GA Depot Trial Reports Lower Relapse Activity vs Placebo

Key Takeaways

• GA Depot was associated with reduced relapse activity and less contrast-enhancing MRI activity than placebo over 52 weeks.
• The phase 3 randomized placebo-controlled trial studied intramuscular GA Depot 40 mg every 4 weeks in adults with relapsing multiple sclerosis.
• Injection site reactions were the most common adverse events and were described as mainly mild and self-limited.

In a 52-week phase 3 trial in relapsing multiple sclerosis, GA Depot given every 4 weeks was associated with a 30.1% relative reduction in relapse rate versus placebo. The long-acting intramuscular glatiramer acetate formulation was studied over a full year in adults with relapsing disease. Researchers also reported less contrast-enhancing MRI activity with GA Depot during follow-up, with the overall pattern favoring reduced clinical and radiological activity versus placebo.

The multicenter, double-blind, placebo-controlled phase 3 trial enrolled adults aged 18 to 55 years with Expanded Disability Status Scale scores of 5.5 or lower. A total of 1016 patients received treatment, with 508 assigned to GA Depot and 508 assigned to placebo. Participants were randomized 1:1 to intramuscular GA Depot 40 mg or matching placebo every 4 weeks for 52 weeks. Annualized relapse rate at 52 weeks was the primary endpoint, and investigators described the formulation as designed for extended dosing intervals. ClinicalTrials.gov lists the study under identifier NCT04121221.

At 52 weeks, adjusted annualized relapse rate was 0.18 with GA Depot and 0.26 with placebo, with p = 0.0066. Those values corresponded to a 30.1% relative risk reduction in favor of GA Depot. The investigators also found a significant reduction in the number of contrast-enhancing lesions, with p = 0.0083. Investigators concluded that these findings reflected reduced clinical and radiological activity with GA Depot compared with placebo over 52 weeks.

Injection site reactions were the most common adverse events, reported in 46.1% of GA Depot recipients and 28.7% of placebo recipients. These reactions were primarily mild and self-limited. The authors also concluded that the formulation recapitulated the favorable profile of subcutaneous glatiramer acetate products while allowing significantly less frequent injections. Overall, the 52-week findings paired lower relapse and MRI activity with a local tolerability profile led by mostly mild injection site reactions.