Good Treatment Adherence Is Maintained in MS Patients Using RebiSmart: Assessment of the MEASURE Primary Endpoint

Background:

Poor treatment adherence in patients with multiple sclerosis (MS) may be associated with increased risk of severe relapse. RebiSmart^TM is the first electronic auto-injector for subcutaneous interferon beta-1a (IFN) treatment of relapsing MS (RMS) and was designed to reduce several barriers to optimal treatment adherence. 

Objectives:

We evaluated adherence over 24 weeks to a regimen of subcutaneous IFN, self-injected thrice-weekly by treatment-naive patients with RMS. Here we present the final  analyses of the MEASURE study primary and secondary endpoints at Week 24.

Methods:

MEASURE (NCT01128075) was a multi-center, two-arm, non-comparative, observational, 96-week Phase IV study. Data from only  the treatment-naïve arm are presented here. The primary endpoint was the proportion of treatment-naïve subjects at Week 24 who were adherent to treatment, defined as having administered ≥80% of scheduled injections, as recorded in the RebiSmart injection log. Treatment adherence was calculated as 100 × the number of administered injections, divided by the expected number of injections (72 injections).  Subjects who discontinued treatment before Week 24 were included in the analyses of 24-week adherence, with all injections scheduled after discontinuation considered missed injections.  A cut-off of ≥80% was defined as good adherence to treatment. Treatment compliance, persistence and fear of injection were also assessed to Week 24. Fear of injection was measured on a scale of 1 (not fearful) to 5 (greatly fearful). Subjects were considered less fearful if their score declined by 1 point or more.

Results:

Final results show that 82.9% (95% CI 76.2%, 88.0%) of patients (n=158) were ≥80% adherent at 24 weeks. The proportion of patients with ≥80% compliance to treatment was 92.4% at Week 24, and the mean (±SD) compliance rate was 95.2 ± 9.7 at Week 24. Only 22 (13.9%) patients discontinued treatment by the 24^th week. At baseline, 48.3% of patients reported at least a moderate  fear (score of 3 on scale of 1 to 5) of injection.   By Week 24, 69.9% of patients became less fearful of injection, compared to baseline. The proportion of patients who were ≥80% adherent at Week 24 was similar for patients with and without  injection fear at baseline (81.5% vs. 84.2%, respectively; p = 0.678).

Conclusions:

RebiSmart^TM is an effective device to maintain good adherence, compliance and persistence on treatment.