An Alzhemer’s Disease Breakthrough?

Alzheimer’s disease is characterized by the development in the brain of microscopic “plaques and tangles”. Plaques are dense collections of insoluble protein material made up of a substance called beta-amyloid, which is derived from a larger precursor molecule. Tangles are twisted insoluble fibers made of tau protein that’s derived from parts of nerve fibers. New investigational drugs are being designed aimed at interrupting the development of plaques and tangles, and one has recently completed a one-year study of effectiveness in patients with early Alzheimer’s. It’s reported in the journal Lancet Neurology.

The drug, tarenflurbil, inhibits the enzyme that breaks off beta-amyloid from its precursor molecule, and thus blocks the production of beta-amyloid. Two dose levels (800 mg and 400 mg twice daily) were compared with placebo in 210 patients with mild to moderate Alzheimer’s (i.e. they scored between 15 and 26 on the Mini-Mental State Exam scale or MMSE).

Neither dose of tarenflurbil had a significant effect in patients with moderate Alzheimer’s, defined by scores of 15 to 19 on the MMSE. However, those with mild Alzheimer’s (MMSE 20-26) showed less decline in overall functioning and daily activities than those taking the placebo. Moreover, those with mild Alzheimer’s had significant slowing in their expected cognitive decline – minus 2.9 points with tarenflurbil vs. minus 11.5 points with the placebo.

Although these results are not as spectacular as the drug company (Myriad Pharmaceuticals) or the investigators had hoped, they are a significant step forward in arresting, or at least slowing, the inevitable deterioration experienced by mild Alzheimer’s patients. It’s another sign of success in the war on this dreadful disease.