CarcinogenicityAccepted with a conditionBeyond the letter
No carcinogenicity studies before approval; two-species carcinogenicity deferred to a postmarketing requirement
“Carcinogenicity studies have not been conducted (with agreement from the Division) prior to submission of the NDA, but these studies will be required as a PMR.”
✓ VerifiedFDA pharmacology/toxicology review, p. 95Source ↗ “As previously communicated with the sponsor (correspondence dated November 10, 2021), carcinogenicity in two species will be needed but may be conducted post-approval.”
✓ VerifiedFDA pharmacology/toxicology review, p. 11Source ↗ Safety pharmacologyVerdict not stated
Safety pharmacology studies done by IV bolus only, not by the clinical oral route
“Safety pharmacology studies with trofinetide were not conducted using the oral route.”
✓ VerifiedFDA pharmacology/toxicology review, p. 94Source ↗ Safety marginVerdict not stated
No exposure margin in the 26-week juvenile rat study: AUC at highest dose similar to pediatric clinical exposure
“Plasma exposure (AUC) at the highest dose tested was similar to that those in pediatric patients at recommended doses.”
✓ VerifiedFDA pharmacology/toxicology review, p. 3Source ↗ Impurity or metaboliteQuestioned
Impurities above the qualification threshold qualified on mg/kg margins; several not qualified when normalized to body surface area
“However, the sponsor calculated margins of the 9 impurities normalized to body weight (mg/kg) instead of normalized to body surface area (mg/m2 ). When margins are normalized to body surface area the following impurities, , are not qualified at the proposed acceptance levels.”
✓ VerifiedFDA pharmacology/toxicology review, p. 12Source ↗