To treat or not to treat: Patient exclusion in immune oncology clinical trials due to preexisting autoimmune disease.

Newly developed immune checkpoint inhibitors (ICIs) demonstrate impressive clinical activity. However, they can also cause life-threatening side effects. The efficacy and toxicity associated with ICIs both derive from unregulated, enhanced immune activation. Health care providers have been hesitant to prescribe these medications to patients who have preexisting autoimmune disease (AD) because of concerns that this may exacerbate their underlying immune condition. These patients have also been excluded from ongoing ICI clinical trials. However, new data suggest that the potential benefits of ICI treatment may outweigh the potential risks for this patient group as long as physicians also provide sufficient monitoring for AD exacerbations or other side effects. Therefore, it may be appropriate to include patients with advanced malignancies and preexisting AD in ICI clinical trials when no other effective cancer treatment options exist. Overall, physicians should avoid excluding patients from ICI therapy unnecessarily when the potential benefits outweigh the potential risks.