Everyone (including me) viewed solanezumab (which binds to the mid domain of A-beta, not to the N-terminus) as safer but less effective than bapineuzumab, but then there was no efficacy signal with bapi... so who knows which mAb will be the winner. I give my vote to the IgG4 one - crenezumab.
Indeed, "Lilly is further behind the rest of the field in planning or thinking on early AD or Prodromal AD or asymptomatic" but they intend starting phase II with their BACE inhibitor, probably in pre-AD patients with MCI. So it will be their first move in this early stage territory, screening patients by PIB-PET imaging.
If there's no clear correlation between biomarkers data and improved cognitive endpoints, sola is dead.
If there is a correlation, another clinical trial would be required, likely in prospectively defined mild AD or prodromal AD (in case the effect is too small in mild, I think they should test in earlier stage AD patient population than those enrolled in the EXPEDITION trials - say MMSE scores of 24-30 and high biomarkers, also cause seems to me the FDA is getting more receptive to accept biomarkers as efficacy endpoint), so they have a better shot to demonstrate sufficient disease modifying efficacy.
