Tradipitant is actually a remedy to treat atopic dermatitis. It is currently in Vanda's pipeline. The FDA is suspending the review of Vanda's clinical trials with the study objective to treat idiopathic and diabetic gastroparesis (gastric paralysis) and has demanded animal experiments with of a second non-rodent species (dog). Vanda contradicted this by pointing out that there are already sufficient data to conduct human studies, and that additional animal experiments with Tradipitant would only lead to  to the death of dozens of dogs (Beagles), as they would be euthanized after completion of this animal study.

The manufacturer justified the right of refusal with the American Administrative Procedure Act of 1946, after which the drug manufacturer can avoid this type of animal testing if they are capable to deliver equivalent data to thise with animals. The FDA, for its part, could, however, make an assessment of the data already available - including of earlier rodent and dog examinations - and explain why they are not equivalent to demand more animal testing.

From the lawsuit brought by the pharmaceutical manufacturer Vanda it was noted, however, that the FDA never provided such a statement, which would justify an additional long-term study over nine months with dogs.

If Vanda's suit fails, the company may still be forced to conduct the nine-month dog study. However, the company hopes that a public support for the case could increase its chances of winning.

In an open letter to the FDA, the company urged other pharmaceutical companies, animal rights groups and the public to speak out against unnecessary animal testing.

Source:
https://www.pharmamanufacturing.com/industrynews/2019/vanda-sues-fda-over-mandate-to-test-drug-on-dogs/
http://www.vandapharma.com/dev-tradipitant.html