Characteristics of Treatment-Naive Patients Initiating Subcutaneous Peginterferon Beta-1a Vs. Subcutaneous Interferon Beta-1a in the United States

Background: Peginterferon beta-1a (pegIFN) is a pegylated interferon beta-1a with a prolonged half-life, allowing for reduced dosing frequency (once every 2 weeks) vs subcutaneous interferon beta-1a three times per week (SC IFN). Since the US launch of pegIFN in 2014, its use by US healthcare providers (HCPs) in clinical practice has not been well characterized.

Objectives: To describe the demographics and clinical characteristics of treatment-naïve multiple sclerosis (MS) patients initiating pegIFN or SC IFN in the US using administrative claims data post-pegIFN approval.

Methods: In the Truven Commercially-Insured Marketscan Database, we analyzed adult patients (18-64 years old) with MS initiating pegIFN or SC IFN on or after US commercial availability of pegIFN (November 3, 2014) until the database cutoff of December 31, 2015. Index date was defined as the date of the first pegIFN or SC IFN claim. Continuous enrollment in the database for 1 year prior (pre-index period) to index date was required. Treatment naïve patients were identified as those with no claim for MS disease modifying therapy (DMT) in the 1-year pre-index period. Demographic and clinical measures were evaluated.

Results: We identified 151 treatment-naïve patients initiating pegIFN and 161 initiating SC IFN during the study period. Patients initiating pegIFN were similarly aged to those initiating SC IFN (45.4 years vs. 43.6 years, p=0.14), but a significantly lower proportion of pegIFN patients were male (16.6 vs. 27.3% male, p=0.022). Annual relapse rate in the pre-index period (prior to treatment initiation) was similar (0.27 for pegIFN vs 0.30 for SC IFN, p=0.29). However, an MS severity measure (based on prevalence of MS-specific comorbidities in the dataset) in the pre-index period was significantly lower for patients initiating pegIFN vs. SC IFN (3.13 vs. 4.09, p=0.009). In the pre-index year, patients initiating pegIFN were less likely to have any inpatient stay (11.9% vs. 23.0%, p=0.01) than patients initiating SC IFN.

Conclusions: This real-world, observational study provides insights into the use of pegIFN and SC IFN in patients untreated with DMTs in the prior year. Overall, characteristics of patients who initiated pegIFN were similar to those initiating SC IFN. However, differences in the severity of MS and healthcare resource utilization in the year prior to initiation suggest that patients initiating SC IFN may have more severe disease than those initiating pegIFN.