Therapeutic advances in pancreatic cancer: miles to go before we sleep

Actively Targeted Nanodelivery of Echinomycin Induces Autophagy-Mediated Death in Chemoresistant Pancreatic Cancer In Vivo

Pancreatic cancer remains a recalcitrant neoplasm associated with chemoresistance and high fatality. Because it is frequently resistant to apoptosis, exploiting autophagic cell death could offer a new treatment approach. We repurpose echinomycin, an antibiotic encapsulated within a syndecan-1 actively targeted nanoparticle, for treatment of pancreatic cancer. Tumor-specific uptake, biodistribution, efficacy of nanodelivered echinomycin, and mechanism of cell death were assessed in aggressive, metastatic models of pancreatic cancer. In these autophagic-dependent pancreatic cancer models, echinomycin treatment resulted in autophagic cell death noted by high levels of LC3 among other autophagy markers, but without hallmarks of apoptosis, e.g., caspase activation and chromatin fragmentation, or necrosis, e.g., plasma membrane degradation and chromatin condensation/degrading. In vivo, biodistribution of syndecan-1-targeted nanoparticles indicated preferential S2VP10 or S2CP9 tumor uptake compared to the liver and kidney (S2VP10 p = 0.0016, p = 0.00004 and S2CP9 p = 0.0009, p = 0.0001). Actively targeted nanodelivered echinomycin resulted in significant survival increases compared to Gemzar (S2VP10 p = 0.0003, S2CP9 p = 0.0017) or echinomycin only (S2VP10 p = 0.0096, S2CP9 p = 0.0073). We demonstrate that actively targeted nanodelivery of echinomycin results in autophagic cell death in pancreatic and potentially other high-autophagy, apoptosis-resistant tumors. Collectively, these findings support syndecan-1-targeted delivery of echinomycin and dysregulation of autophagy to induce cell death in pancreatic cancer.

Gemcitabine Combined with the mTOR Inhibitor Temsirolimus in Patients with Locally Advanced or Metastatic Pancreatic Cancer. A Hellenic Cooperative Oncology Group Phase I/II Study

BACKGROUND

The prognosis of patients with advanced pancreatic cancer is dismal, and there is a need for novel and effective treatments.

OBJECTIVES

Tο determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) of a novel gemcitabine (G) and temsirolimus (T) combination (phase I) and estimate the 6-month progression-free survival (PFS) in patients treated with the T + G combination (phase II).

PATIENTS AND METHODS

Eligible patients with histologically confirmed inoperable or metastatic pancreatic carcinoma (MPC) were entered into the trial. G was given bi-weekly and T weekly in a 4-week cycle. The first dose level was set at G 800 mg/m² and T 10 mg. G was escalated in increments of 200 mg/m² and T in increments of 5 mg until DLT was reached, and the recommended dose was used for the phase II part.

RESULTS

Thirty patients were enrolled in the phase I component at the pre-planned six dose levels; one bilirubin DLT of grade III occurred at the first dose level. The MTD was established as the approved doses of both drugs. Fifty-five patients were entered into the phase II component. Median relative dose intensities administered in the first cycle were 0.75 for T and 0.99 for G. Grade 3-4 hematological toxicities were recorded in 87.3% of patients. The most common non-hematological adverse events were metabolic disorders (81.8%) followed by gastrointestinal disorders (63.6%). Median PFS was 2.69 months (95% CI 1.74-4.95) and median OS was 4.95 months (95% CI 3.54-6.85), while the 6-month PFS rate was 30.9%.

CONCLUSIONS

Combination of G and T is feasible in patients with locally advanced or MPC with manageable side effects, but lacks clinical efficacy. The study was registered in the Australian New Zealand Clinical Trials Registry (ACTRN12611000643976).

Trefoil factor(s) and CA19.9: A promising panel for early detection of pancreatic cancer

Background

Trefoil factors (TFF1, TFF2, and TFF3) are small secretory molecules that recently have gained significant attention in multiple studies as an integral component of pancreatic cancer (PC) subtype-specific gene signature. Here, we comprehensively investigated the diagnostic potential of all the member of trefoil family, i.e., TFF1, TFF2, and TFF3 in combination with CA19.9 for detection of PC.

Methods

Trefoil factors (TFFs) gene expression was analyzed in publicly available cancer genome datasets, followed by assessment of their expression in genetically engineered spontaneous mouse model (GEM) of PC (KrasG12D; Pdx1-Cre (KC)) and in human tissue microarray consisting of normal pancreas adjacent to tumor (NAT), precursor lesions (PanIN), and various pathological grades of PC by immunohistochemistry (IHC). Serum TFFs and CA19.9 levels were evaluated via ELISA in comprehensive sample set (n = 362) comprised of independent training and validation sets each containing benign controls (BC), chronic pancreatitis (CP), and various stages of PC. Univariate and multivariate logistic regression and receiver operating characteristic curves (ROC) were used to examine their diagnostic potential both alone and in combination with CA19.9.

Findings

The publicly available datasets and expression analysis revealed significant increased expression of TFF1, TFF2, and TFF3 in human PanINs and PC tissues. Assessment of KC mouse model also suggested upregulated expression of TFFs in PanIN lesions and early stage of PC. In serum analyses studies, TFF1 and TFF2 were significantly elevated in early stages of PC in comparison to benign and CP control group while significant elevation in TFF3 levels were observed in CP group with no further elevation in its level in early stage PC group. In receiver operating curve (ROC) analyses, combination of TFFs with CA19.9 emerged as promising panel for discriminating early stage of PC (EPC) from BC (AUC_{TFF1+TFF2+TFF3+CA19.9} = 0.93) as well as CP (AUC_{TFF1+TFF2+TFF3+CA19.9} = 0.93). Notably, at 90% specificity (desired for blood-based biomarker panel), TFFs combination improved CA19.9 sensitivity by 10% and 25% to differentiate EPC from BC and CP respectively. In an independent blinded validation set, the combination of TFFs and CA19.9 (AUC_{TFF1+TFF2+TFF3+CA19.9} = 0.82) also improved the overall efficacy of CA19.9 (AUC_CA19.9 = 0.66) to differentiate EPC from CP proving unique biomarker capabilities of TFFs to distinguish early stage of this deadly lethal disease.

Interpretation

In silico, tissue and serum analyses validated significantly increased level of all TFFs in precursor lesions and early stages of PC. The combination of TFFs enhanced sensitivity and specificity of CA19.9 to discriminate early stage of PC from benign control and chronic pancreatitis groups.

Efficient Gene Delivery and Expression in Pancreas and Pancreatic Tumors by Capsid-Optimized AAV8 Vectors

Despite efforts to use adeno-associated viral (AAV) vector-mediated gene therapy for treatment of pancreatic ductal adenocarcinoma (PDAC), transduction efficiency remains a limiting factor and thus improvement of AAV delivery would significantly facilitate the treatment of this malignancy. Site-directed mutagenesis of specific tyrosine (Y) residues to phenylalanine (F) on the surface of various AAV serotype capsids has been reported as a method for enhancing gene transfer efficiencies. In the present studies, we determine whether Y-to-F mutations could also enhance AAV8 gene transfer in the pancreas to facilitate gene therapy for PDAC. Three different Y-to-F mutant vectors (a single-mutant, Y733F; a double-mutant, Y447F+Y733F; and a triple-mutant, Y275F+Y447F+Y733F) and wild-type AAV8 (WT-AAV8) were administered by intraperitoneal or tail-vein routes to Kras^G12D+/-, Kras^G12D+/-/Pten^+/-, and wild-type mice. The transduction efficiency of these vectors expressing the mCherry reporter gene was evaluated 2 weeks post administration in pancreas or PDAC and correlated with viral genome copy numbers. Our comparative and quantitative analyses of the transduction profiles demonstrated that the Y-to-F double-mutant exhibited the highest mCherry expression in pancreatic tissues (range 45-70%) compared with WT-AAV8 (7%; p < 0.01). We also detected a 7-fold higher level of vector genome copy numbers in normal pancreas following transduction with the double-mutant AAV8 compared with WT-AAV8 (10,285 vs. 1,500 vector copies/μg DNA respectively, p < 0.05). In addition, we observed that intraperitoneal injection of the double-mutant AAV8 led to a 15-fold enhanced transduction efficiency as compared to WT-AAV8 in mouse PDAC, with a corresponding ∼14-fold increase in vector genome copy numbers (26,575 vs. 2,165 copies/μg DNA respectively, p < 0.05). These findings indicate that the Y447+Y733F-AAV8 leads to a significant enhancement of transduction efficiency in both normal and malignant pancreatic tissues, suggesting the potential use of this vector in targeting pancreatic diseases in general, and PDAC in particular.

Economic evaluation for the US of nab-paclitaxel plus gemcitabine versus FOLFIRINOX versus gemcitabine in the treatment of metastatic pancreas cancer

BACKGROUND

Nab-paclitaxel plus gemcitabine (NAB-P + GEM) and FOLFIRINOX have shown superior efficacy over gemcitabine (GEM) in the treatment of metastatic pancreatic ductal adenocarcinoma (mPDA). Although the incremental clinical benefits are modest, both treatments represent significant advances in the treatment of a high-mortality cancer. In this independent economic evaluation for the US, the aim was to estimate the comparative cost-utility and cost-effectiveness of these three regimens from the payer perspective.

METHODS

In the absence of a direct treatment comparison in a single clinical trial, the Bucher indirect comparison method was used to estimate the comparative efficacy of each regimen. A Markov model evaluated life years (LY) and quality-adjusted life years (QALY) gained with NAB-P + GEM and FOLFIRINOX over GEM, expressed as incremental cost-effectiveness (ICER) and cost-utility ratios (ICUR). All costs and outcomes were discounted at 3%/year. The impact of parameter uncertainty on the model was assessed by probabilistic sensitivity analyses.

RESULTS

NAB-P + GEM was associated with differentials of +0.180 LY and +0.127 QALY gained over GEM at an incremental total cost of $25,965; yielding an ICER of $144,096/LY and ICUR of $204,369/QALY gained. FOLFIRINOX was associated with differentials of +0.368 LY and +0.249 QALY gained over GEM at an incremental total cost of $93,045; yielding an ICER of $253,162/LY and ICUR of $372,813/QALY gained. In indirect comparison, the overall survival hazard ratio (OS HR) for NAB-P + GEM vs FOLFIRINOX was 0.79 (95%CI = 0.59-1.05), indicating no superiority in OS of either regimen. FOLFIRINOX had an ICER of $358,067/LY and an ICUR of $547,480/QALY gained over NAB-P + GEM. Tornado diagrams identified variation in the OS HR, but no other parameters, to impact the NAB-P + GEM and FOLFIRINOX ICURs.

CONCLUSIONS

In the absence of a statistically significant difference in OS between NAB-P + GEM and FOLFIRINOX, this US analysis indicates that the greater economic benefit in terms of cost-savings and incremental cost-effectiveness and cost-utility ratios favors NAB-P + GEM over FOLFIRINOX.

Economic Evaluations of First-Line Chemotherapy Regimens for Pancreatic Cancer: A Critical Review

Effect sizes of efficacy of first-line treatments for (metastatic) pancreas cancer are constrained, underscoring the need for evaluations of the efficacy-to-cost relationship. We critically review economic evaluations of first-line chemotherapy regimens for pancreatic cancer since the 1997 introduction of gemcitabine. We searched PubMed/MEDLINE and EMBASE (1997-2015), and the websites of health technology assessment agencies. Two authors independently reviewed economic studies for eligibility in this review; evaluated peer-reviewed, journal-published studies in terms of the Drummond Checklist; and critiqued the technical and scientific merit of all studies. Sixteen pharmacoeconomic evaluations were included: ten published in nine peer-reviewed journals and six on three websites. Six were on single-agent therapies and ten on combination therapies. Analyses conducted included cost-effectiveness (three studies), cost-utility (one study), or combined cost-effectiveness and cost-utility (12 studies). Studies diverged in results, mainly because of different assumptions, methods, inputs, and country-specific guidelines. The two most recent regimens, nanoparticle albumin-bound paclitaxel plus gemcitabine (NAB-P + GEM) and the combination of fluorouracil, oxaliplatin, leucovorin, and irinotecan (FOLFIRINOX), were evaluated in an indirect comparison, yielding a statistically similar benefit in overall survival but superior progression-free survival for FOLFIRINOX. NAB-P + GEM showed greater economic benefit over FOLFIRINOX. In conclusion, the divergence in results observed across studies is attributable to economic drivers that are specific to countries and their healthcare (financing) systems. No recommendations regarding the relative economic benefit of treatment regimens, general or country-specific, are made as the purpose of pharmacoeconomic analysis is to inform policy decision-making and clinical practice, not set policy or define clinical practice.