Reasons for discontinuation of subcutaneous interferon β-1a three times a week among patients with multiple sclerosis: a real-world cohort study.
BACKGROUND
Continuation of interferon (IFN) β-based therapies is important for maximum treatment effectiveness in patients with multiple sclerosis (MS); however, few real-world data are available on discontinuation from IFN β. The aim of this cohort analysis was to estimate real-world discontinuation rates up to 3 years among MS patients in the United States taking subcutaneous (sc) IFN β-1a three times a week (tiw) and to identify whether the factors associated with discontinuation change over time.


METHODS
Patient data were pooled from the MarketScan©Commercial and Medicare Supplemental healthcare claims databases. Patients with ≥1 multiple sclerosis diagnosis who were sc IFN β-1a tiw naïve, had ≥1 year of continuous eligibility before treatment, and ≥1 prescription were followed from first prescription (index date) until date of discontinuation, switch, or end of observation. Treatment status was analysed at exactly 1, 2 or 3 years after index. Multivariable models were used to identify drivers of discontinuation.


RESULTS
Data from 5956 patients were included; 2862 patients (48.1%) discontinued therapy. Discontinuation rates were 36.9% (1 year), 49.5% (2 years) and 55.8% (3 years). A greater proportion of discontinuing patients had poor adherence (<80% [94.0%] versus ≥80% [51.7%]) or were taking additional medication at follow-up versus the overall population. Factors independently associated with discontinuation irrespective of time on therapy were increasing number of magnetic resonance imaging scans (1 year adjusted odds ratio 1.45, 95% confidence interval 1.26-1.67; 2 years 1.18, 1.06-1.32; 3 years 1.20, 1.07-1.34) and adherence <80% versus ≥80% (1 year 180.95, 135.84-241.03; 2 years 135.80, 100.10-184.23; 3 years 174.89, 115.27-265.38). Factors associated only with early discontinuation (at 1 year) were ≥3 sets of laboratory investigations versus none (2.54, 1.20-5.38), and anxiolytic use at follow-up (1.40, 1.06-1.82). Factors associated only with later discontinuation (at 2 years and/or at 3 years) were antidepressant use at follow-up (2 years 1.46, 1.10-1.94) and greater number of relapses (2 years 1.60, 1.11-2.30; 3 years 2.31, 1.27-4.22).


CONCLUSIONS
Potential drivers of discontinuation change over time. Improved awareness of the drivers of discontinuation could lead to targeted interventions to improve adherence.
, Frankfurter Str. 250, HPC: F135/201, Darmstadt, 64293, Germany. meritxell.sabido-espin@merckgroup.com.
Meritxell
M
Sabidó-Espin
EMD Serono, Rockland, MA, USA.
Rick
R
Munschauer
D000276:Adjuvants, Immunologic / Q000008:administration & dosage / Q000627:therapeutic use*; D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007279:Injections, Subcutaneous; D007348:Insurance, Health / Q000706:statistics & numerical data*; D000068556:Interferon beta-1a / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000188:drug therapy*; D014481:United States; D016903:Drug Monitoring
D000276:Adjuvants, Immunologic; D000068556:Interferon beta-1a
Adherence; Discontinuation; Interferon β-1a; Multiple sclerosis