You are correct about ability of apabetalone to increase the plasma levels of amyloid-beta 40 (AB40). Results from a 7-day study were reported in 2008 and of the 12-week long ASSERT in 2011. I'm not sure if Resverlogix ever disclosed AB40 levels from the ~6-month long SUSTAIN or ASSURE trials.
From the ASSERT news release: "Several population studies have indicated that high HDL cholesterol is associated with protection from developing Alzheimer's Disease. It has also been shown that low plasma Aβ40 is a risk factor for developing Alzheimer's Disease in older patients. Since the Alzheimer's Disease biomarker Aβ40 bind to ApoA-I it has been hypothesized that increasing ApoA-I would transport Aβ40 out of the brain thereby decreasing the Aβ40 load in the brain, in effect having possible disease modifying effect."