Assessment of the effectiveness and safety of natalizumab for treating relapsing-remitting multiple sclerosis

Objective

Assessing the effectiveness and safety of natalizumab for treating relapsing-remitting multiple sclerosis in a tertiary hospital.

Method

Observational, prospective study of adult patients treated with natalizumab from May 2007 until February 2009. Treatment: 300 mg natalizumab every four weeks. Response criteria: assessment of disease progression, appearance of flare-ups and assessment of magnetic resonance images. Adverse reactions during treatment with natalizumab were recorded.

Results

Thirty patients (73% female); average age 34 ± 8.4 years; mean baseline EDSS 3.4 ± 1.3; number of flare-ups in the past year 2.1 ± 1.2. Treatment was discontinued in five patients, due to refusal in one case, ineffectiveness in two cases and anaphylaxis in the other two cases. Fourteen patients completed one year of treatment with satisfactory results. A lower EDSS score by 36%, 47%, 31%, 54% and 28% was obtained at 3, 6, 9, 12 and 15 months of treatment respectively. The prevalence of relapse-free patients was 94%, 76% and 54% at 3, 6 and 12 months. MRI imaging studies in 11 patients one year after they began treatment showed no new lesions. Two patients suffered severe anaphylactic shock and another one had an outbreak of urticaria. The presence of neutralising antibodies was the reason for suspending treatment in 6.6% of the patients.

Conclusions

The treatment's effectiveness and safety in our patient group suggest that natalizumab is a treatment for refractory patients or those with aggressive types of multiple sclerosis, although we do not yet know about its long-term effects and the evolution of the appearance of neutralising antibodies.