A phase 3 trial evaluating tradipitant, a neurokinin-1 receptor antagonist, in patients with gastroparesis did not meet its prespecified primary endpoint.

The multicenter, randomized, double-blind, placebo-controlled study (ClinicalTrials.gov Identifier: NCT04028492) evaluated the efficacy and safety of tradipitant in relieving nausea and other symptoms of gastroparesis in approximately 250 adults. Patients were randomly assigned to receive tradipitant or placebo orally twice a day. 

Results showed that treatment with tradipitant did not meet the prespecified primary endpoint for the difference in the change of the severity of nausea from baseline at week 12 compared with placebo. However, both treatment arms showed significant improvements from baseline on nausea and other core symptoms of gastroparesis. 

According to the Company, initial exploratory analysis showed that the beneficial effect of tradipitant may have been masked by potential confounders including a baseline imbalance of rescue medication use as well as poor compliance. The Company believes that after adjusting for poor compliance, and restricting the analysis to patients who did not use rescue medications at baseline, there is strong evidence of a drug effect.

Treatment with tradipitant was also found to be safe and well tolerated. Diarrhea was the most common adverse event reported with an incidence greater than placebo.

“While disappointed that the study did not meet its prespecified outcome, we are encouraged by the evidence that is emerging from further analysis that confirms observations made in the prior clinical study,” said Mihael H. Polymeropoulos, MD, Vanda’s President, CEO and Chairman of the Board. “We are committed to completing our analysis and working to bring tradipitant to patients with gastroparesis to fill a significant unmet medical need.”


Vanda Pharmaceuticals reports results from the phase III study of tradipitant in gastroparesis. News release. Vanda Pharmaceuticals Inc. Accessed February 4, 2022. https://www.prnewswire.com/news-releases/vanda-pharmaceuticals-reports-results-from-the-phase-iii-study-of-tradipitant-in-gastroparesis-301475597.html