Monkey immunogenicity could not be assessed reliably (drug interference with ADA assay); exposure maintained on repeat dosing
“The immunogenicity of necitumumab could not be accurately assessed in animal models. High levels of circulating necitumumab may have saturated the anti-drug antibody leaving an insufficient quantity of free binding sites for the assay to detect a response.”
✓ VerifiedFDA pharmacology/toxicology review, p. 64Source ↗
Biodistribution & persistence
TCR in human and monkey tissues: consistent binding, no unexpected cross-reactivity
“In most tissues, binding was consistent in both human and monkey tissue, sometimes with minor differences in localization within the organ. There was no unexpected tissue cross-reactivity based on literature and the biology of EGFR”
On-target EGFR-inhibitor skin toxicity, a major clinical adverse reaction
“Skin toxicity has previously been observed with similar EGFR inhibitors (e.g. cetuximab) and is a major adverse reaction clinically.”
✓ VerifiedFDA pharmacology/toxicology review, p. 12Source ↗
Anti-drug antibodies: animals
ADA evaluation in monkeys confounded by high drug levels; exposure did not decrease on repeated dosing
“Attempts to evaluate the formation of ADA were confounded by high circulating concentrations of necitumumab. However, monkeys were exposed to necitumumab throughout the toxicity evaluations and exposure did not decrease upon repeated dosing.”
ADA in 4.1% (33/814) of patients; neutralizing in 1.4% (11/814)
“In clinical trials, treatment-emergent anti-necitumumab antibodies (ADA) were detected in 4.1% (33/814) of patients using an enzyme-linked immunosorbent assay (ELISA). Neutralizing antibodies were detected in 1.4% (11/814) of patients post exposure to PORTRAZZA.”
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