GLPVerdict not stated
Most nonclinical studies, including all repeat-dose toxicity studies, decades old, non-GLP and reported in literature publications
“Many of the submitted studies were conducted decades ago, without GLP compliance, and are reported in literature publications.”
✓ VerifiedFDA multi-discipline review, p. 42Source ↗ Safety marginVerdict not stated
NOAEL-based human equivalent dose margins only 0.2-1.7 versus the 10-20 mg/kg/day clinical dose
“The human equivalent dose (HED) values for the rat and dog NOAEL values based on body surface area comparison provide only low safety margins of 0.4 for rats and 1.7 for dogs with respect to a 10 mg/kg/day clinical dose and 0.2 for rats and 0.8 for dogs with respect to a 20 mg/kg/day clinical dose.”
✓ VerifiedFDA multi-discipline review, p. 44Source ↗ DARTAccepted with a conditionBeyond the letter
Rat and mouse embryo-fetal studies deficient; new rat embryo-fetal study required after approval
Why: Embryo-fetal toxicity Warning in label; new rat study as postmarketing requirement
“Because of the deficiencies in the embryo-fetal studies in rats and mice, a new embryo-fetal study of acceptable design in rats will be conducted as a postmarketing requirement.”
✓ VerifiedFDA multi-discipline review, p. 46Source ↗ “Based on these findings, nifurtimox-related embryo-fetal toxicity will be addressed in a Warning in the Lampit label, and a new embryo-fetal study in rats will be conducted as a postmarketing requirement to more fully elucidate the effects of nifurtimox in pregnant animals.”
✓ VerifiedFDA multi-discipline review, p. 47Source ↗ CarcinogenicityAccepted
No adequate carcinogenicity study; only limited legacy reports submitted, as treatment lasts under 6 months
Why: Treatment duration under 6 months; genotoxicity and nitrofuran class findings suggest carcinogenic potential · Within the guideline · Class precedent
“Because the proposed treatment duration of nifurtimox is less than 6 months, a carcinogenicity assessment is not required. However, three carcinogenicity studies for nifurtimox were submitted in NDA 213464, two in limited brief study reports and one in a published manuscript.”
✓ VerifiedFDA multi-discipline review, p. 44Source ↗ “However, other findings including the genotoxicity findings for nifurtimox and carcinogenicity findings for other nitrofuran antimicrobials more definitively suggest a carcinogenicity potential for nifurtimox in humans.”
✓ VerifiedFDA multi-discipline review, p. 45Source ↗