Severe oral and cutaneous immune-related adverse events induced by PD-1 inhibitors and antibody–drug conjugates: Case reports and management strategies

With increased use of immune checkpoint inhibitors (ICIs) for treating tumors, immune-related adverse events (IrAEs) have risen. Severe cases of anti-PD-1 therapy-induced IrAEs such as Stevens–Johnson syndrome (SJS)-like and toxic epidermal necrolysis (TEN)-like lesions are rare but fatal. We report two cases of patients with malignant tumors who developed oral and cutaneous severe IrAEs: one induced by a PD-1 inhibitor alone and the other by a combination of a PD-1 inhibitor and an antibody–drug conjugates (ADCs). Both of them developed severe lesions resembling erythema multiforme (EM) and SJS, accompanied by lichenoid reactions. Treatment with short-term low-dose oral glucocorticoids with topical glucocorticoids resulted in satisfactory outcomes. These case reports highlight rare and severe IrAEs induced by PD-1 inhibitors and ADCs and demonstrate how optimal outcomes were achieved for patients with severe IrAEs.