Evolution of Nevi During Treatment With Natalizumab A Prospective Follow-up of Patients Treated With Natalizumab for Multiple Sclerosis

Background: Natalizumab is a monoclonal antibody directed against alpha(4) integrin used in the treatment of multiple sclerosis (MS). Four cases of melanomas occurring in patients prescribed natalizumab to treat MS were recently reported. Although some fundamental data suggested that alpha(4)beta 1 integrin could be linked to the invasiveness of melanoma, none showed any relation with the transformation of melanocytes. Observations: We performed a prospective follow-up of a cohort of patients with MS treated with natalizumab to assess the evolution of nevi under treatment. Clinical dermatologic examination and videodermoscopy were performed every 6 months. Nevi were compared side-by-side with baseline photographs, and histologic analysis was proposed based on clinical and dermoscopic criteria. Forty-four patients were included, and 248 nevi were examined and followed up. The mean duration of follow-up was 14 months (range, 6-20 months). Seventeen lesions (6.8%) showed modifications over time. Only 12 (4.8%) presented substantial dermoscopic changes. Five lesions were removed. All of them were classified as benign after histologic examination. Conclusions: Our results showed the same rate of clinical and dermoscopic changes of nevi during treatment with natalizumab compared with the spontaneous evolution of nevi reported in literature. In accordance with fundamental data, those results suggest that the inhibition of the alpha(4) integrin does not promote the transformation of melanocytic lesions.