Importance: The patents for the first approved treatments for relapsing-remitting multiple sclerosis are expiring, creating the opportunity to develop generic alternatives.
Objective: To evaluate in the Glatiramer Acetate Clinical Trial to Assess Equivalence With Copaxone (GATE) study whether generic glatiramer acetate (hereafter generic drug) is equivalent to the originator brand glatiramer acetate (hereafter brand drug) product, as measured by imaging and clinical end points, safety, and tolerability.
Design, setting, and participants: Randomized, multicenter, double-blind, active and placebo-controlled phase 3 trial. The setting included academic medical centers and clinical practices. Participants were patients with relapsing-remitting multiple sclerosis 18 to 55 years old with at least 1 relapse in the prior year and 1 to 15 gadolinium-enhancing brain magnetic resonance imaging lesions. They were randomized between December 7, 2011, and March 21, 2013. The last participant completed follow-up December 2, 2013.
Interventions: Participants were randomized 4.3:4.3:1 to receive generic glatiramer acetate (20 mg), brand glatiramer acetate (20 mg), or placebo by daily subcutaneous injection for 9 months.
Main outcomes and measures: The primary end point was the total number of gadolinium-enhancing lesions during months 7, 8, and 9. Additional end points included other magnetic resonance imaging parameters, annualized relapse rate, and Expanded Disability Status Scale score. Safety and tolerability were assessed by monitoring adverse events, injection site reactions, and laboratory test results.
Results: In total, 794 participants were randomized and treated with generic drug (n = 353), brand drug (n = 357), or placebo (n = 84). The estimated mean numbers of gadolinium-enhancing lesions with generic drug and brand drug were lower than with placebo (ratio, 0.488; 95% CI, 0.365-0.651; P < 001), confirming study sensitivity. For gadolinium-enhancing lesions, the estimated ratio of generic drug to brand drug was 1.095 (95% CI, 0.883-1.360), which was within the predefined equivalence margin of 0.727 to 1.375. The incidence, spectrum, and severity of reported adverse events, including injection site reactions, were similar in the generic drug and brand drug groups.
Conclusions and relevance: As treatment for relapsing-remitting multiple sclerosis, glatiramer acetate generic drug and brand drug had equivalent efficacy, safety, and tolerability.
Trial registration: clinicaltrials.gov Identifier: NCT01489254.