Study lengthAccepted with a conditionBeyond the letter
No ≥6-month nonrodent toxicity study for unrestricted, repeated intermittent lifetime use; dog studies subchronic only
Why: No sufficient justification; approved with label stating safety not established beyond 90 total doses · Human data
“However, the Applicant did not submit a ≥6-month toxicity study in a nonrodent species and did not provide sufficient scientific justification for why such a study was not warranted to support the safety of unrestricted use of tradipitant over a lifetime for this indication.”
✓ VerifiedFDA integrated review, p. 15Source ↗ “Based on the available safety data, tradipitant is recommended for approval with a description in the label that the safety of tradipitant has not been established for more than 90 total doses to adequately inform prescribers of the safe use of tradipitant.”
✓ VerifiedFDA integrated review, p. 24Source ↗ Impurity or metaboliteAcceptedBeyond the letter
Disproportionate human metabolites M2, M4 and M8 not qualified in animals; qualified by weight of evidence on total drug-related exposure
Why: WoE (structural evaluation, on- and off-target effects) shows no increased or novel toxicities versus tradipitant · Weight of evidence
“Metabolite M3 is the only metabolite qualified by the levels present in the nonclinical studies, while M2, M4, and M8 were not measured, not present, or present at low levels in animals and therefore not considered qualified for safety using typical approaches.”
✓ VerifiedFDA integrated review, p. 285Source ↗ “However, M2, M4, and M8 are not likely to produce increased or novel toxicities compared to tradipitant, based on a Weight of Evidence (WoE) analysis including structural evaluations and assessment of known on- and off-target effects of tradipitant and the metabolites.”
✓ VerifiedFDA integrated review, p. 285Source ↗ GLPQuestioned
Four-organ microphysiological system studies offered in lieu of chronic nonrodent study were not GLP-compliant
“The lack of U.S. FDA GLP compliance and absence of adequate justification by the Applicant for noncompliance are considered limitations of these studies.”
✓ VerifiedFDA integrated review, p. 117Source ↗ Safety marginVerdict not stated
Han Wistar rat male NOAEL (liver necrosis) below the maximum clinical dose on an HED basis
“Based on the adverse findings of necrosis in the liver of males at ≥150 mg/kg/day and females at 1500 mg/kg/day, the NOAEL was considered the lowest dose of 15 mg/kg/day in males (less than the maximum clinical dose, based on HED) and the mid dose of 150 mg/kg/day in females (8.5-fold the maximum clinical dose)”
✓ VerifiedFDA integrated review, p. 109Source ↗