Long-term adherence of patients with relapsing-remitting multiple sclerosis to subcutaneous self-injections of interferon β-1a using an electronic device: the RIVER study

OBJECTIVES: The BRIDGE study has previously shown a high short-term (12 weeks) adherence rate (>85%) of patients with relapsing-remitting multiple sclerosis (RRMS) to subcutaneous self-injections of interferon β-1a using an electronic auto-injection device (RebiSmart®). The primary goal of the RIVER study was to investigate in a real-life setting the long-term adherence to the use of RebiSmart among patients enrolled in the parent BRIDGE study. METHODS: The RIVER study was designed as a real-life extension study of the BRIDGE trial. RRMS patients who completed BRIDGE and still had an indication for treatment were included. Data were collected prospectively through the RebiSmart device, and analyzed retrospectively. Long term adherence (administration of ≥ 80% of injections) to and safety of RebiSmart were assessed. The expected follow-up period ranged from 19 to 26 months. RESULTS: A total of 57 RRMS patients participated in the follow-up study. The mean observation period was 20.5 ± 5.7 months. The overall adherence to the use of RebiSmart in the entire study cohort was 79.8% (median = 85.2%, range = 16-100%). There were 36 patients (63.2%) who completed at least 80% of the scheduled injections. No statistically significant differences were found between adherent and non-adherent patients in terms of age, sex, duration of the observation period, and occurrence of relapses. No serious treatment-related adverse events occurred. CONCLUSIONS: This study showed a high level of long-term adherence to the use of RebiSmart, with 63.2% of participants meeting the criterion for adherence to treatment.