Protein Phosphatases: A Neglected Target Family for Drug Discovery

The gene family of protein phosphatases is a rich but under-exploited source of therapeutically validated drug targets modulating signal transduction pathways. Unlike the kinase family, research and development activities have not yet yielded any approved small-molecule drugs against a phosphatase. Approximately 20 years ago, the phosphatase family was classified as undruggable and intractable. This was primarily due to the spectacular failure of the cumulated industry-wide drug discovery efforts to develop PTP1B inhibitors. Recently, allosteric inhibitors against SHP2, a member of the phosphatase family, have entered clinical trials, which has reawakened industry's interest towards this neglected enzyme family. This contribution reviews the recent R&D trends around small-molecule efforts towards phosphatase modulators over the last years, rather than providing an exhaustive review of the field of allosteric phosphatase inhibitors.