"Bear, MOA for Apabetalone v Aducanumab? What I read is that aducanumab targets the brain plaque which seems to be futile. So apabetalone does what? And how does the BBB enter into all of this?"

The primary mechanism of action (MOA) for apabetalone is bromodomain-2 selective BET inhibition. Plenty of info out there on the Resverlogix posters page on what pathways may be modulated to potentially effect neurodegenerative diseases. Some of these pathways may be direct effects of apabetalone-mediated BET inhibition in the brain; however, I haven't seen any data either way on apabetalone's ability to cross the blood brain barrier (BBB). Some neuroprotective effects of apabetalone may be indirect effects (i.e. effects of apabetalone on circulating factors like inflammatory mediators, apo-AI/HDL) having secondary beneficial effects on the brain.

Here's a sampling of info on how apabetalone may be acting to elicit neuroprotective effects: Poster from last year's CTAD Barcelona conference; poster from last year's CTAD Shanghai conference; poster from the AD/PD conference from 2017; ASSERT data from long ago on amyloid beta 40; upcoming abstract for the AD/PD conference next week. 

As for aducanumab/BAN-2401. As Sumpup indicated, it is a monoclonal antibody. It binds to aggregated forms of amyloid beta to faciliate removal of amyloid beta plaques in the brain. In general, antibodies are horrible at crossing the BBB. However, aducanumab did seem to get across the BBB in sufficient quantities to elicit plaque reduction. There have been many strategies targeting amyloid plaques that have failed. I am not going to review these. There is a lot still not understood about Alzheimer's and other neurodegenerative diseases. Perhaps amyloid beta is still a good target, but targeting a different form of amyloid beta will be more efficacious. Or perhaps strategies to prevent plaque formation instead of removing pre-exisiting plaques is better. Or maybe early detection/early treatment with current amyloid beta interventions is what is needed, as opposed to treating an already advanced form of Alzheimer's. 

BearDownAZ