Anti-drug antibodies in 8 of 12 monkeys (75%) after a single dose
“Anti-product antibodies were detected in samples from 2 monkeys on Day 13 and an additional 6 monkeys on Day 26, for a total of 8 out of 12 monkeys, or 75%.”
✓ VerifiedFDA pharmacology/toxicology review, p. 49Source ↗
Biodistribution & persistence
TCR in human, rat and monkey tissues: cytoplasmic staining only (cytoskeletal elements), considered not relevant
“Staining was reported to be cytoplasmic and was specifically localized to cytoplasmic granules and/or filaments, often associated with cell borders, suggestive of intracellular cytoskeletal elements, and therefore not relevant.”
✓ VerifiedFDA pharmacology/toxicology review, p. 101Source ↗
Modality-specific risk
CNS inflammation and hemorrhage in infected non-survivors attributed to anthrax bacteria, not obiltoxaximab
“Microscopic changes in the non-surviving animals that received obiltoxaximab were due to the presence of extravascular bacteria and not the effect of obiltoxaximab.”
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