Krishna, Somashekar G.

3612 Background: The RAS/RAF/MEK signal transduction pathway is critical to the development of colorectal cancer, and tumors harboring KRAS, NRAS, and BRAF mutations were shown to be resistant to radiation. Thus, we conducted a phase I study of trametinib, a potent MEK1/2 inhibitor, in combination with CRT in patients with LARC. Methods: Phase I trial for patients with Stage II/III rectal cancers with a 3+3 design, and an expansion cohort of 12 patients at the maximum tolerated dose (MTD). Trametinib is given orally at 3 dose levels: 0.5mg, 1mg, and 2mg (Mon-Fri). CRT regimen is infusional 5-flourouracil (5FU) 225mg/m2/day (Mon-Fri) and daily fractions of 1.8 Gy (total 50.4Gy). There is a 5-day trametinib lead-in followed by trametinib and CRT. Six to 10 weeks after completion of CRT, patients then proceed to their surgery and adjuvant therapy. The primary endpoint is to identify the MTD and recommended phase 2 dose of trametinib with CRT. Immunohistochemistry staining for phosphorylated –ERK (pERK) and genomic profiling is performed on the tumor samples. Results: Enrollment is complete at all dose levels with18 patients, and 15 patients evaluable for toxicity and response as of Feb 6. One dose-limiting toxicity of diarrhea was observed at the 2mg dose. Grade 3 and most common toxicities are shown in Table 1. No grade 4/5 toxicities have been observed. At 2mg dose level, 3/9 (33%) patients had pathological complete response (pCR) and 2/9 (22%) had a near pCR. Correlative studies confirm decrease in pERK levels with increasing doses of trametinib. Correlation of genomic mutational status with toxicity, response, and outcomes is being analyzed. Conclusions: The combination of trametinib with 5FU CRT is tolerable with promising preliminary activity. Final results will be presented at the meeting. Toxicities. Clinical trial information: NCT01740648. [Table: see text]

Abstract Background and study aims Endoscopic biliary intervention (BI) is often difficult to perform in patients with prior bariatric surgery (BRS). We sought to analyze outcomes of patients with prior BRS undergoing endoscopic and non-endoscopic BI. Patients and methods The Nationwide Inpatient Sample (2007 – 2011) was reviewed to identify all adult inpatients (≥ 18 years) with a history of BRS undergoing BI. The clinical outcomes of interest were in-patient mortality, length of stay (LOS), and total hospital charges. Results There were 7,343 patients with prior BRS who underwent BIs where a majority were endoscopic (4,482 vs. 2,861, P < 0.01). The mean age was 50±30.8 years and the majority were females (80.5 %). Gallstone-related disease was the most common indication for BI and managed more often with primary endoscopic management (2,146 vs. 1,132, P < 0.01). Inpatient mortality was not significantly different between patients undergoing primary endoscopic versus non-endoscopic BI (0.2 % vs. 0.7 %, P = 0.2). Patients with sepsis were significantly more likely to incur failed primary endoscopic BI (OR 2.74, 95 % CI 1.15, 6.53) and were more likely to be managed with non-endoscopic BI (OR 2.13, 95 % CI 1.3, 3.5). Primary non-endoscopic BI and failed endoscopic BI were both associated with longer LOS (by 1.77 days, P < 0.01 and by 2.17 days, P < 0.01, respectively) and higher hospitals charges (by $11,400, P < 0.01 and by $ 14,200, P < 0.01, respectively). Conclusion Primary endoscopic management may be a safe and cost-effective approach for patients with prior BRS who need BI. While primary endoscopic biliary intervention is more common, primary non-endoscopic intervention may be used more often for sepsis.

Objectives Pancreatic ductal adenocarcinoma (PDAC) is often accompanied by weight loss. We sought to characterize factors associated with weight loss and observed nutritional interventions, as well as define the effect of weight loss on survival. Methods Consecutive subjects diagnosed with PDAC (N = 123) were retrospectively evaluated. Univariate analysis was used to compare subjects with and without substantial (>5%) weight loss. Multivariate logistic regression was performed to identify factors associated with weight loss, and survival analyses were performed using Kaplan-Meier curves and Cox survival models. Results Substantial weight loss at diagnosis was present in 71.5% of subjects and was independently associated with higher baseline body mass index, longer symptom duration, and increased tumor size. Recommendations for nutrition consultation and pancreatic enzyme replacement therapy occurred in 27.6% and 36.9% of subjects, respectively. Weight loss (>5%) was not associated with worse survival on multivariate analysis (hazard ratio, 1.32; 95% confidence interval, 0.76–2.30), unless a higher threshold (>10%) was used (hazard ratio, 1.77; 95% confidence interval, 1.09–2.87). Conclusions Despite the high prevalence of weight loss at PDAC diagnosis, there are low observed rates of nutritional interventions. Weight loss based on current criteria for cancer cachexia is not associated with poor survival in PDAC.

685 Background: RAS/BRAF mutations constitutively activate the MAPK pathway in colorectal cancer, and may promote resistance to CRT. We propose that trametinib, a MEK1/2 inhibitor, in combination with 5FU CRT for patients with LARC will improve outcome. Methods: Phase I study with standard 3+3 design in patients with Stage II/III rectal cancer with 3 dose levels of trametinib: 0.5, 1, and 2mg daily with 5FU 225mg/m2/day and 50.4 Gy. Trametinib was given over a 5-day lead-in and continued through the course of CRT. Patients undergo surgery 6-10 weeks after the completion of CRT. An expansion cohort at the maximum tolerated dose (MTD) with 12 patients is ongoing. Tumor tissue is collected prior to therapy, at day 4/5 of trametinib, and at surgery. The primary endpoint is to determine the MTD of trametinib with CRT. Results: 15 patients (10 males, 5 females) have been enrolled and 14 patients are evaluable for toxicities to date. Median age is 53 years (range 35-74). Patients have completed enrollment to all dose levels, with 1 dose-limiting toxicity of diarrhea attributed to 5FU CRT. No grade 4/5 toxicities, and toxicities are shown in the table. Generalized skin rash led to trametinib discontinuation after 2 weeks of therapy for 1 patient, and was held 3 days for 2 patients. At the trametinib dose level of 2mg, 3 out of 7 (43%) patients had a pathological complete response and the average neoadjuvant rectal (NAR) score is 8.1. Tumor RAS/BRAF mutation status is determined. Analysis of tumor tissue shows dose-dependent decrease in phosphorylated-ERK1/2 with increasing doses of trametinib. Conclusions: Initial evaluation shows that the combination of trametinib with 5FU CRT is tolerable and effective, and warrants further investigation in LARC. Clinical trial information: NCT01740648. [Table: see text]

Abstract Background: Triple negative breast cancer (TNBC) is a heterogeneous disease. Amplification of chromosome 9p24.1 encoding JAK2 and PD-L1 has been reported in up to 25% of TNBC and is associated with poor clinical outcome. In lymphoma, JAK2 is a transcriptional activator of both PD-1 ligands, and chromosome 9p copy number gain has been associated with therapeutic activity of nivolumab. We evaluated the interaction of JAK2 and PD-L1 expression in TNBC. Methods: 9p24.1 amplification in 4 TNBC cell lines (MDA-MB-231, MDA-MB-436, HCC1937, and HCC70) was measured using array comparative genomic hybridization (aCGH). Amplification was defined as aCGH log2ratio&gt;2.0. Cell surface expression of PD-L1 was detected by flow cytometry and compared with the median fluorescence intensity (MFI) of isotype control Ig. To selectively inhibit JAK2, lentiviral vectors encoding two different shRNA were generated. JAK2, pSTAT1 and pSTAT3 expression were measured by immunoblot. The effects of the anti-JAK1/2 inhibitor ruxolitinib and interferon-gamma (IFN-γ) induction of PD-L1 was measured. Results: 9p24.1 copy number loss was measured in MDA-MB-231 (log2ratio =-1), neutral in HCC1937 ((log2ratio =0), gained in MDA-MB-436 ((log2ratio =+1) and amplified in HCC70 ((log2ratio =+2). No correlation was observed between PD-L1 expression and the 9p24.1 amplification, with the MFI ratio range from 5 to 16.5, mean 8.3 by flow cytometry. TNBC cell lines had higher baseline expression of PD-L1 compared to the ER+ cell lines T47D and MCF-7 (ratio, 0 p=0.1). Low dose IFN-γ (1.0-10.0 ng/ml) rapidly induced expression of PD-L1 in MDA-MB-231 (1.5 fold increase) and HCC70 (3.3 fold increase) with significant activation of the JAK2/STAT1 pathway. The induction of pSTAT1 and PD-L1 expression by IFN-γ was blocked with low dose (1mM) JAK1/2 inhibitor ruxolitinib. Knockdown of JAK2 with shRNA (&gt;80%) did not impact PD-L1 baseline expression in MDA-MB-231 and HCC70 but abrogated IFN-γ –mediated induction of PD-L1 and the phosphorylation of STAT1. Conclusion: These data suggest that TNBC cell lines have baseline PD-L1 expression, but the cells with 9p24.1 amplification are highly sensitive to PD-L1 induction with IFN-γ which can be abrogated with inhibition with a JAK1/2 inhibitor or shRNA. Synergistic inhibition of PD1/PD-L1 and JAK2 may have therapeutic efficacy in the subset of TNBC with 9p24.1 amplification, and the dynamic effects of tumor PD-L1 expression in response to local inflammation should be considered in the evaluation of PD-1/PD-L1 checkpoint blockade. Citation Format: Chen M, Pockaj B, Andreozzi M, Barrett MT, Ocal IT, McCullough AE, Krishna S, Anderson KS. JAK2 and PD-L1 amplification enhance the dynamic expression of PD-L1 in triple negative breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-04-18.