Increased glucose availability sensitizes pancreatic cancer to chemotherapy.

Pancreatic Ductal Adenocarcinoma (PDAC) is highly resistant to chemotherapy. Effective alternative therapies have yet to emerge, as chemotherapy remains the best available systemic treatment. However, the discovery of safe and available adjuncts to enhance chemotherapeutic efficacy can still improve survival outcomes. We show that a hyperglycemic state substantially enhances the efficacy of conventional single- and multi-agent chemotherapy regimens against PDAC. Molecular analyses of tumors exposed to high glucose levels reveal that the expression of GCLC (glutamate-cysteine ligase catalytic subunit), a key component of glutathione biosynthesis, is diminished, which in turn augments oxidative anti-tumor damage by chemotherapy. Inhibition of GCLC phenocopies the suppressive effect of forced hyperglycemia in mouse models of PDAC, while rescuing this pathway mitigates anti-tumor effects observed with chemotherapy and high glucose.

Clinical development of IDH1 inhibitors for cancer therapy.

Isocitrate dehydrogenase 1 (IDH1) has been investigated as a promising therapeutic target in select cancers with a mutated version of the enzyme (mtIDH1). With only one phase III trial published to date and two indications approved for routine clinical use by the FDA, we reviewed the entire clinical trial portfolio to broadly understand mtIDH1 inhibitor activity in patients. We queried PubMed.gov and ClinicalTrials.gov to identify published and ongoing clinical trials related to IDH1 and cancer. Progression-free survival (PFS), overall survival (OS), 2-hydroxyglutarate levels, and adverse events were summarized. To date, ten clinical trials investigating mtIDH1 inhibitors among patients with diverse malignancies (cholangiocarcinoma, acute myeloid leukemia, chondrosarcoma, glioma) have been published. Almost every trial (80%) has investigated ivosidenib. In multiple phase I trials, ivosidenib treatment resulted in promising radiographic and biochemical responses with improved survival outcomes (relative to historic data) among patients with both solid and hematologic mtIDH1 malignancies. Among patients enrolled in a phase III trial with advanced cholangiocarcinoma, ivosidenib resulted in a PFS rate of 32% at 6 months, as compared to 0% with placebo. There was a 5.2 month increase in OS with ivosidenib relative to placebo, after considering crossover. The treatment-specific grade ≥3 adverse event rate of ivosidenib was 2%-26% among all patients, and was just 3.6% among 284 patients who had a solid tumor across four trials. Although <1% of malignancies harbor IDH1 mutations, small molecule mtIDH1 inhibitors, namely ivosidenib, appear to be biologically active and well tolerated in patients with solid and hematologic mtIDH1 malignancies.

Cytoplasmic HuR Status Predicts Disease-free Survival in Resected Pancreatic Cancer: A Post-hoc Analysis From the International Phase III ESPAC-3 Clinical Trial.

OBJECTIVES: We tested cytoplasmic HuR (cHuR) as a predictive marker for response to chemotherapy by examining tumor samples from the international European Study Group of Pancreatic Cancer-3 trial, in which patients with resected pancreatic ductal adenocarcinoma (PDA) received either gemcitabine (GEM) or 5-fluorouracil (5-FU) adjuvant monotherapy. BACKGROUND: Previous studies have implicated the mRNA-binding protein, HuR (ELAVL1), as a predictive marker for PDA treatment response in the adjuvant setting. These studies were, however, based on small cohorts of patients outside of a clinical trial, or a clinical trial in which patients received multimodality therapy with concomitant radiation. METHODS: Tissue samples from 379 patients with PDA enrolled in the European Study Group of Pancreatic Cancer-3 trial were immunolabeled with an anti-HuR antibody and scored for cHuR expression. Patients were dichotomized into groups of high versus low cHuR expression. RESULTS: There was no association between cHuR expression and prognosis in the overall cohort [disease-free survival (DFS), P = 0.44; overall survival, P = 0.41). Median DFS for patients with high cHuR was significantly greater for patients treated with 5-FU compared to GEM [20.1 months, confidence interval (CI): 8.3-36.4 vs 10.9 months, CI: 7.5-14.2; P = 0.04]. Median DFS was similar between the treatment arms in patients with low cHuR (5-FU, 12.8 months, CI: 10.6-14.6 vs GEM, 12.9 months, CI: 11.2-15.4). CONCLUSIONS: Patients with high cHuR-expressing tumors may benefit from 5-FU-based adjuvant therapy as compared to GEM, whereas those patients with low cHuR appear to have no survival advantage with GEM compared with 5-FU. Further studies are needed to validate HuR as a biomarker in both future monotherapy and multiagent regimens.

dCK expression correlates with 5-fluorouracil efficacy and HuR cytoplasmic expression in pancreatic cancer: a dual-institutional follow-up with the RTOG 9704 trial.

Deoxycytidine kinase (dCK) and human antigen R (HuR) have been associated with response to gemcitabine in small studies. The present study investigates the prognostic and predictive value of dCK and HuR expression levels for sensitivity to gemcitabine and 5-fluorouracil (5-FU) in a large phase III adjuvant trial with chemoradiation backbone in pancreatic ductal adenocarcinoma (PDA). The dCK and HuR expression levels were determined by immunohistochemistry on a tissue microarray of 165 resected PDAs from the Radiation Therapy Oncology Group (RTOG) 9704 trial. Association with overall survival (OS) and disease-free survival (DFS) status were analyzed using the log-rank test and the Cox proportional hazards model. Experiments with cultured PDA cells were performed to explore mechanisms linking dCK and HuR expression to drug sensitivity. dCK expression levels were associated with improved OS for all patients analyzed from RTOG 9704 (HR: 0.66, 95% CI [0.47-0.93], P = 0.015). In a subset analysis based on treatment arm, the effect was restricted to patients receiving 5-FU (HR: 0.53, 95% CI [0.33-0.85], P = 0.0078). Studies in cultured cells confirmed that dCK expression rendered cells more sensitive to 5-FU. HuR cytoplasmic expression was neither prognostic nor predictive of treatment response. Previous studies along with drug sensitivity and biochemical studies demonstrate that radiation interferes with HuR's regulatory effects on dCK, and could account for the negative findings herein based on the clinical study design (i.e., inclusion of radiation). Finally, we demonstrate that 5-FU can increase HuR function by enhancing HuR translocation from the nucleus to the cytoplasm, similar to the effect of gemcitabine in PDA cells. For the first time, in the pre-treatment tumor samples, dCK and HuR cytoplasmic expression were strongly correlated (chi-square P = 0.015). This dual-institutional follow up study, in a multi-institutional PDA randomized clinical trial, observed that dCK expression levels were prognostic and had predictive value for sensitivity to 5-FU.

Evaluation of adjuvant chemoradiation therapy for ampullary adenocarcinoma: the Johns Hopkins Hospital-Mayo Clinic collaborative study.

BACKGROUND: The role of adjuvant chemoradiation therapy for ampullary carcinoma is unknown. Previous literature suggests that certain populations with high risk factors for recurrence may benefit from adjuvant chemoradiation. We combined the experience of two institutions to better delineate which patients may benefit from adjuvant chemoradiation. METHODS: Patients who underwent curative surgery for ampullary carcinoma at the Johns Hopkins Hospital (n=290; 1992-2007) and at the Mayo Clinic (n=130; 1977-2005) were reviewed. Patients with <60 days of follow-up, metastatic disease at surgery, or insufficient pathologic data were excluded. The final combined study consisted of 186 patients (n=104 Johns Hopkins, n=82 Mayo). Most patients received 5-FU based chemoradiation with conformal radiation. Cox proportional hazards models were used for survival analysis. RESULTS: Median overall-survival was 39.9 months with 2- and 5-year survival rates of 62.4% and 39.1%. On univariate analysis, adverse prognostic factors for overall survival included T3/T4 stage disease (RR=1.86, p=0.002), node positive status (RR=3.18, p<0.001), and poor histological grade (RR=1.69, p=0.011). Patients who received adjuvant chemoradiation (n=66) vs. surgery alone (n=120) showed a higher rate of T3/T4 stage disease (57.6% vs. 30.8%, P<0.001), lymph node involvement (72.7% vs. 30.0%, P<0.001), and close or positive margins (4.6% vs. 0.0%, P=0.019). Five year survival rates among node negative and node positive patients were 58.7% and 18.4% respectively. When compared with surgery alone, use of adjuvant chemoradiation improved survival among node positive patients (mOS 32.1 vs. 15.7 mos, 5 yr OS: 27.5% vs. 5.9%; RR=0.47, P=0.004). After adjusting for adverse prognostic factors on multivariate analysis, patients treated with adjuvant chemoradiation demonstrated a significant survival benefit (RR=0.40, P<0.001). Disease relapse occurred in 37.1% of all patients, most commonly metastatic disease in the liver or peritoneum. CONCLUSIONS: Node-positive patients with resected ampullary adenocarcinoma may benefit from 5-FU based adjuvant chemoradiation. Since a significant proportion of patients develop metastatic disease, there is a need for more effective systemic treatment.

Adjuvant chemoradiation therapy after pancreaticoduodenectomy in elderly patients with pancreatic adenocarcinoma.

PURPOSE: To evaluate the efficacy of adjuvant chemoradiation therapy (CRT) for pancreatic adenocarcinoma patients ≥ 75 years of age. METHODS: The study group of 655 patients underwent pancreaticoduodenectomy (PD) for pancreatic adenocarcinoma at the Johns Hopkins Hospital over a 12-year period (8/30/1993 to 2/28/2005). Demographic characteristics, comorbidities, intraoperative data, pathology data, and patient outcomes were collected and analyzed by adjuvant treatment status and age ≥ 75 years. Cox proportional hazards analysis determined clinical predictors of mortality and morbidity. RESULTS: We identified 166 of 655 (25.3%) patients were ≥ 75 years of age and 489 of 655 patients (74.7%) were <75 years of age. Forty-nine patients in the elderly group (29.5%) received adjuvant CRT. For elderly patients, node-positive metastases (p = 0.008), poor/anaplastic differentiation (p = 0.012), and undergoing a total pancreatectomy (p = 0.010) predicted poor survival. The 2-year survival for elderly patients receiving adjuvant therapy was improved compared with surgery alone (49.0% vs. 31.6%, p = 0.013); however, 5-year survival was similar (11.7% vs. 19.8%, respectively, p = 0.310). After adjusting for major confounders, adjuvant therapy in elderly patients had a protective effect with respect to 2-year survival (relative risk [RR] 0.58, p = 0.044), but not 5-year survival (RR 0.80, p = 0.258). Among the nonelderly, CRT was significantly associated with 2-year survival (RR 0.60, p < 0.001) and 5-year survival (RR 0.69, p < 0.001), after adjusting for confounders. CONCLUSIONS: Adjuvant therapy after PD is significantly associated with increased 2-year but not 5-year survival in elderly patients. Additional studies are needed to select which elderly patients are likely to benefit from adjuvant CRT.

Adjuvant chemoradiation for pancreatic adenocarcinoma: the Johns Hopkins Hospital-Mayo Clinic collaborative study.

BACKGROUND: Survival for pancreatic ductal adenocarcinoma is low, the role of adjuvant therapy remains controversial, and recent data suggest adjuvant chemoradiation (CRT) may decrease survival compared with surgery alone. Our goal was to examine efficacy of adjuvant CRT in resected pancreatic adenocarcinoma compared with surgery alone. MATERIALS AND METHODS: Patients with pancreatic adenocarcinoma at Johns Hopkins Hospital (n = 794, 1993-2005) and Mayo Clinic (n = 478, 1985-2005) following resection who were observed (n = 509) or received adjuvant 5-FU based CRT (median dose 50.4 Gy; n = 583) were included. Cox survival and propensity score analyses assessed associations with overall survival. Matched-pair analysis by treatment group (1:1) based on institution, age, sex, tumor size/stage, differentiation, margin, and node positivity with N = 496 (n = 248 per treatment arm) was performed. RESULTS: Median survival was 18.8 months. Overall survival (OS) was longer among recipients of CRT versus surgery alone (median survival 21.1 vs. 15.5 months, P < .001; 2- and 5-year OS 44.7 vs. 34.6%; 22.3 vs. 16.1%, P < .001). Compared with surgery alone, adjuvant CRT improved survival in propensity score analysis for all patients by 33% (P < .001), with improved survival when stratified by age, margin, node, and T-stage (RR = 0.57-0.75, P < .05). Matched-pair analysis demonstrated OS was longer with CRT (21.9 vs. 14.3 months median survival; 2- and 5-year OS 45.5 vs. 31.4%; 25.4 vs. 12.2%, P < .001). CONCLUSIONS: Adjuvant CRT is associated with improved survival after pancreaticoduodenectomy. Adjuvant CRT was not associated with decreased survival in any risk group, even in propensity score and matched-pair analyses. Further studies evaluating adjuvant chemotherapy compared with adjuvant chemoradiation are needed to determine the most effective combination of systemic and local-regional therapy to achieve optimal survival results.

Genomic copy number changes affecting the thymidylate synthase (TYMS) gene in cancer: a model for patient classification to aid fluoropyrimidine therapy.

Thymidylate synthase (TS) is an important target for 5-fluorouracil (5FU)-based therapy. The TS polymorphic 5'-untranslated region tandem repeat sequence is under investigation to guide 5FU treatment, yet current protocols omit consideration of copy number changes at the TS locus. We surveyed the TS tandem repeat sequence and found copy number changes in gastrointestinal cancers. Ten of 12 informative cases had loss of heterozygosity (LOH), whereas two others and an additional cell line had a novel TS genotype, allelic imbalance at the TS locus due to polysomy. Experimentally, we studied a diploid colorectal cancer line heterozygous at TS to mimic three common TS genotypes of cancers. Using genetic engineering, we deleted the short tandem repeat (two repeats) allele and retained the long (three repeats) allele to produce artificial LOH at the TS gene; the TS(+/-) line had a reduced TS protein expression and was hypersensitive to 5FU and 5-fluoro-2'-deoxyuridine in vitro as compared with syngeneic control lines. We linked this sensitivity directly to the reduced TS expression by introducing exogenous TS cDNA expression into the TS(+/-) line (i.e., increased TS copies). Our model predicts that the 5FU sensitivity of a tumor is modified by aneuploidy producing copy number changes of TS alleles by one or more of the following: LOH, amplification, and, as presented here, copy number changes due to polysomy. The data suggest that TS copy number in a patient's tumor may be a dominating variable affecting 5FU responsiveness.