Low-dose mepolizumab is effective as an add-on therapy for treating long-lasting peripheral neuropathy in patients with eosinophilic granulomatosis with polyangiitis
Yuto Nakamura, Yuma Fukutomi, Kiyoshi Sekiya, Keiichi Kajiwara, Yuichiro Kawasaki, Norihiro Fujita, Kisako Nagayama, Maki Iwata, Keisuke S. Iwamoto, Koichi Yano, Yuto Hamada, Kentaro Watai, Kai Ryu, Hiroaki Hayashi, Yosuke Kamide, Masami Taniguchi
Abstract
OBJECTIVE: To assess the effectiveness of low-dose mepolizumab as an add-on therapy for treating peripheral neurological symptoms in eosinophilic granulomatosis with polyangiitis (EGPA). METHODS: We prospectively studied 13 EGPA patients with conventional treatment-resistant peripheral neuropathy. Their symptoms (pain, numbness, and muscle weakness) were assessed on a visual analogue scale (VAS) before and after 12 months of mepolizumab therapy (100 mg every 4 weeks). Peripheral eosinophil levels and several biomarkers including urinary levels of eosinophil-derived neurotoxin (EDN) were measured before and after therapy. RESULTS: VAS scores for pain and numbness significantly improved after 12 months of mepolizumab therapy (from 67.0 to 48.0, P = 0.012, and from 67.0 to 51.0, P = 0.017, respectively). However, the VAS score for muscle weakness did not improve (P = 0.36). There were significant correlations between treatment-related changes in urinary EDN levels from baseline to 6 months later and percent changes in the VAS scores of pain and numbness (r = 0.75, P = 0.020; r = 0.88, P = 0.002). CONCLUSIONS: Treatment-resistant peripheral neuropathy in EGPA was significantly improved by low-dose mepolizumab, and effectiveness was correlated with decreased urinary EDN. Because the possibility of a placebo effect cannot be formally excluded, placebo-controlled studies will be required in the future.