5056 Background: Resistance to androgen receptor (AR)-directed therapies is a major challenge in advanced prostate cancer, and enzalutamide shows limited activity after progression on abiraterone. Aberrant transforming growth factor-β (TGF-β) signaling promotes prostate cancer progression and contributes to resistance to AR-directed therapies. Preclinical studies suggest TGF-β inhibition may overcome resistance to enzalutamide. We hypothesized that combining TGF-β receptor I kinase inhibitor, galunisertib, with enzalutamide may delay enzalutamide resistance in patients with mCRPC who have progressed on abiraterone. Methods: This multicenter, randomized phase II trial enrolled chemotherapy-naïve mCRPC patients with disease progression on abiraterone. There was a cycle 1 safety run-in for the first 6 patients, followed by a randomized phase with patients assigned 3:2 to receive galunisertib plus enzalutamide or enzalutamide alone. The primary endpoint was radiographic progression-free survival (rPFS). Secondary endpoints included PSA response, overall survival (OS), safety, and tolerability. rPFS and OS were compared between arms using Cox regression, with medians estimated by Kaplan-Meier method. Results: Of 61 patients randomized, 60 received treatment: 23 with enzalutamide and 37 with galunisertib plus enzalutamide. There was no significant difference in rPFS between the combination and enzalutamide arms (HR 1.23; 95% CI: 0.72, 2.11; p =0.44), with a median rPFS of 5.6 and 7.3 months, respectively. The OS was also similar between the two groups (HR 1.00; 95% CI: 0.55, 1.83, p =1.00), with a median OS of 21.6 months in the combination arm and 24 months in the enzalutamide arm. PSA30 response was seen in 22% of patients in the combination arm vs. 35% in the enzalutamide arm ( p =0.30), and PSA50 response in 19% vs. 26%, respectively ( p =0.50). The most common treatment-related adverse events (AEs) were fatigue, anorexia, and nausea. Grade 3-4 treatment-related AEs occurred in 11% of patients in the combination arm vs. 13% in the enzalutamide arm. Conclusions: The addition of galunisertib to enzalutamide did not improve the rPFS, OS, or PSA response compared to enzalutamide alone in patients with chemotherapy-naïve mCRPC with disease progression on abiraterone. These findings do not support further development of galunisertib plus enzalutamide in patients with mCRPC. Clinical trial information: NCT02452008 . Baseline characteristics of randomized patients. N(n=61) Enzalutamide(n=24) Galunisertib + Enzalutamide (n=37) P Age, median (range) 51 72 (57, 84) 68 (53, 85) 0.06 Race, n (%) 58 1.00 White 17 (81.0) 30 (81.1) Other 4 (19.0) 7 (18.9) Ethnicity, n (%) 60 0.66 Hispanic 0 (0.0) 2 (5.4) Non-Hispanic 21 (91.3) 33 (89.2) Unknown 2 (8.7) 2 (5.4) ECOG, n (%) 55 0.16 0 12 (54.5) 24 (72.7) 1 10 (45.5) 9 (27.3) Baseline PSA, median (range) 60 11.1 (1.0, 2151.3) 18.2 (0.2, 522.4) 0.51

We present the case of a 64-year-old patient with metastatic renal cell carcinoma, who experienced disease progression despite undergoing multiple lines of systemic therapy, including immune checkpoint inhibitors (ICI). Two months after stereotactic radiosurgery to his brain lesions and while the patient was not on any systemic therapy, restaging scans demonstrated a dramatic near complete regression of the primary renal lesion and metastatic sites, which was attributed to the abscopal effect, mediated by the exposure to ICI and radiotherapy. While its mechanisms are not fully understood, it is believed to stem from the tumor immunosuppression and immunogenicity induced by radiation.

Cyclic high-dose testosterone administration, known as bipolar androgen therapy (BAT), is a treatment strategy for patients with metastatic castration-resistant prostate cancer (mCRPC). Here, we report the results of a multicenter, single arm Phase 2 study (NCT03554317) enrolling 45 patients with heavily pretreated mCRPC who received BAT (testosterone cypionate, 400 mg intramuscularly every 28 days) with the addition of nivolumab (480 mg intravenously every 28 days) following three cycles of BAT monotherapy. The primary endpoint of a confirmed PSA 50 response rate was met and estimated at 40% ( N = 18/45, 95% CI: 25.7–55.7%, P = 0.02 one-sided against the 25% null hypothesis). Sixteen of the PSA 50 responses were achieved before the addition of nivolumab. Secondary endpoints included objective response rate (ORR), median PSA progression-free survival, radiographic progression-free survival (rPFS), overall survival (OS), and safety/tolerability. The ORR was 24% ( N = 10/42). Three of the objective responses occurred following the addition of nivolumab. After a median follow-up of 17.9 months, the median rPFS was 5.6 (95% CI: 5.4–6.8) months, and median OS was 24.4 (95% CI: 17.6–31.1) months. BAT/nivolumab was well tolerated, resulting in only five (11%) drug related, grade-3 adverse events. In a predefined exploratory analysis, clinical response rates correlated with increased baseline levels of intratumoral PD-1 + T cells. In paired metastatic tumor biopsies, BAT induced pro-inflammatory gene expression changes that were restricted to patients achieving a clinical response. These data suggest that BAT may augment antitumor immune responses that are further potentiated by immune checkpoint blockade.

Background: Cyclical, high-dose testosterone administration, termed bipolar androgen therapy (BAT), can induce clinical responses and restore sensitivity to androgen signalling inhibition in patients with previously treated castration-resistant prostate cancer (PCa) (CRPC). This trial evaluated whether BAT is a safe and effective first-line hormonal therapy for patients with CRPC. Patients and Methods: In cohort C of this single-centre, open-label, phase II, multi-cohort trial (RE-sensitizing with Supraphysiologic Testosterone to Overcome REsistance study), 29 patients with CRPC received first-line hormonal therapy with 400 mg of testosterone cypionate intramuscularly every 28 days concurrent with a luteinising hormone-releasing hormone agonist/antagonist. The primary end-point of the study was the PSA50 response rate to BAT treatment. Results: After treatment with BAT, four of 29 patients (14%; 95% confidence interval [CI]: 4 e32%) experienced a PSA50 response. The median radiographic progression-free survival to BAT was 8.5 months (95% CI: 6.9-15.1) for patients with metastatic CRPC. After progression on BAT, 17 of 18 patients (94%; 95% CI: 73-100%) achieved a PSA50 response and 15 of 18 patients (83%; 95% CI: 59-96) achieved a PSA90 response on abiraterone or enzalutamide. Twelve of 15 patients (80%; 95% CI: 52-96) with metastatic CRPC remain on abiraterone or enzalutamide with a median duration of follow-up of 11.2 months. Conclusion: As first-line hormonal treatment for CRPC, BAT was well tolerated and resulted in prolonged disease stabilisation. After progression on BAT, patients had favourable responses to second-generation androgen receptoretargeted therapy. (C) 2020 Elsevier Ltd. All rights reserved.

5576 Background: A paradoxical inhibition of cell growth has been observed in both androgen-sensitive and castration resistant prostate cancer cell lines following the addition of high-dose testosterone.We have conducted several clinical trials investigating a mode of supraphysiologic testosterone therapy termed, BAT, in which testosterone levels are rapidly driven to the supraphysiologic range followed by a return to near-castrate levels over 28-day treatment cycles with favorable results. We previously reported the efficacy of BAT in mCRPC pts that were progressing on enza. In this study, we compared the effect of BAT in mCRPC pts whose last therapy was abi vs. enza. In addition, we examined the benefit of abi or enza rechallenge after progression on BAT. Methods: 59 mCRPC pts (n = 29 post abi; n = 30 post enza) were enrolled and received at lease one dose of BAT monotherapy, 400mg intramuscularly every 28 days. After clinical or radiographic progression on BAT, pts were rechallenged with the AR targeted therapy to which they were most recently resistant. The co-primary endpoints were a 50% decline in PSA from baseline (PSA50) for BAT and for enza/abi rechallenge. Results: 5/29 (17.2%) of post-abi pts compared to 9/30 (30%) in the post enza group achieved a PSA50 response (P = 0.36). Post BAT rechallenge with abi (n = 19) or enza (n = 22) resulted in a PSA50 response rate of 15.8% (n = 3) and 68.2% (n = 15), respectively (P = 0.001). The total duration of benefit (i.e. PFS on BAT + PFS on rechallenge = “PFS2”) was significantly longer in the post enza vs. post-abi patients (Median PFS2: 12.75 vs. 8.125 months; P = 0.04. Lastly, AR-V7 negative (n = 42) pts has a significantly longer median PFS2 compared to AR-V7 positive (n = 10) pts. (10.3 vs. 7.1 months, P = 0.005). Conclusions: Our data suggest that BAT may be more effective at resensitizing mCRPC to direct AR antagonists (i.e. enza) compared to abi. Detection of AR-V7 portended a worse outcome on BAT/rechallenge. Further clinical study is warranted. Clinical trial information: NCT02090114 . [Table: see text]

The challenges of managing the toxicities associated with the current armamentarium to combat kidney cancer continue to grow. It is therefore paramount for providers to not only have knowledge of the disease, but to also have an understanding of the potential adverse effects associated with the various treatments. In addition, it is important to incorporate palliative care strategies to help manage symptoms, improve quality of life, and support patients and their families throughout the continuum of the disease. This article will discuss the general toxicities and symptomatic issues encountered in patients with kidney cancer who are receiving targeted therapies and immunotherapies. It will also define the components of palliative care and its benefits. The recommendations in this article are from source documentation noted in various guidelines of the Oncology Nursing Society, ASCO, the National Comprehensive Cancer Network, and the Society for Immunotherapy of Cancer. We feel it is appropriate to modify and individualize management as deemed necessary to provide the best outcome for patients and their families.

Background Prostate cancer that progresses after enzalutamide treatment is poorly responsive to further antiandrogen therapy, and paradoxically, rapid cycling between high and low serum testosterone concentrations (bipolar androgen therapy [BAT]) in this setting might induce tumour responses. We aimed to evaluate BAT in patients with metastatic castration-resistant prostate cancer that progressed after enzalutamide. Methods We did this single-centre, open-label, phase 2, multicohort study in the USA. We included patients aged 18 years or older who had histologically confirmed and radiographically documented metastatic castration-resistant prostate cancer, with no more than two previous second-line hormonal therapies, and a castrate concentration of testosterone. Patients were asymptomatic, with Eastern Cooperative Oncology Group performance status of 0-2, and did not have high-risk lesions for tumour flare (eg, > 5 sites of visceral disease or bone lesions with impending fracture). For the cohort reported here, we required patients to have had progression on enzalutamide with a continued prostate-specific antigen (PSA) rise after enzalutamide treatment discontinuation. Patients received BAT, which consisted of intramuscular testosterone cipionate 400 mg every 28 days until progression and continued luteinising hormone-releasing hormone agonist therapy. Upon progression after BAT, men were rechallenged with oral enzalutamide 160 mg daily. The co-primary endpoints were investigator-assessed 50% decline in PSA concentration from baseline (PSA 50) for BAT (for all patients who received at least one dose) and for enzalutamide rechallenge (based on intention-to-treat analysis). These data represent the final analysis for the post-enzalutamide cohort, while two additional cohorts (post-abiraterone and newly castration-resistant prostate cancer) are ongoing. The trial is registered with ClinicalTrials.gov, number NCT02090114. Findings Between Aug 28, 2014, and May 18, 2016, we accrued 30 eligible patients and treated them with BAT. Nine (30%; 95% CI 15-49; p<0.0001) of 30 patients achieved a PSA 50 to BAT. 29 patients completed BAT and 21 proceeded to enzalutamide rechallenge, of whom 15 (52%; 95% CI 33-71; p<0.0001) achieved a PSA(50) response. During BAT, the only grade 3-4 adverse event occurring in more than one patient was hypertension (three [10%] patients). Other grade 3 or worse adverse events occurring during BAT in one [3%] patient each were pulmonary embolism, myocardial infarction, urinary obstruction, gallstone, and sepsis. During enzalutamide retreatment, no grade 3-4 toxicities occurred in more than one patient. No treatment-related deaths were reported during either BAT or enzalutamide retreatment. Interpretation BAT is a safe therapy that resulted in responses in asymptomatic men with metastatic castration-resistant prostate cancer and also resensitisation to enzalutamide in most patients undergoing rechallenge. Further studies with BAT are needed to define the potential clinical role for BAT in the management of metastatic castration-resistant prostate cancer and the optimal strategy for sequencing between androgen and antiandrogen therapies in metastatic castration-resistant prostate cancer to maximise therapeutic benefit to patients.

5017 Background: Androgen receptor (AR) overexpression is a common adaptive resistance mechanism in mCRPC. High dose testosterone in this setting may induce tumor responses and restore normal AR expression. To evaluate BAT, we enrolled men with mCRPC progressing on enza to assess (1) responses to BAT and (2) enza re-challenge after BAT. Methods: Eligible men had minimally symptomatic mCRPC with progression on enza. Subjects received testosterone cypionate 400mg IM every 28d and continued gonadal suppression, until progression. Subjects were evaluated with PSAs each cycle, and CT/bone scans every 3 cycles. Upon progression on BAT, men were re-challenged with enza. The co-primary endpoints were > 50% PSA responses (PSA50) to BAT and PSA50 to enza re-challenge. The null hypothesis was a PSA50 rate of 5% for both endpoints, with alternative hypotheses of 20% to BAT and 25% to enza. 30 subjects were required for 90% and 83% power, respectively, with overall type 1 error of 0.1. Secondary endpoints were safety, objective response, progression-free survival (PFS), and effect on circulating tumor cell-based AR and AR-V7 expression. Results: 30 eligible subjects were accrued (2014-2016). No dose limiting toxicities were seen. 2 subjects had transient pain flares after BAT initiation. Common grade 1-2 adverse events (AE) were musculoskeletal pain (40%), increased hemoglobin (37%), breast tenderness (17%) and rash (17%). 3 Grade 3-4 AE potentially attributable to BAT occurred (pulmonary embolism, NSTEMI, and urinary obstruction). 9/30 men (30% [95% CI: 17-48%]) achieved a PSA50 to BAT. 5/14 men (36%) with measurable disease had an objective response by RECIST 1.1. The median clinical/radiographic PFS on BAT was 8.6 months. 21 subjects proceeded to enza re-challenge, yielding 15 PSA50 responses (54% by intention to treat [95% CI: 34-69%]), with a PFS of 4.8 months. 1/3 AR-V7+ subjects responded to BAT, and all had decreased AR-V7/AR ratios (2 converted to AR-V7-) after 3 cycles. Conclusions: The study met its primary endpoints, demonstrating preliminary efficacy of BAT in men with progressive mCRPC after enza. A randomized study comparing BAT to enza in mCRPC is ongoing. Clinical trial information: NCT02090114.

539 Background: Based on a single phase 3 study, the mTOR inhibitor tem was approved as 1st line therapy for prmRCC. However, in daily practice, prmRCC pts are often treated with the VEGFR and PDGFR inhibitor su. We aimed to compare the clinical effectiveness of su vs tem in prmRCC pts. Methods: We performed an international multicenter retrospective study of pts with prmRCC (HENG criteria), who were treated in 8 centers across 2 different countries. 31 pts were treated with 1st line tem. Each tem treated pt was individually matched with a 1st line su treated pt, by clinicopathologic factors. The effect of tx type (tem vs su) on clinical benefit, progression free survival (PFS) and overall survival (OS), was tested using a chi-square test and partial likelihood test from cox model. Furthermore, univariate and multivariate analyses of association between clinicopathologic factors and tx type (tem vs su), and outcome were performed using the entire pt cohort (n=62). Results: The groups were matched by age (median 65), gender (male 68%), prior nephrectomy (58%), renal cell carcinoma histology (clear cell 81%), smoking status (active in 35%), use of angiotensin system inhibitors (42%), and pre-tx neutrophil to lymphocyte ratio >3 (58%). In tem vs su treated pts, clinical benefit (partial response + stable disease) was 61% (n=19) (partial response 6%, n=2) vs 71% (n=22) (partial response 29%, n=9) (p=0.62). Median PFS was 5 vs 8 mos (p=0.08), and median OS 9 vs 17 mos (p=0.03). In multivariate analyses of the entire pt cohort (n=62), su tx was independently associated with OS (HR 0.6, p=0.001). Conclusions: In prmRCC patient, the VEGFR inhibitor su may be associated with an improved outcome vs the mTOR inhibitor tem.

260 Background: Abi is a standard treatment (tx) in CN-pts with mCRPC. It is a potent and selective CYP 17 inhibitor. However, in many countries where abi has not been approved yet, keto is used as an alternative CYP 17 inhibitor. Preclinical data suggests that keto is a less specific and potent inhibitor of CYP 17. Clinical data (Peer et al, Prostate 2014) suggests that in docetaxel (D) refractory mCRPC, the outcome of abi tx may be superior to keto. However, there are limited clinical data comparing both agents in CN-pts with mCRPC. We aimed to compare the clinical effectiveness of abi vs keto in CN-pts with mCRPC, who were treated after the year 2004 (approval of D for the tx of mCRPC). Methods: Records from 72 CN-pts with mCRPC treated with abi in 5 Israeli centers were reviewed retrospectively, and matched by pre-tx risk category (favorable, intermediate, poor; Keizman, Oncologist 2012) to pts treated with keto 200 - 400 mg 3x day (international database, n = 156, from 4 centers across the US and Israel). We compared the PSA response (decrease ≥ 50% from baseline), biochemical and radiological progression free survival (PFS), and overall survival (OS) between the groups. PFS and OS were determined by Cox regression. Results: The groups were matched by pre-tx risk category (favorable, intermediate, poor; Keizman, Oncologist 2012), based on pretreatment NLR and PSA doubling time, and the prior response to a gonadotropin-releasing hormone agonist. The groups were balanced regarding age (72 abi vs 70 keto), time from primary tx to disease relapse, gleason score, pre-tx disease extent (limited-axial skeleton and/or nodal vs extensive- appendicular skeleton and/or visceral), and ECOG PS. In the groups of abi vs keto, PSA response was 75% vs 47% (OR 3.8, p = 0.04), median biochemical PFS 12 vs 6 months (HR 0.62, p = 0.03), median radiological PFS 16 vs 8 months (HR 0.54, p = 0.01), median OS not reached after a median follow-up time of 18 months vs 26 months, and tx interruption d/t adverse events 10% vs 22% (0R 0.65, p = 0.05). Conclusions: In CN-pts with mCRPC, the outcome of pts treated with abi may be superior to keto.

440 Background: Sunitinib (Su) is a standard treatment (tx) for metastatic renal cell carcinoma (mRCC). Pre-clinical and clinical studies in several cancer types suggest that the antidiabetic agent metformin (Met) has antitumor activity. Met may negatively regulate mTOR activity. Its effect on the outcome of targeted therapies in mRCC is poorly defined. We analyzed the effect of Met use on the outcome sunitinib tx in diabetic patients (pts) with mRCC. Methods: We performed a retrospective study of an unselected cohort of diabetic pts with mRCC, who were treated with Su in 7 centers across 2 countries. Pts were divided into 2 groups: (1) Met users and (2) Met naive. The effect of Met use on response rate (RR), progression free survival (PFS) and overall survival (OS), was tested with adjustment of other known confounding risk factors using a chisquare test and partial likelihood test from Cox model. Furthermore, univariate and multivariate analyses of association between clinicopathologic factors and Met use, and outcome were performed using the entire pt cohort. Results: Between 2004-2014, 108 diabetic pts with mRCC were treated with sunitinib. There were 52 Met users (group 1) and 56 nonusers (group 2). The groups were balanced regarding the following clinicopathologic factors: age, gender, HENG risk, past nephrectomy, mRCC histology, ≥2 metastatic sites, lung/liver/bone metastasis, prior targeted tx, smoking status, use of angiotensin system inhibitors (ASIs), pre-tx neutrophil to lymphocyte ratio (NLR) >3, Su-induced hypertension (HTN), and Su dose reduction/tx interruption. Clinical benefit (partial response + stable disease) in group 1 vs. group 2 was 96% vs. 84%, while 4% vs. 16% had disease progression within the first 3 months of tx (p=0.054). Median PFS was 15 vs. 11.5 months (p=0.1). Median OS was 32 vs. 21 months (p=0.001). In multivariate analyses of the entire pt cohort (n=108), factors associated with PFS were active smoking (HR=2.7, p<0.0001) and pre-tx NLR >3 (HR 1.8, p=0.012). Factors associated with OS were Met use (HR 0.2, p<0.0001), HENG risk (HR 3.3, p=0.008), active smoking (HR=2.9, p<0.0001), liver metastases (HR 1.8, p=0.004), and pre-tx NLR >3 (HR 3.3, p<0.0001). Conclusions: Met use may improve the OS of diabetic pts with mRCC that are treated with Su.

538 Background: Su is a standard treatment (tx) for mRCC. Octogenarian pts (aged ≥ 80) are often considered to be unfit for su tx, and recommendations for their tx is limited by the paucity of clinical trials data in this population. We aimed to study baseline characteristics and outcome of octogenarian vs young (aged ≤45) pts with mRCC treated with su. Methods: We performed an international multicenter retrospective study of pts with mRCC, who were treated with su in 8 centers across 2 different countries. We compared baseline characteristics and outcome of octogenarian versus young pts. The effect of very old age on response rate (RR), progression free survival (PFS) and overall survival (OS), was tested with adjustment of other known confounding risk factors using a chi-square test and partial likelihood test from cox model. Furthermore, univariate and multivariate analyses of association between clinicopathologic factors and age, and outcome were performed using the entire pt cohort. Results: Between 2004-2013, 36 octogenarian (group 1; median age 83) and 37 young (group 2; median age 42) mRCC were treated with su. The groups were balanced regarding the following baseline clinicopathologic characteristics: gender, HENG risk, past nephrectomy, mRCC histology, ≥ 2 metastatic sites, lung/liver/bone metastasis, prior targeted tx, smoking status, use of angiotensin system inhibitors (ASIs), pre-tx neutrophil to lymphocyte ratio (NLR) >3, and sunitinib induced hypertension (HTN). In group 1 vs 2, 53% vs 27% (p=0.006) had dose reduction/treatment interruption d/t side effects. Clinical benefit (partial response + stable disease) in group 1 vs 2 was 76% vs 84%, while 24% vs 16% had disease progression within the first 3 months of tx (p=0.09). Median PFS was 11 vs 8 months (p=0.1). Median OS was 22 vs 20 months (p=0.7). In multivariate analyses of the entire pt cohort (n=73), age was not significantly associated with PFS or OS. Conclusions: Su is active in octogenarian mRCC pts. Vs young pts, a significantly higher proportion of octogenarian pts had dose reduction/treatment interruption d/t side effects.

BACKGROUND Sunitinib is a standard treatment for metastatic clear cell renal cell carcinoma (mccRCC). Data on its activity in the rare variant of metastatic chromophobe renal cell carcinoma (mchRCC), are limited. We aimed to analyze the activity of sunitinib in a relatively large and homogenous international cohort of mchRCC patients in terms of outcome and comparison with mccRCC. METHODS Records from mchRCC patients treated with first-line sunitinib in 10 centers across 4 countries were retrospectively reviewed. Univariate and multivariate analyses of association between clinicopathologic factors and outcome were performed. Subsequently, mchRCC patients were individually matched to mccRCC patients. We compared the clinical benefit rate, progression-free survival (PFS), and overall survival (OS) between the groups. RESULTS Between 2004 and 2014, 36 patients (median age, 64 years; 47% male) with mchRCC were treated with first-line sunitinib. Seventy-eight percent achieved a clinical benefit (partial response + stable disease). Median PFS and OS were 10 and 26 months, respectively. Factors associated with PFS were the Heng risk (hazard ratio [HR], 3.3; p = .03) and pretreatment neutrophil-to-lymphocyte ratio (NLR) >3 (HR, 0.63; p = .02). Factors associated with OS were the Heng risk (HR, 4.1; p = .04), liver metastases (HR, 3.8; p = .03), and pretreatment NLR <3 (HR, 0.55; p = .03). Treatment outcome was not significantly different between mchRCC patients and individually matched mccRCC patients. In mccRCC patients (p value versus mchRCC), 72% achieved a clinical benefit (p = .4) and median PFS and OS were 9 (p = .6) and 25 (p = .7) months, respectively. CONCLUSION In metastatic chromophobe renal cell carcinoma, sunitinib therapy may be associated with similar outcome and toxicities as in metastatic clear cell renal cell carcinoma. The Heng risk and pretreatment NLR may be associated with PFS and OS. IMPLICATIONS FOR PRACTICE Data on the activity of sunitinib in metastatic chromophobe renal cell carcinoma (mchRCC) are limited. This study analyzed the activity of sunitinib in a cohort of mchRCC patients. Of 36 patients with mchRCC who were treated with first-line sunitinib, 78% achieved a clinical benefit. Median PFS and OS were 10 and 26 months, respectively. Treatment outcome was not significantly different between mchRCC patients and individually matched metastatic clear cell RCC patients.

BACKGROUNDPrognostic factors associated with clinical outcomes in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with a novel androgen receptor-directed therapies (ARDT) in the second line setting has not been formally evaluated.PATIENTS AND METHODSWe retrospectively reviewed and analyzed medical records of all patients with mCRPC who received sequential treatment with ARDT. We analyzed potential clinical factors associated with post treatment endpoints including 50% decline in prostatic-specific antigen (PSA), PSA-progression-free survival (PFS), clinical or radiographic PFS and overall survival (OS). Prognostic univariate and multivariate Cox proportional hazard models were developed and assessed.RESULTSOne hundred twenty-six patients with mCRPC treated with a second-line novel ARDT were included. Overall, 50% decline in PSA was observed in 22% of patients and a median PSA-PFS of 2.9 months and a PFS of 3.6 months. After adjusting for potential confounders including prior exposure to docetaxel and number of prior antiandrogen agents, time to development of CRPC was an independent factor associated with PSA-PFS (hazard ratio [HR]: 0.99; 95% confidence interval [CI]: 0.99-1; P=0.02) and PFS (HR: 0.99; CI: 0.98-1; P=0.01). PSA response (50% decline) to first-line novel ARDT correlated negatively with PSA-PFS with second-line novel ARDT (HR: 1.7; 95% CI: 1.14-2.53; P=0.009) and lower pre-treatment levels of albumin were associated with shorter PFS (HR: 0.56; 95% CI: 0.32-0.97; P=0.03). Performance status, pre-treatment levels of albumin, extent of disease and time to development CRPC were associated with OS.CONCLUSIONSSecond-line ARDT is associated with modest outcomes in patients with mCRPC. Time to development of CRPC is the strongest predictor of PSA response, PSA-PFS and OS which suggest that intrinsic resistance to AR directed treatment is the major treatment outcome factor in these patients. Future studies in patients receiving long term ARTD should include the identification of predictive biomarkers to facilitate treatment selection. Prostate 76:512-520, 2016. (c) 2015 Wiley Periodicals, Inc.

429 Background: Sunitinib (Su) is a standard therapy (tx) for mccRCC. Data on its activity in the rare variant of metastatic chromophobe renal cell carcinoma (mchRCC) are limited by very small or heterogeneous (mixed histology with papillary type, or mixed targeted therapies) studies. We analyzed the activity of Su in a relatively large and homogenous international cohort of mchRCC pts, in terms of outcome and comparison to mccRCC. Methods: Records from mchRCC pts treated with first-line Su in 9 centers across 4 countries were retrospectively reviewed. Univariate and multivariate analyses of association between clinicopathologic factors and outcome were performed. Subsequently, mchRCC pts were individually matched to mccRCC pts. We compared the response rate (RR), progression free survival (PFS), and overall survival (OS) between the groups. Results: Between 2004-2014, 33 pts (median age 64, 45% male) with mchRCC were treated with Su as first-line tx. 76% had a prior nephrectomy. HENG risk was good 27%, intermediate 55%, and poor 18%. 33% were active smokers, and 30% users of angiotensin system inhibitors (ASIs). 55%, 27%, and 33% had lung, liver, and bone metastases, respectively. 48% had a pre-tx neutrophil to lymphocyte ratio (NLR) >3. 42% had dose reduction/tx interruption (DR/TI). Su-induced hypertension (HTN) occurred in 48%. 75% achieved a clinical benefit (partial response + stable disease), while 25% had disease progression within the first 3 months of tx. Median PFS and OS were 10 and 26 months, respectively. Factors associated with PFS were the HENG risk (HR 3.8, p=0.025) and pre-tx NLR >3 (HR 0.6, p=0.012). Factors associated with OS were the HENG risk (HR 4.27, p=0.027), liver metastases (HR 4.6, p=0.029), and pre-treatment NLR <3 (HR 0.5, p=0.04). Tx outcome was not significantly different between mchRCC pts and mccRCC pts, who were individually matched by HENG risk, nephrectomy/smoking status, pre-tx NLR, use of ASIs, DR/TI, and Su induced HTN. In mccRCC pts (p value versus mchRCC), 70% achieved a clinical benefit (p=0.58), and median PFS and OS were 9 (p=0.7) and 24 (p=0.6) months, respectively. Conclusions: In mchRCC pts, Su tx may have similar outcome to mccRCC pts.

e15619 Background: Su is a standard tx for mccRCC. Data on its activity in the rare variant of mchRCC, is limited by very small or heterogeneous (mixed histology with papillary type, or mixed targeted therapies) studies. We analyzed the activity of Su in a relatively large and homogenous international cohort of mchRCC pts, in terms of outcome and comparison to mccRCC. Methods: Records from mchRCC pts treated with 1st line Su in 9 centers across 4 countries were retrospectively reviewed. Univariate and multivariate analyses of association between clinicopathologic factors and outcome were performed. Subsequently, mchRCC pts were individually matched to mccRCC pts. We compared the response rate (RR), progression free survival (PFS), and overall survival (OS) between the groups. Results: Between 2004-2014, 33 pts (median age 64, 45% male) with mchRCC were treated with Su as 1st line tx. 76 …

e15550 Background: Targeted txs are the tx of choice in most mRCC pts. However, HDIL2 which may produce durable responses in a small percentage of cases, is still an option in carefully selected pts. While the effect of prior HDIL2 on the outcome of targeted txs in mRCC pts is poorly defined, a recent single center report (Birkhäuser FD, Cancer J 2013) revealed an improved disease-specific survival in pts treated with prior HDIL2. We aimed to study the effect of prior HDIL2 tx on outcome of mRCC pts treated with sunitinib. Methods: Records from 302 mRCC pts treated with Su from 2004 to 2013 in 9 centers across 2 countries were retrospectively reviewed. We compared the response rate, progression free survival (PFS), and overall survival (OS), between post HDIL2 pts (n=27) and individually matched tx naïve pts (n=27). Progression free survival and overall survival were determined by Cox regression. Results: All pts had prior nephrectomy and clear cell histology. The groups were matched by age (median 61), gender (male 74%), Heng risk (favorable 37%, intermediate 59%, poor 4%), sunitinib induced hypertension (67%), sunitinib dose reduction/treatment interruption (41%), smoking status (active 7%), use of angiotensin system inhibitors (41%), the presence of more than one metastases site (96%), and pre-tx neutrophil to lymphocyte ratio (> 3 in 22%). Furthermore, they were balanced regarding the presence of lung (68%), liver (31%), and bone (43%) metastases, and the use of bisphosphonates (32%). In prior HDIL2 versus tx naïve pts, objective response was partial response/stable disease 89% (n=24) versus 74% (n=20), and progressive disease at first imaging evaluation within the first 3 months (mos) 11% (n=3) versus 26% (n=7) (p=0.29, OR 2.4). Median progression free survival was 21 versus 12 mos (HR 2.3, p=0.005), and median overall survival 25 versus 20 mos (HR 2.2, p=0.013). Conclusions: In metastatic renal cell carcinoma patients treated with sunitinib, prior high dose IL-2 therapy may improve the outcome.

486 Background: The VEGFR inhibitor sunitinib is a standard tx for metastatic clear cell RCC. Data on the activity of sunitinib in metastatic non clear cell RCC, is limited by small or heterogeneous (mixed histology or targeted therapies) studies, that revealed a lower antitumor activity than in patients with clear cell histology. We aimed to analyze the activity of sunitinib in a large international cohort of patients with metastatic papillary RCC, and to characterize patients who may benefit for this therapy. Methods: Records from metastatic papillary RCC patients treated with sunitinib in 10 centers across 3 countries were retrospectively reviewed. Univariate and multivariate analyses of association between clinicopathologic factors and clinical outcome were performed using Cox regression. Results: Between 2004-2013, 74 patients (median age 60, 68% male) with metastatic papillary RCC were treated with sunitinib. 78% had a prior nephrectomy. HENG risk was good 11%, intermediate 56%, and poor 33%. 21% were active smokers, and 31% users of angiotensin system inhibitors. 24% and 41% had liver and bone metastases, respectively. 55% had a pre-treatment neutrophil to lymphocyte ratio (NLR) >3. 40% had dose reduction/treatment interruption. Sunitinib induced hypothyroidism and hypertension (HTN) occurred in 30% and 43%, respectively. 70% achieved a clinical benefit (partial response + stable disease), while 30% had disease progression within the first 3 months of therapy. Median progression free survival (PFS) and overall survival (OS) were 5 and 12 months, respectively. 27% had a PFS ≥ 1 year, and 26% survived ≥ 2 years. Factors associated with PFS were sunitinib induced HTN (HR 0.31, p=0.002), pre-treatment NLR >3 (HR 5.3, p=0.001), and active smoking (HR 2.5, p=0.01). Factors associated with OS were sunitinib induced hypothyroidism (HR 0.4, p=0.024), past nephrectomy (HR 0.41, p=0.02), pre-treatment NLR >3 (HR 2.25, p=0.036), and active smoking (HR 2.3, p=0.027). Conclusions: Clinicopathologic factors may be used to identify patients with metastatic papillary RCC who may benefit from sunitinib tx. A prolonged PFS and OS were noted in 26-27% of patients.

256 Background: Standard treatment options for patients (pts) with metastatic castrate-resistant prostate cancer (mCRPC) include docetaxel based chemotherapy, abiraterone, and radium 223. Octogenarian pts (age 80 and older) are often considered to be unfit for chemotherapy. However, recommendations for their management is limited by the paucity of clinical trials data in this population. In countries where abiraterone in the pre-chemotherapy setting has not been approved yet, or for pts who can’t afford it, the CYP 17 inhibitor ketoconazole is used as an alternative advanced hormonal tx. We aimed to study baseline characteristics and outcome of octogenarian versus young (age 60 or younger) pts with mCRPC treated with ketoconazole. Methods: We performed an international multicenter retrospective study of pts with mCRPC, who were treated with ketoconazole at four centers across two different countries. We compared baseline characteristics and outcome of octogenarian versus young pts. The effect of very old age on prostate-specific antigen (PSA) response, progression free survival (PFS), and overall survival (OS), was tested with adjustment of other known confounding risk factors using a chi-square test and partial likelihood test from Cox model. Results: Between 2004 and 2013, 35 octogenarians (median age 83) and 33 young pts with (median age 57) mCRPC were treated with ketoconazole. The groups were balanced regarding the following baseline clinicopathologic characteristics: extent of disease (limited-axial skeleton and/or nodal versus extensive-appendicular skeleton and/or visceral), combined gleason score, pre-treatment risk category (Keizman, Oncologist 2012; based on pre-tx neutrophil to lymphocyte ratio/prostate-specific antigen doubling time, and prior response to ADT), pain intensity, ECOG performance status, alkaline phosphatase level, hemoglobin level, PSA level. In octogenarian versus young pts, PSA response (greater than or equal to 50% decline from baseline) was 40% versus 61% (OR 3.5, p=0.04), median PFS 7 versus 8 months (HR 0.91, p=0.44), and median OS 31 versus 36 months (HR 0.66, p=0.31). Conclusions: In very old vs young mCRPC patients treated with ketoconazole, PSA response was lower. Baseline clinicopathologic characteristics, PFS, and OS were not significantly different between the groups.

Prostate cancer survivors approach 2.8 million in number and represent 1 in 5 of all cancer survivors in the United States. While guidelines exist for timely treatment and surveillance for recurrent disease, there is limited availability of guidelines that facilitate the provision of posttreatment clinical follow-up care to address the myriad of long-term and late effects that survivors may face. Based on recommendations set forth by a National Cancer Survivorship Resource Center expert panel, the American Cancer Society developed clinical follow-up care guidelines to facilitate the provision of posttreatment care by primary care clinicians. These guidelines were developed using a combined approach of evidence synthesis and expert consensus. Existing guidelines for health promotion, surveillance, and screening for second primary cancers were referenced when available. To promote comprehensive follow-up care and optimal health and quality of life for the posttreatment survivor, the guidelines address health promotion, surveillance for prostate cancer recurrence, screening for second primary cancers, long-term and late effects assessment and management, psychosocial issues, and care coordination among the oncology team, primary care clinicians, and nononcology specialists. A key challenge to the development of these guidelines was the limited availability of published evidence for management of prostate cancer survivors after treatment. Much of the evidence relies on studies with small sample sizes and retrospective analyses of facility-specific and population databases.