Erythrodermic Psoriasis Improved by Panitumumab, But Not Bevacizumab

Abstract

Psoriasis is considered to be a disease mediated by Th17/Th1 immunity, with the production of interleukin (IL)-17, IL-22, and interferon (IFN)-γ. Previous evidence has also demonstrated the possible involvement of epidermal growth factor receptor (EGFR) ligands and vascular en-dothelial growth factor (VEGF) (1–5). Panitumumab is a human monoclonal antibody targeting EGFR. On the other hand, bevacizumab is a humanized monoclonal antibody that binds VEGF. Here, we observed clinical effects of these antibodies administered for rectal cancer in a patient with psoriasis.CASE REPORTA 77-year-old man presented with a 35-year history of psoriasis, which was diagnosed at the age of 41 years. The patient had been treated with topical cor-ticosteroids, activated vitamin D3 analogue ointment, oral etretinate, and psoralen plus ultraviolet A (PUVA) therapy, which resulted in only partial and transient improvement. At the age of 65 years, the skin symptoms worsened and became erythrodermic (Fig. 1A–C). At the age of 67 years, he developed rectal cancer that was treated surgically. However, due to subsequent multiple metastases to the lung and lymph nodes, mFOLFOX6 therapy (modified combination therapy of folinic acid and fluorouracil with oxaliplatin) in combination with bevacizumab (anti-vascular endothelial growth factor (anti-VEGF) antibody, 290 mg/day, 2-week intervals) was initiated and continued for 20 months, but it failed to inhibit tumour progression. Treatment with CPT-11 (irinotecan) in combination with bevacizumab for an additional year was also ineffective. Subsequently, chemotherapy was changed to CPT-11 and panitu-mumab (anti-EGFR antibody, 290 mg/day, 2-week intervals). Notably, when panitumumab was first given, the erythrodermic eruption showed dramatic impro-vement within approximately 10 days after treatment (Fig. 1D), despite the fact that bevacizumab had been ineffective for skin symptoms. Although a few small psoriatic lesions recurred periodically within 2 weeks, subsequent administration of panitumumab cleared the skin lesions, and the skin symptoms are currently well controlled together with the metastatic tumour lesions. Therapeutic effects on skin symptoms lasted at least 6 months after the initiation of panitumumab therapy.DISCUSSIONPsoriasis is a chronic skin disease involving kera-tinocyte proliferation, altered differentiation, and vascularization. EGFR and its endogenous ligands are over-expressed in skin lesions and serum in psoriasis (5, 6), leading to keratinocyte proliferation. Levels of