That systematic review is unfortunately severely flawed. They pooled the old anti-amyloid antibodies (which everybody agrees are inefficacious) and were never used outside clinical trials, with the new anti-amyloid antibodies, that does show modest efficacy in reducing the speed of progression.
While these two classes of drugs target the same molecule, they are developed to target amyloid-beta in very different forms. Pooling all those drugs together, and then showing very weak effect, makes absolutely zero sense, and I hope and expect this review to be pulled soon.