identify patients suitable for CN, but data on outcomes are limited. We sought to characterize outcomes of dCN after upfront sunitinib relative to sunitinib alone. Methods: Patients with newly diagnosed mRCC receiving upfront sunitinib were identified from the International mRCC Database Consortium (IMDC) from 2006-2018. All CNs done after initial sunitinib were included, excluding CNs performed after sunitinib failure. The outcomes were overall survival (OS) and time to treatment failure (TTF). Kaplan Meier and multivariable Cox regression analyses were performed; dCN was analyzed as a time-varying covariate to account for immortal time bias. Results: The cohort included 708 patients of whom 53 (7.5%) underwent dCN at a median of 6.5 months (IQR 3.5,10.5) from diagnosis. Patients in the dCN group were more likely to have better Karnofsky performance status (KPS), intermediate IMDC risk, fewer metastatic sites, and response to upfront sunitinib (Table). There were 604 deaths during a median follow-up of 63 months. Median OS and TTF with dCN were 43.5 and 19.8 months vs. 9.4 and 4.3 months without, respectively. Upon multivariable analysis, dCN remained significantly associated with OS (HR 0.45, 95%CI 0.31-0.65; p < 0.001) but not TTF (HR 0.73, 95%CI 0.52-1.01; p = 0.056). Conclusions: Patients who received dCN were carefully selected and achieved long OS. With these benchmark outcomes, optimal selection criteria need to be identified and confirmation of the role of dCN in a clinical trial is warranted. [Table: see text]

Real-world outcomes of nivolumab and cabozantinib in metastatic renal cell carcinoma: results from the International Metastatic Renal Cell Carcinoma Database Consortium

Objectives

In the present study, we explored the real-world efficacy of the immuno-oncology checkpoint inhibitor nivolumab and the tyrosine kinase inhibitor cabozantinib in the second-line setting.

Methods

Using the International Metastatic Renal Cell Carcinoma Database Consortium (imdc) dataset, a retrospective analysis of patients with metastatic renal cell carcinoma (mrcc) treated with nivolumab or cabozantinib in the second line after prior therapy targeted to the vascular endothelial growth factor receptor (vegfr) was performed. Baseline characteristics and imdc risk factors were collected. Overall survival (os) and time to treatment failure (ttf) were calculated using Kaplan-Meier curves. Overall response rates (orrs) were determined for each therapy. Multivariable Cox regression analysis was performed to determine survival differences between cabozantinib and nivolumab treatment.

Results

The analysis included 225 patients treated with nivolumab and 53 treated with cabozantinib. No significant difference in median os was observed: 22.10 months [95% confidence interval (ci): 17.18 months to not reached] with nivolumab and 23.70 months (95% ci: 15.52 months to not reached) with cabozantinib (p = 0.61). The ttf was also similar at 6.90 months (95% ci: 4.60 months to 9.20 months) with nivolumab and 7.39 months (95% ci: 5.52 months to 12.85 months) with cabozantinib (p = 0.20). The adjusted hazard ratio (hr) for nivolumab compared with cabozantinib was 1.30 (95% ci: 0.73 to 2.3), p = 0.38. When adjusted by imdc criteria and age, the hr was 1.32 (95% ci: 0.74 to 2.38), p = 0.35.

Conclusions

Real-world imdc data indicate comparable os and ttf for nivolumab and cabozantinib. Both agents are reasonable therapeutic options for patients progressing after initial first-line vegfr-targeted therapy.

PROSPER: A phase III randomized study comparing perioperative nivolumab (nivo) versus observation in patients with localized renal cell carcinoma (RCC) undergoing nephrectomy (ECOG-ACRIN 8143)

TPS684

Background: The anti-PD-1 antibody nivo improves overall survival in metastatic RCC and is well tolerated. There is no standard adjuvant systemic therapy that increases overall survival (OS) over surgery alone for non-metastatic RCC. Priming the immune system prior to surgery with anti-PD-1 has shown an OS benefit compared to a pure adjuvant approach in mouse solid tumor models. The PROSPER RCC trial aims to improve clinical outcomes by priming the immune system prior to nephrectomy with neoadjuvant nivo and continued engagement with adjuvant blockade in patients with high risk M0 RCC compared to surgery alone. Methods: This global, unblinded, phase 3 National Clinical Trials Network study is currently accruing patients with clinical stage ≥T2 or node positive M0 RCC of any histology. Tumor biopsy prior to randomization is mandatory to ensure RCC and permits in depth correlative science. The investigational arm will receive two doses of nivo 240mg prior to surgery followed by adjuvant nivo for 9 months (q2 wks x 3 mo followed by 480mg q4 wks x 6 mo). The control arm will undergo standard nephrectomy followed by observation. Randomized patients are stratified by clinical T stage, node positivity, and histology. To enhance accrual and patient quality of life, key upcoming amendments are being instituted. These include biopsy only in the nivo arm, allowance of oligometastatic disease and bilateral renal masses that can be fully resected/ablated, and change of nivo dosing to q4 wks (1 neoadj; 9 adj). With accrual of 766 patients, there is 84.2% power to detect a 14.4% absolute benefit in recurrence-free survival (RFS) at 5 years assuming the ASSURE historical control of ~56% to 70% (HR = 0.70). The study is also powered to evaluate a significant increase in overall survival (HR 0.67). Safety, feasibility, and quality of life endpoints critical to adjuvant therapy considerations are incorporated. PROSPER RCC embeds a wealth of translational work aimed at investigating the impact of the baseline immune milieu, the changes induced by neoadjuvant anti-PD-1 priming, and how both correlate with clinical outcomes. Clinical trial information: NCT03055013.

Comprehensive and epidemiological characterization of urachal adenocarcinoma: A pan-Canadian collaboration

516

Background: Urachal cancer is a rare form of urothelial cancer representing 0,1-0,2% of bladder cancers. The exact underlying cause of urachal cancer is still widely unknown and there is much speculation on multiple factors such as genetic and environmental ones that may play a role. Moreover, given the lack of treatment consensus, we proposed the first study that assesses the clinical, genetic and molecular features of this disease in Canada. Methods: This ongoing study is recruiting in Canadian centers from the year 2005 onwards. The clinical database is constructed using the hospital electronic medical file. In addition, pathological tissues are centralized for molecular and genetic analysis. Results: To this date, 15 patients were included, 12 males and 3 females. Median age was of 49 years old with a disease distribution of Stage II (4), Stage III (3) and Stage IV (4). 8/15 patients developed metastasis after initial cystectomy in the lungs (n = 7), peritoneum (n = 2), lymph nodes (n = 4), and bone (1). Median survival of all patients was 23 months. Metastatic patients after cystectomy had a shorter overall survival (OS) of 21 months compared to non-metastatic patients (OS – not reached). The majority of metastatic patients (6/8) died of their underlying malignancy. Conclusions: This study is an ongoing country-wide effort to expand knowledge of this poorly studied disease. With ongoing accrual, the clinical features will be better defined and further molecular characterization will be performed to better predict response to therapy.

First-line (1L) immuno-oncology (IO) combination therapies in metastatic renal cell carcinoma (mRCC): Preliminary results from the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC)

584

Background: In mRCC, ipilimumab and nivolumab (ipi-nivo) is a 1L treatment option. Recent data have also shown efficacy of 1L PD(L)1-VEGF (PV) inhibitor combinations. The efficacy of these two strategies has not been compared. Methods: Using the IMDC dataset, patients (pts) treated with any 1L PV combination were compared to those treated with ipi-nivo. Multivariable Cox regression analysis was performed to control for imbalances in IMDC risk factors. Results: 164 pts received 1L IO combination therapy: 104 treated with PV combinations and 60 with ipi-nivo. Baseline characteristics and IMDC risk factors were comparable between groups (Table). When comparing PV combinations vs ipi-nivo, 1L response rates (RR) were 30% vs 39% (p = 0.29), time to treatment failure (TTF) was 13.2 (95% CI 8.3-16.1) vs 8.5 months (95% CI 5.7-14.0, p = 0.31), and median overall survival (OS) was not reached (NR) (95% CI 19.7-NR) vs NR (95% CI 27.6-NR, p = 0.39). When adjusted for IMDC risk factors, the hazard ratio (HR) for TTF was 0.77 (95% CI 0.44-1.35, p = 0.36) and the HR for death was 0.94 (95% CI 0.33-2.71, p = 0.91). Similar results were seen when restricting the cohort to IMDC intermediate/poor risk pts only. In pts receiving subsequent VEGF TKI monotherapy, second-line (2L) RR (13% vs 45%, p = 0.07) and TTF (5.5 vs 5.4 months, p = 0.80) for PV combinations (n = 15) vs ipi-nivo (n = 20) were not significantly different. Conclusions: There does not appear to be a superior 1L IO combination strategy in mRCC, as PV combinations and ipi-nivo have comparable RR, TTF and OS. Although there is a trend towards differences in RR, there does not appear to be a significant difference in TTF for patients receiving 2L VEGF TKI therapy. [Table: see text]

Real-world assessment of clinical outcomes among first-line (1L) sunitinib (SUN) patients (pts) with metastatic renal cell carcinoma (mRCC) by the international mRCC database consortium (IMDC) risk group

610

Background: Prognostic factors such as the IMDC criteria have included all types of targeted therapy. This study assesses clinical outcomes and provide benchmarks for mRCC pts treated specifically with 1L SUN in the real world to provide contemporary benchmarks for outcomes and survival. Methods: Clear cell mRCC pts initiating SUN as 1L therapy between 2010-2018 were included in a retrospective database study. Kaplan Meier analysis was used to estimate median time to treatment discontinuation (TTD) and overall survival (OS: time to death) by IMDC risk groups based on Karnofsky Performance Status < 80%, diagnosis to treatment interval < 1 year, anemia, neutrophilia, hypercalcemia and thrombocytosis. Results: Among 1,769 1L SUN pts with clear cell in the RW clinical database, 318 (18%) had favorable, 1,031 (58%) had intermediate and 420 (24%) had poor IMDC risk. Across the favorable, intermediate, and poor risk groups, pts had similar mean age in years, gender distribution, and year of SUN initiation (age: 63.8, 62.9 and 62.6; male: 74%, 75%, and 72%; SUN initiation year of 2010-2013: all 71%). In the favorable risk group, 99% received nephrectomy vs 88% in intermediate and 66% in poor risk group. Median TTD was 15.0, 8.5, and 4.2 months (mos) in the favorable, intermediate, and poor risk groups, respectively, and was 7.1 mos in the combined intermediate/poor risk groups. Median OS was 52.1, 31.5, and 9.8 mos in the favorable, intermediate, and poor risk groups, respectively, and was 23.2 mos in the combined intermediate/poor risk groups. Conclusions: This real world study based on a contemporary cohort of 1L SUN mRCC pts found a median OS of 52 mos which sets a new benchmark for clear cell mRCC in the favorable risk group. OS in the intermediate and poor risk groups are similar to previous reports. This affects pt counselling and clinical trial design.

Impact of body mass index (BMI) on treatment outcomes to immune checkpoint blockade (ICB) in metastatic renal cell carcinoma (mRCC)

566

Background: An elevated BMI is associated with improved survival in mRCC patients treated with oral targeted therapies (TT); however, this relationship in the contemporary treatment landscape is unknown. We investigated the effect of BMI on outcomes in mRCC patients treated with PD-1/PD-L1 ICB. Methods: We analyzed 147 patients with mRCC who received ICB alone or in combination with VEGF or other therapies. The association of BMI with objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) was evaluated using logistic and Cox regression models, adjusted for known prognostic factors including International Metastatic RCC Database Consortium (IMDC) risk groups, line of therapy, ECOG (0 vs ≥1), and histology. Results: Median follow up was 25.5 (4.3-78.6) months (mos). Median time on ICB was 5.1 ( < 0.1-69.7) mos. Overall, most patients were male (71%), had clear cell histology (85%), and were intermediate risk (60%). 43% received first-line ICB and 45% received ICB in combination therapy (37% with VEGF inhibition, 8% with other therapies). At ICB initiation, 46 (31%) patients were considered underweight/normal weight (BMI < 25 kg/m2), 56 (38%) overweight (BMI 25-30 kg/m2), and 45 (31%) obese (BMI > 30 kg/m2). Patients with high BMI (≥ 25) had improved OS (median 34.3 vs 16.7 mos, 2-yr OS 61 vs 42%, p = 0.016) compared to those with low BMI ( < 25), with an adjusted hazard ratio (HR) = 0.74 (0.44-1.26). ORR (33 vs 28%, p = 0.7) and PFS (median 8.2 vs 5.9 mos, p = 0.4) did not statistically differ. Patients who experienced a BMI change from ≥ 25 at start of first-line TT to < 25 at start of subsequent-line ICB displayed shorter OS (adjusted HR = 2.25 (0.94-5.35)) compared to those with no change. Conclusions: High BMI appears to be associated with improved OS in mRCC patients treated with ICB. This contemporary data is consistent with the “obesity paradox” demonstrated in the TT era. Validation with the IMDC database and examination of underlying mechanisms are ongoing.

Efficacy of targeted therapy (TT) after checkpoint inhibitors (CPI) in metastatic renal cell carcinoma (mRCC): Results from the Canadian Kidney Cancer Information System (CKCis)

568

Background: While the use of CPI has demonstrated clinical benefit in patients with mRCC, data showing the efficacy of subsequent TT is limited. This real-world analysis evaluated the efficacy of TT post CPI in mRCC patients. Methods: Data was collected and analyzed from CKCis. Patients with mRCC who received TT after CPI were identified and analyzed based on line of therapy. Time to treatment failure (TTF – time from starting first subsequent TT to stopping TT) and overall survival (OS) were calculated. Hazard Ratio (HR) calculations were adjusted for IMDC group and age. Results: 102 patients were treated with TT post CPI (table). Those who received first-line ipilimumab + nivolumab (I/N) versus a vascular endothelial growth factor inhibitor (VEGFi) + CPI combination prior to second-line TT had a median TTF of 8.0 vs 5.2 months (m) (HR=0.43, 95% CI: 0.13-1.44) and median OS of 16.5 m vs not reached (HR=0.76, 95% CI: 0.11-5.24). Patients who received a VEGFi versus a mammalian target of rapamycin inhibitor (mTORi) as third-line TT had a median TTF of 7.6 vs 4.4 m (HR=0.52, 95% CI: 0.24-1.10) and median OS of 21.7 vs 16.2 m (HR=0.41, 95% CI: 0.16-1.08). All third-line TT patients received first-line VEGFi and second-line nivolumab. Of the third-line VEGFi TT patients, 24 received axitinib (TTF 7.1 m, OS 21.7 m) and 22 received cabozantinib (data immature). Conclusions: Activity of TT in mRCC patients after CPI is demonstrated in multiple lines. In second-line, VEGFi TT had numerically better outcomes after I/N than after VEGFi+CPI combination. Efficacy of third-line TT was seen with a trend favoring VEGFi over mTORi. Axitinib in the third-line has notable activity after CPI, while data on cabozantinib and fourth-line TT are maturing. These results support the use of VEGFi after CPI in mRCC patients. [Table: see text]

Active Smoking Is Associated With Worse Prognosis in Metastatic Renal Cell Carcinoma Patients Treated With Targeted Therapies

BACKGROUND

Smoking increases the risk of developing renal cell carcinoma (RCC) but the effect of tobacco consumption on survival outcome of patients with metastatic RCC (mRCC) treated with targeted therapies has not been well characterized.

PATIENTS AND METHODS

The primary outcome was overall survival (OS) and secondary outcome was progression-free survival (PFS). Patients with mRCC were categorized as current, former, and nonsmokers at the time of starting targeted therapy. Smoking data from 1980 patients with mRCC treated with targeted therapy were collected through the International mRCC Database Consortium (IMDC) from 12 international cancer centers.

RESULTS

Although former and nonsmokers had comparable OS times (23.8 vs. 23.4 months; P = .898), current smokers had significantly shorter OS (16.1 months; P < .001) than nonsmokers. Current but not former smoking status was an independent poor prognosis factor (hazard ratio [HR], 1.3; P = .002) when adjusted for the IMDC risk criteria. Each pack-year increased the risk of death by 1% (HR, 1.01; P = .036). The duration of first-line therapy response was not different and was 7.7 months versus 7.5 months versus 6.4 months in never, former (P = .609), and current smokers (P = .839), respectively.

CONCLUSION

Active smoking is associated with diminished OS in mRCC patients treated with targeted therapy agents. However, patients who quit smoking returned to a similar risk of death from RCC compared with patients who never smoked. Smoking cessation should be a counseling priority among mRCC patients receiving targeted agents and smoking should be considered as a confounding factor in major clinical trials.