Background Natalizumab is a selective adhesion molecule inhibitor and binds to the α4 subunit of human integrins. Natalizumab 300 mg is administered by intravenous infusion once every 4 weeks (standard dose).

Purpose To evaluate and compare the effectiveness of natalizumab administered every 6 weeks versus the standard dose in patients diagnosed with relapsing remitting multiple sclerosis (RRMS).

Material and methods A retrospective and observational study of patients diagnosed with RRMS treated with natalizumab between January 2013 and June 2016 was conducted. Inclusion criteria: patients ≥18 years old, optimal response to natalizumab and <65 kg. Variables collected: demographics (age and sex); clinical: mental state/mood (MS/M), vision (V), language (L), hearing/vertigo (H/V), swallow (S), cerebellum (C), cranial (PC), cervical mobility (CM), motor system (MS), sensitive system (SS), balance (BA), Romberg (R), March (M), sphincters/sexual function (SF), buds (B) and presence of anti-John Cunningham virus (JCV) antibodies at 0, 3 and 6 months of dosing change. Statistical analysis was performed using the Epidat 3.1 programme.

Results 30 patients were included (23% men) with a mean age of 36.1±12.9 years. The following table shows the number of patients who developed alterations for each of the variables studied.

Conclusion No statistically significant differences were observed when comparing the results obtained for each of the items studied at 0, 3 and 6 months after the change in dose, so we conclude, based on these preliminary data, that both dosing regimens appear to be equally effective in this group of patients.

No conflict of interest