Pilot Trial of Interferon Beta-1a in Alzheimer's Disease

Alzheimer's disease is characterized by progressive cognitive impairment resulting from neuronal loss. The primary pathological feature of the disease is the extracellular deposition of fibrillary amyloid and its compaction into senile plaques. The senile plaque is the focus of a complex cellular reaction involving the activation of both microglia and astrocytes adjacent to the amyloid plaque. In fact, microglias are the most abundant and prominent cellular components associated with these plaques. Plaque-associated microglia exhibits a reactive or activated phenotype. Through the acquisition of a reactive phenotype, microglia responds to various stimuli, as is evident by the increased expression of numerous cell-surface molecules, including major histocompatibility complex (MHC) class-II antigens and complement receptors.

Traditionally, multiple sclerosis (MS) has been considered a "demyelinating" disease. Recent immunocytochemical studies suggest that MS may be more than a demyelinating disorder, and that even in early stages of the disease, MS pathological scenario envisages axonal damage. Interferons, the modern therapeutic strategies for the treatment of MS, are cytokines - proteins which lead to a network of signals within different cells. In the immune system, IFNs act at different levels. For example, IFNs increase the expression of MHC class II antigens and, thereby, facilitate the antigen-presenting process and the activation of lymphocytes. T-lymphocytes are important targets of IFN immunomodulation. In MS, it is believed that IFN beta suppresses the production of proinflammatory cytokines such as IFN-γ and TNF-α, and increases the production of immunosuppressive cytokines such as interleukin-4 (IL-4) and IL-10. Since the activation of microglia and astrocytes is common to both AD and MS, IFN beta could have therapeutic applications in the treatment of AD. Furthermore, recent studies have also found that through astrocyte production, IFNs promote the activation of nerve-growth factor.

OBJECTIVES

• To evaluate safety, tolerability and clinical efficacy of IFN beta-1a (Rebif® 22 mcg, tiw) in the treatment of AD

In this study, subjects were randomized into two groups: the first group (treatment arm, n=20) received Rebif® 22 mcg tiw; the second group (placebo arm, n=20) received placebo. The treatment period was for 28 weeks and subjects were followed up to Week 52. Efficacy was determined by comparing neuropsychological performance changes into placebo and treatment arms from screening/baseline to Week 52.