Time to Sustained Improvement in Bowel Movement Frequency with Telotristat Ethyl: Analyses of Phase III Studies in Carcinoid Syndrome.

BACKGROUND: Telotristat ethyl is approved to treat carcinoid syndrome diarrhea in combination with somatostatin analogs. In TELESTAR and TELECAST phase III studies, patients with carcinoid syndrome received telotristat ethyl 250 or 500 mg 3 times per day (tid) or placebo tid in addition to somatostatin analogs. The aim of this prespecified analysis was to examine the time to reductions in bowel movements (BMs) in the TELESTAR and TELECAST studies using survival analysis methods. METHODS: First occurrence of sustained response was defined as the time to the first day of 2 consecutive weeks with a mean BM frequency improvement of ≥ 30% from baseline during the 12-week double-blind treatment periods. Time to first ≥ 30% worsening in BM frequency was also measured. Treatments were compared with the log-rank test; Cox regression models provided point and confidence interval estimates of the hazard ratios for each trial. RESULTS: In TELESTAR and TELECAST, majority of patients (69%) on telotristat ethyl experienced a sustained ≥ 30% improvement in BM frequency. The median time to sustained reduction of at least 30% in BM frequency was significantly faster (fewer days to onset) for telotristat ethyl compared with placebo in both TELESTAR (250 mg, HR = 2.3 [95% CI, 1.3-4.1, P = 0.004]; 500 mg, HR = 2.2 [95% CI, 1.2-3.9, P = 0.009]) and TELECAST (250 mg, HR = 3.9 [95% CI, 1.6-11.1, P = 0.003]; 500 mg, HR = 4.2 [95% CI, 1.7-11.7, P = 0.002]). In TELECAST, 42% of patients on placebo experienced sustained worsening in BM frequency compared with 20% on telotristat ethyl; no significant difference was observed in TELESTAR. CONCLUSION: The time of onset of sustained BM frequency improvement mean and range are important when considering use of telotristat ethyl in patients with carcinoid syndrome diarrhea. Telotristat ethyl may also reduce sustained worsening in BM frequency. TRIAL REGISTRATION: ClinicalTrials.gov Identifiers: NCT01677910, NCT02063659.

Clinical Benefits of Telotristat Ethyl in Patients With Neuroendocrine Tumors and Low Bowel Movement Frequency: An Observational Patient-Reported Outcomes Study.

OBJECTIVES: We evaluated carcinoid syndrome (CS) symptoms and the real-world effectiveness of telotristat ethyl (TE) among patients with ≤3 bowel movements (BM) per day. METHODS: Patients with CS initiating TE between March and November 2017 could participate in a nurse support program collecting demographic and CS symptom data before TE initiation (baseline) and during ≥1 monthly follow-up within 3 months. Symptoms for patients averaging ≤3 BM/d at baseline were evaluated using pre/post-Student t tests. RESULTS: Sixty-eight patients reported ≤3 BM/d at baseline. Symptom burden was high and similar to participants with higher daily BM frequency. After 3 months of TE, most patients reported stable or improved symptoms with significant improvements in urgency (88%; mean [SD], -13.2 [32.2]), stool consistency (88%; -1.3 [2.0]), BMs per day (81%; -0.2 [1.2]), abdominal pain (86%; -13.7 [25.8]), nausea (85%; -30.9 [35.7]), and daily flushing episodes (83%; -1.7 [4.4]; all except BMs per day, P < 0.05). CONCLUSIONS: This analysis illustrates high CS symptom burden among patients with relatively low daily BM frequency. After initiating TE, patients reported significant improvements in urgency, stool consistency, abdominal pain, nausea, and flushing episodes. Clinicians and population health managers should consider CS symptom burden beyond daily BM frequency when evaluating treatment selection.

Serotonin pathway in carcinoid syndrome: Clinical, diagnostic, prognostic and therapeutic implications.

Carcinoid syndrome represents the most common functional syndrome that affects patients with neuroendocrine neoplasms. Its clinical presentation is really heterogeneous, ranging from mild and often misdiagnosed symptoms to severe manifestations, that significantly worsen the patient's quality of life, such as difficult-to-control diarrhoea and fibrotic complications. Serotonin pathway alteration plays a central role in the pathophysiology of carcinoid syndrome, accounting for most clinical manifestations and providing diagnostic tools. Serotonin pathway is complex, resulting in production of biologically active molecules such as serotonin and melatonin, as well as of different intermediate molecules and final metabolites. These activities require site- and tissue-specific catalytic enzymes. Variable expression and activities of these enzymes result in different clinical pictures, according to primary site of origin of the tumour. At the same time, the biochemical diagnosis of carcinoid syndrome could be difficult even in case of typical symptoms. Therefore, the accuracy of the diagnostic methods of assessment should be improved, also attenuating the impact of confounding factors and maybe considering new serotonin precursors or metabolites as diagnostic markers. Finally, the prognostic role of serotonin markers has been only evaluated for its metabolite 5-hydroxyindole acetic acid but, due to heterogeneous and biased study designs, no definitive conclusions have been achieved. The most recent progress is represented by the new therapeutic agent telotristat, an inhibitor of the enzyme tryptophan hydroxylase, which blocks the conversion of tryptophan in 5-hydroxy-tryptophan. The present review investigates the clinical significance of serotonin pathway in carcinoid syndrome, considering its role in the pathogenesis, diagnosis, prognosis and therapy.

CSTI-300 (SMP-100); a Novel 5-HT3 Receptor Partial Agonist with Potential to Treat Patients with Irritable Bowel Syndrome or Carcinoid Syndrome.

The 5-hydroxytryptamine (5-HT) (serotonin) 5-HT3 receptor represents a clinical target for antagonists to deliver symptomatic relief to patients with diarrhea-predominant irritable bowel syndrome (IBS-d) or carcinoid syndrome. Unfortunately, this pharmacological strategy can present side effects (e.g., severe constipation). The present study investigates the potential of a novel 5-HT3 receptor partial agonist, CSTI-300, to treat patients with IBS-d and other conditions associated with discomfort from colonic distension, with a predicted reduced side-effect profile. The in vitro and in vivo preclinical pharmacology of the drug CSTI-300 was investigated to explore the potential to treat patients with IBS-d. CSTI-300 displayed selective high affinity for the human and rat 5-HT3 receptor (Ki approximately 2.0 nM) and acted as a partial agonist (approximately 30%-50% intrinsic efficacy) in vitro. In an in vivo model of IBS-d, the rat colon distension model, CSTI-300 displayed dose-dependent efficacy. In addition, oral administration of CSTI-300 to dogs that achieved plasma levels of the drug exceeding the Ki value for the 5-HT3 receptor failed to either evoke emesis or alter the state of feces. Pharmacokinetics for CSTI-300 in rat and dog identified high levels of oral availability with t 1/2 range of 1.6-4.4 hours. The preclinical pharmacology of the lead candidate drug, CSTI-300, supports the potential of this novel drug to offer symptomatic relief to patients with irritable bowel syndrome and carcinoid syndrome with a rationale for a reduced "on-target" side-effect profile relative to 5-HT3 receptor antagonists, such as alosetron. SIGNIFICANCE STATEMENT: There is a lack of effective current treatment for diarrhea-predominant irritable bowel syndrome and carcinoid syndrome, and in both conditions, overactivity of the 5-hydroxytryptamine (5-HT) 5-HT3 receptor is thought to be implicated in the pathophysiology. Because 5-HT3 receptor blockade with antagonists results in significant side effects, we present evidence that treatment with a suitable 5-HT3 receptor partial agonist will alleviate some symptoms associated with these conditions yet, without fully inhibiting the receptor, predict a less pronounced side-effect profile associated with this therapeutic strategy.

Long-Term Safety Experience with Telotristat Ethyl Across Five Clinical Studies in Patients with Carcinoid Syndrome.

BACKGROUND: Patients with neuroendocrine tumors (NETs) and carcinoid syndrome experience considerable morbidity and mortality; carcinoid syndrome may be associated with shorter survival. Carcinoid syndrome is linked to tumoral secretion of serotonin and other bioactive substances. The subsequent debilitating diarrhea and urgency to defecate pose significant health risks. In previous studies, telotristat ethyl, a tryptophan hydroxylase inhibitor, was effective and well tolerated in treating carcinoid syndrome diarrhea. We present pooled safety data from five clinical trials with telotristat ethyl in patients with carcinoid syndrome. SUBJECTS, MATERIALS, AND METHODS: Adverse events reported during telotristat ethyl treatment were pooled from two phase II and three phase III clinical trials in 239 patients with carcinoid syndrome. Long-term safety of telotristat ethyl and causes of hospitalization and death were reviewed; overall survival was estimated. RESULTS: Mean (median; range) duration of exposure and follow-up was 1.3 years (1.1 years; 1 week to 5.7 years), with 309 total patient-years of exposure. Leading causes of hospitalization were gastrointestinal disorders or were related to the underlying tumor and related treatment. Survival estimates at 1, 2, and 3 years were 93%, 88%, and 77%. Nearly all deaths were due to progression or complication of the underlying disease; none were attributable to telotristat ethyl. There was one death in year 4. CONCLUSION: Based on long-term safety data, telotristat ethyl is well tolerated and has a favorable long-term safety profile in patients with carcinoid syndrome. IMPLICATIONS FOR PRACTICE: Carcinoid syndrome can cause persistent diarrhea, even in patients treated with somatostatin analogs. Across five clinical trials in patients with carcinoid syndrome, telotristat ethyl has been well tolerated and efficacious, providing clinicians with a new approach to help control carcinoid syndrome diarrhea, in addition to somatostatin analog therapy. By reducing the stool frequency in patients with carcinoid syndrome whose diarrhea is refractory to anticholinergics, such as loperamide and atropine/diphenoxylate, and somatostatin analog dose escalation, improvement in quality of life becomes an achievable goal.

A prospective study of the pathophysiology of carcinoid crisis.

BACKGROUND: Sudden massive release of serotonin, histamine, kallikrein, and bradykinin is postulated to cause an intraoperative carcinoid crisis. The exact roles of each of these possible agents, however, remain unknown. Optimal treatment will require an improved understanding of the pathophysiology of the carcinoid crisis. METHODS: Carcinoid patients with liver metastases undergoing elective abdominal operations were studied prospectively, using intraoperative, transesophageal echocardiography, pulmonary artery catheterization, and intraoperative blood collection. Serotonin, histamine, kallikrein, and bradykinin levels were analyzed by enzyme-linked immunosorbent assay. RESULTS: Of 46 patients studied, 16 had intraoperative hypotensive crises. Preincision serotonin levels were greater in patients who had crises (1,064 vs 453 ng/mL, P = .0064). Preincision hormone profiles were otherwise diverse. Cardiac function on transesophageal echocardiography during the crisis was normal, but intracardiac hypovolemia was observed consistently. Pulmonary artery pressure decreased during crises (P = .025). Linear regression of preincision serotonin levels showed a positive relationship with mid-crisis cardiac index (r = 0.73, P = .017) and a negative relationship with systemic vascular resistance (r=-0.61, P = .015). There were no statistically significant increases of serotonin, histamine, kallikrein, or bradykinin levels during the crises. CONCLUSION: The pathophysiology of carcinoid crisis appears consistent with distributive shock. Hormonal secretion from carcinoid tumors varies widely, but increased preincision serotonin levels correlate with crises and with hemodynamic parameters during the crises. Statistically significant increases of serotonin, histamine, kallikrein, or bradykinin during the crises were not observed.

Cases in a series of carcinoid syndrome and carcinoid heart disease.

Although carcinoid syndrome is regarded as a rare entity, carcinoid patients with evidence of cardiac involvement show a markedly reduced survival time. Patients with advanced signs of right-sided heart failure represent a subgroup at particularly high risk. Echocardiography remains the gold standard to diagnose or confirm structural cardiac involvement in patients with underlying carcinoid disease. This is the notion that propelled us to report on cases of carcinoid syndrome with cardiac involvement. We also review carcinoid syndrome and carcinoid heart disease, and challenges regarding the diagnosis and management of carcinoid heart disease.

Carcinoid syndrome: update on the pathophysiology and treatment.

Approximately 30-40% of patients with well-differentiated neuroendocrine tumors present with carcinoid syndrome, which is a paraneoplastic syndrome associated with the secretion of several humoral factors. Carcinoid syndrome significantly and negatively affects patients' quality of life; increases costs compared with the costs of nonfunctioning neuroendocrine tumors; and results in changes in patients' lifestyle, such as diet, work, physical activity and social life. For several decades, patients with neuroendocrine tumors and carcinoid syndrome have been treated with somatostatin analogues as the first-line treatment. While these agents provide significant relief from carcinoid syndrome symptoms, there is inevitable clinical progression, and new therapeutic interventions are needed. More than 40 substances have been identified as being potentially related to carcinoid syndrome; however, their individual contributions in triggering different carcinoid symptoms or complications, such as carcinoid heart disease, remain unclear. These substances include serotonin (5-HT), which appears to be the primary marker associated with the syndrome, as well as histamine, kallikrein, prostaglandins, and tachykinins. Given the complexity involving the origin, diagnosis and management of patients with carcinoid syndrome, we have undertaken a comprehensive review to update information about the pathophysiology, diagnostic tools and treatment sequence of this syndrome, which currently comprises a multidisciplinary approach.

Carcinoid syndrome: update on the pathophysiology and treatment

Approximately 30-40% of patients with well-differentiated neuroendocrine tumors present with carcinoid syndrome, which is a paraneoplastic syndrome associated with the secretion of several humoral factors. Carcinoid syndrome significantly and negatively affects patients' quality of life; increases costs compared with the costs of nonfunctioning neuroendocrine tumors; and results in changes in patients' lifestyle, such as diet, work, physical activity and social life. For several decades, patients with neuroendocrine tumors and carcinoid syndrome have been treated with somatostatin analogues as the first-line treatment. While these agents provide significant relief from carcinoid syndrome symptoms, there is inevitable clinical progression, and new therapeutic interventions are needed. More than 40 substances have been identified as being potentially related to carcinoid syndrome; however, their individual contributions in triggering different carcinoid symptoms or complications, such as carcinoid heart disease, remain unclear. These substances include serotonin (5-HT), which appears to be the primary marker associated with the syndrome, as well as histamine, kallikrein, prostaglandins, and tachykinins. Given the complexity involving the origin, diagnosis and management of patients with carcinoid syndrome, we have undertaken a comprehensive review to update information about the pathophysiology, diagnostic tools and treatment sequence of this syndrome, which currently comprises a multidisciplinary approach.

Mega-dose intravenous octreotide for the treatment of carcinoid crisis: a systematic review.

PURPOSE: Carcinoid crises are rare life-threatening events involving cardiac instability when carcinoid tumours release vasoactive peptides. Such events can occur in the perioperative setting. Octreotide, a somatostatin analogue, is administered as a bolus dose of 100-500 µg iv or by infusion to treat carcinoid crises. Due to the apparent low risk-to-benefit profile, a much higher dose is sometimes used in urgent situations. The purpose of this study was to assess the evidence for administering doses or hourly infusions of octreotide that exceeded 1,500 µg iv to treat carcinoid crises. We also sought to identify which patients may require large doses and to describe the adverse effects of such doses. SOURCE: We systematically searched Medline, EMBASE, and Cochrane databases and hand-searched reference lists of relevant articles in 2006 and again in 2010 and 2011. All study designs were included in our search. Resolution of crisis symptoms was the primary outcome. PRINCIPAL FINDINGS: Eighteen articles were included. No patient died during a carcinoid crisis. A retrospective chart review of 89 patients with carcinoid heart disease reported octreotide doses of 25-54,000 µg to treat carcinoid crises, although neither crisis symptoms nor outcomes were described. CONCLUSION: In the included case reports, carcinoid crises were managed effectively using octreotide 25-500 µg iv. Previous exposure to octreotide and carcinoid heart disease may warrant the need for higher doses. In addition to the low quality of the articles and the small sample size, inconsistent use of the term "carcinoid crisis" and paucity of reported outcomes were also limitations of this systematic review. These findings highlight the need for further investigation into dose-response relationships of octreotide for the treatment of carcinoid crisis.

Carcinoid syndrome and perioperative anesthetic considerations.

Carcinoid tumors are uncommon, slow-growing neoplasms. These tumors are capable of secreting numerous bioactive substances, which results in significant potential challenges in the management of patients afflicted with carcinoid syndrome. Over the past two decades, both surgical and medical therapeutic options have broadened, resulting in improved outcomes. The pathophysiology, clinical signs and symptoms, diagnosis, treatment options, and perioperative management, including anesthetic considerations, of carcinoid syndrome are presented.

Carcinoid crisis 24 hours after bland embolization: A case report.

Within 24 h of bland embolization of carcinoid liver metastasis, patient developed flushing and severe hypotension consistent with carcinoid crisis. Octreotide pre- and post-procedure remains the mainstay for prevention and treatment of carcinoid crisis.

The case report and palliative management of a patient with carcinoid syndrome and crises.

The case report of a patient who suffered from severe carcinoid syndrome and frequent carcinoid crises. The discussion highlights key points in the palliative management of this rare, complex condition.

Central nervous system plus autonomic nervous system disorders responsible for gastrointestinal and pancreatobiliary diseases.

Clinical digestive disorders depend on the non-adequate coupling of functioning of the gastrointestinal tract with that of its affluent systems, namely, the pancreatic exocrine and the hepato-biliary secretions. The secretion of gastrointestinal hormones is monitored by the peripheral autonomic nervous system. However, the latter is regulated by the central nervous system (CNS) circuitry localized at the medullary pontine segment of the CNS. In turn, both parasympathetic and adrenergic medullary circuitries are regulated by the pontine A5 noradrenergic (NA) and the dorsal raphe serotonergic nuclei, respectively. DR-5HT is positively correlated with the C1-Ad medullary nuclei (responsible for adrenal gland secretion), whereas the MR-5HT nucleus is positively correlated with the A5-NA pontomedullary nucleus. The latter is responsible for neural sympathetic activity (sympathetic nerves). Both types of sympathetic activities maintain an alternation with the peripheral parasympathetic branch, which is positively correlated with the enterochromaffin cells that secrete serotonin. Serotonin displays hormonal antagonism to the circulating catecholamines.

Clinical and biochemical aspects of the carcinoid syndrome in neuroendocrine tumors of the abdominal and retroperitoneal organs and its impact for the disease prognosis.

Overall and relapse-free survival of 238 patients with neuroendocrine tumors of the abdominal and retroperitoneal organs was evaluated with consideration for the presence of the carcinoid syndrome. The incidence of the carcinoid syndrome was 15.6%. The presence of the carcinoid syndrome was inessential for survival and relapse prognosis in patients with neuroendocrine tumors of the abdominal and retroperitoneal organs. A trend to the development of earlier relapses was noted in patients with this syndrome. Diarrhea was found to be a prognostically unfavorable factor. The time of the carcinoid syndrome development was prognostically significant in patients with malignant neuroendocrine tumors. The mean secretion of epinephrine, norepinephrine, and dopamine with daily urine was significantly higher in patients with the carcinoid syndrome. A significant positive correlation between urinary excretion of catecholamines was detected (r=0.53; p<0.05).

Primary hepatic carcinoid tumours: clinical features with an emphasis on carcinoid syndrome and recurrence.

This study sought to determine the clinical profiles and optimal management of primary hepatic carcinoid tumours. The clinical features of nine Chinese patients and 64 patients reported in the English-language literature were characterized. Recurrence rate and survival analysis were performed with the Kaplan-Meier method. The impact of surgical resection and post-operative recurrence on survival was determined by means of the log-rank test. Carcinoid syndrome complicated 10 cases (14%). Sixty-two patients (85%) underwent surgical resection. Actuarial 5- and 10-year survival rates for resected patients were 80% and 75%, respectively. Twelve patients experienced recurrences: the recurrence rate at 5 years post-operatively was 26%. All patients with resectable recurrent disease achieved good long-term survival and no significant relationship was found between recurrence and survival. Owing to the high incidence of recurrence, long-term follow-up is necessary and it is recommended that recurrent cases should be managed with judicious surgical resection.

Scleroderma-like disorders.

Fibrosing disorders comprise a wide spectrum of heterogeneous diseases characterized by sclerosis of the dermis, subcutis, and sometimes the underlying soft tissues and bone. The hallmark of this group of diseases is skin thickening as in systemic sclerosis with a different distribution pattern and for this reason they have also been referred to as "scleroderma-like" disorders. These diseases may have a different clinical course ranging from a benign disease with a localized cutaneous involvement, to a widespread, systemic, life-threatening disease. Some of them are associated with autoantibodies and/or autoimmune conditions. An accurate recognition of these scleroderma-like diseases is important for the institution of the most appropriate treatment.