Vanda Pharmaceuticals Inc. (NASDAQ: VNDA) announced the initiation of the Thetis clinical trial to evaluate NEREUS (tradipitant) for preventing vomiting in patients receiving GLP-1 receptor agonist therapies.

The multicenter, randomized, double-blind, placebo-controlled trial will assess the efficacy and safety of oral tradipitant in patients starting high doses of GLP-1 receptor agonists. The primary endpoint measures the proportion of patients free from vomiting episodes during treatment.

NEREUS was recently approved for preventing motion-induced vomiting. GLP-1 receptor agonists, including semaglutide and tirzepatide, are used to treat type 2 diabetes and obesity but commonly cause gastrointestinal side effects that lead to treatment discontinuation or dose reduction.

A previous Phase 2 study showed positive results, with 29.3% of tradipitant-treated participants experiencing vomiting compared to 58.6% on placebo when pre-treated before receiving a 1 mg injection of Wegovy. This represented a 50% relative reduction in vomiting episodes.

"GLP-1 receptor agonists offer significant benefits, but vomiting and nausea can severely impact patient adherence and quality of life," said Mihael H. Polymeropoulos, President CEO and Chairman of Vanda Pharmaceuticals. "NEREUS has demonstrated potent antiemetic effects in prior clinical studies."

Vanda expects topline results from the Thetis study by Q4 2026. The company noted that additional study data may be required before approval of a New Drug Application.

NEREUS is a neurokinin-1 receptor antagonist licensed by Vanda from Eli Lilly and Company. The drug is currently in clinical development for various indications, including gastroparesis and prevention of GLP-1-induced nausea and vomiting.