DARTAccepted with a conditionBeyond the letter
Rabbit embryofetal study inadequate (plasma exposure below detection in some dams); second-species study required postapproval
“Potential adverse effects of zuranolone on embryofetal development in pregnant rabbits were not adequately assessed because TK data in satellite animals demonstrated that plasma exposures in some dams were below the limit of detection.”
✓ VerifiedFDA integrated review, p. 147Source ↗ “As a result, the Agency requires the Applicant to conduct an adequate embryofetal development study in a second species, other than rat, to completely evaluate the potential toxicity during organogenesis and fulfil the nonclinical study requirements for embryofetal development.”
✓ VerifiedFDA integrated review, p. 147Source ↗ CarcinogenicityAcceptedBeyond the letter
Mouse and rat carcinogenicity studies reached only about 4- to 5-fold human exposure; higher doses limited by sedation
Why: Short-term treatment; no tumour increase at achievable exposures · Pharmacology or kinetics · Other reason
“In both species the exposure was limited (around 4-fold human exposure in mouse and 4 to 5-fold in rats) but higher doses were not achievable due to pharmacological effects of sedation.”
✓ VerifiedEMA assessment report, p. 43Source ↗ “At these exposures, no increase in tumour incidence was observed in either species, as compared to control groups. Carcinogenic risk of zuranolone is low, and not relevant for the current indication as the duration of treatment is short term.”
✓ VerifiedEMA assessment report, p. 43Source ↗ Safety marginAcceptedBeyond the letter
Dog studies: sedation below clinical exposure; doses limited by sedation
Why: Higher doses not achievable due to the sedative effect · Pharmacology or kinetics
“Sedation was seen at exposures below the clinical exposure, and tremors were seen at about 5.5-fold the clinical exposure. Higher doses were not achievable due to the sedative effect, but is considered sufficient.”
✓ VerifiedEMA assessment report, p. 41Source ↗ Juvenile toxCriticised but acceptedBeyond the letter
Neonatal rat (PND 7) apoptotic neurodegeneration with low margin (1.4-fold at no-effect dose)
Why: Indication restricted to women after childbirth · Other reason
“In a juvenile rat study with a single dose at PND 7, which corresponds to brain development at the end of the third trimester in humans, apoptotic neurodegeneration in one area of the brain (subiculum) in both males and females was seen. The safety margin is low (1.4-fold at NOEAL).”
✓ VerifiedEMA assessment report, p. 42Source ↗ “This risk is sufficiently mitigated by the change in indication, which now only includes women after childbirth.”
✓ VerifiedEMA assessment report, p. 42Source ↗