The use of weight-of-evidence approaches to characterize developmental toxicity risk for therapeutic monoclonal antibodies in humans without in vivo studies.

Regulatory guidance for global drug development relies on animal studies to evaluate safety risks for humans, including risk of reproductive toxicity. Weight-of-evidence approaches (WoE) are increasingly becoming acceptable to evaluate risk. A WoE for developmental risk of monoclonal antibodies (mAbs) was evaluated for its ability to retrospectively characterize risk and to determine the need for further in vivo testing based on the remaining uncertainty. Reproductive toxicity studies of 65 mAbs were reviewed and compared to the WoE. Developmental toxicities were absent in 52/65 (80%) mAbs. Lack of toxicity was correctly predicted in 29/52 (56%) cases. False positive and equivocal predictions were made in 9/52 (17%) and 14/52 (27%) cases. For 3/65 (5%) mAbs, the findings were equivocal. Of mAbs with developmental toxicity findings (10/65, 15%), the WoE correctly anticipated pharmacology based reproductive toxicity without any false negative predictions in 9/10 (90%) cases, and in the remaining case (1/10, 10%) an in vivo study was recommended due to equivocal WoE outcome. Therefore, this WoE approach could characterize presence and absence of developmental risk without animal studies. The current WoE could have reduced the need for developmental toxicity studies by 42% without loss of important patient information in the label.