Citations

Abstract The ability of breast cancer cells to transiently transition between epithelial and mesenchymal states contributes to their metastatic potential. Therefore, driving tumor cells into a stable mesenchymal state, as opposed to complete tumor cell eradication, presents an opportunity to pharmacologically limit disease progression by promoting an asymptomatic state of dormancy. Here, we compare a reversible model of epithelial–mesenchymal transition (EMT) induced by TGFβ to a stable mesenchymal phenotype induced by chronic exposure to the ErbB kinase inhibitor lapatinib. Only cells capable of returning to an epithelial phenotype resulted in skeletal metastasis. Gene expression analyses of the two mesenchymal states indicated similar transition expression profiles. A potently downregulated gene in both datasets was spleen tyrosine kinase (SYK). In contrast to this similar diminution in mRNA, kinome analyses using a peptide array and DNA-conjugated peptide substrates showed a robust increase in SYK activity upon TGFβ-induced EMT only. SYK was present in cytoplasmic RNA processing depots known as P-bodies formed during the onset of EMT, and SYK activity was required for autophagy-mediated clearance of P-bodies during mesenchymal–epithelial transition (MET). Genetic knockout of autophagy-related 7 (ATG7) or pharmacologic inhibition of SYK activity with fostamatinib, a clinically approved inhibitor of SYK, prevented P-body clearance and MET, inhibiting metastatic tumor outgrowth. Overall, this study suggests assessment of SYK activity as a biomarker for metastatic disease and the use of fostamatinib as a means to stabilize the latency of disseminated tumor cells. Significance: These findings present inhibition of spleen tyrosine kinase as a therapeutic option to limit breast cancer metastasis by promoting systemic tumor dormancy. See related commentary by Farrington and Narla, p. 1756

588 Background: CALGB/SWOG 80405 found no difference in overall survival (OS) or progression-free survival (PFS) in 1137 patients with KRAS wild-type metastatic colorectal cancer (mCRC) treated with either the anti-VEGF agent bevacizumab (Bev) or the anti-EGFR agent cetuximab (Cet) in combination with chemotherapy (FOLFOX or FOLFIRI) as first-line therapy. Additional molecular biomarkers are required for the optimization of treatment choices for patients with mCRC. Methods: Levels of 24 proteins were assayed in EDTA-plasma samples using multiplex ELISA techniques. Plasma samples were collected at baseline and cycle 2 day 1 (C2D1). Analyses of baseline markers have been presented previously. Changes from baseline to C2D1 were expressed as an L-ratio (LR, log2 of C2D1 divided by baseline measure). LRs dichotomized at 0 were analyzed for potential prognostic and predictive effects on OS and PFS using Cox models while adjusting for confounders (post-hoc optimized cutpoints were used for PLGF, TIMP1, VCAM1, and VEGFR3 due to skew in the distributions of these markers). P-values are not corrected for multiple testing. Results: Baseline and matched C2D1 samples from 446 patients (212 Bev/234 Cet) were available for analysis. Thirteen markers were differentially modulated between arms (p < 0.05). Early increases in CD73 (p = 0.001), ICAM1 (p = 0.022), TIMP1 (p = 0.001), TSP2 (p = 0.024), and VEGFR3 (p = 0.006) were prognostic for shorter OS. Increases in ICAM1 (p = 0.008), TIMP1 (p = 0.042), and TGFB1 (p = 0.039) were prognostic for shorter PFS. Changes in VEGFR3 (pint = 0.097) and TGFBR3 (pint = 0.052) were predictive for OS and PFS, respectively. No other markers were predictive for OS or PFS (p < 0.1). Conclusions: Changes in circulating plasma protein biomarkers observed in patients enrolled in CALGB/SWOG 80405 were both prognostic and predictive for OS and PFS and warrant further study. Such changes could provide valuable information and help guide treatment decisions. Support: U10CA180821, U10CA180882, U10CA180888, U10CA180830; ClinicalTrials.gov: NCT00265850. [Table: see text]

Pyridostigmine without atropine, pyridostigmine with atropine or neostigmine with atropine were used to antagonise neuro-muscular blockade induced by d-tubocurarine in forty otherwise healthy, female patients recovering from gynaecological surgery. Pulse rates fell significantly (P < 0.01 control heart rate 72 ± 18 beats/min (M ± SD) to 55 ± 13 beats/min) at ten minutes after pyridostigmine (10 mg/70 kg), necessitating administration of atropine (1.25 mg/70 kg) by fifteen minutes after pyridostigmine. After an initial rise in rate, pulse rates also fell significantly (P < 0 01 control heart rate 70 ± 12 beats/min to 44 ± 11 beats/min) at fifteen minutes after injection of neostigmine (2.5 mg/70 kg) with atropine (1.25 mg/70 kg) By contrast when pyrdostigmine and atropine were used together, pulse rates rose and then fell, but mean values never fell below control during a twenty-minute observation period. It was concluded that pyridostigmine should not be given alone, but requires the use of atropine to prevent bradycardia. This combination may, however, provide a more stable heart rate than that seen with neostigmine and atropine in usual doses, when these drugs are used to antagonise d-tubocurarine.

Objective Surveillance interval protocols after complete remission of intestinal metaplasia (CRIM) post radiofrequency ablation (RFA) in Barrett’s oesophagus (BE) are currently empiric and not based on substantial evidence. We aimed to assess the timeline, location and patterns of recurrence following CRIM to inform these guidelines. Design Data on patients undergoing RFA for BE were obtained from prospectively maintained databases of five (three USA and two UK) tertiary referral centres. RFA was performed until CRIM was confirmed on two consecutive endoscopies. Results 594 patients achieved CRIM as of 1 May 2017. 151 subjects developed recurrent BE over a median (IQR) follow-up of 2.8 (1.4–4.4) years. There was 19% cumulative recurrence risk of any BE within 2 years and an additional 49% risk over the next 8.6 years. There was no evidence of a clinically meaningful change in the recurrence hazard rate of any BE, dysplastic BE or high-grade dysplasia/cancer over the duration of follow-up, with an estimated 2% (95% CI −7% to 12%) change in recurrence rate of any BE in a doubling of follow-up time. 74% of BE recurrences developed at the gastro-oesophageal junction (GOJ) (24.1% were dysplastic) and 26% in the tubular oesophagus. The yield of random biopsies from the tubular oesophagus, in the absence of visible lesions, was 1% (BE) and 0.2% (dysplasia). Conclusions BE recurrence risk following CRIM remained constant over time, suggesting that lengthening of follow-up intervals, at least in the first 5 years after CRIM, may not be advisable. Sampling the GOJ is critical to detecting recurrence. The requirement for random biopsies of the neosquamous epithelium in the absence of visible lesions may need to be re-evaluated.

TPS873 Background: Initial treatment of metastatic colorectal cancer (mCRC) involves a 5-fluorouracil based chemotherapy regimen, often in combination with anti-VEGF therapy. Upon disease progression, multiple studies have suggested a benefit for continued anti-VEGF therapy. There is increasing evidence that VEGF plays a role in cancer immune evasion. Targeting of inflammatory and immune checkpoints are attractive approaches to enhance the benefits of anti-VEGF therapy. The safety and activity of the anti-PD-L1 antibody atezolizumab with bevacizumab and with 5-FU, oxaliplatin, and bevacizumab have been recently reported; the combinations were well-tolerated and suggested clinical activity. Therefore, bevacizumab may increase the immunogenicity of colorectal cancers, and the combination of atezolizumab plus bevacizumab may be associated with clinically meaningful response rates and disease control. Furthermore, there may be candidate biomarkers that may identify those patients most likely to benefit from this combination. Methods: In this randomized, double-blind, multicenter, placebo-controlled phase II study, 135 patients with mCRC will be randomized 2:1 to receive capecitabine/bevacizumab/atezolizumab or capecitabine/bevacizumab/placebo. Patients with prior PD-L1/PD-1 therapy are ineligible. Primary and secondary efficacy will be conducted using ITT analysis. Safety analyses will include all randomized patients who receive at least one dose of study treatment. The primary objective is PFS. The secondary objectives are ORR, OS, safety, and tolerability. The primary comparison will be superiority of the active treatment for the PFS endpoint, atezolizumab versus placebo testing at 1-sided α = 0.1 (log rank test). A PFS hazard ratio of 0.618 (active treatment versus placebo) is detectable with 86% power (1 sided α = 0.1). No interim analyses for futility or efficacy will be conducted. A subset analysis will be performed in the microsatellite-high patients looking at potential differences in PFS and OS. Trial is active and currently recruiting patients. Clinical trial information: NCT02873195.

726 Background: Primary tumor location is an important prognostic factor in mCRC. Efficacy differences with EGFR antibodies by tumor location show a predictive effect (Arnold et al. Ann Oncol 2017). Two first-line (1L) pivotal bev trials showed the prognostic value of sidedness (Loupakis et al. J Natl Cancer Inst 2015). In this exploratory study, further analysis of the predictive effect of bev is presented. Methods: Data from two randomized phase III studies (NO16966 [NCT00069095], AVF2107g [NCT00109070]) of bev+CT vs CT-alone as 1L treatment for mCRC were analyzed retrospectively. Patients (pts) with sidedness information available were included; pts from NO16966 (part 1) randomized to CT only were excluded. Sidedness was identified by case report forms. Results: Sidedness was determined in 1590 pts (27% Right and 73% Left) out of 2214 pts total (Table). In the pooled analysis, PFS improved with bev+CT compared to CT only in both right-sided (HR=0.75; 95% CI 0.61, 0.93) and left-sided (HR=0.76; 95% CI 0.67, 0.86) mCRC with similar magnitude of benefit in both sides. OS also improved with bev+CT in right-sided (HR=0.82; 95% CI 0.65, 1.03) and left-sided (HR=0.85; 95% CI 0.74, 0.98) pts. Conclusions: This exploratory subgroup analysis of two pivotal studies indicates that the effect of bev is independent of tumor location in mCRC patients. Survival outcomes. Clinical trial information: NCT00069095 and NCT00109070. [Table: see text]