SpeciesVerdict not stated
No pharmacologically active species; off-target toxicity in monkeys (6-week only) and on-target effects with a murine surrogate in transgenic PDAPP mice
Why: Donanemab not pharmacologically active in normal rodents or nonrodents · No relevant species
“Donanemab is not pharmacologically active in normal rodent or nonrodent; therefore, toxicity studies were conducted in cynomolgus monkey (6-week IV donanemab) to assess for any off-target toxicity, and in the PDAPP transgenic mouse model (6-week and 6- month SC mE8c, a murine surrogate) to assess for relevant on-target effects (toxicity and pharmacology).”
✓ VerifiedFDA pharmacology/toxicology review, p. 1Source ↗ Study lengthAcceptedBeyond the letter
GLP six-month surrogate study in aged PDAPP mice terminated early, giving about five months of dosing
Why: Early termination due to age-related mortality in aged transgenic mice · Other reason
“groups were terminated early due to age-related mortality (primarily associated with lymphoma and murine progressive cardiomyopathy) on Day 140/141 (F) or Day 151/152 (M). The dosing period was approximately 5 months.”
✓ VerifiedFDA pharmacology/toxicology review, p. 16Source ↗ “The NOAEL was the HD. Determination of m2Ec plasma concentrations at the end of the dosing period confirmed systemic exposure at both doses. The study was adequately conducted.”
✓ VerifiedFDA pharmacology/toxicology review, p. 16Source ↗ CarcinogenicityAcceptedBeyond the letter
No carcinogenicity studies for long-term therapy; weight-of-evidence assessment instead
Why: Target absent in wild-type rodents; transgenic rodent studies not feasible · No relevant species · Weight of evidence
“Carcinogenicity studies of donanemab were not conducted because its target, human AβN3pE-x peptide, is not present in wild-type rodents, and carcinogenicity studies in transgenic rodents are not feasible.”
✓ VerifiedFDA pharmacology/toxicology review, p. 17Source ↗ “Following review of an initial carcinogenicity assessment, the sponsor was informed that carcinogenicity studies of donanemab would not be required to support a BLA (see July 20, 2020, Type C Meeting Written Responses, and review by Dr. Hawver, February 4, 2021).”
✓ VerifiedFDA pharmacology/toxicology review, p. 17Source ↗ DARTAcceptedBeyond the letter
No reproductive and developmental toxicity studies
Why: Age of the Alzheimer’s disease population · Other reason
“The sponsor was informed that reproductive and developmental toxicology studies are generally not required to support clinical development or marketing approval for products intended for the treatment of Alzheimer’s disease, based on the age of the population with that condition”
✓ VerifiedFDA pharmacology/toxicology review, p. 17Source ↗