**6. Conclusion and future prospects**

The need for novel treatment strategies for TB is becoming more urgent if the goal of a TB-free world is to be realised. While the current treatment regimens have a success rate of 85% for DS-TB, there is, unfortunately, an increase in the incidence of DR-TB, which only has a treatment success rate of 57% and harsh side-effects for patients [1]. The drug discovery pipeline is relatively rich with new material; however, the conventional screening and development strategies have led to the identification of multiple chemical scaffolds that inhibit the same targets, referred to as promiscuous targets e.g. DprE1, MmpL3 and QcrB [58]. Furthermore, the global economic climate has significantly reduced the available funding for scientific research and due to the low return on investment, several pharmaceutical companies no longer support in-house drug discovery programs for infectious diseases [6], further hampering the quest for new drugs with novel targets. To this end, drug repurposing provides an appealing strategy with several advantages as outlined above. The success of Rif, Linezolid and the fluoroquinolones provides strong support for drug repurposing for the treatment of TB. The high number of repurposed drugs in the discovery phase of compound development and in advanced clinical trials suggests that this strategy is becoming more widely accepted in the TB research community and has good potential for success. Furthermore, with the continual advances in computational biology and open sharing of compound data across disease areas, it is not unreasonable to expect a boost in drug repurposing research in the future. This could possibly further reduce the time and cost to develop repurposed TB drugs, and aid in trying to meet the global goals of eradicating TB.
