ADA in at least 22% of monkeys causing variable exposure; peripheral blood immunophenotyping unremarkable
“though anti-drug antibody (ADA) responses seen in at least 22% of monkeys resulted in variable exposure in all toxicology studies.”
✓ VerifiedFDA multi-discipline review, p. 30Source ↗
Biodistribution & persistence
TCR with rabbit anti-PDGFRα: similar human and monkey staining of mesenchymal, glial, endothelial cells; surrogate crossed mouse placenta
“Anti-PDGFR-α staining was generally similar between human and cynomolgus monkey tissues.”
✓ VerifiedFDA multi-discipline review, p. 51Source ↗
Modality-specific risk
Embryo-fetal toxicity from PDGFRα inhibition (critical for organogenesis); potential delayed tissue inflammation/fibrosis
“Data from PDGFR-α knockout mice demonstrated that PDGFR-α is critical for normal embryonic survival, development, and organogenesis, and suggested that inhibition of the PDGFR-α signaling pathway with olaratumab may be embryonic lethal and teratogenic.”
✓ VerifiedFDA multi-discipline review, p. 31Source ↗
Anti-drug antibodies: animals
ADA in at least 22% of monkeys, causing variable exposure across toxicology studies
“though anti-drug antibody (ADA) responses seen in at least 22% of monkeys resulted in variable exposure in all toxicology studies.”
✓ VerifiedFDA multi-discipline review, p. 30Source ↗
Anti-drug antibodies: patients
3.5% (13/370) treatment-emergent anti-olaratumab antibodies; all were neutralizing
“In clinical trials, 13/370 (3.5%) of evaluable LARTRUVO-treated patients tested positive for treatment-emergent anti-olaratumab antibodies by an enzyme-linked immunosorbent assay (ELISA). Neutralizing antibodies were detected in all patients who tested positive for treatment-emergent anti-olaratumab 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