Bevacizumab combined with 5-FU/streptozocin in patients with progressive metastatic well-differentiated pancreatic endocrine tumours (BETTER trial)--a phase II non-randomised trial

AIM OF THE STUDY

Neuroendocrine tumours are highly vascular neoplasms known to overexpress vascular endothelial growth factor (VEGF) and its receptor. Bevacizumab, an inhibitor of VEGF, was assessed in combination with chemotherapy in pancreatic neuroendocrine tumour (P-NET).

PATIENTS AND METHODS

BETTER was a multicentre, open-label, non-randomised, two-group phase II trial. Patients with progressive metastatic, well-differentiated P-NET received a minimum of 6 month treatment of bevacizumab at 7.5 mg/kg IV on d1 q3w with 5-FU at 400 mg/m2/day and streptozocin at 500 mg/m2/day IV from d1 to d5 every 42 days. The primary end-point was progression-free survival (PFS); secondary end-points were overall survival (OS), overall response rate, safety and quality of life.

RESULTS

A total of 34 patients were included. Median age was 55 years, 65% of patients were men, 97% had an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 and 97% had a Ki-67 proliferative index of <15%. After a maximum of 24 month follow-up per patient, the median PFS assessed by investigators was 23.7 months [95% confidence interval (CI): 13.1; not reached], 19 (56%) patients had a partial response and 15 (44%) had stable disease as best response. OS rate at 24 months was 88%. The most frequently reported grade 3-4 adverse events were hypertension (21% patients), abdominal pain (12%) and thromboembolic events (9%).

CONCLUSION

Bevacizumab with 5-FU/streptozocin in the treatment of pancreatic NETs seems to be feasible with a PFS of 23.7 months, which deserves further attention. No unexpected toxicity was observed.

Bevacizumab plus capecitabine in patients with progressive advanced well-differentiated neuroendocrine tumors of the gastro-intestinal (GI-NETs) tract (BETTER trial)--a phase II non-randomised trial

AIM OF THE STUDY

Gastro-intestinal neuroendocrine tumours (GI-NETs) are chemotherapy-resistant tumours. Bevacizumab, an inhibitor of vascular endothelial growth factor (VEGF), has shown promising results in several phase II trials of gastro-entero-pancreatic-NETs. We assessed bevacizumab combined with capecitabine, specifically in GI-NET patients.

PATIENTS AND METHODS

BEvacizumab in The Treament of neuroEndocrine tumoRs (BETTER) was a multicentre, open-label, non-randomised, two-group phase II trial. Here we present the group of patients with progressive, metastatic, well-differentiated GI-NETs. Patients Eastern Cooperative Oncology Group-performance status (ECOG-PS)⩽2, Ki-67 proliferation rate <15% and no prior systemic chemotherapy were treated with bevacizumab (7.5 mg/kg/q3w) and capecitabine (1000 mg/m2 twice daily, orally d1-14, resumed on d22) for 6-24 months. The primary end-point was progression-free survival (PFS); secondary end-points included overall survival (OS), response rate, safety and quality of life.

RESULTS

Of the 49 patients included, 53% were men, median age was 60 years (41-82), primary tumour site was ileal in 82% patients and Ki-67 was <15% in 48 patients and not available for one patient. After a maximum of 24 month follow-up per patient, the median PFS by investigator assessment was 23.4 months [95% confidence interval (CI): 13.2; not reached] and the overall disease control rate was 88% (18% partial response, 70% stable disease). The 2-year survival rate was 85%. Median OS was not reached. The most frequent grade 3-4 adverse events were hypertension (31%), diarrhoea (14%) and hand-foot syndrome (10%).

CONCLUSION

The combination of bevacizumab and capecitabine showed clinical activity and a manageable safety profile in the treatment of GI-NETs that warrant confirmation in a randomised phase III trial.

Survival outcomes and prognostic factors of transcatheter arterial chemoembolization for hepatic neuroendocrine metastases

PURPOSE

To report survival outcomes in patients with neuroendocrine tumor (NET) with hepatic metastasis who were treated by transcatheter arterial chemoembolization and determine prognostic factors that affect clinical outcome.

MATERIALS AND METHODS

Patients with NET with hepatic metastasis who underwent chemoembolization between April 2002 and July 2011 were included in this single-center, retrospective study. Progression-free survival (PFS) and overall survival (OS) were calculated by Kaplan-Meier method. The influence of possible prognostic factors on survival was analyzed by log-rank method and multivariate Cox proportional-hazards method.

RESULTS

Forty-six patients with hepatic metastasis from nonpancreatic NETs (npNETs; n = 24) or pancreatic NETs (pNETs; n = 22) were included. The median PFS and OS times for the entire group were 16.2 and 38.6 months, respectively, and response rate was 58.1%. Patients with npNET had a similar PFS (17.4 mo vs 15.3 mo) and longer OS (55.0 mo vs 27.6 mo) compared with those with pNET, but there were no significant differences in PFS and OS between groups (P = .398 and P = .375, respectively). By univariate analysis, enterobiliary communication, hepatic tumor burden, and extrahepatic metastasis before the first chemoembolization were significant prognostic factors for poor OS (P = .001, P = .010, and P<.0001, respectively). By multivariate analysis, the same prognostic factors were significant and had relative risks of 4.63, 2.71, and 5.09, respectively.

CONCLUSIONS

Transcatheter arterial chemoembolization is an effective treatment modality for hepatic metastasis from NETs, with a median OS of 38.6 months and response rate of 58%. Enterobiliary communication, large hepatic tumor burden, and extrahepatic metastasis were significant risk factors for poor survival outcome.

New treatment options for patients with advanced neuroendocrine tumors

Well- to moderately differentiated neuroendocrine tumors (NET) are a heterogeneous group of malignancies for which a range of therapeutic options have been employed. For patients with localized NET, surgical resection remains the mainstay of treatment. Surgical resection of hepatic metastases or hepatic artery embolization may also be beneficial in patients with hepatic-predominant metastatic disease. Symptoms of hormonal excess, such as carcinoid syndrome and syndromes associated with functional pancreatic NET, can be effectively treated with somatostatin analogs. Systemic treatment options for patients with advanced NET have been limited. Treatment with the somatostatin analog octreotide has been shown to improve progression-free survival in patients with advanced midgut carcinoid tumors, and the potential antiproliferative effect of somatostatin analogs in patients with other NET subtypes is currently under investigation. Patients with advanced pancreatic NET may also respond to treatment with streptozocin or temozolomide-based therapy. In patients with advanced pancreatic NET, randomized, placebo-controlled studies have recently demonstrated that treatment with the tyrosine kinase inhibitor sunitinib or with the mTOR inhibitor everolimus is associated with improved progression-free survival. Based on these studies, sunitinib or everolimus should now be considered as therapeutic options in patients with advanced pancreatic NET. Initial phase II studies have also suggested activity associated with VEGF pathway and mTOR inhibitors in patients with advanced carcinoid tumors. Future studies will likely further define the role of these agents in the advanced carcinoid patient population.

Treatment of gastrointestinal neuroendocrine tumors with inhibitors of growth factor receptors and their signaling pathways: recent advances and future perspectives

The limited efficacy of conventional cytotoxic treatment regimes for advanced gastrointestinal neuroendocrine cancers emphasizes the need for novel and more effective medical treatment options. Recent findings on the specific biological features of this family of neoplasms has led to the development of new targeted therapies, which take into account the high vascularization and abundant expression of specific growth factors and cognate tyrosine kinase receptors. This review will briefly summarize the status and future perspectives of antiangiogenic, mTOR- or growth factor receptor-based pharmacological approaches for the innovative treatment of gastrointestinal neuroendocrine tumors. In view of the multitude of novel targeted approaches, the rationale for innovative combination therapies, i.e. combining growth factor (receptor)-targeting agents with chemo- or biotherapeutics or with other novel anticancer drugs such as HDAC or proteasome inhibitors will be taken into account.

Conventional and novel PET tracers for imaging in oncology in the era of molecular therapy

In the last ten years, the development of several novel targeted drugs and the refinement of state of the art technologies such as the genomics and proteomics and their introduction to clinical practice have revolutionized the management of patients affected by cancer. However, everyday practice points out several clinical questions: the difficulty of response assessment to new drugs especially using standard RECIST criteria that do not provide information on biological, vascular or metabolic variations; the inadequate selection of patients who are likely to benefit from a targeted therapy excluding those with breast cancer and gastrointestinal stromal tumours; the need to know the global biological background of diseases especially in metastatic setting using repeatable non-invasive procedures. Molecular imaging could provide information on in vivo distribution of biological markers in response to targeted therapy and could improve the selection of patients before therapies. The aim of this review is to analyze the current role of conventional and innovative positron emission tomography (PET) radiotracers in clinical practice and to explore the promising perspectives of molecular imaging in cancer research.

Persistent low urinary excretion of 5-HIAA is a marker for favourable survival during follow-up in patients with disseminated midgut carcinoid tumours

Survival of patients with disseminated midgut carcinoid tumours varies. We investigated which factors predict survival at referral and during follow-up, with emphasis on urinary 5-hydroxyindolacetic acid (5-HIAA) levels. Between 1992 and 2003, 76 patients were studied; urine was prospectively collected over a 24 h period every 3 months in order to measure 5-HIAA levels. Uni- and multivariate analyses were performed. Median follow-up was 55 months with a median survival of 54 months. Prognostic factors for poor survival were high age, high gamma-glutamyltransferase levels and greatly increased 5-HIAA levels (>20 mmol/mol creatinine) The Hazard Ratio (HR) of a greatly increased 5-HIAA level was 3.33 (95% confidence interval (CI) 1.66-6.66, p=0.001). In a multivariate survival analysis with the 5-HIAA level as time dependent covariable, the HR for the 5-HIAA level was 1.007 (95% CI 1.004-1.010, p=0.000). In conclusion, patients with persistent moderately increased urinary 5-HIAA levels (< or =20 mmol/mol creatinine) have favourable outcome.

Treatment of gastroenteropancreatic neuroendocrine tumors

Neuroendocrine tumors are rare; thus, individual experience with the diagnosis and treatment of these tumors is mostly low, except in specialized centers. For histological diagnosis, standards have been described recently. Pathological classification and clinical staging influence diagnostic and therapeutic decisions. This chapter aims at demonstrating the importance of pathological and clinical classification of neuroendocrine tumors on therapeutic decisions, indicating the appropriate therapy for different stages of the disease. Surgical therapy will be discussed shortly, including palliative surgical strategies. However, the focus of the manuscript is medical therapy. Biotherapy, its effects, and remaining uncertainties are presented as well as different chemotherapeutic schemes. Finally, new options of palliative medical therapies like kinase inhibitors and anti-angiogenetic drugs will be discussed.

New drug development in digestive neuroendocrine tumors

The traditional cytotoxic agents are of limited efficacy in the treatment of neuroendocrine tumors of the gastrointestinal tract (NETs). Recent investigations have brought up a number of biological features in this family of neoplasms that could represent targets for anticancer treatment. NETs seem to have an extraordinary tumor vascularization with high expression of proangiogenic molecules such as the vascular endothelial growth factor along with overexpression of certain tyrosine kinase receptors such as the epidermal growth factor receptor (EGFR), the insulin growth factor receptor (IGFR) and their downstream signaling pathway components (PI3K-AKT-mTOR). The rationale of an antiangiogenic approach in the treatment of NETs and the use of other pharmacological strategies such as EGFR, IGFR and mammalian target of rapamycin inhibitors are discussed. Additionally, the emerging results of recent clinical trials with these targeted drugs are presented.

Islet Cell Carcinoma: Neuroendocrine Tumors of the Pancreas and Periampullary Region

Most patients who have islet cell tumors, except those who have insulinomas, present with locally advanced or metastatic disease. In contrast with patients who have adenocarcinoma of the pancreas, those who have islet cell carcinomas can achieve long-term survival even if their disease is advanced. Liver-directed therapies, somatostatin analogs, and interferon are not curative but can be used to relieve tumor-associated symptoms. Similarly, palliative chemotherapy has been used with limited success. Advances in our understanding of the molecular mechanisms underlying tumor progression have translated into intense interest in biologically based strategies to treat this disease.

Clinical Presentation and Management of Carcinoid Tumors

The generally indolent nature of neuroendocrine tumors is an advantage in the management of patients who have localized disease, and surgery alone is often curative. This same property presents a challenge in the treatment of patients who have metastatic disease, in whom standard cytotoxic chemotherapy has a limited benefit. In such patients, the use of somatostatin analogs, interferon, and the treatment of hepatic metastases may provide effective palliation. The highly vascular nature of carcinoid tumors has led to the investigation of antiangiogenic agents in this setting. Preliminary reports of activity associated with agents targeting the vascular endothelial growth factor pathway suggest that such strategies may play a role in the future treatment of patients who have this disease.

Current medical treatment of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (NETs) consist of a wide group of neoplasms, with different biological behaviors in terms of aggressiveness and hormone production. In the last two decades, significant progress has been observed in our understanding of their biology, diagnosis and treatment. Surgery remains to be the only curative approach, but unfortunately the diagnosis is often delayed due to the slow growth of these tumors and the difficulty in identifying the symptoms related to the tumor-released hormones. In addition to surgery, other approaches to control the disease are biological therapy consisting of somatostatin analogs and interferon (IFN), systemic chemotherapy, radioligand therapy and local therapy with chemoembolization. Several newer cytotoxic agents, including irinotecan, gemcitabine, taxanes, oxaliplatin, capecitabine and PS-341 have been studied in metastatic patients. Considering the high vascularity of these tumors, antiangiogenic agents like endostatin and thalidomide have also been evaluated in advanced NETs. Although these agents seem to have potential activity in NETs and may increase progression free survival, none of these currently available medical therapeutic options are curative. While more efficient novel strategies are to be developed, the rationale use of the current therapeutic options may improve quality of life, control the symptoms related to the hypersecretion of hormones and/or peptides, control tumor proliferation and prolong survival in patients suffering from NETs.

A review of the current clinical trials for gastroenteropancreatic neuroendocrine tumours

Neuroendocrine tumours of the gastroenteropancreatic axis include carcinoid tumours and islet cell tumours of the pancreas (pancreatic endocrine tumours). Standard medical therapies prescribed for these malignancies include long-acting somatostatin analogues (octreotide and lanreotide) for the palliation of hormonal syndromes; cytotoxic agents (streptozocin, dacarbazine, adriamycin and 5-fluorouracil), which are primarily for the management of advanced islet cell tumours; and hepatic artery embolisation or chemoembolisation for the treatment of liver metastases. Clinical research promises to expand this therapeutic armamentarium. Most of the experimental treatments that are being evaluated in human clinical trials fall into the following categories: angiogenesis inhibitors, novel somatostatin analogues, radiolabelled somatostatin analogues, mTOR inhibitors and novel cytotoxic agents. This review summarises the present scope of clinical research in this field.

Phase II study of recombinant human endostatin in patients with advanced neuroendocrine tumors

PURPOSE

Endostatin is a 20-kd proteolytic fragment of collagen XVIII that, in preclinical studies, has been shown to have antiangiogenic and antitumor activity. Both preclinical and human phase I studies of recombinant human endostatin (rhEndostatin) suggested activity in neuroendocrine tumors, which are known to be hypervascular. We therefore performed a multicenter phase II study of rhEndostatin in patients with carcinoid or pancreatic neuroendocrine tumors.

PATIENTS AND METHODS

Forty-two patients with advanced pancreatic endocrine tumors or carcinoid tumors were treated with rhEndostatin administered as a bid subcutaneous injection at a starting dose of 60 mg/m2/d. Steady-state trough levels were obtained after 6 weeks of therapy; patients who did not achieve a target therapeutic level of 300 ng/mL underwent dose escalation to 90 mg/m2/d. Patients were observed for evidence of toxicity, response, and survival.

RESULTS

rhEndostatin was associated with minimal toxicity. However, among 40 patients assessable for radiologic response, none experienced partial response to therapy, as defined by WHO criteria. The median steady-state trough level achieved after dose escalation was 331 ng/mL, within the postulated therapeutic range.

CONCLUSION

Treatment with rhEndostatin did not result in significant tumor regression in patients with advanced neuroendocrine tumors.

Phase II study of temozolomide and thalidomide in patients with metastatic neuroendocrine tumors

PURPOSE

Standard, intravenous chemotherapy regimens for neuroendocrine tumors have been associated with limited response rates and significant toxicity. We evaluated the efficacy of an oral regimen of temozolomide and thalidomide in patients with metastatic carcinoid, pheochromocytoma, or pancreatic neuroendocrine tumors.

PATIENTS AND METHODS

Twenty-nine patients were treated with a combination of temozolomide, administered at a dose of 150 mg/m2 for 7 days, every other week, and thalidomide at doses of 50 to 400 mg daily. Patients were followed for evidence of toxicity, biochemical response, radiologic response, and survival.

RESULTS

Treatment with temozolomide and thalidomide was associated with an objective biochemical (chromogranin A) response rate of 40%, and a radiologic response rate of 25% (45% among pancreatic endocrine tumors, 33% among pheochromocytomas, and 7% among carcinoid tumors). The median duration of response was 13.5 months, 1-year survival was 79%, and 2-year survival was 61%. The median administered dose of temozolomide was 150 mg/m(2), and the median administered dose of thalidomide was 100 mg daily. Grade 3-4 toxicities were uncommon, with the exception of grade 3-4 lymphopenia, which developed in 69% of the patient population. Opportunistic infections occurred in three patients (10%) during the time of lymphopenia, and included single cases of Pneumocystis carinii pneumonia, disseminated varicella zoster virus, and herpes simplex virus.

CONCLUSION

Orally administered temozolomide and thalidomide seems to be an active regimen for the treatment of neuroendocrine tumors. In this 29-patient study, this regimen appeared more active in pancreatic endocrine tumors than in carcinoid tumors.

Investigating the potential of bevacizumab in other indications: metastatic renal cell, non-small cell lung, pancreatic and breast cancer

Bevacizumab (Avastin) has unprecedented survival benefit in patients with metastatic colorectal cancer. Trials are already in progress to investigate the potential of bevacizumab in indications including metastatic renal cell cancer (RCC), non-small cell lung cancer (NSCLC), pancreatic cancer, breast and ovarian cancer. Bevacizumab offers the potential to increase survival without substantially altering the toxicity profile in these tumor types. Bevacizumab has shown activity in patients with refractory metastatic RCC, where progression-free survival (PFS) was significantly longer in patients treated with bevacizumab (10 mg/kg every 2 weeks) than those treated with placebo (hazard ratio=2.55, p<0.001). In addition, combining bevacizumab with erlotinib (Tarceva) has shown a median time to progression of more than 11 months. In NSCLC, a phase II trial revealed that adding bevacizumab to chemotherapy increased therapeutic benefit compared with chemotherapy alone. Adverse events were mild and easily managed, but six patients receiving bevacizumab developed severe hemoptysis. Entry criteria for NSCLC trials have been adjusted to exclude patients with squamous cell histology to try to avoid this issue. Adding bevacizumab (10 mg/kg) to the current standard of care, gemcitabine, in stage IV pancreatic cancer has also shown promising efficacy. Partial responses were seen in 19% of patients, with a further 48% having stable disease. Several ongoing clinical trials are also studying bevacizumab with various chemotherapy and radiotherapy regimens. Bevacizumab combined with carboplatin (Paraplatin)/paclitaxel (Taxol) was further examined in a phase III randomized trial that accrued 878 patients with advanced non-squamous cell NSCLC. Patients given chemotherapy (paclitaxel and carboplatin) plus bevacizumab had a higher response rate, longer PFS and an increase in survival compared with patients on chemotherapy alone. Both regimens were generally well tolerated. Bevacizumab has also shown activity in patients with metastatic breast cancer. In 715 patients, a significant, 2-fold increase in response rate was observed in patients receiving bevacizumab plus paclitaxel compared with paclitaxel alone. Median PFS was also significantly increased (p<0.001). Bevacizumab has the potential to provide significant efficacy benefits for patients with metastatic RCC, NSCLC, pancreatic cancer, and other tumor types when used first line in combination with standard therapy.

Advances in the treatment of neuroendocrine tumors

Gastrointestinal neuroendocrine tumors are characterized by generally slow growth rates and the ability to secrete a variety of hormones and biogenic amines. For patients with localized disease, surgical resection alone is often curative; however, patients with metastatic disease often present a therapeutic challenge. Although somatostatin analogs are highly effective in controlling symptoms of hormonal secretion, they are rarely associated with tumor regression. Selected patients with hepatic metastases may benefit from surgical debulking, embolization, or other ablative therapies. The clinical benefit associated with the administration of systemic agents such as alpha interferon or cytotoxic chemotherapy is less clear, and the widespread use of such regimens has been limited by their relatively modest antitumor activity as well as by concerns regarding their potential toxicity. The highly vascular nature of neuroendocrine tumors has led to interest in angiogenesis inhibition as a potentially novel treatment strategy. In addition, several small molecule tyrosine kinase inhibitors are currently being evaluated in a Phase II setting. The naturally indolent growth of neuroendocrine tumors presents a challenge in interpreting efficacy endpoints from small Phase II studies. Larger, randomized trials, along with the evaluation of surrogate endpoints of biologic activity, may be necessary to establish the potential clinical benefit of these novel agents.