LpxC inhibitors: a patent review (2010-2016)

The Zn²⁺-dependent deacetylase LpxC is an essential enzyme of lipid A biosynthesis in Gram-negative bacteria and a promising target for the development of antibiotics selectively combating Gram-negative pathogens. Researchers from industry and academia have synthesized structurally diverse LpxC inhibitors, exhibiting different LpxC inhibitory and antibacterial activities. Areas covered: A brief introduction into the structure and function of LpxC, showing its suitability as antibacterial target, along with the structures of several reported LpxC inhibitors, is given. The article reviews patents (reported between 2010 and 2016) and related research publications on novel small-molecule LpxC inhibitors. Emphasis is placed on structure-activity relationships within the reported series of LpxC inhibitors. Expert opinion: The performed analysis of patents revealed that the current search for novel LpxC inhibitors is focused on small molecules, sharing common structural features like a Zn²⁺-chelating group as well as a highly lipophilic side-chain. However, despite the promising preclinical data of many of the reported compounds, besides the recently withdrawn clinical candidate ACHN-975, no other LpxC inhibitor has entered clinical trials. The lack of clinical candidates might be related with undesired effects caused by the common structural elements of the LpxC inhibitors.