Adherence to interferon β-1a therapy using an electronic self-injector in multiple sclerosis: a multicentre, single-arm, observational, phase IV study

Abstract

Background: In a multicentre, single-arm, observational, phase IV study, we evaluated 24-week treatment adherence of relapsing multiple sclerosis (RMS) patients using an electronic auto-injection device (RebiSmart(®)) for subcutaneous injection of interferon (IFN) β-1a.

Methods: A total of 162 adult participants with RMS were enrolled into the study to use RebiSmart(®) to self-administer IFN β-1a 44 μg three times weekly for a maximum of 96 weeks. The number of administered injections was recorded in the electronic device log. Adherence to treatment was defined as the administration of ≥80% of expected injections. Cognitive impairment and injection anxiety were assessed via questionnaires.

Results: Overall, 91.8 and 82.9% of participants were adherent to treatment at weeks 12 and 24, respectively. By weeks 12 and 24, 8.2 and 13.9% of participants had discontinued treatment. There were no statistically significant differences in adherence rates at weeks 12 and 24 according to cognitive impairment status or injection anxiety. By week 24, 69.9% of participants were less fearful of injection than when they started the study. According to participant evaluations, the absence of a visible needle, comfort settings, and the calendar for tracking the injection schedule were all important features of the RebiSmart(®) injection system. At week 24, 99.3% of participants reported that they would like to continue using RebiSmart(®) as their injector.

Conclusions: RebiSmart(®) use is associated with high treatment adherence, as objectively assessed using electronic injection logs. Future research should examine if RebiSmart(®) use improves long-term treatment outcomes in RMS. This study was registered with ClinicalTrials.gov as NCT01128075, on May 20, 2010.

Figures

Fig. 1

Schedule of study assessments. Asterisk assessments at weeks 4, 8, and 16 were done by telephone contact. The current report focuses on data up to week 24 of treatment. BRB brief repeatable battery, HAD hospital anxiety and depression scale, SD1 study day 1, STAI state–trait anxiety inventory

Fig. 2

Proportion of participants with ≥80 % treatment adherence and compliance at week 12 and 24 (mITT population). Adherence calculated as 100 × the number of administered injections recorded in the electronic device log divided by the expected number of injections (e.g., 72 injections over 24 weeks). Compliance calculated as 100 times the number of injections recorded in the electronic device log divided by (the number of days on-study) × 3/7. mITT modified intent-to-treat

Fig. 3

Proportion of participants with ≥80 % treatment adherence according to cognitive impairment at weeks 12 and 24 (mITT population). p value assessed via Fisher’s exact test. mITT modified intent-to-treat

Fig. 4

Participant self-reported fear of injection at baseline, week 12, and week 24 (mITT population). Based on patient response to the following question: “Please rate your current fear of self-injection.” mITT modified intent-to-treat

Fig. 5

Proportion of participants with ≥80 % treatment adherence according to fear of injection at weeks 12 and 24 (mITT population). p value assessed via Fisher’s exact test. mITT modified intent-to-treat

Fig. 6

Patient self-reported degree of “bother” associated with RebiSmart® use (mITT population) Based on patient response to the following question: “How bothersome was the amount of time and preparation it took to get everything ready for your Rebif® injection with RebiSmart®?”