Generic glatiramer acetate provided reductions in gadolinium-enhancing lesions and annualized relapse rate that were similar to the brand-name version of the drug, Copaxone, in patients with relapsing-remitting multiple sclerosis without any additional safety concerns in a phase III trial.
The combined number of gadolinium-enhancing lesions over months 7, 8, and 9 of the 9-month, double-blind, placebo-controlled, randomized GATE trial, sponsored by Synthon BV, served as the primary endpoint and indicated equivalent efficacy based on the predefined equivalence margin for the ratio of new lesions between generic glatiramer acetate and Copaxone in the study of 794 total patients. Both drugs reduced the number of new lesions, compared with placebo. The annualized relapse rates were comparable across all the groups: 0.31 (generic glatiramer acetate), 0.41 (Copaxone), and 0.39 (placebo).
Dr. Jeffrey Cohen
The active treatment groups had similar incidence, spectrum, and severity of reported adverse events, including injection site reactions. Dr. Jeffrey A. Cohen, director of the experimental therapeutics program at the Cleveland Clinic’s Mellen Center for Multiple Sclerosis Treatment and Research, will report the results on Sept. 12 at the joint meeting of the European and Americas Committees for Treatment and Research in Multiple Sclerosis in Boston.
On Sept. 11, Dr. Cohen also will speak about the need for generic equivalents to drugs that will soon be coming off patent protection. Although there is great potential for "cost savings to patients and third-party payers based on the more limited testing required for approval and resultant reduced development costs," Dr. Cohen wrote in his abstract that there are many difficulties in the process of developing these generics. As is the case for the highly complex peptide mixture that constitutes glatiramer acetate, interferons or monoclonal antibodies are biologics with highly complex chemical structures whose properties are vulnerable to changes on many levels that are difficult to predict without thorough testing. However, it will probably be necessary for developers to use more sensitive biologic markers of drug response, such as MRI, that have been previously well characterized for the original innovator product, as well as trials that use new designs and statistical analyses, he wrote.