For the approximately 30% of pediatric multiple sclerosis patients who are partial or non-responders to first-line treatment with interferon-beta or glatiramer acetate, natalizumab (Tysabri) may be an effective option.
The results, from an Italian cohort, were published in BMC Neurology. Angelo Ghezzi, MD, of the Hospital of Gallarte, and colleagues, studied 101 patients total (69 females) whose mean age of MS onset was 12.9 years. Mean age at natalizumab initiation was 14.7 years, and mean treatment duration was 34.2 months. A standard 300mg dose of natalizumab was administered every 28 days.
Prior to treatment, the annualized relapse rate was 2.3, but after treatment, it fell to 0.1 at the time of last infusion. Overall, 15 relapses occurred in nine patients, eight of which occurred during the first year of treatment.
Expanded Disability Status Scale (EDSS) scores decreased from 2.6 at initiation of treatment to 1.8 at time of last visit. At MRI follow-up, new T2 or gadolinium-enhancing lesions were observed in 10 of 91 patients after six months, 6 of 97 after 12 months, 2 of 61 after 18 months, 2 of 68 after 24 months, 3 of 62 after 30 months, and 5 of 43 after longer follow-up. At the time of last observation, 58% of patients showed no evidence of disease activity. Sixty-six clinical adverse events occurred in 36% of patients, however all were mild and none caused drug discontinuation.
At baseline, 43% of patients were positive for serum anti-JCV antibodies. The test was repeated on 45 patients during follow-up, with 20 remaining negative, 18 remaining positive, five becoming positive, and two becoming negative. The researchers pointed out the relatively low risk of PML, but advised that testing be conducted cyclically in order to re-assess PML risk.
Overall, the researchers concluded that natalizumab is safe, well-tolerated, and efficacious in the large majority of patients, and recommended its use in pediatric MS patients with an aggressive disease course.