Acetato de lanreotida e acetato de octreotida de liberação prolongada para o tratamento de pacientes com sintomas associados a tumores endócrinos gastroenteropancreáticos funcionais / Lanreotide acetate and extended-release octreotide acetate for the treatment of patients with symptoms associated with functional gastroenteropancreatic endocrine tumors

INTRODUÇÃO: Os tumores neuroendócrinos (TNE) são neoplasias, com origem mais comum no trato gastrointestinal, que podem cursar com liberação de hormônios associado a sintomas, levando a síndrome carcinoide, com incidência anual estimada em 0,25/1.000.000 na Europa (ano de 2008). As manifestações clínicas mais comuns incluem diarreia secretória e rubor súbito, mas a diarreia é considerada mais debilitante com potencial risco de morte. Quando o tratamento curativo com ressecção completa não é viável pela presença de doença metastática, o tratamento é direcionado para o controle dos sintomas da síndrome carcinoide e os análogos da somatostatina (octreotida ou lanreotida) são considerados terapia de primeira linha na SC. PERGUNTAS DE PESQUISA: O acetato de octreotida de liberação prolongada (octreotida LAR) e o acetato de lanreotida de liberação prolongada (lanreotida LP) são eficazes, seguros e custo-efetivos para o tratamento dos sintomas relacionados à SC associados ao TNE gastroenteropancreático funcional em pacientes adultos? EVIDÊNCIAS CLÍNICAS: Foram selecionados três ensaios clínico

Comparison of Octreotide and Vasopressors as First-Line Treatment for Intraoperative Carcinoid Crisis.

BACKGROUND: Intraoperative carcinoid crisis is typically sudden onset of profound hypotension during operations on patients with neuroendocrine tumors. The crisis was thought to be due to massive release of hormones, and perioperative octreotide was recommended as a prophylaxis against the crisis and as first-line treatment. Recent studies show that octreotide does not prevent the crisis and that no massive release of hormones occurs. Therefore, the authors hypothesized that octreotide is not effective for treating the crisis. METHODS: A prospective carcinoid anesthesia database was analyzed for occurrences of crisis. Outcomes were compared between protocols when first-line therapy was bolus octreotide and when it was vasopressors without octreotide. Significance was determined by Student's t test, the Mann-Whitney U test, and Fisher's exact test. RESULTS: Among operations performed with octreotide as first-line treatment (n = 150), crisis occurred for 45 (30 %) patients, the median crisis duration was 6 min, 12 (27 %) patients had crises longer than 10 min, 42 patients (93 %) required subsequent vasopressor administration to resolve the crisis, and 3 (2 %) operations were aborted. Among operations performed with vasopressors as the first-line treatment (n = 195), crisis occurred for 49 (25 %) patients (p = 0.31), the median crisis duration was 3 min (p < 0.001), and no crisis lasted longer than 10 min (p = 0.001). Patients treated with vasopressors were less likely to have multiple crises and had a shorter total time in crisis, a shorter anesthesia time, and no aborted operations (p < 0.05 for all). CONCLUSIONS: First-line octreotide was ineffective treatment for carcinoid crisis, with patients requiring vasopressors to resolve the crisis, and many crises lasting longer than 10 min. First-line vasopressor treatment resulted in significantly shorter crisis durations, fewer crises and aborted operations, and shorter anesthesia times. Vasopressors should be used as first-line treatment for intraoperative crisis, and treatment guidelines should be changed.

Breakthrough Symptoms Remain an Unmet Need in Symptomatic Patients With Neuroendocrine Tumors and Carcinoid Syndrome.

OBJECTIVES: The aims of the study were to assess the effects of breakthrough carcinoid syndrome symptoms on well-being in neuroendocrine tumor (NET) patients insufficiently controlled on long-acting somatostatin analog (SSA) and to assess patient experience with treatment options, physician communication, and disease information sources. METHODS: This study surveyed US NET patients from 2 online communities, experiencing at least one symptom, by utilizing a 64-item questionnaire. RESULTS: One hundred patients participated: 73% female, 75% age 56 to 75 years, and 93% White. Primary tumor distribution was as follows: gastrointestinal NET (n = 55), pancreatic NET (n = 33), lung NET (n = 11), and other NET (n = 13). All patients were actively treated with one long-acting SSA and experiencing breakthrough symptoms: diarrhea, flushing, or other (13% experienced one, 30% two, 57% greater than two). More than one third of treated patients experienced carcinoid-related symptoms daily. Sixty percent of respondents reported not having short-acting "rescue" treatment available, impacting well-being though anxiety or depression (45%), trouble exercising (65%), sleeping (57%), employment (54%), and maintaining friendships (43%). CONCLUSIONS: Breakthrough symptoms remain an unmet need, even in treated patients with NETs. Though still relying on physicians, NET patients are now also using the Internet. Improved awareness of optimal SSA use may improve syndrome control.

Carcinoid Heart Disease Management: A Multi-Disciplinary Collaboration.

Carcinoid heart disease (CaHD) is an important complication among patients with metastatic neuroendocrine tumors and carcinoid syndrome (CS). CS patients (25%-65%) eventually develop CaHD; these patients face a significantly increased risk of morbidity and mortality. Guidance papers (eg, clinical practice guidelines, consensus guidelines, and expert statements) have been established by major organizations across the disciplines of cardiology and oncology; however, these recommendations are not routinely implemented. The aim of this article is to encourage the integration of current recommendations from national societies into clinical practice. Early screening upon recognition of CS and prior to the development of CaHD symptoms is paramount, as no existing therapies are approved to reverse the fibrotic damage to the heart once it occurs. Valvular replacement is the only definitive treatment for CaHD once it has developed. When patients are noted to have urinary 5-hydroxyindoleacetic acid (5-HIAA) levels ≥300 µmol/24 h and/or serum N-terminal pro B-type natriuretic peptide (NT-proBNP) levels >260 pg/mL, echocardiography is recommended. Systemic approaches to control tumor growth and hormonal secretion include somatostatin analogs (SSAs), followed by options including peptide receptor radiotherapy (PRRT), everolimus and liver embolization. Telotristat is the primary choice for control of diarrhea refractory to SSA. Diuretics are the mainstay of heart failure symptom management for patients who develop CaHD. Considerations for future research are discussed, including the ongoing TELEHEART (TELotristat Ethyl in a HEART biomarker study) trial involving telotristat and not yet activated CHARRT (Carcinoid Heart disease And peptide Receptor Radiotargetted Therapy) study involving PRRT with lutetium 177 (177Lu) dotatate.

Prescribing Characteristics of Octreotide Immediate-Release and Long-Acting Release in Patients with Neuroendocrine Tumors.

BACKGROUND: Treatment recommendations for patients with neuroendocrine tumors (NETs) include the use of octreotide long-acting release (LAR) for long-term therapy and immediate-release (IR) as rescue therapy to control the breakthrough symptoms of carcinoid syndrome (CS). High doses of LAR are commonly used in clinical practice. This study aimed to evaluate the real-world utilization of LAR and preceding IR use at the prescription and patient levels. METHODS: We used an administrative claims database (2009-2018) containing privately insured enrollees. We calculated the normalized LAR dose from pharmacy claims and the initial mean IR daily dose at the prescription level. At the patient level, we conducted a retrospective cohort study that included patients continuously enrolled with ≥1 pharmacy claim of LAR and evaluated the frequency and the clinical reason for dose escalation of LAR. The definition of the above-label maximum dose of LAR was ≥30 mg/4 weeks. RESULTS: Nineteen percent of LAR prescriptions had an above-label maximum dose. Only 7% of LAR prescriptions had preceding IR use. There were 386 patients with NETs or CS vs. 570 with an unknown diagnosis. Comparing patients with NETs or CS to those with an unknown diagnosis, 22.3% vs. 11.0 % experienced dose escalations and 29.0% vs. 26.6% had IR use before dose escalation, respectively. LAR dose escalation occurred in 50.9% vs. 39.2% for symptom control, 12.3% vs. 7.1% for tumor progression control, and 16.6% vs. 6.0% for both reasons in NETs/CS and unknown groups, respectively. CONCLUSION: Octreotide LAR dosing above the label-maximum dose is common and IR rescue dosing appears to be underutilized.

Carcinoid syndrome and somatostatin analogues.

Clinical experience is herein reported with somatostatin analogues (octreotide and lanreotide) in the management of 10 CS out of a series of 14 collected cases of carcinoid syndrome (CS).

Carcinoid Syndrome: Preclinical Models and Future Therapeutic Strategies.

Carcinoid syndrome represents a debilitating paraneoplastic disease, caused by the secretion of several substances, occurring in about 10-40% of patients with well-differentiated neuroendocrine tumors (NETs). The main signs and symptoms associated with carcinoid syndrome are flushing, diarrhea, hypotension, tachycardia, bronchoconstriction, venous telangiectasia, dyspnea and fibrotic complications (mesenteric and retroperitoneal fibrosis, and carcinoid heart disease). Although there are several drugs available for the treatment of carcinoid syndrome, the lack of therapeutic response, poor tolerance or resistance to drugs are often reported. Preclinical models are indispensable tools for investigating the pathogenesis, mechanisms for tumor progression and new therapeutic approaches for cancer. This paper provides a state-of-the-art overview of in vitro and in vivo models in NETs with carcinoid syndrome, highlighting the future developments and therapeutic approaches in this field.

Efficacy, safety and unmet needs of evolving medical treatments for carcinoid syndrome.

This review reports on the currently available medical treatment options for the control of symptoms due to carcinoid syndrome in patients with neuroendocrine tumors. The efficacy and adverse events (AEs) of approved drugs such as somatostatin analogues (SSA), telotristat ethyl (TE) and interferon-alpha, are reviewed. Somatostatin analogues remain the standard treatment of carcinoid syndrome based on the high expression of somatostatin receptors and the resulting inhibition of secretion of bioactive compounds; their use is associated with relatively mild AEs, involving mainly the gastrointestinal system, and being usually transient. Although dose escalation of SSA remains an unapproved option, it is clinically implemented to alleviate symptoms in refractory carcinoid syndrome and supported by the most recent guidelines. The side effects associated with the increased dose are in general mild and consistent with standard dose of SSA. Telotristat ethyl, an oral inhibitor of tryptophan hydroxylase, the rate-limiting enzyme in serotonin biosynthesis, represents a rather novel innovative treatment option in patients with carcinoid syndrome suffering from diarrhea and complements the standard therapy of SSA. Given the low toxicity profile, TE may be considered an early add-on treatment to SSA in patients with uncontrolled carcinoid syndrome. However, further prolonged follow-up of patients treated with TE may be needed to exclude potential AEs, such as liver toxicity or depressed mood, in patients with long-term treatment. Interferon alpha is a cytokine with direct inhibitory effect on hormone secretion and tumor cell proliferation and an approved therapy in carcinoid syndrome but is associated with significant AEs in the majority of the patients requiring frequently dose reduction. The finding of a more favorable tolerability of pegylated interferon needs to be confirmed in a prospective study.

Sex differences in carcinoid syndrome: A gap to be closed.

The incidence of neuroendocrine neoplasms and related carcinoid syndrome (CS) has markedly increased over the last decades and women seem to be more at risk than men for developing CS. Nevertheless, very few studies have investigated sex differences in clinical presentation and outcomes of CS. However, as per other tumours, sex might be relevant in influencing tumour localization, delay in diagnosis, clinical outcomes, prognosis and overall survival in CS. The present review was aimed at evaluating sex differences in CS, as they emerge from an extensive search of the recent literature. It emerged that CS occurs more frequently in female than in male patients with NENs and women seem to have a better prognosis and a slight advantage in overall survival and response to therapy. Moreover, the disease likely impacts differently the quality of life of men and women, with different psychological and social consequences. Nevertheless, sex differences, even if partially known, are deeply underestimated in clinical practice and data from clinical trials are lacking. There is urgent need to increase our understanding of the sex-related differences of CS, in order to define tailored strategies of management of the disease, improving both the quality of life and the prognosis of affected patients.

Long-Term Treatment with Telotristat Ethyl in Patients with Carcinoid Syndrome Symptoms: Results from the TELEPATH Study.

INTRODUCTION: Telotristat ethyl is indicated for use in combination with somatostatin analogs (SSAs) to treat carcinoid syndrome (CS) diarrhea uncontrolled by SSAs alone in adults, but long-term safety and efficacy data beyond 48 weeks are needed. OBJECTIVES: The aims of the study were to evaluate the long-term safety and tolerability of telotristat ethyl and its effect on quality of life (QOL) in patients with CS. METHODS: In this phase 3, nonrandomized, multicenter, open-label, long-term extension study (TELEPATH), patients who participated in phase 2 or 3 trials of telotristat ethyl continued treatment at their present dose level (250 or 500 mg thrice daily) for 84 weeks. Safety and tolerability, the primary endpoint, were assessed by monitoring adverse events (AEs), serious AEs, AEs of special interest (AESIs; including liver-related AEs, depression, and gastrointestinal AEs), and deaths. The secondary objective was to evaluate changes in patients' QOL using validated cancer questionnaires and a subjective global assessment of CS symptoms. RESULTS: In 124 patients exposed to telotristat ethyl for a mean of 102.6 ± 53.2 weeks, the type and frequency of AEs were consistent with those reported in previous trials. The occurrence of AESIs was not related to dosage or duration of therapy. Most AEs were mild to moderate in severity, and no deaths were related to telotristat ethyl. QOL scores remained stable, and the majority of patients reported adequate symptom relief throughout the study. CONCLUSIONS: Safety results of TELEPATH support the long-term use of telotristat ethyl in patients with CS diarrhea. Telotristat ethyl was well-tolerated and associated with sustained improvement in QOL scores (NCT02026063).

Weight Maintenance up to 48 Weeks in Patients With Carcinoid Syndrome Treated With Telotristat Ethyl: Pooled Data From the Open-Label Extensions of the Phase III Clinical Trials TELESTAR and TELECAST.

Reported incidences of neuroendocrine tumors (NETs) appear to be increasing, possibly due to greater disease awareness and increased accuracy of diagnosis. Approximately 20% of patients with NETs develop carcinoid syndrome (CS), which arises from elevated secretion of bioactive compounds, including serotonin, from NETs. This leads to symptoms including diarrhea and flushing, which result in weight loss and are associated with considerable negative impact on patients' quality of life. We previously reported significant weight gain and improved nutritional status in patients with NETs who were treated with telotristat ethyl (TE) for 12 weeks. In this follow-up analysis, using pooled data from the 36-week open-label extensions of the TELESTAR (NCT01677910) and TELECAST (NCT02063659) phase III trials, we demonstrate that improvements in weight and nutritional parameters were sustained or further improved in patients with CS through to week 48 of treatment with TE. At week 48/end of study, 68.7% of all patients maintained a stable weight or had weight gain and the mean changes from baseline in cholesterol and albumin levels in patients treated with TE were +0.41 mmol/L and -0.34 g/L, respectively. These results indicate that TE, alongside routine clinical practice, may provide long-term benefits in nutritional intake and weight evolution in patients with CS.

A Systematic Review of Economic and Quality-of-Life Research in Carcinoid Syndrome.

BACKGROUND: To date, the economic burden and patient-reported outcomes associated with carcinoid syndrome (CS) in patients with neuroendocrine tumor (NET) remain largely unknown. OBJECTIVES: The objective of this study was to perform a systematic review of economic and quality-of-life (QOL) studies related to the treatment of CS. METHODS: Articles included in the review were extracted from PubMed, Embase, and the Cochrane Library. Studies had to be in English and published between 1 January 2000 and 2 July 2020. Other study eligibility criteria included patients with NET with CS receiving treatment for CS, study outcomes of cost or QOL, and clinical trials or population-based studies using claims or other secondary databases. The interventions included somatostatin analogs, telotristat ethyl, or other treatment for CS. To evaluate the quality and bias of the included studies, the 24-item CHEERS and 10-item Gill and Feinstein checklists were used. We report a narrative synthesis of the findings from the selected studies. RESULTS: A total of 12 economic and 12 QOL studies met the inclusion criteria and were included for review. Patients with uncontrolled CS symptoms had 23-92% higher costs than those with controlled CS; mostly, ambulatory/outpatient services were the primary drivers of the costs. The use of telotristat ethyl may be cost effective if the societal willingness to pay is as high as $US150,000 per quality-adjusted life-year in the USA. Of the 12 QOL papers, only three case-control studies assessed QOL at baseline and more than two follow-up time points. Seven studies evaluated QOL at two or more time points but lacked a control group, obscuring direct intervention effects on patients' well-being. CONCLUSIONS: We observed wide variations in the reviewed studies evaluating the economic burden and patient-reported outcomes, in terms of cost and QOL, of patients with CS. Although QOL is consistently impaired and costs are consistently increased by CS, the numbers of both cost and QOL studies among this patient population remain sparse, and many of the existing studies indicated an important need for quality improvement.

Multicenter, Observational Study of Lanreotide Autogel for the Treatment of Patients with Neuroendocrine Tumors in Routine Clinical Practice in Germany and Austria.

BACKGROUND: The long-acting somatostatin analog lanreotide autogel is effective in the treatment of patients with neuroendocrine tumors. OBJECTIVE: To evaluate the long-term treatment response in patients with neuroendocrine tumors receiving lanreotide autogel in routine clinical practice. METHODS: Non-interventional, 24-month study in patients with neuroendocrine tumors treated with lanreotide autogel (NCT01840449). RESULTS: Patients (n=80) from 26 centers in Germany and Austria were enrolled. Neuroendocrine tumors were mainly grade 1/2, metastasized, intestinal, and associated with carcinoid syndrome; 88.9% had received previous neuroendocrine tumor treatment. Of those, 84.4% had previous surgery, 18.7% had received octreotide. The primary endpoint, defined by a <50% chromogranin A increase at month 12 compared with the lowest value between baseline and month 3 was achieved by 89.5% patients. Stable disease according to Response Evaluation Criteria in Solid Tumors 1.1 was observed in 76.9 and 75.0% patients at months 12 and 24 of lanreotide treatment, respectively. Mean change of chromogranin A levels from baseline to month 24 was -0.12 × upper limit of normal (95% CI, -0.22; -0.45). In a post hoc analysis, 38.5% of the subgroup of patients with carcinoid syndrome had daily diarrhea at baseline vs. 21.4% at month 24. At baseline, 27.8% of patients received lanreotide 120 mg every 4 weeks vs. 56.7% at month 24. Quality of life data were heterogeneous. No new safety issues arose and/or required further investigation. CONCLUSIONS: Our study reflects routine lanreotide autogel use in patients with advanced/metastatic neuroendocrine tumors. This analysis shows effectiveness with stabilization of disease-related symptoms and good tolerability of lanreotide autogel in clinical practice.

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.

A Budget Impact Model of the Addition of Telotristat Ethyl Treatment to the Standard of Care in Patients with Uncontrolled Carcinoid Syndrome.

BACKGROUND: Carcinoid syndrome, a rare condition in patients with neuroendocrine tumours, characterised by flushing and diarrhoea, severely affects patients' quality of life. The current carcinoid syndrome standard of care includes somatostatin analogues, but some patients experience uncontrolled symptoms despite somatostatin analogue therapy. Telotristat ethyl is a novel treatment approved by the European Medicines Agency (EMA) and US FDA that significantly reduces bowel movement frequency in patients with uncontrolled carcinoid syndrome. OBJECTIVE: We developed a model to evaluate the 5-year budget impact of introducing telotristat ethyl to standard care in Swedish patients with uncontrolled carcinoid syndrome. METHODS: Treatment response in the 12-week phase III TELESTAR trial (NCT01677910) informed telotristat ethyl efficacy; subsequently, health states were captured by a Markov model using 4-week cycles. TELESTAR open-label extension data informed telotristat ethyl discontinuation. The number of treatment-eligible patients was estimated from literature reviews reporting the prevalence, incidence and mortality of carcinoid syndrome. A Swedish database study informed real-world costs related to carcinoid syndrome and carcinoid heart disease costs. Telotristat ethyl market share was assumed to increase annually from 24% (year 1) to 70% (year 5). RESULTS: Over the 5-year model horizon, 44 patients were expected to initiate telotristat ethyl treatment. The cumulative net budget impact of adding telotristat ethyl to current standard of care was €172,346; per-year costs decreased from €66,495 (year 1) to €29,818 (year 5). Increased drug costs from adding telotristat ethyl were offset by reduced costs elsewhere. CONCLUSIONS: The expected budget impact of adding telotristat ethyl to the standard of care in Sweden was relatively low, largely because of the rarity of carcinoid syndrome.

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.