SpeciesVerdict not stated
Mouse instead of rat as the rodent for long-term toxicology and developmental studies
Why: Mouse forms detectable levels of the active N-desmethyl metabolite, giving toxicological coverage · Pharmacology or kinetics
“The Applicant chose the mouse as the rodent species for the long-term toxicology and developmental studies due to detectable levels of the active N-desmethyl metabolite in this species that allowed for toxicological coverage; there were no unique human metabolites or other metabolites that needed toxicological coverage in animals.”
✓ VerifiedFDA multi-discipline review, p. 43Source ↗ DARTAcceptedBeyond the letter
Embryo-fetal development tested in mouse only (no second species)
Why: Embryolethality and teratogenicity already shown in mice · Other reason
“A second species was not used for investigating the potential effects on embryo-foetal development, which is acceptable in view of the toxicological findings reported in mice (embryolethality, teratogenicity).”
✓ VerifiedEMA assessment report, p. 44Source ↗ Juvenile toxAcceptedBeyond the letter
No dedicated juvenile toxicity studies for a paediatric indication
Why: Studies in sexually immature primates and younger mice cover children from 12 years onwards · Weight of evidence
“No specific juvenile toxicity studies have been conducted but studies performed in sexually immature primates and younger mice cover the age of children from 12 years onwards.”
✓ VerifiedEMA assessment report, p. 44Source ↗ “Therefore, concerning pharmacokinetics, exposure assessments at dose levels investigated in adults are considered to be sufficient to evaluate exposures expected in the younger population, e.g. from 3 years onwards.”
✓ VerifiedEMA assessment report, p. 44Source ↗ GenotoxicityAcceptedBeyond the letter
Positive mouse micronucleus test via an aneugenic mode of action accepted for long-term paediatric use
Why: Aneugenicity is a known MEK-inhibitor pharmacological effect; carcinogenicity studies showed no neoplastic changes · Class precedent · Weight of evidence
“Aneugenic effects of selumetinb are known as pharmacological action of MEK inhibitors. However, no neoplastic changes were observed in carcinogenicity studies supporting the long-term treatment of children with selumetinib.”
✓ VerifiedEMA assessment report, p. 44Source ↗ Safety marginVerdict not stated
No NOAEL or safety margin for irreversible corneal mineralisation in the 1-month mouse study
“In 1-month study in mice, ophthalmology findings (oval opacities across the cornea, rough appearance to the surface of the cornea) were observed at all doses and histopathologic exam revealed a dose-dependent mineralisation of the cornea which is not reversible after cessation of treatment. No NOAEL and no safety margin could be determined.”
✓ VerifiedEMA assessment report, p. 43Source ↗