Changing the paradigm in conducting randomized clinical studies in advanced pancreatic cancer: an opportunity for better clinical development

Cancer Genetics and Implications for Clinical Management

There is now compelling evidence that the molecular heterogeneity of cancer is associated with disparate phenotypes with variable outcomes and therapeutic responsiveness to therapy in histologically indistinguishable cancers. This diversity may explain why conventional clinical trial designs have mostly failed to show efficacy when patients are enrolled in an unselected fashion. Knowledge of the molecular phenotype has the potential to improve therapeutic selection and hence the early delivery of the optimal therapeutic regimen. Resolution of the challenges associated with a more stratified approach to health care will ensure more precise diagnostics and enhance therapeutic selection, which will improve overall outcomes.

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.

A phase I dose-escalation study of lenalidomide in combination with gemcitabine in patients with advanced pancreatic cancer

Purpose

Lenalidomide have both immunomodulatory and anti-angiogenic properties which could confer anti-cancer effects. The aim of this study was to assess the feasibility of combining lenalidomide with the standard treatment gemcitabine in pancreatic cancer patients with advanced disease.

Patients and Methods

Eligible patients had locally advanced or metastatic adenocarcinoma of the pancreas. Patients received lenalidomide days 1–21 orally and gemcitabine 1000 mg/m2 intravenously (days 1, 8 and 15), each 28 day cycle. Three cohorts of lenalidomide were examined (Cohort I = 15 mg, Cohort II = 20 mg and Cohort III = 25 mg daily). The maximum tolerated dose (MTD) of lenalidomide given in combination with gemcitabine was defined as the highest dose level at which no more than one out of four (25%) subjects experiences a dose-limiting toxicity (DLT). Patients should also be able to receive daily low molecular weight heparin (LMWH) (e.g. dalteparin 5000 IU s.c. daily) as a prophylactic anticoagulant for venous thromboembolic events (VTEs). Twelve patients (n = 4, n = 3 and n = 5 in cohort I, II and III, respectively) were enrolled in this study.

Results

Median duration of treatment was 11 weeks (range 1–66), and median number of treatment cycles were three (range 1–14). The only DLT was a cardiac failure grade 3 in cohort III. Frequent treatment-related adverse events (AEs) (all grades) included neutropenia, leucopenia and fatigue (83% each, but there was no febrile neutropenia); thrombocytopenia (75%); dermatological toxicity (75%); diarrhea and nausea (42% each); and neuropathy (42%).

Discussion

This phase I study demonstrates the feasibility of the combination of lenalidomide and gemcitabine as first-line treatment in patients with advanced pancreatic cancer. The tolerability profile demonstrated in the dose escalation schedule of lenalidomide suggests the dosing of lenalidomide to be 25 mg daily on days 1–21 with standard dosing of gemcitabine and merits further evaluation in a phase II trial.

Trial Registration

ClinicalTrials.gov NCT01547260

Pancreatic biomarkers: Could they be the answer?

Pancreatic ductal adenocarcinoma (PDA) is known for its poor prognosis. Most of the patients are diagnosed with advanced stages, when no curative treatment is available. Currently, despite extensive clinical research on PDA, the median overall survival remains short. Diagnosis delay and primary chemo-resistance due to its intrinsic biological nature may explain the challenges to improve our results. Our knowledge about the molecular biology of PDA has exponentially increased during the last decades and its use for the development of biomarkers could help to reach better results in the clinical setting. These biomarkers could be the clue for the improvement in PDA clinical research by earlier detection strategies with diagnostic biomarkers, and by an individualization of treatment approach with prognostic and predictive biomarkers. This review summarizes the current knowledge about the molecular biology of PDA and the status of the most important prognostic and predictive biomarkers.

A randomised, double-blind, placebo-controlled trial of trametinib, an oral MEK inhibitor, in combination with gemcitabine for patients with untreated metastatic adenocarcinoma of the pancreas

BACKGROUND

Trametinib, an oral mitogen/extracellular signal-related kinase (MEK)1/2 inhibitor, holds promise for malignancies with rat sarcoma (RAS) mutations, like pancreas cancer. This phase II study was designed to determine overall survival (OS) in patients with pancreas cancer treated with trametinib and gemcitabine. Secondary end-points included progression-free survival (PFS), overall response rate (ORR) and duration of response (DOR); safety end-points were also assessed.

METHODS

Adults with untreated metastatic adenocarcinoma of the pancreas were randomised (1:1) to receive intravenous gemcitabine 1000 mg/m(2) (weekly × 7 for 8 weeks, then days 1, 8 and 15 of 28-day cycles) plus trametinib or placebo 2mg daily. RAS mutations were determined in circulating free DNA (cfDNA) and archival tumour tissue. OS was evaluated in kirsten rat sarcoma viral oncogene homolog (KRAS) mutant and wild-type subgroups.

RESULTS

Baseline characteristics for 160 patients were similar in both treatment arms. There was no significant difference in OS (hazard ratio (HR) 0.98; 95% confidence interval (CI), 0.67-1.44; P=.453); median OS was 8.4 months with gemcitabine plus trametinib and 6.7 months with gemcitabine plus placebo. Median PFS (16 versus 15 weeks), ORR (22% versus 18%) and median DOR (23.9 versus 16.1 weeks) were also similar for trametinib and placebo arms, respectively. KRAS mutation-positive patients (n=103) showed no difference in OS between arms. Thrombocytopenia, diarrhoea, rash and stomatitis were more frequent with trametinib, as was grade 3 anaemia.

CONCLUSIONS

The addition of trametinib to gemcitabine did not improve OS, PFS, ORR or DOR in patients with previously untreated metastatic pancreas cancer. Outcomes were independent of KRAS mutations determined by cfDNA.

Pancreatic cancer genomics

Pancreatic cancer is one of the most lethal malignancies. The overall median survival even with treatment is only 6-9 months, with almost 90% succumbing to the disease within a year of diagnosis. It is characterised by an intense desmoplastic stroma that may contribute to therapeutic resistance, and poses significant challenges for genomic sequencing studies. It is recalcitrant to almost all therapies and consequently remains the fourth leading cause of cancer death in Western societies. Genomic studies are unveiling a vast heterogeneity of mutated genes, and this diversity may explain why conventional clinical trial designs have mostly failed to demonstrate efficacy in unselected patients. Those that are available offer only marginal benefits overall, but are associated with clinically significant responses in as yet undefined subgroups. This chapter describes our current understanding of the genomics of pancreatic cancer and the potential impact of these findings on our approaches to treatment.

Triple approach strategy for patients with locally advanced pancreatic carcinoma

BACKGROUND

Radiofrequency ablation (RFA) is a relatively new technique, applied to metastatic solid tumours which, in recent studies, has been shown to be feasible and safe on locally advanced pancreatic carcinoma (LAPC). RFA can be combined with radio-chemotherapy (RCT) and intra-arterial plus systemic chemotherapy (IASC). The aim of this study was to investigate the impact on the prognosis of a multimodal approach to LAPC and define the best timing of RFA.

METHODS

This is a retrospective observational study of patients who have consecutively undergone RFA associated with multiple adjuvant approaches.

RESULTS

Between February 2007 and December 2011, 168 consecutive patients were treated by RFA, of which 107 were eligible for at least 18 months of follow-up. Forty-seven patients (group 1) underwent RFA as an up-front treatment and 60 patients as second treatment (group 2) depending on clinician choice. The median overall survival (OS) of the whole series was 25.6 months: 14.7 months in the group 1 and 25.6 months in the group 2 (P = 0.004). Those patients who received the multimodal treatment (RFA, RCT and IASC-triple approach strategy) had an OS of 34.0 months.

CONCLUSIONS

The multimodal approach seems to be feasible and associated with an improved longer survival rate.

Pancreatic cancer: why is it so hard to treat?

No common malignancy is as rapidly and inevitably fatal as pancreatic ductal adenocarcinoma (PDA). This grim fact has driven substantial research efforts into this disease in recent decades. Unfortunately, the investment has yet to result in a meaningful increase in 5-year survival. This has prompted many pancreatic cancer researchers and advocates to redouble their efforts, but also requires one to step back and ask why the previous efforts were lacking and to consider why pancreatic cancer is so difficult to treat. The difficulties are legion. PDA is characterized by an insidious clinical syndrome, but is rarely diagnosed at a time when surgical resection is feasible. We lack markers of early detection and screening programs remain unproven even in high risk populations. The location of the tumor in the retroperitoneum, the advanced age of patients, and the systemic effects of disease limit the options for local therapy. Chemotherapy may provide a small benefit, but most efforts to improve on the current regimens consistently and stubbornly fail in advanced clinical trials. The molecular and cellular features of ductal pancreatic tumors are aggressive and underlay multiple levels of therapeutic resistance. Non-cell-autonomous features including stromal proliferation, reduced vascular density and immune suppression also contribute to therapeutic resistance. Growing awareness of these the fundamental features of PDA has begun to guide ongoing research efforts. Clinical trials are now specifically targeting these tumor properties and actively focusing on the therapeutic implications of tumor stroma. As reviewed here, reflecting on the fundamental question of why pancreatic cancer is so difficult to treat is a necessary and informative exercise that will aid our efforts to improve patient outcomes. These efforts will lead to improvements in clinical trial design, expand our focus to include the molecular and histologic implications of novel treatment paradigms, and ultimately change the lives of our patients.

A first-in-class, first-in-human, phase I trial of p28, a non-HDM2-mediated peptide inhibitor of p53 ubiquitination in patients with advanced solid tumours

Background:

This first-in-human, phase I clinical trial of p28 (NSC745104), a 28-amino-acid fragment of the cupredoxin azurin, investigated the safety, tolerability, pharmacokinetics and preliminary activity of p28 in patients with p53⁺ metastatic solid tumours.

Methods:

A total of 15 patients were administered p28 i.v. as a short infusion three times per week for 4 weeks followed by a 2-week rest under an accelerated titration 3+3 dose escalation design until either a grade 3-related adverse event occurred or the maximum tolerated dose (MTD) was reached. Single-dose and steady-state serum pharmacokinetics were characterised. Assessments included toxicity, best objective response by RECIST 1.1 Criteria, and overall survival.

Results:

No patients exhibited any dose-limiting toxicities (DLTs), significant adverse events or exhibited an immune response (IgG) to the peptide. The No Observed Adverse Effect Level (NOAEL) and MTD were not reached. Seven patients demonstrated stable disease for 7–61 weeks, three a partial response for 44–125 weeks, and one a complete response for 139 weeks. Three patients are still alive at 158, 140, and 110 weeks post therapy completion.

Conclusion:

p28 was tolerated with no significant adverse events. An MTD was not reached. Evidence of anti-tumour activity indicates a highly favourable therapeutic index and demonstrates proof of concept for this new class of non-HDM2-mediated peptide inhibitors of p53 ubiquitination.

Lenalidomide in combination with gemcitabine as first-line treatment for patients with metastatic carcinoma of the pancreas: a Sarah Cannon Research Institute phase II trial

OBJECTIVES

To evaluate the 6-mo overall survival, safety and tolerability of lenalidomide in combination with standard gemcitabine as first-line treatment for patients with metastatic pancreatic cancer.

METHODS

Eligibility included: previously untreated metastatic adenocarcinoma of the pancreas with metastases incurable by surgery/radiation therapy; ECOG PS 0-2; adequate organ function; prophylactic anticoagulation for venous thromboembolic events (VTEs). Patients received lenalidomide 25 mg PO (days 1-21) and gemcitabine 1,000 mg/m ( 2) IV (days 1, 8 and 15) each 28-day cycle, with response evaluations every eight weeks.

RESULTS

Between 5/2009-4/2010, 72 patients (median age 64 years; 68% male; 42% ECOG PS 0) were enrolled in this multicenter, community-based study. Six-month OS was 37% (95% CI 26-48%). Median PFS and OS were 2.3 (95% CI 1.9-3.5) and 4.7 (95% CI 3.4-5.7) months, respectively. Eight partial responses (11%) were documented. Thirty-nine patients (54%) experienced thrombocytopenia (2 patients, 3% grade 4). Hematologic toxicities resulted in dose modifications for the majority of patients. Twenty patients (28%) developed VTEs during treatment.

CONCLUSIONS

The observed 6-month OS (37%) of lenalidomide with gemcitabine does not suggest improvement compared with historical results with gemcitabine alone. Toxicities and dose modifications likely limited dose intensity. Further development of this regimen in pancreas cancer is not recommended.

PIK3CA/PTEN mutations and Akt activation as markers of sensitivity to allosteric mTOR inhibitors

PURPOSE

We sought to determine whether phosphoinositide 3-kinase (PI3K) pathway mutation or activation state and rapamycin-induced feedback loop activation of Akt is associated with rapamycin sensitivity or resistance.

EXPERIMENTAL DESIGN

Cancer cell lines were tested for rapamycin sensitivity, Akt phosphorylation, and mTOR target inhibition. Mice injected with breast or neuroendocrine cancer cells and patients with neuroendocrine tumor (NET) were treated with rapalogs and Akt phosphorylation was assessed.

RESULTS

Thirty-one cell lines were rapamycin sensitive (RS) and 12 were relatively rapamycin resistant (RR; IC(50) > 100 nmol/L). Cells with PIK3CA and/or PTEN mutations were more likely to be RS (P = 0.0123). Akt phosphorylation (S473 and T308) was significantly higher in RS cells (P < 0.0001). Rapamycin led to a significantly greater pathway inhibition and greater increase in p-Akt T308 (P < 0.0001) and p-Akt S473 (P = 0.0009) in RS cells. Rapamycin and everolimus significantly increased Akt phosphorylation but inhibited growth in an in vivo NET model (BON). In patients with NETs treated with everolimus and octreotide, progression-free survival correlated with p-Akt T308 in pretreatment (R = 0.4762, P = 0.0533) and on-treatment tumor biopsies (R = 0.6041, P = 0.0102). Patients who had a documented partial response were more likely to have an increase in p-Akt T308 with treatment compared with nonresponders (P = 0.0146).

CONCLUSION

PIK3CA/PTEN genomic aberrations and high p-Akt levels are associated with rapamycin sensitivity in vitro. Rapamycin-mediated Akt activation is greater in RS cells, with a similar observation in patients with clinical responses on exploratory biomarker analysis; thus feedback loop activation of Akt is not a marker of resistance but rather may function as an indicator of rapamycin activity.

Combined modality treatment for patients with locally advanced pancreatic adenocarcinoma

BACKGROUND

Radiofrequency ablation (RFA) is an emerging treatment for patients with locally advanced pancreatic carcinoma, and can be combined with radiochemotherapy and intra-arterial plus systemic chemotherapy.

METHODS

This observational study compared two groups of patients with locally advanced pancreatic carcinoma treated with either primary RFA (group 1) or RFA following any other primary treatment (group 2).

RESULTS

Between February 2007 and May 2010, 107 consecutive patients were treated with RFA. There were 47 patients in group 1 and 60 in group 2. Median overall survival was 25·6 months. Median overall survival was significantly shorter in group 1 than in group 2 (14·7 versus 25·6 months; P = 0·004) Patients treated with RFA, radiochemotherapy and intra-arterial plus systemic chemotherapy (triple-approach strategy) had a median overall survival of 34·0 months.

CONCLUSION

RFA after alternative primary treatment was associated with prolonged survival. This was further extended by use of a triple-approach strategy in selected patients. Further evaluation of this approach seems warranted.

ATP assay-guided chemosensitivity testing for gemcitabine with biopsy specimens obtained from unresectable pancreatic cancer using endoscopic ultrasonography-guided fine-needle aspiration

OBJECTIVES

This study evaluates the feasibility of chemosensitivity testing by use of endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) samples and determines the optimum cut-off value for gemcitabine.

METHODS

Thirty-four consecutive patients with unresectable pancreatic cancer were enrolled. Chemosensitivity (treated/control ratio: T/C ratio) was calculated as the quantity of adenosine triphosphate for a tumor treated with gemcitabine as a percentage of that for the control. To identify the cut-off value sufficient to predict 180 days of progression-free survival (PFS), the receiver operating characteristic curve and the corresponding area under the curve (AUC) were calculated.

RESULTS

The success of this assay was 88.2% (30/34); therefore, 30 patients were assessable and included in the population of analyzable patients.. The response was 6.7%. Median PFS was 96 days and median overall survival was 241 days, respectively. The cut-off value was determined as 74% (AUC, 0.745; p = 0.053; 95% CI 0.485-1.005). According to this cut-off value, we predicted 180 days PFS with a sensitivity and specificity of 71.4 and 91.3%, respectively. When patients were divided into two groups at T/C ratio 74%, a significant difference was found in PFS (median 77 vs. 205 days, p = 0.0036). Moreover, T/C ratio < 74% and decrease of CA19-9 were significant and independent prognostic factors by multivariate analysis.

CONCLUSION

Chemosensitivity testing by use of EUS-FNA samples in patients with unresectable pancreatic cancer is feasible. This definition emphasizes the possibility of selecting patients for whom favorable results from gemcitabine treatment can be expected.

Human Equilibrative Nucleoside Transporter 1 (hENT1) in Pancreatic Adenocarcinoma: Towards Individualized Treatment Decisions

Pancreatic cancer is one of the most lethal cancers, where curative surgical resections are rare and less than 5% of patients experience long-term survival. Despite numerous clinical trials, improvements in the systemic treatment of this disease have been limited. Gemcitabine, a nucleoside analogue, is still considered the standard of care chemotherapy for most patients in the advanced disease setting. To exert its cytotoxic effects, gemcitabine must enter cells via nucleoside transporters, most notably human equilibrative nucleoside transporter 1 (hENT1). Increasingly strong evidence suggests hENT1 is a prognostic biomarker in gemcitabine-treated pancreatic cancer, and may well be a predictive biomarker of gemcitabine efficacy. In this review, we synthesize the literature surrounding hENT1 in pancreatic cancer, identify the key outstanding questions, and suggest strategies to prospectively evaluate the clinical utility of hENT1 in future clinical studies.

A phase I, dose-escalation study of pomalidomide (CC-4047) in combination with gemcitabine in metastatic pancreas cancer

INTRODUCTION

Pomalidomide is an investigational immunomodulating drug (IMiD) that also inhibits angiogenesis and has direct anti-tumour effects. This phase I study was performed to identify the optimal dose of pomalidomide to be used in combination with gemcitabine in the treatment of patients with metastatic pancreatic cancer.

METHODS

Eligible patients had histologically documented metastatic adenocarcinoma of the pancreas. No prior gemcitabine for metastatic disease or for primary treatment of locally advanced disease was allowed although prior radiation therapy with 5-flourouracil (5-FU) or gemcitabine as a radiosensitizer was allowed. All patients received gemcitabine 1000 mg/m(2) IV on days 1, 8 and 15 of a 28 day cycle. Pomalidomide was administered orally on days 1-21 at doses escalated from 2 to 10mg daily. Patients were re-evaluated every 8 weeks; treatment continued until disease progression or intolerable toxicity occurred.

RESULTS

Twenty-three patients were enrolled with a median age of 62 and Eastern Cooperative Oncology Group (ECOG) performance status 0 (87%) and 1 (13%). The maximum tolerated dose (MTD) was 10mg/day on days 1-21. Neutropaenia was the most common grade 3/4 toxicity (38%); other grade 3/4 toxicity included deep vein thrombosis (DVT) (22%) and anaemia (9%). While efficacy was not a primary end-point of this study, 3 of 20 evaluable patients (15%) had partial responses and 10 patients (50%) had >50% decrease in CA 19-9 levels.

CONCLUSIONS

The combination of pomalidomide and gemcitabine was feasible and safe in most patients receiving first-line chemotherapy for metastatic pancreatic cancer. Neutropaenia, the dose-limiting toxicity, was brief and reversible. Intermittent dosing of pomalidomide allowed substantially higher doses than were previously reported with a continuous schedule. This combination merits further evaluation in the treatment of metastatic pancreatic cancer.

Current and emerging therapies for the treatment of pancreatic cancer

Pancreatic adenocarcinoma carries a dismal prognosis and remains a significant cause of cancer morbidity and mortality. Most patients survive less than 1 year; chemotherapeutic options prolong life minimally. The best chance for long-term survival is complete resection, which offers a 3-year survival of only 15%. Most patients who do undergo resection will go on to die of their disease. Research in chemotherapy for metastatic disease has made only modest progress and the standard of care remains the purine analog gemcitabine. For resectable pancreatic cancer, presumed micrometastases provide the rationale for adjuvant chemotherapy and chemoradiation (CRT) to supplement surgical management. Numerous randomized control trials, none definitive, of adjuvant chemotherapy and CRT have been conducted and are summarized in this review, along with recent developments in how unresectable disease can be subcategorized according to the potential for eventual curative resection. This review will also emphasize palliative care and discuss some avenues of research that show early promise.

A combination of DR5 agonistic monoclonal antibody with gemcitabine targets pancreatic cancer stem cells and results in long-term disease control in human pancreatic cancer model

Pancreatic ductal adenocarcinoma (PDA) is an aggressive malignancy with one of the worst outcomes among all cancers. PDA often recurs after initial treatment to result in patient death despite the use of chemotherapy or radiation therapy. PDA contains a subset of tumor-initiating cells capable of extensive self-renewal known as cancer stem cells (CSC), which may contribute to therapeutic resistance and metastasis. At present, conventional chemotherapy and radiotherapy are largely ineffective in depleting CSC pool, suggesting the need for novel therapies that specifically target the cancer-sustaining stem cells for tumor eradication and to improve the poor prognosis of PDA patients. In this study, we report that death receptor 5 (DR5) is enriched in pancreatic CSCs compared with the bulk of the tumor cells. Treating a collection of freshly generated patient-derived PDA xenografts with gemcitabine, the first-line chemotherapeutic agent for PDA, is initially effective in reducing tumor size, but largely ineffective in diminishing the CSC populations, and eventually culminated in tumor relapse. However, a combination of tigatuzumab, a fully humanized DR5 agonist monoclonal antibody, with gemcitabine proved to be more efficacious by providing a double hit to kill both CSCs and bulk tumor cells. The combination therapy produced remarkable reduction in pancreatic CSCs, tumor remissions, and significant improvements in time to tumor progression in a model that is considered more difficult to treat. These data provide the rationale to explore the DR5-directed therapies in combination with chemotherapy as a therapeutic option to improve the current standard of care for pancreatic cancer patients.