Repositioning of a Diaminothiazole Series Confirmed to Target the Cyclin-Dependent Kinase CRK12 for Use in the Treatment of African Animal Trypanosomiasis

Alasdair Smith, Richard J. Wall, Stephen Patterson, Tim Rowan, Eva Rico Vidal, Laste Stojanovski, Margaret Huggett, Shahienaz E. Hampton, Michael G. Thomas, Victoriano Corpas Lopez, Kirsten Gillingwater, Jeff Duke, Grant Napier, Rose Peter, Hervé S. Vitouley, Justin R. Harrison, Rachel Milne, Laura Jeacock, Nicola Baker, Susan H. Davis, Frederick Simeons, Jennifer Riley, David Horn, Reto Brun, Fabio Zuccotto, Michael J Witty, Susan Wyllie*, Kevin D. Read*, and Ian H. Gilbert*

J. Med. Chem. 2022, 65, 7, 5606–5624
Publication Date:March 18, 2022
African animal trypanosomiasis or nagana, caused principally by infection of the protozoan parasites Trypanosoma congolense and Trypanosoma vivax, is a major problem in cattle and other livestocks in sub-Saharan Africa. Current treatments are threatened by the emergence of drug resistance and there is an urgent need for new, effective drugs. Here, we report the repositioning of a compound series initially developed for the treatment of human African trypanosomiasis. A medicinal chemistry program, focused on deriving more soluble analogues, led to development of a lead compound capable of curing cattle infected with both T. congolense and T. vivax via intravenous dosing. Further optimization has the potential to yield a single-dose intramuscular treatment for this disease. Comprehensive mode of action studies revealed that the molecular target of this promising compound and related analogues is the cyclin-dependent kinase CRK12