Immunotoxicology is the study of how the immune system reacts to a drug. With biological drugs this is very important, as it is possible to have immune reactions to the drug. Some common biological drug reactions include cytokine storm, infusion reactions, and producing anti-drug antibodies.
Due to the possibility of these reactions, phase I trials will always use the minimal anticipated biological effect, reducing the potential for adverse immune reactions to occur.
During the phase I clinical trial of TGN1412, all of the participants receiving the active drug experienced cytokine storms. All were transferred to intensive care units, after having multiple organ failure. This has led to changes to protocols for clinical trials, improving the safety of participants.