Quinn, David I

LBA4500 Background: Cisplatin-based chemo is a standard 1L treatment (tx) for mUC and the only tx that prolongs OS; however, age or comorbidities render many pts ineligible, and 30-50% receive no tx. Atezo (MPDL3280A) is active and well tolerated in platinum-treated mUC, justifying testing atezo as 1L tx in cisplatin-ineligible pts. Methods: Pts were chemo naive in the metastatic setting and cisplatin ineligible (renal [GFR > 30 but < 60 mL/min]/hearing impairment, ≥ G2 peripheral neuropathy [PN] or ≥ ECOG PS2). Atezo 1200 mg was given IV q3w until PD (RECIST v1.1). Centrally assessed PD-L1 on tumor infiltrating immune cells (IC; SP142 IHC assay) was scored IC2/3, 1 or 0. The primary efficacy endpoint was confirmed ORR assessed per RECIST v1.1 (central independent review facility) using a data cutoff of Sep 14, 2015. Results: 119 efficacy/safety-evaluable pts of any PD-L1 IC had a median age of 73 y: 21% ≥ 80 y. 18% had prior systemic tx (21% [neo]adjuvant); 10% had radiotherapy. 66% had visceral mets. 71% had CrCl < 60 mL/min; 13% had hearing loss ≥ 25 dB; 6% had prior PN ≥ G2; 20% had ECOG PS2. ORR was 19% (95% CI 13-28; 5% CR), and responses occurred in all IC subgroups (Table; includes DCR/PFS/OS) and in pts with poor prognostic factors. 22/23 responses were ongoing with mDOR not reached. Median follow-up was 8.5 mo (range 0.2-14.3); median tx duration was 15 wk. Atezo was generally well tolerated. Tx-related all-G and G3-4 AEs were seen in 64% and 12% of pts, respectively. Related all-G AEs ≥ 10% included fatigue, pruritus, diarrhea. 1 G5 related AE occurred (sepsis). 3% had a G3-4 immune-mediated AE. Conclusions: Atezo has clinically meaningful activity in 1L cisplatin-ineligible mUC pts, and preliminary OS is encouraging. The durable nature of response and favorable AE profile makes this an attractive alternative to chemo. NCT02108652. Clinical trial information: NCT02108652. [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.

29 Background: Better biomarkers are needed in prostate cancer (PCa) to predict disease recurrence and guide optimal therapy. We investigated whether genes associated with a highly tumorigenic, drug resistant, progenitor cancer phenotype impact PCa biology and clinical outcomes in localized disease. Methods: Genes associated with self-renewal, drug resistance, and tumorigenicity were analyzed by qRT-PCR on PCa mRNA from radical prostatectomy (RP) specimens (+/- disease recurrence). Wilcoxon rank sum two-sample test, multivariable recursive partitioning, and bootstrap internal validation measured and confirmed associations with recurrence. Further validation was conducted in external cohorts and in-silico, as well as in vitro and in vivo using siRNA knockdown and lentiviral overexpression to determined the effect of gene expression on PCa proliferation, invasion and tumor growth. Results: Four candidate genes were differentially expressed in PCa recurrence, and of these, low AXIN2 expression was internally validated. Validation in external cohorts demonstrated low AXIN2 expression was associated with more aggressive prostate cancer and was independently associated with biochemical recurrence (BCR) and metastasis-free survival (MFS) after RP. In vitro, low AXIN2 expression was associated with a cancer stem-like cell-surface signature, and siRNA knockdown of AXIN2 resulted in significantly greater invasiveness. Conversely, ectopic overexpression of AXIN2 significantly reduced cell proliferation and tumor growth in mice. Conclusions: Low AXIN2 expression was associated with PCa recurrence after RP in our test population as well as in external validation cohorts. AXIN2 expression levels in PCa cells significantly impacted invasiveness, proliferation and tumor growth. AXIN2 represents a putative biomarker and potential therapeutic target in early prostate cancer.

Purpose This trial assessed the efficacy and safety of docetaxel monotherapy or docetaxel in combination with ramucirumab (vascular endothelial growth factor receptor 2 antibody) or icrucumab (vascular endothelial growth factor receptor 1 antibody) after progression during or within 12 months of platinum-based regimens for patients with locally advanced or metastatic urothelial carcinoma. Patients and Methods Patients were randomly assigned (1:1:1) to receive docetaxel 75 mg/m2 intravenously (IV) on day 1 of a 3-week cycle (arm A), docetaxel 75 mg/m2 IV plus ramucirumab 10 mg/kg IV on day 1 of a 3-week cycle (arm B), or docetaxel 75 mg/m2 IV on day 1 plus icrucumab 12 mg/kg IV on days 1 and 8 of a 3-week cycle (arm C). Treatment continued until disease progression or unacceptable toxicity. The primary end point was investigator-assessed progression-free survival (PFS). Results A total of 140 patients were randomly assigned and treated in arms A (n = 45), B (n = 46), or C (n = 49). PFS was significantly longer in arm B compared with arm A (median, 5.4 months; 95% CI, 3.1 to 6.9 months v 2.8 months; 95% CI, 1.9 to 3.6 months; stratified hazard ratio, 0.389; 95% CI, 0.235 to 0.643; P = .0002). Arm C did not experience improved PFS compared with arm A (1.6 months; 95% CI, 1.4 to 2.9; stratified hazard ratio, 0.863; 95% CI, 0.550 to 1.357; P = .5053). The most common grade 3 or worse adverse events (arms A, B, and C) were neutropenia (36%, 33%, and 39%), fatigue (13%, 30%, and 20%), febrile neutropenia (13%, 17%, and 6.1%), and anemia (6.7%, 13%, and 14%, respectively). Conclusion The addition of ramucirumab to docetaxel met the prespecified efficacy end point for prolonging PFS in patients with locally advanced or metastatic urothelial carcinoma receiving second-line treatment and warrants further investigation in the phase III setting.