Telotristat etiprate (LX1032/LX1606)

Indication*
Carcinoid Syndrome

Overview 

Telotristat etiprate, or LX1032, is an orally-delivered small molecule compound that we are developing for the treatment of carcinoid syndrome. Telotristat etiprate was internally generated by our medicinal chemists and inhibits tryptophan hydroxylase, or TPH, the rate-limiting enzyme for serotonin production found primarily in enterochromaffin, or EC, cells of the gastrointestinal tract. Our scientists found that mice lacking the non-neuronal form of this enzyme, TPH1, have virtually no serotonin in the gastrointestinal tract, but maintain normal levels of serotonin in the brain. Telotristat etiprate was specifically designed to achieve enhanced systemic exposure to address disorders such as carcinoid syndrome that require regulation of serotonin levels beyond the EC cells in the gastrointestinal tract without impacting brain serotonin production.

Telotristat etiprate reduces peripheral serotonin production by inhibiting the enzyme TPH in metastatic carcinoid tumors.


Clinical Data

We initiated a single, pivotal Phase 3 clinical trial of telotristat etiprate in October 2012 evaluating the safety and tolerability of telotristat etiprate and its effect on symptoms associated with carcinoid syndrome. The trial is expected to enroll approximately 120 patients with inadequately controlled carcinoid syndrome on background somatostatin analog therapy (including at least 105 patients on octreotide therapy) in a randomized, double-blind, placebo-controlled study of 250mg three times daily and 500mg three times daily doses of telotristat etiprate over a 12-week treatment period, followed by a 36-week, open-label extension where all patients will receive 500mg three times daily doses of telotristat etiprate. The primary efficacy endpoint under evaluation in the trial is the number of daily bowel movements, with secondary efficacy endpoints including stool form, a global assessment of symptoms associated with carcinoid syndrome and other factors. The Phase 3 program of telotristat etiprate also includes an additional companion study in carcinoid syndrome patients who do not meet certain of the inclusion criteria for the pivotal Phase 3 clinical trial.

We reported top-line data in October 2012 from an open-label Phase 2 clinical trial evaluating the safety and tolerability of telotristat etiprate and its effects on symptoms associated with carcinoid syndrome. The trial enrolled 15 patients with metastatic carcinoid syndrome who were refractory to or could not tolerate somatostatin analog therapy in an open-label study of ascending doses of 150mg, 250mg, 350mg and 500mg of telotristat etiprate, administered three times daily, for 14 days on each dose until reaching the maximal dose, which was then continued until the completion of 12 weeks of therapy. The primary efficacy endpoint under evaluation in the trial was the reduction of bowel movements from baseline to week 12, with secondary endpoints including relief of symptoms and reduction in serotonin synthesis. Top-line data from the study showed that patients experienced a 46.4% median reduction from baseline at week 12, with the number of daily bowel movements steadily decreasing over time. All observed changes from baseline were statistically significant at p<0.001. This change corresponded with an increased proportion of patients reporting adequate relief of their carcinoid symptoms, a global assessment which also improved over time, with 75% of the patients with data at week 12 reporting improvement. Clinically relevant decreases from baseline were likewise seen for a number of key secondary endpoints, including statistically significant improvements in stool consistency (p<0.001) and trends of reductions which did not achieve statistical significance in abdominal pain and the number of cutaneous flushing episodes. The median percentage reductions from baseline of urinary 5- HIAA, a biomarker of serotonin synthesis, at weeks 8 and 12 were 68.3% and 72.7%, respectively (each, p<0.05). Telotristat etiprate was well tolerated in the study, with no dose-limiting toxicity observed. Three patients reported serious adverse events, none of which were related to telotristat etiprate, and no patient discontinued from the study due to an adverse event.

We reported top-line data in August 2011 from a Phase 2 clinical trial evaluating the safety and tolerability of telotristat etiprate and its effects on symptoms associated with carcinoid syndrome. The trial enrolled 23 patients with symptomatic carcinoid syndrome who were refractory to octreotride therapy in a double-blind, randomized, placebo-controlled study of 150mg, 250mg, 350mg and 500mg doses of telotristat etiprate, each administered three times daily over a 28-day treatment period in combination with octreotide therapy. The efficacy endpoints under evaluation in the trial included the number of daily bowel movements, stool form, urgency, a global assessment of symptoms associated with carcinoid syndrome, flushing episodes and an assessment of pain and discomfort. Top-line data from the trial showed evidence of efficacy across multiple endpoints, including improvements in bowel movement frequency, decreased levels of urinary 5-HIAA, the primary metabolite of serotonin and a biomarker for serotonin production, and improvements in the assessment of pain and discomfort. Telotristat etiprate demonstrated a favorable safety profile in the trial, with no dose-limiting toxicity observed. Adverse events were generally mild to moderate and similarly distributed across all groups, including the placebo group.

Telotristat etiprate has received Fast Track status and Orphan Drug designation from the United States Food and Drug Administration, or FDA, for the treatment of gastrointestinal symptoms associated with carcinoid syndrome in patients who no longer respond to standard care. Telotristat etiprate has also received Orphan Drug designation from the Committee for Orphan Medical Products of the European Medicines Agency for the treatment of carcinoid tumors.

About Fast Track Designation
Telotristat etiprate has received Fast Track designation from the United States Food and Drug Administration (FDA) for the treatment of symptoms associated with carcinoid syndrome in certain patients.  FDA’s Fast Track program facilitates the development of potential new drugs and expedites the review of new drugs intended to serve unmet medical needs in serious or life-threatening conditions.  Fast Track status also provides formal mechanisms for sponsors to communicate with the FDA on product development issues, including clinical trial design.  Fast Track benefits include eligibility for an early review process that may significantly shorten FDA approval times by allowing for the possibility of a “rolling submission” for marketing authorization.

About Orphan Designation
Telotristat etiprate has received orphan drug designation from both the FDA and the European Medicines Agency (EMA). The goal of the FDA and EMA orphan drug programs are to promote the development of drugs intended for the prevention or treatment of life-threatening or chronically debilitating conditions that affect limited populations.  Incentives for developing new drugs under orphan drug designation in the U.S. and E.U. include 7 and 10 years of marketing exclusivity, respectively, regulatory assistance, reduced regulatory fees associated with applying for marketing approval and assistance with clinical trial design.

About Carcinoid Syndrome
Carcinoid tumors are a type of neuroendocrine tumor (NET) that typically form in the gastrointestinal system.  Carcinoid NETs may arise from multiple different organ systems, including the small bowel, appendix, rectum, stomach, and lung, but most are derived from enterochromaffin (EC) cells of the midgut, and often produce and release large amounts of serotonin (5-HT).  Carcinoid syndrome is a combination of symptoms, including severe diarrhea, bronchial restriction, facial flushing and rapid heartbeat, caused by the release of excessive serotonin and other substances into the blood stream from metastatic carcinoid tumors.

Carcinoid syndrome is a combination of symptoms caused
by the release of excessive serotonin and other substances
into the blood stream from metastatic carcinoid tumors.


Carcinoid Syndrome Prevalence

According to the American Cancer Society there are approximately 100,000 patients with carcinoid tumors in the U.S.  About 10% of people with carcinoid tumors will develop carcinoid syndrome and many of these patients will often live for several years without adequate relief of their symptoms.

Related Publications
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Current Status on clinicaltrials.gov

Telotristat Etiprate (Carcinoid Syndrome) (Phase 3)

TELESTAR Details

Please find more detail on our TELESTAR program: http://telotristat-telestar.com

* Safety and efficacy have not been evaluated by any regulatory authorities for the indications described.