The two defining pathological hallmarks of Alzheimer's disease are extracellular amyloid plaques and intracellular tau protein tangles, and both have become therapeutic targets for disease modification. Leuco-methylthioninium bis(hydromethanesulfonate; (LMTM), is a tau aggregation inhibitor and which has an anti-tau mechanism of action. An editorial notes that despite its negative findings, this study is an important step in the development of anti-tau medications. Although this study was not powered to detect the efficacy of LMTM as monotherapy, results of a prespecified post-hoc analysis suggest that monotherapy with the investigational agent may have a significant effect on disease progression in this population, and further studies will be required to elucidate whether this effect can be utilised in the management of Alzheimer’s disease.