The chemical biology of new drugs in the development for tuberculosis.

With the worldwide emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Mycobacterium tuberculosis (Mtb), there are serious concerns about the continued ability to contain this disease. We discuss the most promising new drugs in late-stage development that might be useful in treating MDR and XDR forms of the disease. These agents have novel mechanisms of action that are not targeted by the standard drugs used presently to treat susceptible strains.