Patient satisfaction following transition from the original to the new formulation of subcutaneous interferon beta-1a in relapsing multiple sclerosis: a randomized, two-arm, open-label, Phase IIIb study

OBJECTIVE: To assess satisfaction with the serum-free formulation of subcutaneous (sc) interferon (IFN) beta-1a among patients with relapsing multiple sclerosis (MS). METHODS: Patients with relapsing MS who had been receiving sc IFN beta-1a for at least 6 months, were transitioned to the new formulation, 44 μg three times weekly. Patients were randomized to preventative ibuprofen (400 mg 30–60 minutes prior to injection) or ibuprofen as needed (PRN) for 4 weeks. The primary endpoint was the ‘flu-like’ symptom (FLS) domain score of the validated Multiple Sclerosis Treatment Concern Questionnaire (MSTCQ). RESULTS: Of the 117 patients enrolled, 109 (93.2%) completed the study. Neither group’s MSTCQ FLS score showed a clinically meaningful change from baseline to week 4: mean ± SD changes were −1.1 ± 4.4 in the preventative ibuprofen group and 0.8 ± 3.6 in the ibuprofen PRN group. MSTCQ injection system satisfaction and global side-effect scores were unchanged; total and injection-site reaction scores improved moderately in both groups between baseline and week 4. CONCLUSIONS: Results showed continued or increased levels of satisfaction with the new formulation of sc IFN beta-1a. FLS occurring with the new formulation were generally mild and seldom sufficiently bothersome to require ibuprofen treatment.