by Lindsey Shapiro, PhD | 

GA Depot, an experimental long-acting version of glatiramer acetate, significantly reduced relapse rates and prevented the development of new lesions among people with relapsing forms of multiple sclerosis, according to new data from a Phase 3 clinical trial.

Disability levels also were significantly reduced with the treatment, given via monthly injections, as compared with a placebo.

According to researchers, these findings suggest that GA Depot may serve as a more convenient alternative to Copaxone, an approved version of glatiramer acetate that is given either once daily or three times per week via under-the-skin (subcutaneous) injections.

“The results of this trial are very, very comparable to the clinical trial results originally reported with” Copaxone, Aaron Miller, MD, the study’s lead investigator, said in a poster presentation at the recent Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) Forum 2023, held in San Diego. Miller is a professor of neurology at the Icahn School of Medicine at Mount Sinai, and medical director of the Corinne Goldsmith Dickinson Center for MS, both in New York.

Miller’s poster was titled, “Results of a Phase III, Multinational, Double Blind, Placebo-Controlled Study in Subjects with Relapsing Forms of Multiple Sclerosis to Assess the Efficacy, Safety and Tolerability of GA Depot, a Long-Acting IM Injection of Glatiramer Acetate, Administered Once Every Four Weeks.” The trial was funded by Mapi Pharma, the developer of GA Depot.

“Glatiramer acetate is a drug that’s been available for roughly 30 years now, and has been one of the mainstays for treatment of MS,” Miller said, adding, “Its disadvantage is that it’s given by self-injection three times a week, so 13 injections a month.”

GA Depot was designed to provide glatiramer acetate in a more convenient manner; it’s administered with a once per month injection into the muscle.

The treatment contains extended-release microspheres, or tiny particles that release small amounts of the medication over an extended period of time, which allows the treatment to be delivered less frequently.

The ongoing Phase 3 clinical trial (NCT04121221) enrolled 1,016 people with relapsing-remitting MS and active secondary progressive MS, ages 18-55, who had experienced at least one relapse in the year prior to the study or two relapses in the previous two years.

Participants were randomly assigned to receive 40 mg GA Depot or a placebo, once per month for one year, for a total of 13 injections.

In September, Mapi announced the trial had met its primary goal of showing that GA Depot could significantly reduce the rate of relapses, by 30.1%, which Miller said “was very comparable to what we saw in the [original] clinical trials of glatiramer acetate.”

During the one-year trial, participants given a placebo had experienced on average 0.26 relapses per year, while those assigned the investigational therapy experienced 0.182 relapses per year.

In the poster, Miller also reported additional outcomes related to secondary trial goals. In particular, GA Depot was associated with a significant reduction, of 28.5%, in the number of inflammatory brain lesions among patients compared with a placebo. The results also showed a 17.3% reduction in new or enlarging lesions.

Moreover, participants given GA Depot experienced a slowing in disability accumulation, as suggested by smaller increases in Expanded Disability Status Scale (EDSS) scores.

Safety findings were similar to those seen with Copaxone and its generics, with no new safety signals reported.

The most common treatment-emergent adverse event was infusion site reactions. While those did occur at a higher rate in the GA Depot group (46.1%) compared with the placebo group (28.7%), most reactions were mild.