ADA in 1/6 low, 1/6 mid, 4/12 high-dose monkeys (1/12 controls); reduced exposure only in 2 high-titer recovery animals
“Anti-drug antibodies (ADA) were present in samples from 1/12 control, 1/6 LD, 1/6 MD, and 4/12 HD animals; donanemab concentrations in serum were only affected by ADA in the 2 HD recovery animals with the highest titers”
✓ VerifiedFDA pharmacology/toxicology review, p. 16Source ↗
Biodistribution & persistence
TCR in human and monkey tissues: only cytoplasmic/nuclear binding, considered toxicologically irrelevant
“Tissue cross-reactivity studies conducted in a panel of normal human and cynomolgus monkey tissues demonstrated specific binding of donanemab that was exclusively cytoplasmic and/or nuclear, and, therefore, toxicologically irrelevant”
✓ VerifiedFDA pharmacology/toxicology review, p. 20Source ↗
Modality-specific risk
ARIA/microhemorrhage from plaque removal; surrogate did not worsen microhemorrhage in aged PDAPP mice, but ARIA seen clinically
“These results suggest that the removal of amyloid plaques is not associated with exacerbation of CAA-related microhaemorrhage in aged PDAPP mice up to three months of dosing. In contrast, amyloid-related imaging abnormalities (ARIAs) were observed in clinical studies with donanemab.”
In vitro whole-blood cytokine release far below alemtuzumab/TGN1412 controls; no effects on monkey TDAR, lymphocyte subsets or serum cytokines; ADA in some monkeys