ProMIS Neurosciences Inc. announced further results of its previously announced and ongoing preclinical program for Alzheimer's disease (AD). The company announced that its lead product candidate for AD, PMN310, compared to aducanumab (Biogen) showed significantly greater binding to the neurotoxic oligomer-enriched fraction of amyloid beta (A) in brain extract from eight confirmed AD brains. Recent reports from the scientific literature1-5 indicate that small, low molecular weight A oligomers, consisting of twelve strands of A (dodecamers), four strands (tetramers) or two strands (dimers) of A are the toxic oligomer form. To test the binding to these toxic oligomers by PMN310 and other A-directed antibodies, ProMIS isolated the soluble low molecular weight (LMW) fraction of brain material from eight AD brains expected to contain dodecamers, tetramers and dimers. Binding by aducanumab, bapineuzumab and humanized PMN310 to the toxic oligomer fraction from these brains was assessed by surface plasmon resonance (SPR). The results showed greater binding of aducanumab to the toxic oligomer LMW fraction compared to bapineuzumab, in line with the greater therapeutic benefit of aducanumab. Importantly, PMN310 showed even greater binding (1.5-2 fold) compared to aducanumab. The ability to selectively target LMW toxic A oligomers without binding A monomers (reduced efficacy) or plaque (increased risk of brain swelling, also called ARIA-E) is expected to allow for safe administration of higher effective doses and greater therapeutic potency.