Drug-resistant tuberculosis (DR-TB) is still a significant global health threat, posing challenges to public health systems worldwide. The emergence of DR-TB is primarily driven by delayed diagnosis, inadequate treatment regimens and poor drug adherence. Since rifampicin is the key first-line drug for shortening treatment duration, the impact of mycobacterium tuberculosis resistant to rifampicin is crucial.
Globally, the treatment success rate of rifampicin-resistant/multidrug-resistant TB (RR/MDR-TB) patients has been low. The long treatment duration and toxicities associated with second-line regimens are well-known barriers that hinder drug compliance and favourable treatment outcomes. Although recent advancements in molecular testing and the development of novel medications offer hope for better control of RR/MDR-TB, their accessibility remains problematic. While recent clinical trials, such as the ZeNix, TB-PRACTECAL, BEAT-TB and EndTB, have identified shorter and safer all-oral regimens, further evidence for generalizing these promising results to diverse populations is awaiting.
There have also been reports of emerging resistance to newer drugs (e.g. linezolid, bedaquiline resistance), highlighting the need to strengthen drug susceptibility testing to second line drugs. When a substantial rate of resistance to these novel drugs is observed, the development of the next cascade of new drugs and regimens will be imperative.
In Hong Kong, with all the concerted efforts, the rate of RR/MDR-TB has remained low at around 1% of all culture-confirmed TB cases. The main strategies of local RR/MDR-TB control include early identification of RR/MDR-TB by molecular testing, prompt initiation of effective second-line treatment regimen, strictly implemented directly observed therapy and the adoption of a close surveillance system. Our local experience in using the new RR/MDR-TB regimens will be discussed in the meeting.
