Summary
Mitoxantrone is used for aggressive multiple sclerosis (MS), but concerns about safety, including cardiotoxicity and other laboratory measures, prevail. Reseachers sought to evaluate the incidence and potential predictors of adverse events associated with mitoxantrone at the MS Clinic, University of British Columbia, Canada. Neurology; 2010;74:1822-1826 ; E. Kingwell, PhD, M. Koch, MD, PhD, B. Leung, BSc, S. Isserow, MD, J. Geddes, RN, BSn, P. Rieckmann, MD and H. Tremlett, PhD
Details
Retrospective review of patients treated with mitoxantrone by
standard protocol was conducted.The maximum cumulative dose
was 120 mg/m2. Left ventricular ejection fraction (LVEF) was
measured with regular multiple-gated acquisition (MUGA) scans;
blood cell counts and biochemical liver tests were performed
before infusions. Generalized estimating equations were used to
examine potential predictors of adverse events (graded according
to the Common Toxicity Criteria, version 4) in patients with
normal baseline and ≥ 1 follow-up MUGA or laboratory
assessment.
All 163 patients (58% women) treated with mitoxantrone from 1999
to 2007 were reviewed. Mean baseline age was 41.9 (SD 10.8)
years, cumulative dose was 59.7 (SD 26.0) mg/m2, and median
follow-up duration was 14 months (maximum 6.5 years). By study
end, 14% developed de novo cardiotoxicity (grade ≥ 2) as measured
by decreased LVEF, 27% neutropenia (grade ≥ 1), 15% anemia (grade
≥ 1), and 15% liver toxicity (grade ≥ 1). Possible predictors of
adverse events included sex, age, disease duration, and
cumulative dose; only women exposed to a higher cumulative dose
were at a greater risk of anemia (adjusted odds ratio 1.26, 95%
confidence interval 1.08–1.48 per 10 mg/m2).
Conclusions: Based on cardiac and laboratory
assessments, mitoxantrone was reasonably well tolerated. However,
cardiotoxicity was evident after doses well below current maximum
recommended levels. A dose-response effect was not apparent.
Findings emphasize the importance of monitoring; the long-term
effects of mitoxantrone in multiple sclerosis require
investigation.