Baxter International Inc. (NYSE: BAX) and The Alzheimer?s Disease Cooperative Study (ADCS) group announced the decision to pursue a multi-center U.S. Phase III study evaluating the role of Gammagard Liquid [Immune Globulin Intravenous (Human)] (IGIV) , an intravenous immunoglobulin preparation, for the treatment of patients with mild to moderate Alzheimer?s disease.
GAMMAGARD Liquid contains a broad spectrum of immunoglobulins (antibodies), and is indicated as an immunoglobulin replacement therapy in patients with primary immunodeficiency.
GAMMAGARD Liquid is processed from large pools of human plasma. IGIV has been used for almost three decades to treat primary immunodeficiency. IGIV is not currently approved for the treatment of Alzheimer?s disease, and to date has not been established to be effective in this indication.
The rationale for testing IGIV as a possible treatment for Alzheimer?s is based on the presence of natural antibodies that are directed against several forms of beta amyloid. Beta amyloid is a protein found in plaques that accumulate in the brains of patients with Alzheimer?s disease, and is considered to play a key role in the cognitive decline observed in these patients. Treatment with naturally occurring antibodies against beta amyloid contained in IGIV may result in clearance of beta amyloid from the brain and dissolution of plaques.
The decision to pursue the Phase III study is based on the results of two completed open-label clinical studies, and the preliminary analysis of interim data from a double-blind, placebo-controlled phase II study by Dr. Norman Relkin and his colleagues at Weill Cornell Medical College in New York City. In this study, 24 patients with mild to moderate Alzheimer?s disease were randomly assigned to receive GAMMAGARD Liquid, GAMMAGARD S/D or placebo (eight patients were treated with GAMMAGARD Liquid, eight patients were treated with GAMMAGARD S/D and eight patients received placebo) for six months. Cognitive, behavioral and functional measures were collected at baseline, three months and six months of treatment. The primary endpoints of the Phase II trial were cognitive function (as measured by ADAS-Cog score) and global function (as assessed by ADCS-CGIC rating). The pre-specified criterion for going forward with Phase III was a favorable outcome in IGIV-treated patients relative to those given placebo. Final results of the analysis of the Phase II study are expected later this year.
The Phase II study follows Dr. Relkin?s earlier Phase I results in eight patients that were reported at the International Conference on Alzheimer?s Disease in Madrid in July, 2006. Although these findings are promising, both studies were small and results must therefore be confirmed in a larger, sufficiently powered study.
The study protocol will be submitted to the U.S. Food and Drug Administration for review in the coming months with the intention of initiating patient recruitment early in 2008. The ADCS Phase III trial is sponsored jointly by the National Institutes of Health and Baxter. The trial will include approximately 35 leading academic centers in the U.S. that are members of ADCS.