Human equilibrative nucleoside transporter 1 is not predictive for gemcitabine efficacy in advanced pancreatic cancer: Translational results from the AIO-PK0104 phase III study with the clone SP120 rabbit antibody

A review of the Augustine blood group system

Augustine is a newly identified blood group system comprising four antigens, one of which is the high-frequency antigen Ata in the original "series". Four antigens are located on a multipass membrane glycoprotein equilibrative nucleoside transporter 1 (ENT1), and equilibrative nucleoside transporter is encoded by SLC29A1. In 2016, the International Society of Blood Transfusion (ISBT) recognised Augustine as a blood group system and numbered it as 036. The glycoprotein ENT1 transports nucleotides into cells to participate in the synthesis of DNA and RNA, and this is an important link for chemotherapeutic glycosides to enter tumour cells. Augustine antibodies are clinically relevant in blood transfusion and pregnancy.

hENT1's role in adjuvant intra-arterial gemcitabine-based chemotherapy for resectable pancreatic cancer patients

BACKGROUND

We aimed to verify the role of hENT1 as a prognostic predictor for patients with resectable pancreatic ductal adenocarcinoma (PDAC) who underwent radical resection followed by intra-arterial infusion of gemcitabine-based regimen.

METHODS

We collected surgical samples from 102 patients with resectable PDAC who received radical resection followed by intra-arterial infusion of gemcitabine-based regimen. The hENT1 expression with the help of immunohistochemistry was conducted using formalin-fixed and paraffin embedded tissues. The Kaplan-Meier analyses and Cox regression were used to evaluate the mortality hazard associated with the discrepancy between strong and weak of hENT1 expression. Patients' clinical and pathological characteristics were compared between the two groups, then the role of hENT1 as a prognostic predictor was further explored.

RESULTS

A total of 102 patients were included to assess the hENT1 expression. 50 patients were classified into high hENT1 expression group, the other 52 patients were attributed into low hENT1 expression group. High hENT1 expression was related to a significantly improved overall survival (OS) (p = 0.014) and disease-free survival (DFS) (p = 0.004). Both univariate (p = 0.001) and multivariate analyses (p < 0.001) indicated that high hENT1 expression was related to a decreased mortality.

CONCLUSIONS

High expression of hENT1 is positive prognostic factor for adjuvant intra-arterial gemcitabine-based chemotherapy in resectable PDAC.

Concordance of human equilibrative nucleoside transporter-1 expressions between murine (10D7G2) and rabbit (SP120) antibodies and association with clinical outcomes of adjuvant chemotherapy for pancreatic cancer: A collaborative study from the JASPAC 01 trial

BACKGROUND

Expression of human equilibrative nucleoside transporter-1 (hENT1) is reported to predict survival of gemcitabine (GEM)-treated patients. However, predictive values of immunohistochemical hENT1 expression may differ according to the antibodies, 10D7G2 and SP120.

AIM

We aimed to investigate the concordance of immunohistochemical hENT1 expression between the two antibodies and prognosis.

METHODS

The subjects of this study were totally 332 whose formalin-fixed paraffin-embedded specimens and/or unstained sections were obtained. The individual H-scores and four classifications according to the staining intensity were applied for the evaluation of hENT1 expression by 10D7G2 and SP120, respectively.

RESULTS

The highest concordance rate (79.8%) was obtained when the cut-off between high and low hENT1 expression using SP120 was set between moderate and strong. There were no correlations of hENT1 mRNA level with H-score (p = .258). Although the hENT1 mRNA level was significantly different among four classifications using SP120 (p = .011), there was no linear relationship among them. Multivariate analyses showed that adjuvant GEM was a significant predictor of the patients with low hENT1 expression using either 10D7G2 (Hazard ratio [HR] 2.39, p = .001) or SP120 (HR 1.84, p < .001). In contrast, agent for adjuvant chemotherapy was not significant predictor for the patients with high hENT1 expression regardless of the kind of antibody.

CONCLUSION

The present study suggests that the two antibodies for evaluating hENT1 expression are equivalent depending on the cut-off point and suggests that S-1 is the first choice of adjuvant chemotherapy for pancreatic cancer with low hENT1 expression, whereas either S-1 or GEM can be introduced for the pancreatic cancer with high hENT1 expression, no matter which antibody is used.

Class III β-Tubulin Expression Is of Value in Selecting nab -Paclitaxel and Gemcitabine as First-Line Therapy in Unresectable Pancreatic Cancer

OBJECTIVES

Nab -paclitaxel and gemcitabine (GnP) or FOLFIRINOX (a combination of leucovorin, fluorouracil, irinotecan, and oxaliplatin [FFX]) is currently recognized as the standard first-line regimen for unresectable pancreatic ductal adenocarcinoma (PDAC). Class III β-tubulin (TUBB3) has the potential to predict resistance to taxane in various tumors; therefore, this study aimed to clarify whether TUBB3 is a predictive marker for GnP response.

METHODS

We retrospectively reviewed 113 patients with PDAC who received GnP or FFX as first-line chemotherapy and examined immunohistochemically the TUBB3 expression in specimens obtained by endoscopic ultrasound-guided fine-needle aspiration.

RESULTS

High TUBB3 expression was associated with a significantly lower disease control rate ( P = 0.017) and shorter progression-free survival (PFS) ( P = 0.019), and multivariate analysis revealed that TUBB3 expression was an independent variable for PFS in the GnP first-line group ( P = 0.045). In addition, in the FFX first-line group, TUBB3 expression was not correlated with PFS or overall survival (OS). In all 113 patients, TUBB3 expression was not also associated with OS.

CONCLUSIONS

Class III β-tubulin might be a predictive factor for the response of GnP, but not a prognostic factor for OS, helping the selection of an optimized first-line chemotherapy regimen for unresectable PDAC.

Tailored adjuvant gemcitabine versus 5-fluorouracil/folinic acid based on hENT1 immunohistochemical staining in resected pancreatic ductal adenocarcinoma: A biomarker stratified prospective trial

BACKGROUND

The study aimed to evaluate the clinical outcomes of tailored adjuvant chemotherapy according to human equilibrative nucleoside transporter 1 (hENT1) expression in resected pancreatic ductal adenocarcinoma (PDA).

METHODS

Patients who underwent pancreatectomy for PDA were enrolled prospectively. According to intra-tumoral hENT1 expression, the high hENT1 (≥50%) group received gemcitabine and the low hENT1 (<50%) group received 5-fluorouracil plus folinic acid (5-FU/FA). The propensity score-matched control consisted of patients who received hENT1-independent adjuvant chemotherapy. The primary outcome was recurrence free survival (RFS) and the secondary outcomes were overall survival (OS) and toxicities.

RESULTS

Between May 2015 and June 2017, we enrolled 44 patients with resected PDA. During a median follow-up period of 28.5 months, the intention-to-treat population showed much longer median RFS [22.9 (95% CI, 11.3-34.5) vs. 10.9 (95% CI, 6.9-14.9) months, P = 0.043] and median OS [36.2 (95% CI, 26.5-45.9) vs. 22.1 (95% CI, 17.7-26.6) months, P = 0.001] compared to the controls. Among 5 patients in the low hENT1 group who discontinued treatment, 2 patients receiving 5-FU/FA discontinued treatment due to drug toxicities (febrile neutropenia and toxic epidermal necrolysis).

CONCLUSION

Tailored adjuvant chemotherapy based on hENT1 staining provides excellent clinical outcomes among patients with resected PDA.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT02486497.

Emerging roles of the solute carrier family in pancreatic cancer

Pancreatic cancer is a gastrointestinal tumor with a high mortality rate, and advances in surgical procedures have only resulted in limited improvements in the prognosis of patients. Solute carriers (SLCs), which rank second among membrane transport proteins in terms of abundance, regulate cellular functions, including tumor biology. An increasing number of studies focusing on the role of SLCs in tumor biology have indicated their relationship with pancreatic cancer. The mechanism of SLC transporters in tumorigenesis has been explored to identify more effective therapies and improve survival outcomes. These transporters are significant biomarkers for pancreatic cancer, the functions of which include mainly proliferative signaling, cell death, angiogenesis, tumor invasion and metastasis, energy metabolism, chemotherapy sensitivity and other functions in tumor biology. In this review, we summarize the different roles of SLCs and explain their potential applications in pancreatic cancer treatment.

"Open Sesame?": Biomarker Status of the Human Equilibrative Nucleoside Transporter-1 and Molecular Mechanisms Influencing its Expression and Activity in the Uptake and Cytotoxicity of Gemcitabine in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive tumor characterized by early invasiveness, rapid progression and resistance to treatment. For more than twenty years, gemcitabine has been the main therapy for PDAC both in the palliative and adjuvant setting. After the introduction of FOLFIRINOX as an upfront treatment for metastatic disease, gemcitabine is still commonly used in combination with nab-paclitaxel as an alternative first-line regimen, as well as a monotherapy in elderly patients unfit for combination chemotherapy. As a hydrophilic nucleoside analogue, gemcitabine requires nucleoside transporters to permeate the plasma membrane, and a major role in the uptake of this drug is played by human equilibrative nucleoside transporter 1 (hENT-1). Several studies have proposed hENT-1 as a biomarker for gemcitabine efficacy in PDAC. A recent comprehensive multimodal analysis of hENT-1 status evaluated its predictive role by both immunohistochemistry (with five different antibodies), and quantitative-PCR, supporting the use of the 10D7G2 antibody. High hENT-1 levels observed with this antibody were associated with prolonged disease-free status and overall-survival in patients receiving gemcitabine adjuvant chemotherapy. This commentary aims to critically discuss this analysis and lists molecular factors influencing hENT-1 expression. Improved knowledge on these factors should help the identification of subgroups of patients who may benefit from specific therapies and overcome the limitations of traditional biomarker studies.

Human equilibrative nucleoside transporter-1 expression is a predictor in patients with resected pancreatic cancer treated with adjuvant S-1 chemotherapy

The high expression of human equilibrative nucleoside transporter-1 (hENT1) and the low expression of dihydropyrimidine dehydrogenase (DPD) are reported to predict a favorable prognosis in patients treated with gemcitabine (GEM) and 5-fluorouracil (5FU) as the adjuvant setting, respectively. The expression of hENT1 and DPD were analyzed in patients registered in the JASPAC 01 trial, which showed a better survival of S-1 over GEM as adjuvant chemotherapy after resection for pancreatic cancer, and their possible roles for predicting treatment outcomes and selecting a chemotherapeutic agent were investigated. Intensity of hENT1 and DPD expression was categorized into no, weak, moderate or strong by immunohistochemistry staining, and the patients were classified into high (strong/moderate) and low (no/weak) groups. Specimens were available for 326 of 377 (86.5%) patients. High expression of hENT1 and DPD was detected in 100 (30.7%) and 63 (19.3%) of 326 patients, respectively. In the S-1 arm, the median overall survival (OS) with low hENT1, 58.0 months, was significantly better than that with high hENT1, 30.9 months (hazard ratio 1.75, P = 0.007). In contrast, there were no significant differences in OS between DPD low and high groups in the S-1 arm and neither the expression levels of hENT1 nor DPD revealed a relationship with treatment outcomes in the GEM arm. The present study did not show that the DPD and hENT1 are useful biomarkers for choosing S-1 or GEM as adjuvant chemotherapy. However, hENT1 expression is a significant prognostic factor for survival in the S-1 arm.

Predictive and Prognostic Properties of Human Equilibrative Nucleoside Transporter 1 Expression in Gemcitabine-Treated Pancreatobiliary Cancer: A Meta-Analysis

Purpose

Gemcitabine, the primary drug for the treatment of pancreatobiliary cancer (PBC), requires human equilibrative nucleoside transporter 1 (hENT1) to enter cells. High tumoral hENT1 expression has been linked with improved survival among patients with PBC treated with gemcitabine; however, this finding has been inconsistent, and studies used different expression assays.

Methods

Databases were reviewed for studies that examined hENT1 and clinical outcome in PBC. Of 307 publications, 34 studies were found that used immunohistochemistry (IHC) with one of eight anti–hENT1 antibody assays. Five studies were excluded for redundancy, and 29 studies underwent detailed review.

Results

On average, 51% of tumor samples had high hENT1 expression (range, 7% to 92%). Among studies that examined hENT1 expression and overall survival (OS), 58% (15 of 26 studies) showed an association between high tumoral hENT1 and improved OS for gemcitabine-treated patients. Among 10D7G2 antibody studies, 88% (seven of eight studies) demonstrated this association. Studies with other antibodies—in particular, SP120 (two of nine studies)—were less consistent. The ability to detect an association between improved OS and high hENT1 was antibody dependent (χ2 P = .0237). An association between high tumoral hENT1 expression and improved disease-free/progression-free survival (DFS/PFS) was demonstrated in 71% of studies (15 of 21 studies). Pooled hazard ratio (HR) analyses of all antibody studies demonstrated a link between high hENT1 tumor expression and improved OS (HR, 0.674; 95% CI, 0.509 to 0.893; P = .006) and DFS/PFS (HR, 0.740; 95% CI, 0.517 to 0.1.059; P = .10). This signal was stronger among studies that used the 10D7G2 antibody in comparison to those in which another antibody was used, with HRs of 0.488 (95% CI, 0.396 to 0.602; P < .001) and 0.410 (95% CI, 0.280 to 0.599; P < .001), respectively.

Conclusion

High tumoral hENT1 expression on IHC with 10D7G2 is a strong and reproducible prognostic marker for improved outcome among gemcitabine-treated patients with PBC.

hENT1 Testing in Pancreatic Ductal Adenocarcinoma: Are We Ready? A Multimodal Evaluation of hENT1 Status

Gemcitabine is still one of the standard chemotherapy regimens for pancreatic ductal adenocarcinoma (PDAC). Gemcitabine uptake into tumor cells is mainly through the human equilibrative nucleoside transport 1 (hENT1). It was therefore proposed as a potential predictive biomarker of gemcitabine efficacy but reports are conflicting, with an important heterogeneity in methods to assess hENT1 expression. A multicenter cohort of 471 patients with a resected PDAC was used to assess simultaneously the predictive value of the 2 best described hENT1 antibodies (10D7G2 and SP120). Three additional antibodies and the predictive value of hENT1 mRNA were also tested on 251 and 302 patients, respectively. hENT1 expression was assessed in 54 patients with matched primary tumors and metastases samples. The 10D7G2 clone was the only hENT1 antibody whose high expression was associated with a prolonged progression free survival and overall survival in patients who received adjuvant gemcitabine. hENT1 mRNA level was also predictive of gemcitabine benefit. hENT1 status was concordant in 83% of the cases with the best concordance in synchronous metastases. The 10D7G2 clone has the best predictive value of gemcitabine benefit in PDAC patients. Since it is not commercially available, hENT1 mRNA level could represent an alternative to assess hENT1 status.

Human equilibrative nucleoside transporter 1 (hENT1) expression as a predictive biomarker for gemcitabine chemotherapy in biliary tract cancer

Gemcitabine is a principal chemotherapeutic agent for biliary tract cancer (BTC). Expression of human equilibrative nucleoside transporter 1 (hENT1) is regarded as a potential predictive biomarker for a gemcitabine response in some cancers. This study was conducted to investigate the association between hENT1 expression and the effects of gemcitabine on BTC cell lines and on patients with advanced BTC receiving gemcitabine-based chemotherapy. A total of four BTC cell lines, HuCCT1, SNU-478, SNU-1079, and SNU-1196, were tested. mRNA and protein expression levels of hENT1 were measured by quantitative reverse-transcription polymerase chain reaction and western blotting, respectively. Cell viability after gemcitabine treatment was measured in a chemosensitivity assay. For clinical assessment, 40 patients with unresectable or recurrent BTC who were treated with gemcitabine (1000 mg/m²) and cisplatin (25 mg/m²) between June 2012 and May 2014 were enrolled. Among the four cell lines, SNU1196 showed the highest mRNA and protein levels of hENT1. Expression of hENT1 showed a linear correlation with the log value of the half-maximal inhibitory concentration of gemcitabine. During incubation with gemcitabine, pretreatment with hENT1-specific small interfering RNA (siRNA) resulted in higher cell viability than that in samples pretreated with control siRNA. In a clinical evaluation, the median progression-free survival was 24 and 11 weeks among patients with strong and weak intratumoral hENT1 immunohistochemical staining (P = 0.05), and the median overall survival was 52 and 26 weeks (P = 0.15), respectively. In conclusion, this study showed that increased hENT1 expression is associated with a stronger toxic effect of gemcitabine on BTC cell lines. The clinical outcomes in this study suggest that increased intratumoral hENT1 immunohistochemical staining is a possible biomarker predicting better therapeutic effects of gemcitabine on patients with advanced BTC. Further studies are needed to determine the precise role of hENT1 in BTC.

[Personalized cancer medicine : Biomarkers for molecular therapy stratification in pancreatic carcinoma]

Ductal adenocarcinoma of the pancreas has a very poor prognosis and a rising incidence. Even after curative intent resection, which is possible in a minority of patients, most patients relapse, whereas the majority is diagnosed with inoperable or metastatic disease. That's why palliative systemic chemotherapy is the current therapeutic mainstay. Biomarker-based tumor characterization could identify potential therapy targets and enable a personalized cancer medicine. Although potentially targetable alterations occur at very low frequencies, the possible impact on patient outcome can be significant. This article summarizes some of the contributions to these aspects and gives an outlook on their clinical meaning.

Retrospective analysis of efficacy and safety of Gemcitabine-based chemotherapy in patients with metastatic pancreatic adenocarcinoma experiencing disease progression on FOLFIRINOX

Background

Metastatic pancreatic adenocarcinoma (MPA) represents a highly lethal condition. Despite the improvements seen with FOLFIRINOX, there is no randomized data to guide treatment selection beyond this regimen. We aimed to evaluate the outcomes of patients with MPA progressing on FOLFIRINOX who were treated with Gemcitabine-based chemotherapy afterwards.

Methods

We included patients aged 18 years or older, treated for MPA with FOLFIRINOX in the first-line setting and who experienced disease progression, with Eastern Cooperative Oncology Group (ECOG) performance status 0-2, and treated with at least one cycle of Gemcitabine-based chemotherapy in second or further lines of treatment. We used descriptive statistics to characterize the study population and Cox proportional-hazards models to describe factors associated with survival. As an exploratory analysis, we compared the outcomes of patients treated with single-agent Gemcitabine with those of patients undergoing Gemcitabine-based polychemotherapy.

Results

The study population consisted of 42 patients. Median age was 59 years and 78.6% of patients presented ECOG 0-1. Thirty-three patients (78.6%) were treated with Gemcitabine-based chemotherapy in the second-line setting and 27 patients (64.3%) were treated with single-agent Gemcitabine. Objective response rate and disease control rate were 2.4% and 33.4%, respectively. Median progression-free survival (PFS) and median overall survival (OS) were 2.9 and 5.5 months, respectively. Six-month PFS and OS rates were 19.2% and 46.2%, respectively. We observed no significant difference in OS according to the type of Gemcitabine-based chemotherapy, despite numerically improved disease control rate and PFS for those treated with Gemcitabine-based polychemotherapy. In multivariate analysis, ECOG 2 (vs. ECOG 0-1) was the only factor significantly associated with inferior PFS and OS.

Conclusions

a subgroup of patients with MPA derives benefit from treatment with Gemcitabine-based regimens after FOLFIRINOX. There is a suggestion that Gemcitabine-based combinations, in particular Gemcitabine plus Nab-Paclitaxel, provide superior outcomes compared to single-agent Gemcitabine. Additionally, treatment in this setting should be offered carefully to patients with ECOG 2, as they present shorter survival and increased risk of toxicity.

Advanced pancreatic cancer: The standard of care and new opportunities

Presentation of pancreatic cancer is localized, locally advanced or metastatic. With the later represented the main bulk (more than 80%). Despite the significant innovation in molecular analysis and therapeutic approach in many types of cancer in the last two decades, still the outcome of advanced pancreatic cancer is disappointing and the mortality rate approximately unchanged. In this mandated review we intended to highlight the standard of care and emerging agents for advanced pancreatic cancer treatment.

A predictive analysis of the SP120 and 10D7G2 antibodies for human equilibrative nucleoside transporter 1 (hENT1) in pancreatic ductal adenocarcinoma treated with adjuvant gemcitabine

Expression of human equilibrative nucleoside transporter 1 (hENT1) in pancreatic ductal adenocarcinoma (PDAC) has been postulated to be a marker of sensitivity to gemcitabine. However, heterogeneity in the studies attempting to quantify hENT1 expression in patients with PDAC treated with gemcitabine has yielded inconclusive results that impede the adoption of hENT1 expression as a predictive biomarker. Tissue microarrays consisting of PDAC specimens from 227 patients acquired between 1987 and 2013 annotated with treatment and outcome information were subjected to staining with two antibodies for hENT1 (10D7G2 and SP120) on a single automated platform and scored by two independent pathologists blinded to treatment and outcome. The resultant scores were subjected to individual predictive disease-specific survival analysis and to unsupervised hierarchical clustering to generate a multi-marker classification. Tumour cell staining prevalence using either SP120 or 10D7G2 was predictive of gemcitabine sensitivity (p = 0.02; p = 0.01). When combined, three groups emerged, classified as SP120_Low_10D7G2_Low, SP120_Low_10D7G2_High, and SP120_High_10D7G2_High, in which adjuvant gemcitabine conferred median survival differences of 0.2, 0.8, and 1.5 (p = 0.76, p = 0.06, p = 0.01) years, respectively. These results were largely replicated in multivariable analysis with the P value for the SP120_Low_10D7G2_High cluster achieving statistical significance (p = 0.03). These data suggest that either antibody for hENT1 can be used to predict gemcitabine sensitivity in resected PDAC. However, using both antibodies adds valuable information that enables the stratification of patients who can expect to have a good, intermediate, and poor response to adjuvant gemcitabine.

Use of gemcitabine as a second-line treatment following chemotherapy with folfirinox for metastatic pancreatic adenocarcinoma

There is a lack of prospective data about second-line treatments for metastatic pancreatic ductal adenocarcinoma patients. This is partially due to recent changes in first-line chemotherapy treatments. Despite this dearth of information, 50.0% of the patients who experience failure with first-line folinic acid, 5-fluorouracil, irinotecan and oxaliplatin (folfirinox) treatment are eligible for additional chemotherapy. In this setting, gemcitabine is widely used without any standard recommendations available. The present study evaluated 42 patients who received gemcitabine subsequent to a first-line treatment of folfirinox between January 2008 and December 2012 at the Centre Léon Bérard (Lyon, France). Clinical data, biological data and tumor characteristics were retrospectively analyzed to identify prognostic factors for successful treatment with gemcitabine. In total, 11 patients (26.2%) experienced control of their cancer with gemcitabine treatment. However, there was no predictive marker for their response to the drug. The median overall survival was 3.6 months from gemcitabine initiation [95% confidence interval (CI), 2.1-5.1]. The median length of gemcitabine treatment was 1.5 months (95% CI, 0.3-13.3). Among the 11 patients who were successfully treated with gemcitabine, 6 were resistant to first-line folfirinox treatment. Patients who were non responsive to folfirinox had a higher probability of success with gemcitabine compared with patients that responded to folfirinox (54.5 vs. 21.4%, respectively; P=0.061). The present study did not identify any clinical or biological marker with a predictive value for successful gemcitabine treatment. Furthermore, successful gemcitabine treatment was not correlated with patients' response to first-line folfirinox treatment. This suggests an absence of cross-resistance in the chemotherapy protocols and provides evidence for effective cancer treatment with the second-line gemcitabine therapy.

Immunohistochemical hENT1 expression as a prognostic biomarker in patients with resected pancreatic ductal adenocarcinoma undergoing adjuvant gemcitabine-based chemotherapy

BACKGROUND

Human equilibrative nucleoside transporters (hENTs) are transmembranous proteins that facilitate the uptake of nucleosides and nucleoside analogues, such as gemcitabine, into the cell. The abundance of hENT1 transporters in resected pancreatic ductal adenocarcinoma (PDAC) might make hENT1 a potential biomarker of response to adjuvant chemotherapy. The aim of this study was to see whether hENT1 expression, as determined by immunohistochemistry, was a suitable predictive marker for subsequent treatment with gemcitabine-based adjuvant chemotherapy.

METHODS

A systematic review was performed, searching databases from January 1997 to January 2016. Articles pertaining to hENT1 immunohistochemical analysis in resected PDAC specimens from patients who subsequently underwent adjuvant gemcitabine-based chemotherapy were identified. Eligible studies were required to contain survival data, reporting specifically overall survival (OS) and disease-free survival (DFS) with associated hazard ratios (HRs) stratified by hENT1 status.

RESULTS

Of 42 articles reviewed, eight were suitable for review, with seven selected for quantitative meta-analysis. The total number of patients included in the meta-analysis was 770 (405 hENT1-negative, 365 hENT1-positive). Immunohistochemically detected hENT1 expression was significantly associated with both prolonged DFS (HR 0·58, 95 per cent c.i. 0·42 to 0·79) and OS (HR 0·52, 0·38 to 0·72) in patients receiving adjuvant gemcitabine but not those having fluoropyrimidine-based adjuvant therapy.

CONCLUSION

Expression of hENT1 is a suitable prognostic biomarker in patients undergoing adjuvant gemcitabine-based chemotherapy.

Biomarkers in pancreatic adenocarcinoma: current perspectives

Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis, with a 5-year survival rate of 7.7%. Most patients are diagnosed at an advanced stage not amenable to potentially curative resection. A substantial portion of this review is dedicated to reviewing the current literature on carbohydrate antigen (CA 19-9), which is currently the only guideline-recommended biomarker for PDAC. It provides valuable prognostic information, can predict resectability, and is useful in decision making about neoadjuvant therapy. We also discuss carcinoembryonic antigen (CEA), CA 125, serum biomarker panels, circulating tumor cells, and cell-free nucleic acids. Although many biomarkers have now been studied in relation to PDAC, significant work still needs to be done to validate their usefulness in the early detection of PDAC and management of patients with PDAC.

Gemcitabine versus FOLFIRINOX in patients with advanced pancreatic adenocarcinoma hENT1-positive: everything was not too bad back when everything seemed worse

PURPOSE

hENT1 is a transmembrane protein which acts as a nucleoside transporter and is the main mediator of Gemcitabine (GEM) uptake into human cells. In this retrospective study we compared GEM versus FOLFIRINOX in patients with metastatic pancreatic cancer in which hENT1 evaluation was available.

METHODS

149 patients affected by unresectable metastatic pancreatic cancer, treated in our institution from 2009 to 2013, have been screened for inclusion in this retrospective study. Seventy patients, treated with GEM or FOLFIRINOX in first-line therapy, fulfilled clinical inclusion criteria for survival analysis. Thirty-one patients were available and contained sufficient quality/quantity RNA for evaluation of hENT1 expression by RT-PCR. The primary endpoint was OS and the secondary endpoint was PFS.

RESULTS

The survival analysis, carried out on 70 patients regardless of hENT1 expression, showed a statistically longer OS and PFS in the group treated with FOLFIRINOX compared to GEM. Within the exploratory analysis, which included 31 patients, no differences were found in hENT1 positive patients treated with FOLFIRINOX compared to GEM in terms of OS (8.5 vs 7 months, HR: 0.89; 95 % CI 0.3-2.5; p = 0.8) and PFS (5.5 vs 5 months, HR: 0.8, 95 % CI 0.2-2.2; p = 0.61). GEM-treated hENT1 positive patients showed a statistically significant improvement both of OS (8 vs 2 months; p = 0.0012) and PFS (5 vs 1 months; p = 0.0004) in comparison to GEM-treated hENT1 negative patients.

CONCLUSIONS

In our exploratory analysis GEM seems as effective as FOLFIRINOX in terms of survival with a better safety profile in hENT1 positive metastatic pancreatic cancer.

Drug metabolism and pancreatic cancer

Pancreatic cancer remains a fatal disease in the majority of patients. The era of personalized medicine is upon us: customizing therapy according to each patient's individual cancer. Potentially, therapy can be targeted at individuals who would most likely have a favorable response, making it more efficacious and cost effective. This is particularly relevant for pancreatic cancer, which currently portends a very poor prognosis. However, there is much to be done in this field, and more studies are needed to bring this concept to reality.

Human Equilibrative Nucleoside Transporter 1 Expression in Endoscopic Ultrasonography-Guided Fine-Needle Aspiration Biopsy Samples Is a Strong Predictor of Clinical Response and Survival in the Patients With Pancreatic Ductal Adenocarcinoma Undergoing Gemcitabine-Based Chemoradiotherapy

OBJECTIVES

This study aimed to clarify whether pretreatment human equilibrative nucleoside transporter (hENT1) expressions in endoscopic ultrasonography-guided fine-needle aspiration biopsy (EUS-FNAB) specimens obtained from resectable, borderline resectable, and locally advanced unresectable pancreatic ductal adenocarcinoma (PDAC) are concordant with those in the resected specimen after gemcitabine-based chemoradiotherapy (Gem-CRT) and to validate the utility of hENT1 expression using EUS-FNAB samples as a prognostic marker.

METHODS

We evaluated the relationship between hENT1 expressions assessed by immunohistochemical staining and clinical outcomes in 51 of 76 patients with PDAC who were diagnosed by EUS-FNAB and received preoperative Gem-CRT.

RESULTS

The concordance rate of hENT1 expressions was 89.2% (K = 0.681). Median survival time (month) in the 51 whole patients and 37 patients with resection was significantly longer in hENT1 positive than in hENT1 negative: 25.0 and 30.0 versus 9.0 and 9.0, respectively. A multivariate analysis confirmed that hENT1 expression was an independent prognostic factor in both whole patients and those with resection. Regardless of T3 and T4, hENT1-positive patients with resection had significantly better prognosis than hENT1-negative patients, whose prognosis was similar to those without resection.

CONCLUSIONS

The assessment of hENT1 expression using EUS-FNAB samples before Gem-CRT provides important information on patients with PDAC who can benefit from curative-intent resection.

Current standards and new innovative approaches for treatment of pancreatic cancer

Pancreatic adenocarcinoma remains a devastating disease with a 5-year survival rate not exceeding 6%. Treatment of this disease remains a major challenge. This article reviews the state-of-the-art in the management of this disease and the new innovative approaches that may help to accelerate progress in treating its victims. After careful pre-therapeutic evaluation, only 15-20% of patients diagnosed with a pancreatic cancer (PC) are eligible for upfront radical surgery. After R0 or R1 resection in such patients, evidence suggests a significantly positive impact on survival of adjuvant chemotherapy comprising 6 months of gemcitabine or fluorouracil/folinic acid. Delayed adjuvant chemoradiation is considered as an option in cases of positive margins. Borderline resectable pancreatic cancer (BRPC) is defined as a tumour involving the mesenteric vasculature to a limited extend. Resection of these tumours is technically feasible, yet runs the high risk of a R1 resection. Neoadjuvant treatment probably offers the best chance of achieving successful R0 resection and long-term survival, but the best treatment options should be determined in prospective randomised studies. Gemcitabine has for 15 years been the only validated therapy for advanced PC. Following decades of negative phase III studies, increasing evidence now suggests that further significant improvements to overall survival can be achieved via either Folfirinox or gemcitabine + nab-paclitaxel regimens. Progress in systemic therapy may improve the chances of resection in borderline resectable pancreatic cancer (BRPC) or locally advanced PC. This requires first enhancing knowledge of the genetic events driving carcinogenesis, which may then be translated into clinical studies.

A randomized phase II study of weekly nab-paclitaxel plus gemcitabine or simplified LV5FU2 as first-line therapy in patients with metastatic pancreatic cancer: the AFUGEM GERCOR trial

BACKGROUND

Metastatic pancreatic adenocarcinoma (PAC) prognosis remains dismal and gemcitabine monotherapy has been the standard treatment over the last decade. Currently, two first-line regimens are used in this setting: FOLFIRINOX and nab-paclitaxel plus gemcitabine. Increasing translational data on the predictive value of hENT1 for determining gemcitabine efficacy suggest that a non-gemcitabine-based regimen is favored in about 60 % of patients with PAC due to high resistance of PAC to this cytotoxic drug. This study aims to evaluate the efficacy of weekly nab-paclitaxel combined with gemcitabine or a simplified (s) LV5FU2 regimen in patients with previously untreated metastatic PAC.

METHODS/DESIGN

AFUGEM is a two-stage, open-label, randomized, multicenter, phase II trial. Patients with PAC who meet the inclusion criteria and provide written informed consent will be randomized in a 1:2 ratio to either nab-paclitaxel (125 mg/m(2)) plus gemcitabine (1000 mg/m(2)) given on days 1, 8, and 15 every 28 days or nab-paclitaxel (125 mg/m(2)) plus sLV5FU2 (leucovorin 400 mg/m(2) followed by bolus 400 mg/m(2) 5-fluorouracil and by 5-fluorouracil 2400 mg/m(2) as an 46-h intravenous infusion) given on days 1 and 15 every 28 days. A total of 114 patients will be randomized to one of the treatment arms. The primary endpoint is progression-free survival at 4 months. Secondary outcomes are rate and duration of response, disease control, overall survival, safety, and quality of life. Potential biomarkers of gemcitabine (hENT1, dCK) and 5-fluorouracil (TS) efficacy will be assessed.

DISCUSSION

The AFUGEM trial is designed to provide valuable information regarding efficacy and tolerability of nab-paclitaxel plus gemcitabine and nab-paclitaxel plus sLV5FU2 regimens. Identification of potential predictive biomarkers of gemcitabine and 5-fluorouracil is likely to drive therapeutic decisions in patients with metastatic PAC.

TRIAL REGISTRATION

AFUGEM is registered at Clinicaltrials.gov: NCT01964534 , October 15, 2013.

Pancreatic cancer genomics: where can the science take us?

The incidence of pancreatic ductal adenocarcinoma (PDAC) is steadily increasing and the annual death-to-incidence ratio approaches one. This is a figure that has not changed for several decades. Surgery remains the only chance of cure; however, only less than 20% of patients are amenable to operative resection. Despite successful surgical resection, the majority of the patients still succumb to recurrent metastatic disease. Therefore, there is an urgent need to develop novel therapeutic strategies and to better select patients for current therapies. In this review, we will discuss current management by highlighting the landmark clinical trials that have shaped current care. We will then discuss the challenges of therapeutic development using the current randomized-controlled trial paradigm when confronted with the molecular heterogeneity of PDAC. Finally, we will discuss strategies that may help to shape the management of PDAC in the near future.

Nucleoside transporter proteins as biomarkers of drug responsiveness and drug targets

Nucleoside and nucleobase analogs are currently used in the treatment of solid tumors, lymphoproliferative diseases, viral infections such as hepatitis and AIDS, and some inflammatory diseases such as Crohn. Two gene families are implicated in the uptake of nucleosides and nucleoside analogs into cells, SCL28 and SLC29. The former encodes hCNT1, hCNT2, and hCNT3 proteins. They translocate nucleosides in a Na⁺ coupled manner with high affinity and some substrate selectivity, being hCNT1 and hCNT2 pyrimidine- and purine-preferring, respectively, and hCNT3 a broad selectivity transporter. SLC29 genes encode four members, being hENT1 and hENT2 the only two which are unequivocally implicated in the translocation of nucleosides and nucleobases (the latter mostly via hENT2) at the cell plasma membrane. Some nucleoside-derived drugs can also interact with and be translocated by members of the SLC22 gene family, particularly hOCT and hOAT proteins. Inter-individual differences in transporter function and perhaps, more importantly, altered expression associated with the disease itself might modulate the transporter profile of target cells, thereby determining drug bioavailability and action. Drug transporter pharmacology has been periodically reviewed. Thus, with this contribution we aim at providing a state-of-the-art overview of the clinical evidence generated so far supporting the concept that these membrane proteins can indeed be biomarkers suitable for diagnosis and/or prognosis. Last but not least, some of these transporter proteins can also be envisaged as drug targets, as long as they can show “transceptor” functions, in some cases related to their role as modulators of extracellular adenosine levels, thereby providing a functional link between P1 receptors and transporters.

Time and concentration dependency of P-gp, MRP1 and MRP5 induction in response to gemcitabine uptake in Capan-2 pancreatic cancer cells

1. Influx and efflux proteins play a major role in the overall uptake and efficacy of chemotherapeutic agents and cellular chemo-resistance. 2. The present study investigated the time course and dose dependency of the induction of three efflux proteins, P-gp, MRP1 and MRP5, in response to gemcitabine exposure in Capan-2 pancreatic cancer cell line at transcriptional and translational levels. The influence of exposure on the influx protein (ENT1), the net cellular uptake of the gemcitabine, the overall ATPase activity and the cell death rate were also measured. 3. The time course of the expression exhibited an initial rise, toward a plateau level. The estimated Km and Vmax confirmed that MRP5 and to a lesser extent MRP1 are the prominent proteins for efflux of gemcitabine. Both mRNA and protein expression demonstrated the time and concentration dependency of the induction; and the elevated ATPase activity validated that the induced efflux proteins are functionally active. 4. The results of the study revealed that the efficacy window of gemcitabine as it relates to the function of the efflux proteins is concentration and temporal dependent and is well correlated to the first 60 min of exposure.

Human equilibrative nucleoside transporter 1 testing in pancreatic ductal adenocarcinoma: a comparison between murine and rabbit antibodies

AIMS

The human equilibrative nucleoside transporter 1 (hENT1) expression level in pancreatic ductal adenocarcinoma (PDAC) may predict survival in gemcitabine-treated patients after resection. These results have been obtained with a murine anti-hENT1 antibody (10D7G2) that is not commercially available. Another antibody, which is rabbit-derived (SP120), appears to have no predictive value in local, advanced or metastatic PDAC. We aimed to study whether the two antibodies are equivalent.

METHODS AND RESULTS

We compared hENT1 expression with both antibodies in resected PDAC. The results were correlated with overall survival (OS) following gemcitabine treatment. Tissues from two sets of patients (n = 147 each) were stained with SP120 by the use of different equipment, with an amplification technique being used for set 2. The rate of 'hENT1 high' cases was lower with SP120 (set 1, 7% versus 48%; set 2, 11% versus 38%). With the amplification technique, the rate of hENT1 high cases was globally similar between both antibodies. However, concordance between the antibodies was found in only 50% of cases. High hENT1 expression was predictive of OS only with 10D7G2 (hazard ratio 0.49; 95% confidence interval 0.24-0.98; P = 0.045).

CONCLUSIONS

The two antibodies are not equivalent. Further prospective studies seem to be warranted before hENT1 testing for PDAC is used in daily practise.