Stable Multiple Sclerosis Patients on an Interferon Therapy Have Better Outcomes When Staying on Therapy Than Patients Who Switch to Another Interferon (P2.396)

Objective: To compare outcomes of stable multiple sclerosis (MS) patients on an interferon who stayed on therapy vs. switched to another interferon. Background: Real-world outcomes from staying on an interferon vs. switching to another interferon could help guide treatment decisions. Design/Methods: MS patients from the Clinformatics Data Mart Multi-Plan from Optum Insights who were 18 to 64 years old, relapse-free (stable) over one year while continuously treated with an interferon from January 1, 2004 to September 30, 2015 were identified. Relapses were defined as any MS hospitalizations or any MS outpatient visit within 30 days of an IV steroid use, ACTH, oral steroid daily dose of >= 500 mg prednisone, or total plasma exchange. Patients were propensity score matched 3:1 using age, gender, previous interferon, adherence, and month and year (first claim=index date) for patients who stayed on the initial interferon (No Switch) to patients who switched to another interferon (Switch). Patients had to be continuously enrolled for one year prior to (baseline) and one year after the index date (follow-up). Relapses were recorded during the follow-up. Results: After matching, there were 381 patients in the Switch group and 1143 in the No Switch group. Baseline characteristics were well matched between groups (46 years old; 72% female). The percentage of patients experiencing a relapse during the follow-up was significantly higher in the Switch group compared with the No Switch group (21% vs. 12%, p Conclusions: MS patients stable on interferon therapy who remain on initial therapy had significantly better outcomes (lower annual relapse rate and percentage of patients with relapses) than patients who switched to another interferon. This supports the benefits of allowing patients to remain on current interferon therapy when stable. Study Supported by: Biogen, Inc. Disclosure: Dr. Chen has received personal compensation for activities with Biogen. Dr. Wu has received personal compensation for activities with Biogen Idec as an employee. Dr. Wu holds stock and/or stock options in Biogen Idec. Dr. Watson has received personal compensation for activities with Biogen.