Vanda Pharmaceuticals, a Washington, D.C.-based biopharmaceutical company developing treatments for medical conditions with unmet needs, announced on October 27, 2026 results from its Phase III Study 3601 evaluating NEREUS™ (tradipitant) for the prevention of vomiting associated with glucagon-like peptide-1 (GLP-1) receptor agonist therapy. The randomized, placebo-controlled study found a 27% relative reduction in the incidence of vomiting among participants receiving NEREUS, alongside reductions in more frequent and severe vomiting patterns.
“These results demonstrate that NEREUS can meaningfully reduce vomiting and frequent multi-day vomiting induced by GLP-1 therapy, which are key contributors to treatment discontinuation,” said Dr. Mihael H. Polymeropoulos, President, CEO and Chairman of the Board of Vanda.
Inside the Phase III Study
Study 3601 evaluated NEREUS, an oral neurokinin-1 (NK-1) receptor antagonist, for its ability to prevent vomiting associated with semaglutide treatment.
Vomiting occurred in 43.0% of NEREUS-treated participants compared with 58.5% receiving placebo, meeting the study’s primary endpoint with a statistically significant difference (p=0.006).
The study also reported:
- Vomiting With Severe Nausea: 33.1% of NEREUS-treated participants experienced vomiting combined with severe nausea, compared with 50.6% receiving placebo, representing a 35% relative reduction.
- Frequent Multi-Day Vomiting: 6.3% of participants receiving NEREUS experienced more than two vomiting episodes on multiple days, compared with 15.9% receiving placebo, a 60% relative reduction.
- Extreme Vomiting: 2.8% of NEREUS-treated participants experienced more than 10 total vomiting episodes, compared with 14.6% receiving placebo, an 81% relative reduction.
The analyses of frequent multi-day and extreme vomiting were conducted after the study and are considered exploratory rather than prespecified primary endpoints.
Vanda reported that NEREUS was generally well tolerated, with no new safety signals identified.
Early Treatment May Be Key to Preventing Vomiting
The study also examined when vomiting occurred following semaglutide administration.
Nearly all vomiting episodes across both treatment groups occurred within the first two days, with the greatest separation between NEREUS and placebo observed on Days 1 and 2.
Participants received a single 1 mg dose of semaglutide without the gradual dose escalation typically used in clinical practice. The study design was intended to evaluate NEREUS under conditions associated with a high incidence of vomiting.
A pooled analysis of Phase II and Phase III data found that the treatment effect remained consistent across the observed semaglutide concentration range. Vanda believes these findings support further investigation of NEREUS for patients receiving GLP-1 therapies under standard dosing conditions.
NEREUS works by blocking substance P signaling through NK-1 receptors in brain pathways involved in vomiting. The company believes this mechanism could support its use with multiple GLP-1 receptor agonist therapies, although the Phase III study specifically evaluated semaglutide-induced vomiting.
Vanda Plans FDA Submission for Expanded NEREUS Use
NEREUS received U.S. Food and Drug Administration (FDA) approval in December 2025 for the prevention of motion-induced vomiting.
Following the Phase III results, Vanda plans to discuss its findings with the FDA and submit a supplemental New Drug Application (sNDA) seeking approval of NEREUS for the prevention of vomiting associated with GLP-1 receptor agonist treatment.
GLP-1 therapies are used to treat conditions including type 2 diabetes and obesity, but gastrointestinal side effects can affect treatment continuation.
Vanda cited research indicating that approximately half of patients discontinue GLP-1 treatment within one year, with gastrointestinal symptoms among the reported reasons. The company believes improving tolerability could help patients remain on prescribed therapy, although the current study did not establish improved long-term treatment adherence.
About Vanda Pharmaceuticals
Vanda Pharmaceuticals is a biopharmaceutical company focused on developing and commercializing treatments for medical conditions with unmet needs. Its portfolio includes approved therapies and clinical-stage programs addressing neurological, psychiatric, and other disorders.
