Effectiveness and safety of generic memantine hydrochloride manufactured in China in the treatment of moderate to severe Alzheimer's disease: a multicenter, double-blind randomized controlled trial

BACKGROUND: Memantine hydrochloride is a N-methyl-D-aspartate (NMDA) antagonist that may be useful in the treatment of Alzheimer's disease. AIM: Compare the efficacy and safety of generic memantine hydrochloride produced in China to that of the imported proprietary version of the medication (Ebixa) in the treatment of moderate to severe Alzheimer's disease (AD). METHODS: In this multicenter, double-blind randomized controlled trial 229 patients with moderate to severe AD were randomly assigned to a 16-week trial of either the generic preparation or the proprietary preparation of memantine hydrochloride. All participants were assessed at baseline and at 4, 8, 12 and 16 weeks after enrolment. The primary outcome variable was the Alzheimer Disease Assessment Scale-cognition (ADAS-Cog) score. Secondary outcomes were scores in the Mini-Mental State Examination (MMSE), the Activities of Daily Living (ADL) scale and the Clinical Global Impression (CGI) scale. RESULTS: Sample sizes for the safety set (SS) analysis, full analysis set (FAS) and per protocol set (PPS) analysis were 112, 109 and 103 in the generic medication group, and 111, 107 and 101 in the proprietary medication group, respectively. The ADAS-Cog and ADL total scores at the end of weeks 4, 8, 12, and 16 decreased significantly compared with baseline for both groups (p<0.001) and the MMSE total scores at the end of weeks 4, 8, 12, and 16 increased significantly compared with baseline for both groups (p<0.001). There were no significant differences in ADAS-Cog total scores, ADL total scores and level of improvement based on the CGI scores between the two groups at any of the follow-up assessments. The occurrence of adverse events was 20.5% in the generic medication group and 27.0% in the proprietary medication group; this difference was not statistically significant (χ(2)=1.30, p=0.255). CONCLUSION: There are no significant differences in the effectiveness or safety between memantine that is generically produced in China and imported proprietary memantine in the treatment of individuals with moderate and severe AD during the first 16 weeks of treatment.