Metastatic Midgut Neuroendocrine Tumors Research Articles

Phase 3 Trial of 177Lu-Dotatate for Midgut Neuroendocrine Tumors

BackgroundPatients with advanced midgut neuroendocrine tumors who have had disease progression during first-line somatostatin analogue therapy have limited therapeutic options. This randomized, controlled trial evaluated the efficacy and safety of lutetium-177 (177Lu)–Dotatate in patients with advanced, progressive, somatostatin-receptor–positive midgut neuroendocrine tumors.MethodsWe randomly assigned 229 patients who had well-differentiated, metastatic midgut neuroendocrine tumors to receive either 177Lu-Dotatate (116 patients) at a dose of 7.4 GBq every 8 weeks (four intravenous infusions, plus best supportive care including octreotide long-acting repeatable [LAR] administered intramuscularly at a dose of 30 mg) (177Lu-Dotatate group) or octreotide LAR alone (113 patients) administered intramuscularly at a dose of 60 mg every 4 weeks (control group). The primary end point was progression-free survival. Secondary end points included the objective response rate, overall survival, safety, and the side-effect profile. The final analysis of overall survival will be conducted in the future as specified in the protocol; a prespecified interim analysis of overall survival was conducted and is reported here.ResultsAt the data-cutoff date for the primary analysis, the estimated rate of progression-free survival at month 20 was 65.2% (95% confidence interval [CI], 50.0 to 76.8) in the 177Lu-Dotatate group and 10.8% (95% CI, 3.5 to 23.0) in the control group. The response rate was 18% in the 177Lu-Dotatate group versus 3% in the control group (P<0.001). In the planned interim analysis of overall survival, 14 deaths occurred in the 177Lu-Dotatate group and 26 in the control group (P=0.004). Grade 3 or 4 neutropenia, thrombocytopenia, and lymphopenia occurred in 1%, 2%, and 9%, respectively, of patients in the 177Lu-Dotatate group as compared with no patients in the control group, with no evidence of renal toxic effects during the observed time frame.ConclusionsTreatment with 177Lu-Dotatate resulted in markedly longer progression-free survival and a significantly higher response rate than high-dose octreotide LAR among patients with advanced midgut neuroendocrine tumors. Preliminary evidence of an overall survival benefit was seen in an interim analysis; confirmation will be required in the planned final analysis. Clinically significant myelosuppression occurred in less than 10% of patients in the 177Lu-Dotatate group. (Funded by Advanced Accelerator Applications; NETTER-1 ClinicalTrials.gov number, NCT01578239; EudraCT number 2011-005049-11.)

Tumeurs neuroendocrines de l’intestin grêle : actualités sur le traitement médical

ContextMid gut neuroendocrine tumors (NET) are rare tumors whose incidence is increasing. Curative surgery remains the gold standard for the treatment of NETs of the small intestine. Surgery should be considered as soon as possible even if a metastatic stage is diagnosed. The management of unresectable well-differentiated metastatic NETs of the small intestine recently changed with the publication of trials demonstrating the benefit of targeted therapies and metabolic radiotherapy, leading to a change of practices and update of French and international recommendations. ObjectiveThe objective of this review is to present the recent data consisting of three phase III studies, which modify the management of well-differentiated metastatic midgut NETs and make an inventory of the available treatment options. Documentary sourcesThe documentary sources used were gathered through the PubMed website using keyword searching (neurendocrine tumor, mid gut, treatment). We also referred to recommendations of the European Society of neuroendocrine tumors (ENETS) trials presented at ESMO Congress 2015 (European Society for Medical Oncology). Study selectionWe excluded studies of exclusive extra-digestive NETs, poorly differentiated NETs, surgical treatments and phase I studies. ResultsWe discussed three randomized phase III trials: CLARINET, RADIANT and NETTER studies. These studies demonstrated the efficacy of respectively somatostatin analogues, mTOR inhibitors and metabolic radiotherapy. ConclusionThis review highlights the validation by randomized studies of an mTOR inhibitor and metabolic radiotherapy in metastatic non-pancreatic digestive NETs unresectable well-differentiated grade of G1/2 in progression under somatostatin analogues.

Placebo-Controlled, Double-Blind, Prospective, Randomized Study on the Effect of Octreotide LAR in the Control of Tumor Growth in Patients with Metastatic Neuroendocrine Midgut Tumors (PROMID): Results of Long-Term Survival

Background: Somatostatin analogs have been shown to control the growth of well-differentiated metastatic neuroendocrine tumors. Their effect on overall survival is a matter of debate. We analyzed the prognostic significance of early treatment with octreotide LAR and of hepatic tumor load in the PROMID trial cohort. Patients and Methods: Between 2001 and 2008, 85 treatment-naïve patients were randomly assigned to monthly octreotide LAR 30 mg or placebo until tumor progression or death. Post-study treatment was at the discretion of the investigator. Upon disease progression, 38 out of 43 placebo patients (88.4%) received octreotide LAR. For survival, patients were followed until May 2014. Results: Forty-eight out of 85 patients (56.5%) died. In 38 patients (79.2%), death was tumor related. The median overall survival (84.7 and 83.7 months) was only slightly different in patients assigned to octreotide and placebo [HR = 0.83 (95% CI: 0.47-1.46); p = 0.51]. The median overall survival was 84.7 months for all 85 patients, 107.6 months in the low-tumor-load (n = 64) and 57.5 months in the high-tumor-load (n = 21) subgroups [HR = 2.49 (95% CI: 1.36-4.55); p = 0.002]. There was a trend towards improved overall survival in patients with a low hepatic tumor load receiving octreotide compared to placebo [‘median not reached' and 87.2 months; HR = 0.59 (95% CI: 0.29-1.2); p = 0.142]. Conclusion: The extent of tumor burden is a predictor for shorter survival. Overall survival was similar in patients receiving octreotide LAR or placebo treatment at randomization. Crossover of the majority of placebo patients to octreotide LAR may have confounded the data on overall survival.

Expression of CD24, a Stem Cell Marker, in Pancreatic and Small Intestinal Neuroendocrine Tumors.

CD24 has been considered a normal and cancer stem cell marker. Potential intestinal stem cells weakly express CD24. In the pancreas, CD24 is a possible cancer stem cell marker for ductal adenocarcinoma. Expression of CD24 in intestinal and pancreatic neuroendocrine tumors (NETs) was examined. Immunohistochemistry was performed on benign duodenum, ileum mucosa, and pancreas, as well as primary duodenal, primary and metastatic ileal, and pancreatic NETs. Scattered CD24-positive cells were noted in the duodenal and ileal crypts, most of which showed a strong subnuclear labeling pattern. Similar expression was observed in 41 (95%) of 43 primary ileal NETs but in only four (15%) of 26 duodenal NETs (P < .01). In addition, metastatic ileal NETs retained CD24 expression. Pancreatic islets did not express CD24, and only rare cells had subnuclear labeling of CD24 in the pancreatic ducts. Unlike ileal NETs, only five (5%) of 92 pancreatic NETs expressed CD24 in the subnuclear compartment (P < .01). All five NETs showed a unique morphology with prominent stromal fibrosis. CD24 expression was frequent in primary and metastatic midgut NETs but rare in pancreatic and duodenal NETs. Expression of CD24 in ileal NETs may have future diagnostic and therapeutic implications.

The expanding role of somatostatin analogs in gastroenteropancreatic and lung neuroendocrine tumors.

Somatostatin analogs (SSAs) were initially developed as antisecretory agents used for the control of hormonal syndromes associated with neuroendocrine tumors (NETs). In recent years, accumulating evidence has also supported their role as antiproliferative agents in well or moderately differentiated NETs. The phase III PROMID trial demonstrated that octreotide long-acting repeatable (LAR) can significantly prolong time to progression among patients with metastatic midgut NETs. More recently, the randomized CLARINET trial reported a significant improvement in progression-free survival in a heterogeneous population of patients with gastroenteropancreatic (GEP)-NETs treated with depot lanreotide. Octreotide and lanreotide target somatostatin receptor subtypes in a similar fashion, and appear to be clinically interchangeable; however, comparative noninferiority trials have not been performed. Further studies are needed to evaluate the efficacy of novel SSAs such as pasireotide in the refractory setting, and the role of high-dose SSAs for symptom and tumor control.

The role of chemotherapy and/or octreotide in patients with metastatic gastroenteropancreatic and hepatobiliary neuroendocrine carcinoma.

Neuroendocrine carcinomas (NECs) of the gastro-entero-pancreatic (GEP) and hepatobiliary (HB) tract are rare and a heterogenous group of malignancies. Octreotide showed the anti-tumor activity in functional and nonfunctional well differentiated metastatic midgut neuroendocrine tumors (NETs). However, the effect of octreotide on survival has not been evaluated. We analyzed 17 patients (6 HB- and 11 GEP- tract) with metastatic NEC diagnosed between January 2009 and June 2012. All patients had one or more cytotoxic chemotherapy and nine patients had received octreotide as single agent (n=3) or combination of cytotoxic chemotherapy (n=6). The median age was 68 years (range, 23-79 years) and median Eastern Cooperative Oncology Group performance status (ECOG PS) was 1. Sixteen of all patients (n=17) received cytotoxic chemotherapy with or without octreotide as the first line therapy and 10 of 16 patients who experienced disease progression to the first line therapy received the second line therapy. Overall response rates (RR) and disease control rates (DCR) to the 1(st) line therapy were 41.2% and 76.5%, respectively. The median overall survival (OS) was 16 months [95% confidence interval (CI), 12.8-19.2] and the median OS in patients receiving octreotide during treatment was 40.2 months. In univariate analysis, any clinico-pathologic features including sex, the location of primary tumor, the number of metastatic sites, the debulking operation and the liver metastasis did not have prognostic value regarding OS. However, the use of octreotide offered favorable trend for OS (P=0.091). The use of octreotide may benefit for patients with GEP- and HB- NECs as a single agent or a combination therapy.

Efficacy of octreotide LAR (OCT) in patients (pts) with advanced neuroendocrine tumors (NET): A post hoc analysis of the placebo (PBO) arm of the phase III RADIANT-2 study with updated survival data.

265 Background: In pts with metastatic midgut NET, OCT showed antitumor activity and significantly extended time to tumor progression (TTP) vs PBO (PROMID trial, Rinke et al. 2009). We present a post hoc analysis assessing efficacy of OCT (30 mg q28d) in the PBO+ OCT arm of the phase III RADIANT-2 study. Methods: For this post hoc analysis, progression-free survival (PFS by central review, cutoff Apr 2, 2010) and overall survival (OS, cutoff Jun 13, 2013) in the PBO + OCT arm were estimated by prior somatostatin analogue (SSA) use and primary tumor location subgroups using the Kaplan-Meier (KM) method. Results: 213 pts were randomized to PBO + OCT (median age, 60 yrs; male, 58%; WHO PS: 0/1/2 in 66%/29%/5% pts; &gt;80% had well-differentiated disease). Of these, 47 (22%) were SSA naïve (foregut, 32%; midgut, 51%; hindgut, 4%; not classified or missing, 13%) and 166 (78%) had received SSA (foregut, 10%; midgut, 72%; hindgut, 11%; not classified or missing, 7%) prior to study entry. Median PFS (95% CI) for pts who were SSA naïve vs who had received SSA was 13.6 (8.2-22.7) mos vs 11.1 (8.4-14.2) mos. By primary tumor location, median PFS (95% CI) in SSA naïve pts vs who received SSA was 5.7 (2.8-27.8) mos vs 8.7 (2.8-13.9) mos for foregut, 22.2 (8.3-29.5) mos vs 12.0 (8.4-17.7) mos for midgut, and not-reached (NR; 4.7-NR) vs 6.6 (3.0-13.0) mos for hindgut. OS analysis is in table. Conclusions: This post hoc analysis of the PBO + OCT arm of the RADIANT-2 study showed a PFS of 13.6 mos in SSA naïve pts treated with OCT. While the RADIANT-2 study PBO arm differs from PROMID in patient population and method of assessment of tumor progression, the data from this post hoc analysis provide additional evidence of the antiproliferative effect of OCT in NET. Clinical trial information: NCT00412061. [Table: see text]

Placebo controlled, double blind, prospective, randomized study on the effect of octreotide LAR in the control of tumor growth in patients with metastatic neuroendocrine midgut tumors (PROMID): Results on long-term survival.

4030 Background: Octreotide LAR (O) compared to placebo (P) lengthens significantly time to tumor progression (TTP) in patients with metastatic midgut neuroendocrine tumors (Rinke et al. 2009). The antiproliferative response was more pronounced in patients with low (≤ 10%) hepatic tumor load (HL). To investigate whether this beneficial effect also affects overall survival (OS), patients included in the PROMID trial were followed until January 2013 at least once a year. Methods: Between July 2001 and January 2008, 42 and 43 patients were randomly assigned to receive O or P. Post study treatment was at the discretion of the local investigator. Data on cause of death and on post study treatment were documented. OS was analyzed using the Kaplan-Meier method. Treatment groups (O vs. P; HL at study entry ≤ 10% vs. &gt;10%) were compared using the log rank test and hazard ratios were estimated with the use of the Cox proportional hazards model. Results: 41 of 85 patients died until January 2013. 19 in the octreotide and 22 in the placebo arm. Median OS for all 85 patients was 85 months, “not reached” in the O arm and 84 months in the P arm (p=0.59, HR=0.85 [CI 0.46; 1.56]). Cause of death was unrelated to the tumor disease in 8 patients. 26 of 64 patients (10 in the O vs. 16 in the P arm) died in the HL ≤ 10% subgroup and 15 of 21 patients (9 in the O vs. 6 in the P arm) in the HL &gt; 10 % (p=0.002, HR=2.7). Median OS in the HL ≤ 10% subgroup was “not reached” (octreotide) vs 80.5 months (placebo) (p=0.14, HR=0.56 [CI 0.25; 1.23]). In the HL &gt; 10% subgroup the respective numbers were 35 vs. 84 months (p=0.14, HR=2.18 [CI 0.75; 6.33]). Post study treatment in the O and P groups included octreotide LAR (29 vs. 38 patients), hepatic CHE (5 vs. 12 patients), PRRT (13 vs. 13 patients) and CHT (4 vs. 5 patients). Conclusions: Octreotide LAR not only prolongs TTP but also extends OS in the subgroup of patients with metastatic midgut NETs and a low HL (≤ 10% at study entry) but not in the high (HL &gt; 10%) subgroup. Almost all patients who were randomized at study entry in the P group received octreotide LAR after disease progression, but these experienced a less favourable OS in the low HL subgroup. Clinical trial information: NCT00171873.

A review of the use of somatostatin analogs in oncology.

Somatostatin is a neuropeptide produced by paracrine cells that are located throughout the gastrointestinal tract, lung, and pancreas, and is also found in various locations of the nervous system. It exerts neural control over many physiological functions including inhibition of gastrointestinal endocrine secretion through its receptors. Potent and biologically stable analogs of somatostatin have been developed. These somatostatin analogs show different efficacy on different receptors, and receptors are varyingly concentrated in specific tissues. Antitumor and antisecretory effects of somatostatin analogs in cancer have been shown in several in vivo and in vitro studies. However, these activities have not always yielded into clinically relevant patient outcome benefit. Somatostatin analogs are of clinical benefit in treating symptoms of ectopic hormone secretion (adrenocorticotropic hormone, growth hormone-releasing hormone) in lung cancer, without inducing a significant tumor response. They have also been shown to induce a statistically significant decrease in bone pain and increase in Karnofsky performance status in patients with metastatic prostate cancer. Somatostatin analogs alone or in combination with other agents have only limited antitumoral effect in breast cancer. In gastrointestinal cancers, studies have not shown an objective tumor response to somatostatin analogs except in endocrine tumors of the liver with symptomatic and biochemical improvement. In neuroendocrine tumors of the gastrointestinal system and pancreas, very high symptomatic and biochemical response rates have been achieved with somatostatin analogs. Antiproliferative activity has been clearly shown in metastatic midgut neuroendocrine tumors.

Octreotide – A Review of its Use in Treating Neuroendocrine Tumours

Neuroendocrine tumours (NETs) are a heterogeneous group of neoplasms whose incidence has dramatically increased in recent years. Octreotide is a somatostatin analogue used in the treatment of NETs, and its use in clinical trials has been associated with substantially increased survival. Although traditionally used for the relief of symptoms that result from release of peptides and neuroamines, there has been a growing body of evidence that suggest octreotide has antiproliferative effects. A phase III clinical study has demonstrated that the long-acting formulation (LAR), octreotide LAR, lengthens time to tumour progression in patients with well-differentiated metastatic midgut NETs, and that octreotide LAR is a treatment option for patients with metastatic midgut NETs, regardless of functional status. Furthermore, octreotide LAR has demonstrated clinical efficacy in different types of NETs. These data, along with emerging data on somatostatin analogs, may change the way doctors approach this patient population and reinforce the use of these drugs as a treatment option for patients with non-functioning tumours.

Antitumour Effects of Somatostatin Analogues in the Treatment of Neuroendocrine Tumours

Neuroendocrine tumours (NETs) are rare and heterogeneous neoplasms that can present with functional syndromes due to the hypersecretion of peptides. Somatostatin analogues (SSAs) have been used since the 1980s for the treatment of neuroendocrine tumours, with the aim of controlling the symptoms of functioning tumours and improving patients’ quality of life. Data from preclinical studies offer evidence of both direct and indirect mechanisms by which SSAs can exert antitumour effects. The activation of somatostatin receptors by SSAs leads to the activation of phosphotyrosine phosphatases, which control downstream apoptotic and antiproliferation signalling pathways. Also, the suppression of secretion of several growth factors and inhibition of antiangiogenic activity by SSAs indirectly inhibits tumour cell proliferationin vitro. Previous uncontrolled studies had shown tumour shrinkage and disappearance in response to the SSA octreotide. Recent results from the randomised and placebo-controlled PROMID trial have demonstrated that octreotide has antitumour activity in patients with metastatic mid-gut NETs. This article examines recent data providing evidence of the antitumour activity of somatostatin analogues.

The Management of Neuroendocrine Tumours: Current and Future Medical Therapy Options

Neuroendocrine tumours (NETs) are a genetically diverse group of malignancies that sometimes produce peptides causing characteristic hormonal syndromes. NETs can be clinically symptomatic (functioning) or silent (non-functioning); both types frequently synthesise more than one peptide, although often these are not associated with specific syndromes. Based on data from various sources, the incidence and prevalence of NETs is increasing. The primary treatment goal for patients with NETs is curative, with symptom control and the limitation of tumour progression as secondary goals. Surgery is the only possible curative approach and so represents the traditional first-line therapy. However, as most patients with NETs are diagnosed once metastases have occurred, curative surgery is generally not possible. Patients therefore require chronic postoperative medical management with the aim of relieving symptoms and, in recent years, suppressing tumour growth and spread. Somatostatin analogues, such as octreotide long-acting repeatable (LAR), can improve the symptoms of carcinoid syndrome and stabilise tumour growth in many patients. Results from the PROMID study show that octreotide LAR 30mg is an effective antiproliferative treatment in patients with newly diagnosed, functionally active or inactive, well-differentiated metastatic midgut NETs. An antiproliferative effect can also be achieved with everolimus, and combination therapy with octreotide LAR has shown synergistic antiproliferative activity. In the future, pasireotide, the multi-receptor targeted somatostatin analogue, has the potential to be an effective therapy for de novo or octreotide-refractory carcinoid syndrome and for inhibiting tumour cell proliferation. Peptide receptor radiotherapy with [90]yttrium-DOTATOC or [177]lutetium-DOTATE is also a new interesting treatment option for NETs.

Long-term results of treatment of malignant carcinoid syndrome with prolonged release Lanreotide (Somatuline Autogel)

Somatostatin analogues are the mainstay of therapy for malignant carcinoid syndrome. There is clear evidence that the once monthly intramuscular formulation, Octreotide LAR, controls symptoms of carcinoid syndrome, and recent data also suggests an antitumour effect. There is limited data on prolonged release Lanreotide (Somatuline Autogel, Ipsen Pharma Biotech, Signes, France) and no long-term data to date. To present long-term results of prolonged release Lanreotide in a large cohort of patients with malignant carcinoid syndrome, assessing clinical and objective response and tolerance. Seventy six patients with metastatic midgut neuroendocrine tumours and carcinoid syndrome were included in this 9-year retrospective study. Clinical response was based on symptom score with radiological assessment based on RECIST (Response Evaluation Criteria In Solid Tumours). Data were available in 69 patients. Ninety four percent achieved symptomatic response at first follow-up visit. Forty six percent had loss of symptomatic response, but 44% of these achieved control with an increase in dose of prolonged release Lanreotide. Overall, symptoms were well controlled throughout the study period with prolonged release Lanreotide alone in 74% of patients. Twenty six percent required additional treatment despite good initial response. Only 30% demonstrated radiological progression. Eleven patients who were switched from Octreotide LAR had return of symptomatic control. No significant adverse effects were experienced. Prolonged release Lanreotide provides good symptomatic control of diarrhoea and flushing as well as tumour stability in patients with malignant carcinoid syndrome.

Management of neuroendocrine tumors: current and future therapies

Neuroendocrine tumors (NETs) are a genetically diverse group of malignancies that sometimes produce peptides that cause characteristic hormonal syndromes. NETs can be clinically symptomatic (functioning) or silent (nonfunctioning); both types frequently synthesize more than one peptide, although often these are not associated with specific syndromes. Based on data from various sources, the incidence and prevalence of NETs is increasing. The primary treatment goal for patients with NETs is curative, with symptom control and the limitation of tumor progression as secondary goals. Surgery is the only possible curative approach and so represents the traditional first-line therapy. However, as most patients with NETs are diagnosed once metastases have occurred, curative surgery is generally not possible. Patients therefore require chronic postoperative medical management with the aim of relieving symptoms and, in recent years, suppressing tumor growth and spread. Somatostatin analogues, such as octreotide long-acting repeatable (LAR), can improve the symptoms of carcinoid syndrome and stabilize tumor growth in many patients. Results from the placebo-controlled, double-blind, prospective randomized study on the effect of octreotide LAR in the control of tumor growth in patients with metastatic neuroendocrine midgut tumors (PROMID study) demonstrate that octreotide LAR 30 mg is an effective antiproliferative treatment in patients with newly diagnosed, functionally active or inactive, well-differentiated metastatic midgut NETs. An antiproliferative effect can also be achieved with everolimus, and combination therapy with octreotide LAR has shown synergistic antiproliferative activity. Sunitinib, a tyrosine kinase inhibitor, is active in pancreatic NETs. In the future, pasireotide, the multireceptor targeted somatostatin analogue, has the potential to be an effective therapy for de novo or octreotide-refractory carcinoid syndrome and for inhibiting tumor cell proliferation. Peptide receptor radiotherapy with 90Yttrium-DOTATOC or 177Lutetium-DOTATE is also a new interesting treatment option for NETs.

Objective radiological disease control with Sandostatin monotherapy in metastatic neuroendocrine tumours

Conventional cytotoxic chemotherapy is not usually effective in neuroendocrine tumours (NET). Somatostatin analogues (SSA) such as octreotide (Sandostatin; octreotide LAR and lanreotide) are typically used to treat symptoms caused by NET, but not as the primary treatment aiming for an objective response. Recently, results from the PROMID (Placebo-controlled prospective Randomized study on the antiproliferative efficacy of Octreotide LAR in patients with metastatic neuroendocrine MIDgut tumours) trial were published showing that octreotide LAR significantly lengthens the time to tumour progression compared with a placebo in patients with functionally active and inactive metastatic midgut NET. We report a retrospective descriptive analysis of six patients, treated at two Australian institutions, who obtained an objective radiological tumour response on long acting SSA. In this retrospective series of NET, radiological responses were observed using single agent SSA, which was administered mainly for symptom management. This could be due to an antiproliferative and/or antiangiogenic activity of this agent in NET. A response can occur beyond 12 months, which might explain why the response rate is under reported in NET trials. Further investigation in prospective trials is warranted and the possibility for late responses might have implications for trial design.

Antitumour Effects of Somatostatin Analogues in the Treatment of Neuroendocrine Tumours

Neuroendocrine tumours (NETs) are rare and heterogeneous neoplasms that can present with functional syndromes due to the hypersecretion of peptides. Somatostatin analogues (SSAs) have been used since the 1980s for the treatment of neuroendocrine tumours, with the aim of controlling the symptoms of functioning tumours and improving patients’ quality of life. Data from preclinical studies offer evidence of both direct and indirect mechanisms by which SSAs can exert antitumour effects. The activation of somatostatin receptors by SSAs leads to the activation of phosphotyrosine phosphatases, which control downstream apoptotic and antiproliferation signalling pathways. Also, the suppression of secretion of several growth factors and inhibition of antiangiogenic activity by SSAs indirectly inhibits tumour cell proliferationin vitro. Previous uncontrolled studies had shown tumour shrinkage and disappearance in response to the SSA octreotide. Recent results from the randomised and placebo-controlled PROMID trial have demonstrated that octreotide has antitumour activity in patients with metastatic mid-gut NETs. This article examines recent data providing evidence of the antitumour activity of somatostatin analogues.

Octreotide - A Review of its Use in Treating Neuroendocrine Tumours.

Neuroendocrine tumours (NETs) are a heterogeneous group of neoplasms whose incidence has dramatically increased in recent years. Octreotide is a somatostatin analogue used in the treatment of NETs, and its use in clinical trials has been associated with substantially increased survival. Although traditionally used for the relief of symptoms that result from release of peptides and neuroamines, there has been a growing body of evidence that suggest octreotide has antiproliferative effects. A phase III clinical study has demonstrated that the long-acting formulation (LAR), octreotide LAR, lengthens time to tumour progression in patients with well-differentiated metastatic midgut NETs, and that octreotide LAR is a treatment option for patients with metastatic midgut NETs, regardless of functional status. Furthermore, octreotide LAR has demonstrated clinical efficacy in different types of NETs. These data, along with emerging data on somatostatin analogs, may change the way doctors approach this patient population and reinforce the use of these drugs as a treatment option for patients with non-functioning tumours.

Antiproliferative effect of somatostatin analogs in gastroenteropancreatic neuroendocrine tumors

Somatostatin analogs were initially developed for the control of hormonal syndromes associated with neuroendocrine tumors (NETs). In recent years, accumulating data has supported their role as antiproliferative agents, capable of stabilizing tumor growth in patients with metastatic neuroendocrine malignancies, including carcinoid and pancreatic endocrine tumors. A phase III, randomized, placebo-controlled trial has now demonstrated that octreotide long-acting repeatable (LAR) 30 mg can significantly prolong time to tumor progression among patients with metastatic midgut NETs regardless of functional status, chromogranin A level or age. In addition to significantly lengthening time to tumor progression in the overall study population, subset analysis suggests that patients with low tumor burden are most likely to experience disease stabilization with octreotide LAR 30 mg, supporting the early use of octreotide LAR in patients with metastatic disease. Further research efforts are underway to evaluate the use of somatostatin analogs as antiproliferative agents in other types of gastroenteropancreatic-NETs. Ongoing studies are also evaluating novel somatostatin analogs and somatostatin analogs in combination with other anti-tumor therapies.

Antitumor Effect of Somatostatin Analogs in Neuroendocrine Tumors

TO THE EDITOR: We read with interest the report by Rinke et al 1 of the interim analysis of a randomized, placebo-controlled trial of octreotide LAR, the long-acting somatostatin analog (SSA), in metastatic midgut neuroendocrine tumors (NETs), along with the companion editorial by Oberg. 2 These results are an important contribution to our understanding of the biology of NETs. However, although scientifically provocative and supportive of the long-held belief of many clinicians in this field that SSAs have an antiproliferative effect in this heterogeneous group of diseases, the data published thus far still leave some important issues unresolved. The study planned to enroll 162 patients, but after nearly 8 years, only 85 were randomly assigned. Despite the much-reduced accrual, Rinke et al reported a marked difference in median time to progression on the basis of WHO radiologic criteria in the intent-to-treat population of 14.3 months with octreotide LAR compared with 6.0 months with placebo (hazard ratio [HR], 0.33; 95% CI, 0.20 to 0.59;P.000072). Importantly, similar benefits were demonstrated regardless of the presence or absence of carcinoid syndrome ( 40% of patients had carcinoid syndrome). As impressive as these results seem, we have concerns about whether both study arms are comparable. Notably, there was a highlystatisticallysignificantimbalanceinthetimesincediagnosis between the study arms in favor of the octreotide LAR arm, with a medianof7.5monthscomparedwith3.3monthsfortheplaceboarm (P.0096). Given the heterogeneous natural history of these tumors and the relatively small size of the analyzed population, it is unclear how this imbalance might have influenced the overall outcome of the study. A longer duration between diagnosis and treatment suggests more indolent disease; if by chance more of these patients were in the experimental treatment arm, as seems to have been the case in this trial, a longer time to progression could have ensued, whether or not the treatment was effective. Similarly, the planned subgroup analysis suggested that the benefit of octreotide LAR was greatest in patients withlimited(0%to10%)liverinvolvement(HR,0.17;95%CI,0.08to 0.40). Conceivably, those patients with a longer time since diagnosis were also those with limited liver involvement as a result of lower biologic aggressiveness. However, the explanation for the suggestion ofreducedactivityofoctreotideLARinthosepatientswithsignificant liver involvement in this trial was not discussed. If there is a proportionate increase in the overall quantity of somatostatin receptors with tumor bulk, the dose of octreotide LAR used may have been inade

Long‐term results of patients with malignant carcinoid syndrome receiving octreotide LAR

Octreotide LAR is an established treatment for malignant carcinoid syndrome. However, studies with large number of patients and long follow-up are lacking. To present long-terms results with octreotide LAR, assessing duration of clinical and objective response and treatment tolerance, in a large, homogeneous cohort of patients with malignant carcinoid syndrome. A total of 108 patients with metastatic midgut neuroendocrine tumours were included in this 8-year study. Clinical evaluation was based on a symptom score. Radiological assessment was based on RECIST (Response Evaluation Criteria In Solid Tumours) criteria. Of the 108 patients, 24% had a sustained symptomatic response. In the remaining patients, loss of symptomatic response with the initial dose was noted within 3-60 months. In 17% of them, symptoms were controlled by just an increase of octreotide LAR dose, whilst the other patients required additional treatment. Overall, in 45.3% of patients, symptoms were well controlled during the study period with only octreotide LAR, and no additional treatment was required. No significant adverse effects were noted. Octreotide LAR treatment provides a sustained symptomatic response in about half of the patients with malignant carcinoid syndrome and contributes to disease stabilization for a longer period than previously described.