Matching comparisons of therapeutic efficacy suggest better clinical outcomes for patients treated with peginterferon beta-1a than with glatiramer acetate

Background: Peginterferon beta-1a and glatiramer acetate (GA) are approved first-line therapies for the treatment of relapsing forms of multiple sclerosis, but their therapeutic efficacy has not been compared directly.

Methods: Clinical outcomes at 2 years, including no evidence of disease activity (NEDA), for patients receiving peginterferon beta-1a 125 mcg every 2 weeks (Q2W) or GA 20 mg/ml once daily (QD) were compared by propensity score matching analysis using individual patient data from ADVANCE and CONFIRM phase III clinical trials. In addition, clinical outcomes at 1-3 years for patients receiving peginterferon beta-1a Q2W or GA 40 mg/ml three times a week (TIW) were evaluated using a matching-adjusted comparison analysis of individual patient data from ADVANCE and the ADVANCE extension study, ATTAIN, and aggregate patient data from the phase III GALA and the GALA extension studies.

Results: Propensity-score-matched peginterferon beta-1a patients (n = 336) had a significantly lower annualized relapse rate [ARR (0.204 versus 0.282); rate ratio = 0.724; p = 0.045], a significantly lower probability of 12-week confirmed disability worsening (10.0% versus 14.6%; hazard ratio = 0.625; p = 0.048), and a significantly higher rate of NEDA (20.3% versus 11.5%; p = 0.047) compared with GA 20 mg/ml QD patients after 2 years of treatment. Matching-adjusted peginterferon beta-1a patients (effective n = 276) demonstrated a similar ARR at 1 year (0.278 versus 0.318; p = 0.375) and significantly lower ARR at 2 years (0.0901 versus 0.203; p = 0.032) and 3 years (0.109 versus 0.209; p = 0.047) compared with GA 40 mg/ml TIW patients (n = 834).

Conclusion: Results from separate matching comparisons of phase III clinical trials and extension studies suggest that peginterferon beta-1a 125 mcg Q2W may provide better clinical outcomes than GA (20 mg/ml QD or 40 mg/ml TIW).