telotristat and Neuroendocrine-Tumors

Many patients with neuroendocrine tumour-related carcinoid syndrome treated with somatostatin analogues (SSA) won't achieve adequate symptom relief with the SSA alone; new treatment options are required. Telotristat ethyl is a tryptophan hydroxylase inhibitor, developed for the treatment of carcinoid syndrome. Areas covered: This review summarises the evidence supporting the role of telotristat ethyl in the management of carcinoid syndrome. Rationale, pharmacodynamics, pharmacokinetics, metabolism, clinical experience, efficacy and toxicity profiles are covered. Expert opinion: The efficacy of telotristat ethyl in producing a statistically-significant and clinically-meaningful reduction in daily bowel movements has been confirmed in phase III clinical trials. Two pivotal trials, TELESTAR and TELECAST, explored the role of telotristat ethyl in the management of patients with carcinoid syndrome refractory to SSAs focusing on patients with ≥4 and <4 daily bowel movements, respectively. In addition, benefit was confirmed in patient-reported outcomes. Based on activity and safe toxicity profile, telotristat ethyl is pending regulatory agencies evaluation and is likely to add to the armamentarium used to treat carcinoid syndrome. Long-term safety and efficacy data will be available from the ongoing TELEPATH study. The impact on carcinoid heart disease, mesenteric fibrosis and other long-term complications of carcinoid syndrome as well as its role earlier in patients' pathways remain investigational.

Topics: Animals; Carcinoid Tumor; Clinical Trials as Topic; Humans; Malignant Carcinoid Syndrome; Neuroendocrine Tumors; Phenylalanine; Pyrimidines; Somatostatin; Tryptophan Hydroxylase

Telotristat ethyl (Xermelo™) is a peripheral tryptophan hydroxylase (TPH) inhibitor that was developed by Lexicon Pharmaceuticals, Inc. for the treatment of carcinoid syndrome. Many neuroendocrine tumours secrete serotonin (5-HT) into the blood stream, resulting in a number of symptoms, notably diarrhoea. Telotristat ethyl inhibits TPH, thereby reducing the production of 5-HT. In February 2017, telotristat ethyl was approved in the USA for the treatment of carcinoid syndrome diarrhoea in combination with somatostatin analog (SSA) therapy in adults inadequately controlled by SSA therapy. This article summarizes the milestones in the development of telotristat ethyl leading to this first global approval.

Topics: Animals; Diarrhea; Drug Approval; Drug Therapy, Combination; Humans; Malignant Carcinoid Syndrome; Neuroendocrine Tumors; Phenylalanine; Pyrimidines; Randomized Controlled Trials as Topic; Somatostatin; Tryptophan Hydroxylase; United States; United States Food and Drug Administration