High risk PML patients switching from natalizumab to alemtuzumab (P2.407)

Objective: Aim of this study is to evaluate the efficacy of alemtuzumab when used in patient who have stopped natalizumab. Background: The choice of therapy in patients withdrawing natalizumab treatment is still an open question and neurologists need strategies to manage this group of patients. Design/Methods: 16 patients stopped natalizumab treatment after a median number of 20 infusions (range 12–114); all the patients were responder to natalizumab (neither clinical nor radiological activity during natalizumab therapy) and the reason for stopping was the risk of PML for all of them. Patients were switched to alemtuzumab after a median wash out period of 70 days (range 41–99 days); patients underwent brain MRI every three months during natalizumab treatment and then just before starting alemtuzumab in order to exclude signs suggestive of PML; then contrast-enhanced brain MRI was planned 6 and 12 months after alemtuzumab infusion. Results: At present 8 out of 16 patients have a follow up > 6 months and 2 out of 8 reached one year follow up; 5 have a follow up of 3–6 months and 3 have a follow up Conclusions: Alemtuzumab showed efficacy in controlling disease course in patients who stopped natalizumab; these patients must be carefully monitorated with brain MRI before starting alemtuzumab for the risk of PML. Study Supported by: Not applicable Disclosure: Dr. Bertolotto received personal compensation for activities with Almirall, Biogen, Merck, Novartis, Sanofi Genzye, and TEVA as a speaker and/or consultant. Dr. Bertolotto has received research support from Biogen, Merck, Novartis, and TEVA. Dr. Capobianco has received personal compensation for activities with TEVA, Almirall, Biogen, Sanofi Genzyme, Merck Serono, Bayer Schering, Novartis, and Roche as a speaker and advisory board member. Dr. Lo Re has received personal compensation for activities with Biogen. Dr. Malentacchi has received personal compensation for activities with Biogen as a speaker. Dr. Sperli has received personal compensation for activities with Biogen Idec and Novartis as a speaker. Dr. Matta has received personal compensation for activities with Biogen and Novartis. Dr. di Sapio has received personal compensation for activities with Biogen-Dompe, Novartis, and Teva Neuroscience as a speaker and consultant and for activities with Merck-Serono, Biogen-Dompe, and Farmades as a reimbursement. Dr. Malucchi has received personal compensation from Biogen, Merck, Serono, and Novartis as a speaker.