Adherence to, and effectiveness of, subcutaneous interferon β-1a administered by RebiSmart® in patients with relapsing multiple sclerosis: results of the 1-year, observational SMART study

BACKGROUND: Patients with multiple sclerosis who have poor adherence to treatment have a higher risk of relapse than adherent patients. This study assessed adherence to, and effectiveness and convenience of, treatment with subcutaneous (sc) interferon (IFN) β-1a (Rebif®, Merck Serono SA) 44 or 22 μg three times weekly in patients with relapsing multiple sclerosis (RMS) using the RebiSmart® electronic, multidose, autoinjector for 1 year.

STUDY DESIGN: European, multicentre, observational study among neurologists: inclusion criteria included RMS, Expanded Disability Status Scale score ≤ 6, sc IFN β-1a administered by RebiSmart for ≤ 6 weeks. The primary endpoint was cumulative adherence recorded by RebiSmart.

RESULTS: The safety population included 912 patients, 77.4% (n = 823) of whom completed the Month-12 visit. Mean (± standard deviation) cumulative adherence was 97.1 ± 7.3% (n = 791). The most common reason for missed injection was 'forgot to inject' (37.0%). At Month 12/ED, 79.5% of patients were relapse-free. Of 353 patients who rated the convenience of the device, 68.3% found injecting 'very easy'. No unknown safety issues were detected.

CONCLUSIONS: Patients with RMS self-injecting sc IFN β-1a with RebiSmart had excellent adherence at Month 12/ED, which was associated with good clinical outcomes and no unexpected safety issues. Patients rated RebiSmart as convenient and easy to use.