**Acknowledgements**

Springer is the original publisher of images shown in **Figure 2**. These pictures were reproduced with permission from Springer and were adapted from [12] (please see full credits in the reference list). The authors wish to thank the original publisher as well as the original authors (Dr. Isidre Ferrer and co-workers) for allowing reproduction of these images in the present work. Information concerning clinical trials of several drugs has been obtained from the website http://www.alzforum.org/therapeutics. This work was supported in part by grants from the Spanish Ministerio de Economía y Competitividad (BIO2010-21132, IPT-010000-2010-16, BIO2013-49006-C2-1-R, RTC-2015-3542, RTC-2015-4094 to PVE and XB), with co-financing from EU FEDER funds, by grants to Research Groups of Excellence from the Govern de les Illes Balears, Spain (PVE), and by the Marathon Foundation (Spain). MT was a recipient of a Torres-Quevedo contract from the Spanish Ministerio de Economía y Competi‐ tividad.

#### **Conflict of interest**

MT was supported by a Torres-Quevedo Research Contract granted to Lipopharma Thera‐ peutics, S.L., from the Ministerio de Economía y Competitividad (Spanish Government). Lipopharma Therapeutics, S.L., is a spin-off company from the University of the Balearic Islands.
