WASHINGTON, April 8, 2026
Vanda Pharmaceuticals Inc. has announced the initiation of the Thetis clinical trial evaluating NEREUS™ (tradipitant) for the prevention of vomiting in patients treated with GLP-1 receptor agonists, addressing a major limitation in widely used diabetes and obesity therapies. The study represents a significant step in improving treatment tolerability and patient adherence in one of the fastest-growing therapeutic areas.
Thetis Trial Targets Key Side Effects of GLP-1 Therapies
The Thetis study is a multicenter, randomized, double-blind, placebo-controlled clinical trial designed to evaluate the efficacy and safety of oral tradipitant in patients initiating high-dose GLP-1 receptor agonist therapy. These therapies, including widely prescribed agents for diabetes and obesity, are known to cause gastrointestinal side effects such as nausea and vomiting, which often lead to treatment discontinuation or dose reduction.
The primary endpoint of the trial focuses on the proportion of patients who remain free from vomiting episodes, a critical factor in improving patient adherence and overall treatment outcomes. By targeting this unmet need, Vanda aims to enhance the clinical utility of GLP-1 therapies, enabling more patients to benefit from their proven metabolic and weight-loss effects.
The study builds on the growing importance of GLP-1 receptor agonists, which have revolutionized the management of type 2 diabetes and obesity, but continue to face challenges related to tolerability and patient compliance.
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Strong Phase 2 Data Supports Clinical Advancement
The initiation of the Thetis trial is supported by positive results from a prior Phase 2 study, which demonstrated that tradipitant significantly reduced vomiting and nausea in patients receiving GLP-1 therapies. In that study, only 29.3% of patients treated with tradipitant experienced vomiting compared to 58.6% in the placebo group, representing a 50% relative reduction in vomiting incidence.
Additionally, the therapy showed improvement in combined endpoints of vomiting and significant nausea, further validating its potential as an effective antiemetic solution in this setting. These findings highlight tradipitant’s mechanism as a neurokinin-1 (NK-1) receptor antagonist, which plays a key role in controlling nausea and vomiting pathways.
NEREUS™ has already received approval for the prevention of motion-induced vomiting, providing a strong safety and efficacy foundation for its continued development in additional indications. The current trial aims to expand its therapeutic use into the rapidly growing GLP-1 treatment landscape.
Advancing Patient-Centric Innovation in Biopharma
The development of tradipitant for GLP-1-induced vomiting reflects a broader shift toward patient-centric drug development, where improving treatment tolerability is as critical as efficacy. By addressing side effects that limit adherence, Vanda is contributing to a more comprehensive approach to chronic disease management, particularly in conditions requiring long-term therapy.
The company expects topline results from the Thetis study by Q4 2026, which will inform future regulatory pathways, including potential submission of a New Drug Application (NDA). Additional data may be required to support regulatory approval, depending on trial outcomes.
This program also highlights the importance of adjunctive therapies in enhancing the effectiveness of existing treatments, a strategy increasingly adopted in the pharmaceutical industry to maximize patient benefit. By improving tolerability, such therapies can increase adherence, optimize dosing, and ultimately improve clinical outcomes.
The initiation of the Thetis trial marks a key milestone in Vanda Pharmaceuticals’ clinical development pipeline, focusing on improving the tolerability of GLP-1 therapies through targeted antiemetic intervention. With strong supporting data and a well-defined clinical strategy, NEREUS™ has the potential to transform patient experience and enhance the effectiveness of widely used metabolic treatments, reinforcing the role of innovation in modern biopharmaceutical development.
Source: Vanda Pharmaceuticals press release
