New anti-protozoal agents

Some drugs are available for the chemoprophylaxis and treatment of all the major protozoal diseases of man. However, such drugs are not always active by the oral route, efficacy is sometimes limited, toxicity can be severe and drug resistance is an increasing problem. Clearly novel drugs, which do not suffer from such problems, are urgently required. Unfortunately, the discovery and development of such drugs poses serious scientific and commercial problems. Despite this, there are real prospects, over the next 10 years, that new treatments will be available for some of the diseases caused by Trypanosoma, Leishmania and Plasmodium, but probably not those caused by Trichomonas, Giardia, Entamoeba and Toxoplasma. The prospects are also good for longer term projects, using highly rational approaches, provided these do not lose sight of the pharmacological hurdles that have to be overcome before the “magic bullet” can strike its target.