Two diseases, one approach: multitarget drug discovery in Alzheimer's and neglected tropical diseases

In the past decade, scientific advances in network pharmacology have laid the foundations for a polypharmacological approach to discover new drugs for complex diseases. There is now a comprehensive understanding that many incurable diseases are multifactorial in nature and, consequently, conventional drugs directed to a single molecular target are inadequate. To achieve a desired clinical outcome, a polypharmacological approach seeks to intervene in the diseased network using either combinations of multiple drugs or single small molecules modulating multiple targets. Both these approaches are equally feasible from a clinical standpoint. However, for various reasons which will be discussed in this review, the latter approach may be favoured for Alzheimer's disease (AD) and neglected tropical diseases (NTDs). With each passing year, an increasing number of multitarget drugs and drug candidates are being identified, and several proof-of-concepts for treating these two diseases have emerged. Herein, with an awareness of the obstacles and challenges faced, we explore small molecules that seek to modulate multiple targets with the ultimate goal of harnessing network pharmacology for therapeutic applications in AD and NTDs.