The US Food and Drug Administration (FDA) today approved the oral therapy telotristat ethyl (Xermelo, Lexicon Pharmaceuticals) in combination with somatostatin analog (SSA) therapy for the treatment of adults with carcinoid syndrome diarrhea that is inadequately controlled with SSA therapy alone.
Carcinoid syndrome is a cluster of symptoms that can develop in patients with metastatic neuroendocrine tumors (mNETs) and the related diarrhea results from the overproduction of serotonin by these tumors. Complications of uncontrolled diarrhea include weight loss, malnutrition, dehydration, and electrolyte imbalance.
The syndrome may also cause facial flushing, abdominal pain, fatigue, and, over time, heart valve damage. Telotristat is the first and only approved oral therapy for carcinoid syndrome diarrhea that targets the overproduction of serotonin by mNET cells, according to a company statement.
"Today's approval will provide patients whose carcinoid syndrome diarrhea is not adequately controlled with another treatment option," said Julie Beitz, MD, director of the Office of Drug Evaluation III in the FDA's Center for Drug Evaluation and Research.
Telotristat, in combination with SSA therapy, is approved in tablet form to be taken orally three times daily with food.
The safety and efficacy of telotristat were established in a 12-week, double-blind, placebo-controlled trial in 90 adult participants with well-differentiated mNET and carcinoid syndrome diarrhea. These patients were having between four and 12 daily bowel movements despite the use of SSA at a stable dose for at least 3 months.
In the trial, all patients remained on their SSA treatment, and were randomly assigned to add placebo or telotristat three times daily. The study investigators reported that 33% of patients in the telotristat-plus-SSA group had an average reduction of two bowel movements per day compared with just 4% of the placebo-plus-SSA group.
The most common side effects of telotristat include nausea, headache, increased levels of the liver enzyme gamma-glutamyl transferase, depression, peripheral edema, flatulence, decreased appetite, and fever.
Telotristat may cause constipation, and the risk of developing constipation may be heightened in patients whose bowel movement frequency is less than four bowel movements per day.
In clinical trials, some patients treated with a higher than recommended dosage of telotristat developed severe constipation, including one who required hospitalization and two others who developed complications of either intestinal perforation or intestinal obstruction. Patients should be monitored for severe constipation.
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Cite this: FDA Approves Xermelo for Carcinoid Syndrome Diarrhea - Medscape - Feb 28, 2017.