**Raphael Gries 1,2, Claudia Sala <sup>3</sup> and Jan Rybniker 1,2,4,\***


Received: 9 March 2020; Accepted: 9 April 2020; Published: 13 April 2020

**Abstract:** Despite global efforts to contain tuberculosis (TB), the disease remains a leading cause of morbidity and mortality worldwide, further exacerbated by the increased resistance to antibiotics displayed by the tubercle bacillus *Mycobacterium tuberculosis*. In order to treat drug-resistant TB, alternative or complementary approaches to standard anti-TB regimens are being explored. An area of active research is represented by host-directed therapies which aim to modulate the host immune response by mitigating inflammation and by promoting the antimicrobial activity of immune cells. Additionally, compounds that reduce the virulence of *M. tuberculosis*, for instance by targeting the major virulence factor ESX-1, are being given increased attention by the TB research community. This review article summarizes the current state of the art in the development of these emerging therapies against TB.

**Keywords:** tuberculosis; *Mycobacterium tuberculosis*; host-directed therapy; anti-virulence compounds
