Low-dose interleukin-2 combined with thalidomide for a severe cutaneous immune-related adverse event associated with PD-1/CTLA-4 bispecific antibody therapy: a case report

Immune checkpoint inhibitors (ICIs), including novel bispecific antibodies targeting programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), have expanded therapeutic options but have also increased the incidence and complexity of immune-related adverse events (irAEs). Low-dose interleukin-2 (Ld-IL2) has been explored as a potential immunomodulatory strategy. However, its role in real-world combination regimens for managing severe cutaneous irAEs remains to be fully elucidated. We report the case of a patient with gastric cancer who developed rapidly progressive erythema and pruritus after treatment with iparomlimab and tuvonralimab. Symptoms worsened despite corticosteroids, intravenous immunoglobulin (IVIG) and antihistamines. After Ld-IL2 and thalidomide were added while corticosteroid treatment was continued, clinical improvement was observed within 48 hours, with complete resolution of the skin lesions at 2 weeks. Because Ld-IL2, thalidomide, and corticosteroids were administered concurrently, the independent contribution of each treatment and the underlying immunological mechanism could not be determined. However, further studies are warranted to clarify the potential value of this combined regimen in the management of such adverse events.