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Alzheimer’s Drug Fails Phase III Study
A phase III clinical trial of immunoglobulin (IG, Baxter) did not meet its co-primary endpoints of reducing cognitive decline and preserving functional abilities in patients with mild-to-moderate Alzheimer's disease (AD).
Analyses from the randomized, double-blind, placebo-controlled Gammaglobulin Alzheimer's Partnership (GAP) study found that, after 18 months of treatment, patients with mild-to-moderate AD receiving the IG treatment at either the 400 mg/kg or 200 mg/kg dose did not demonstrate a statistically significant difference in the mean rate of cognitive decline compared with placebo (7.4 in the 400 mg/kg group, 8.9 in the 200 mg/kg group, and 8.4 in the placebo group). The results also did not indicate a statistically significant mean change in functional ability compared with placebo (–11.4 in the 400 mg/kg group, –12.4 in the 200 mg/kg group, and –11.4 in the placebo group).
While the study was not powered to show statistical significance among the subgroups in a pre-specified subgroup analysis, the 400 mg/kg treatment arm showed a positive, numerical difference in the change from baseline in cognition versus placebo, as measured by the Alzheimer's Disease Assessment Scale–Cognitive Subscale (ADAS-Cog) and the Modified Mini-Mental State (3MS) examination among both patients with moderate AD and carriers of the ApoE4 genetic marker. These differences ranged between 16% and 29%.
Based on these results, the drug’s developer (Baxter) will discontinue current studies of IG in mild-to-moderate AD.
The GAP trial enrolled 390 patients with mild-to-moderate AD in the U.S. and Canada. The patients were randomly assigned to receive either IG treatment (400 mg/kg or 200 mg/kg) or placebo every 2 weeks for 18 months. All of the patients were required to maintain their treatment regimen of approved medications for AD symptom management.
Source: Baxter; May 7, 2013.