Human PBMC cytokine release limited to a 5-7 fold TNFα increase at 24 hours
“The results were limited to a 5-7 fold increase in TNFα following 24 hours of exposure to avelumab at concentrations ≥ 14.4 ng/mL.”
✓ VerifiedFDA multi-discipline review, p. 52Source ↗
Biodistribution & persistence
Human and monkey tissue staining generally comparable
“Overall, except for these differences, avelumab staining of normal human and cynomolgus tissues was generally comparable.”
✓ VerifiedFDA multi-discipline review, p. 52Source ↗
Modality-specific risk
Immune-related toxicity from loss of PD-L1-mediated self-tolerance
“Avelumab’s mode of action removes the suppressive effects of PD-L1 on T cells, which may lead to decreases in self-tolerance and immune-related effects.”
4-week monkey study: 3/12 (25%) ADA-positive; decreased exposure in ADA-positive animals at 20 mg/kg
“Antigenicity: 3/12 (25%) monkeys treated with avelumab tested positive for anti-drug antibodies (ADA). Two were in the low dose and one in the high dose group. At 20 mg/kg, a decrease of exposure was observed in ADA-positive animals.”
5.9% (96/1,627) treatment-emergent ADA at 10 mg/kg Q2W
“Of 1,738 patients treated with avelumab 10 mg/kg as an intravenous infusion every 2 weeks, 1,627 were evaluable for treatment-emergent anti-drug antibodies (ADA) and 96 (5.9%) tested positive.”
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