160 Ten-year clinical outcomes post treatment with mitoxantrone for relapsing remitting MS

Mitoxantrone has been used as induction or escalation treatment in highly-active relapsing-remitting multiple sclerosis (RRMS). Whilst effective, its use is limited by adverse events (AE). Objective To report the clinical effectiveness and AE profile following mitoxantrone in a patient cohort with RRMS over a 10-year follow-up period. Methods This retrospective study included all patients treated with mitoxantrone in the Leeds MS service between 2003 and 2015. We measured expanded disability status scale (EDSS) scores annually and recorded AEs and secondary progression (SPMS). Results Forty-two patients (25 female, 17 male) were reviewed. Twenty-three (55%) received disease-modifying therapy (DMT) pre-mitoxantrone (17 interferon beta-1a, 4 glatiramer acetate, 2 natalizumab). Nineteen (45%) received further DMT post-mitoxantrone (1 interferon beta-1a, 9 glatiramer acetate, 5 natalizumab, 2 fingolimod, 2 dimethyl fumarate). Median pre-mitoxantrone EDSS score was 6.0 (95%CI 5–6). Median EDSS score at year 10 was 6.5 (95%CI 5–7). Nine (21%) developed SPMS. Commonest AE was nausea, n=6 (14%). Four (10%) developed serious AEs (1 arrhythmia, 1 left ventricular impairment, 1 pancytopaenia, 1 acute myeloid leukaemia). All serious AEs resolved and AML remains in remission for over 6 years. Conclusion Mitoxantrone therapy is effective and relatively low risk with evidence of long-term benefits in RRMS patients.