Study lengthAcceptedBeyond the letter
Abbreviated program for an NME: 28-day repeat-dose studies in rat and dog only; no chronic adult toxicity studies
Why: No unique adverse findings for SDX compared to d-MPH in the 28-day rat and dog studies · Weight of evidence
“The Division agreed to review 28-day repeat-dose toxicology data in two species, an embryo-fetal development study in the rabbit, and 6- month juvenile rabbit study to support this position.”
✓ VerifiedFDA multi-discipline review, p. 46Source ↗ “Upon review, it was concluded that additional nonclinical studies are not needed for SDX because there were no unique, adverse findings for SDX compared to d-MPH in 28-day repeat-dose toxicology studies in rat and dog”
✓ VerifiedFDA multi-discipline review, p. 46Source ↗ CarcinogenicityAcceptedBeyond the letter
No carcinogenicity studies for an NME with a chronic indication; relies on referenced d-MPH labeling
Why: Prodrug of approved d-MPH releasing MPH and endogenous or dietary products; weight of evidence · Weight of evidence · Pharmacology or kinetics
“Typically, an NME for a chronic indication would require carcinogenicity studies in two species. However, SDX is a prodrug for an approved product (d-MPH) that predominantly releases MPH and other products that are either found endogenously and/or obtained in diet at levels greater than what will be released at the MRHD.”
✓ VerifiedFDA multi-discipline review, p. 61Source ↗ “Therefore, considering the weight-of-evidence, we agree that carcinogenicity studies are not needed for SDX.”
✓ VerifiedFDA multi-discipline review, p. 61Source ↗ DARTAcceptedBeyond the letter
No fertility/early embryonic or pre- and postnatal development studies; embryo-fetal study in rabbit only
Why: No unique toxicities in embryo-fetal and chronic juvenile studies; referenced d-MPH labeling · Weight of evidence
“Fertility and early embryonic development studies were not conducted with SDX. The Applicant is relying upon the developmental toxicity data in the referenced product labeling.”
✓ VerifiedFDA multi-discipline review, p. 62Source ↗ “Based on results from the embryo-fetal development and chronic juvenile animal studies, we agree that fertility and early embryonic development and prenatal and postnatal development studies do not need to be conducted with SDX.”
✓ VerifiedFDA multi-discipline review, p. 62Source ↗ Juvenile toxAcceptedBeyond the letter
Pivotal chronic juvenile toxicity study conducted in rabbit, a non-conventional juvenile species
Why: Testing in a species that minimizes d-MPH exposure allows adequate SDX doses with high margins · Pharmacology or kinetics
“Although rabbit is not a conventional species for a juvenile animal study, we agree that it is the most appropriate species for the two pivotal studies (rabbit is typically used for embryo-fetal development).”
✓ VerifiedFDA multi-discipline review, p. 62Source ↗ “In addition, because d-MPH-related clinical signs are dose-limiting in animals and already known (both for animals and humans), testing SDX in a species that minimizes d-MPH exposure is also needed in order to test adequate SDX doses that provide high margins to human doses.”
✓ VerifiedFDA multi-discipline review, p. 62Source ↗ Safety marginVerdict not stated
Rat NOAEL exposure below human exposure at the MRHD; dog NOAEL not established
“For rats, the exposures at the no adverse effect level (NOAEL) for stimulant-related findings (25 mg/kg) was less than the human exposure at the MRHD. For dogs, the NOAEL for stimulant-related findings was not established because the NOAEL is less than the lowest dose tested.”
✓ VerifiedFDA multi-discipline review, p. 45Source ↗