No serum IFN-γ, IL-2, IL-5, IL-6, IL-10 or TNF-α increase in monkeys; partially reversible NK-cell decreases
“No target organs for margetuximab were identified, nor were there margetuximab-related increased release of IFN-γ, IL-2, IL-5, IL-6, IL-10, or TNF-α in serum. Margetuximab treatment resulted in partially reversible decreases in blood CD3-/CD159a+ and CD16+/CD159a+ NK cells when compared to vehicle controls.”
✓ VerifiedFDA multi-discipline review, p. 37Source ↗
Biodistribution & persistence
TCR in human and monkey tissues matched HER2 expression sites; similar to trastuzumab
“These studies revealed margetuximab staining patterns consistent with reported sites of HER2 expression on human and cynomolgus monkey tissues. Direct comparison of margetuximab and trastuzumab revealed similar tissue staining.”
✓ VerifiedFDA multi-discipline review, p. 49Source ↗
Modality-specific risk
Embryo-fetal toxicity: oligohydramnios and fetal renal toxicity, a HER2-directed antibody class effect
“Oligohydramnios and associated renal toxicity are class effects of HER2-directed antibodies.”
✓ VerifiedFDA multi-discipline review, p. 37Source ↗
Anti-drug antibodies: animals
Minimal: ADA in 6 of 108 monkeys, mainly at lower doses; faster drug clearance in ADA-positive animals
“Margetuximab produced a minimal immunogenic response in cynomolgus monkeys. Positive confirmation of ADA following margetuximab administration was detected in 6 of 108 animals across all 4 studies, primarily at lower dose levels. A more rapid decline in margetuximab serum concentrations was observed in animals that had confirmed ADAs.”
✓ VerifiedFDA multi-discipline review, p. 41Source ↗
Anti-drug antibodies: patients
2% (7/350) anti-margetuximab antibodies; no treatment-emergent neutralizing antibodies
“the incidence of anti-margetuximab antibodies was 2% (7/350). No patients developed treatment-emergent neutralizing antibodies.”
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