Long-term MRI follow-up of patients in the ALLEGRO study: results from the yearly frequent MRI sub-cohort (P7.258)

OBJECTIVE: To assess long-term MRI measures of inflammation in patients participating in the frequent MRI sub-study of the ALLEGRO core study and its open-label (OL) extension. BACKGROUND: ALLEGRO was a 24-month, double-blind, placebo-controlled (PC), pivotal study of laquinimod 0.6 mg once daily in patients with relapsing-remitting multiple sclerosis. It showed that laquinimod reduced annualized relapse rate (primary outcomes) and slowed disability progression and improved MRI outcomes (secondary outcomes). The OL extension, in which all patients receive laquinimod, is ongoing. DESIGN/METHODS: Patients who participated in the frequent MRI sub-study of the PC phase and consented to MRI scans during the OL phase were evaluated yearly. Early start patients (n=82) received laquinimod throughout the PC and OL phases. Delayed start patients (n=83) switched from placebo to laquinimod at the end of the PC phase. Month 36 MRI data are available for 165 patients, Month 48 data for 104 patients. RESULTS: In the early start group, the decrease in the number of gadolinium-enhancing (GdE) and new/enlarging T2 lesions observed at Month 12 was maintained over time (mean GdE: 1.7, 0.4, 0.5, 0.4, 0.3 at Months 0, 12, 24, 36, 48; mean new/enlarging T2: 2.8, 2.0, 2.1, 0.9 at Months 12, 24, 36, 48). Delayed start patients showed a similar pattern of decrease after switching to laquinimod but did not achieve levels observed in early start patients (mean GdE: 1.6, 1.6, 1.4 at Months 0, 12, 24 of the PC phase, 0.8 and 0.5 at Months 36, 48; mean new/enlarging T2: 5.9, 4.0, 2.8, 2.1 at Months 12, 24, 36, 48). CONCLUSIONS: Patients treated with laquinimod for up to 48 months maintain low MRI activity after the first year. Patients switching from placebo to laquinimod show a reduction in MRI activity.