Motzer, Robert J.

4505 Background: While inhibiting VEGF improves outcomes in mRCC pts, most develop resistance, often within a year. Here, we report results from a Ph II study of atezo (anti–PD-L1) and bev (anti-VEGF) vs and following atezo or sun (TKI) in mRCC pts. Methods: Pts with untreated mRCC were enrolled in the hypothesis generating IMmotion150 study (NCT01984242) and randomized to atezo 1200 mg IV q3w + bev 15 mg/kg IV q3w, atezo alone or sun 50 mg PO QD 4 wk on/2 wk off. After progression on atezo or sun, crossover to atezo + bev was allowed. PD-L1 status was scored on tumor-infiltrating immune cells (IC, SP142 IHC assay). The primary analysis was modified prior to final analysis to reflect the coprimary endpoints of IRF-assessed PFS (RECIST v1.1) in ITT pts and pts with PD-L1 expression on ≥ 1% of IC (PD-L1+). Results: 54% of pts were PD-L1+. In PD-L1+ pts 1L treatment resulted in a PFS hazard ratio (HR) of 0.64 for atezo + bev vs sun (table). After 1L treatment, 78% of sun and 60% of atezo pts who progressed subsequently received atezo + bev and achieved ORRs of 28% and 24%, respectively (table). Safety was comparable to the known individual profiles of atezo and bev. Additional clinical, safety and biomarker data will be presented. Conclusions: Atezo + bev resulted in encouraging antitumor activity in 1L pts with PD-L1+ mRCC. Preliminary activity in the 2L setting was demonstrated in pts who crossed over to atezo + bev, regardless of prior therapy. 1L atezo + bev vs sun is being evaluated in the ongoing Ph III study IMmotion151 (NCT02420821). Clinical trial information: NCT01984242. [Table: see text]

SNF'ing out antitumor immunity Immune checkpoint inhibitors induce durable tumor regressions in some, but not all, cancer patients. Understanding the mechanisms that determine tumor sensitivity to these drugs could potentially expand the number of patients who benefit (see the Perspective by Ghorani and Quezada). Pan et al. discovered that tumor cells in which a specific SWI/SNF chromatin remodeling complex had been experimentally inactivated were more sensitive to T cell–mediated killing. The cells were more responsive to interferon-γ, leading to increased secretion of cytokines that promote antitumor immunity. Miao et al. examined the genomic features of tumors from patients with metastatic renal cell carcinoma who had been treated with immune checkpoint inhibitors. Tumors harboring inactivating mutations in PBRM1 , which encodes a subunit of the same SWI/SNF complex, were more likely to respond to the drugs. Science , this issue p. 770 , p. 801 ; see also p. 745

522 Background: In the METEOR study (NCT01865747), cabo demonstrated improved progression-free survival (median 7.4 vs. 3.8 mo; HR 0.58, 95% CI 0.45–0.74; p<0.0001), OS (median 21.4 vs. 16.5 mo; HR 0.66, 95% CI 0.53-0.83, p=0.0003), and objective response rate (17% vs. 3%; p<0.0001) compared with eve in patients (pts) with advanced RCC who had received prior VEGFR TKI therapy (Choueiri NEJM 2015, Lancet Oncol 2016). Here we evaluate the impact of changes in target lesion size from baseline on OS. Methods: 658 pts were randomized 1:1 to receive cabo (60 mg qd) or eve (10 mg qd). Stratification factors were MSKCC risk group and number of prior VEGFR TKIs. Target lesion size was assessed per independent radiology review by CT/MRI scans at baseline, every 8 weeks for the first 12 months, and every 12 weeks thereafter. Three subgroups were defined by best change in target lesion size from baseline: decrease ≥30%, decrease <30%, and any increase. Results: The rate of target lesion regression was higher in the cabo arm (75%) compared with the eve arm (48%). A higher fraction of pts had a decrease ≥30% in target lesion size in the cabo arm, while a higher fraction of pts had an increase in target lesion size in the eve arm (Table). Medians for OS with cabo were not estimable (NE) (95% CI, NE‒NE), 20.8 mo (95% CI, 18.1‒NE), and 11.1 mo (95% CI, 7.6‒15.2) for the ≥30% decrease, <30% decrease, and any increase subgroups, respectively. Medians for OS with eve were NE (95% CI, 19.3‒NE), 18.0 mo (95% CI, 15.9‒20.4), and 14.0 mo (95% CI, 10.5‒16.3) for the ≥30% decrease, <30% decrease, and any increase subgroups, respectively. Median duration of follow-up for OS was 18.7 mo (IQR 16.1–21.1) for cabo and 18.8 mo (16.0–21.2) for eve. A higher proportion of pts received subsequent anticancer therapy in the any increase subgroup compared with the other subgroups. Conclusions: Cabo demonstrated a higher rate of tumor target lesion regression than eve, and greater target lesion regression was associated with improved OS in pts with advanced RCC. Clinical trial information: NCT01865747. [Table: see text]

431 Background: While targeting VEGF improves outcomes for mRCC pts, resistance invariably develops, often within the first year. Here, we describe the efficacy and safety of atezo (anti-PD-L1) with bev (anti-VEGF) and atezo monotherapy vs sun (TKI) in first-line mRCC. Methods: Treatment-naïve mRCC pts were enrolled in a hypothesis generating Ph II study (IMmotion150; NCT01984242) and randomized to atezo 1200 mg IV q3w + bev 15 mg/kg IV q3w, atezo alone or sun 50 mg PO QD 4 wk on/2 wk off. Crossover to atezo + bev after disease progression was allowed for pts receiving atezo or sun. PD-L1 expression was scored on tumor-infiltrating immune cells (IC, SP142 IHC assay). Coprimary endpoints were PFS (RECIST v1.1 by independent review [IRF]) in ITT pts and pts with PD-L1 expression on ≥ 1% of IC (PD-L1+). Results: Baseline characteristics were comparable across arms and between ITT and PD-L1+ pts. The majority of sun and atezo pts subsequently received atezo + bev. Median survival follow up was 20.7 mo. The PFS HR in ITT pts for atezo + bev vs sun was 1.00 and 1.19 for atezo vs sun. In PD-L1+ pts, the PFS HR for atezo + bev vs sun was 0.64 and 1.03 for atezo vs sun (table). Tx-related Gr 3-4 AEs were seen in 40%, 16% and 57% of pts in the atezo + bev, atezo and sun arms, respectively. AEs leading to death occurred in 3%, 2% and 2% of pts, respectively. Conclusion: Atezo + bev resulted in encouraging antitumor activity in the PD-L1+ subgroup of first-line RCC pts. Atezo + bev safety is consistent with the known profile of atezo and bev individually. The clinical benefit of atezo + bev vs sun will be evaluated in the ongoing Ph III study IMmotion151 (NCT02420821). Clinical trial information: NCT01984242. [Table: see text]

364 Background: Flavopiridol + FOLFOX showed activity in refractory GCT pts in a phase I trial (Rathkopf, Clin Cancer Res, 2009). This phase II study assessed the efficacy of this regimen in refractory GCT and the necessity of including 5-FU/LV. Methods: Previously treated pts with progressive GCT were eligible if they had received or were not candidates for high-dose chemotherapy (HDCT). Pts on Arm A received flavopiridol 70mg/m2 plus oxaliplatin 85mg/m2. Arm B (flavopiridol + FOLFOX) tested identical doses of flavopiridol and oxaliplatin plus 5-FU (400mg/m2 bolus, then 1800mg/m2 over 48 hours) and LV 400mg/m2. Treatment was every 2 weeks in 6-week cycles. The primary endpoint was response rate (RR) by RECIST. An identical Simon 2-stage design was used for each arm to differentiate between a RR ≥40% vs. ≤20%, with arm B opening only if arm A was ineffective. With ≥3 responses among the first 12 pts, another 13 pts would be enrolled with responses in ≥8/25 pts needed to show efficacy. Tumor biopsies pre-, during, and post-treatment were assessed by IHC for p53, p21, and cleaved caspase-3. Results: Of 36 pts (7 arm A, 29 arm B), 33 had nonseminoma. Primary site was testis in 27 and mediastinum in 7; 22 pts had received prior HDCT and 13 had LR (>2 years), including 2 on arm A and 11 on arm B. Arm A closed early after 0/7 pts responded (2 SD). Of 25 evaluable pts on arm B, 6 achieved a PR, 9 had SD, and 10 had PD. Notably, 5/10 evaluable LR pts on Arm B had a PR, including 1 pathologic CR, 1 PR-negative markers who received radiation (RT) to a residual bone metastasis, and 1 PR-positive markers who received RT to a residual nodal mass. These 3 pts remain disease-free ≥19 months (m) post-chemotherapy and ≥17m post-RT or surgery. Median PFS and OS were 2.3m and 7.3m for all pts and 3.2m and 11.2m for arm B pts. There was 1 treatment-related death due to sepsis. Conclusions: Although neither arm met the prespecified endpoint, flavopiridol plus FOLFOX (arm B) was particularly active in LR pts, with a 50% overall RR, including several durable responses. Further study of FOLFOX with or without flavopiridol is warranted in LR pts. Correlative data will be presented. Clinical trial information: NCT00957905.

Abstract Purpose: The interaction of programmed death-1 ligand (PD-L1) with its receptor (PD-1) on T cells inactivates antitumor immune responses. PD-L1 expression has been associated with poor outcomes in renal cell carcinoma (RCC) but has not been investigated in advanced RCC patients receiving VEGF-targeted therapy. Experimental Design: Formalin-fixed paraffin-embedded specimens were collected at baseline from patients in the COMPARZ trial. Tumor cell PD-L1 expression by IHC was evaluated using H-score (HS). Dual PD-L1/CD68 staining was used to differentiate PD-L1 tumor expression from tumor-associated macrophages. Intratumor CD8-positive T cells were quantified morphometrically. Associations between biomarkers and survival were investigated using the log-rank test. Results: HS data were available from 453 of 1,110 patients. Sixty-four percent of patients had negative PD-L1 expression (HS = 0). Patients with HS &gt; 55 (n = 59, 13%) had significantly shorter overall survival (OS) than those with HS ≤ 55 in both pazopanib and sunitinib arms (median 15.1 vs. 35.6 and 15.3 vs. 27.8 months, respectively, P = 0.03). In both arms, median OS was shortest in patients with HS &gt; 55 and intratumor CD8-positive T-cell counts &gt; 300 (9.6 and 11.9 months with pazopanib and sunitinib, respectively). Median OS in patients with HS ≤ 55 and CD8-positive T-cell counts ≤ 300 was 36.8 and 28.0 months with pazopanib and sunitinib, respectively. Progression-free survival results were similar to OS results. Conclusions: Increased tumor cell PD-L1, or PD-L1 plus tumor CD8-positive T-cell counts, were associated with shorter survival in patients with metastatic RCC receiving VEGF-targeted agents. These findings may have implications for future design of randomized clinical trials in advanced RCC. Clin Cancer Res; 21(5); 1071–7. ©2014 AACR.