The World Health Organization (WHO) has issued new conditional recommendations for the use of a shorter treatment regimen in patients with Multidrug-Resistant Tuberculosis (MDR-TB).
TB bacteria resistant to the medicines used in its treatment occur in countries all over the world. Drug resistance is fuelled by inadequate treatment; once TB bacteria acquire drug resistance they can spread from person to person in the same way as drug-susceptible TB.
Rifampicin-resistant TB (RR-TB) is caused by TB bacteria that are resistant to at least rifampicin, one of the most effective anti-TB medicines. These patients need second-line treatment similar to MDR-TB patients
Multidrug-resistant TB (MDR-TB) is caused by TB bacteria that are resistant to at least isoniazid and rifampicin, the two most effective anti-TB drugs. These patients need second-line treatment
Extensively drug-resistant TB (XDR-TB) is a form of MDR-TB that is also resistant to any fluoroquinolone and any of the second–line anti-TB injectable agents (i.e. amikacin, kanamycin or capreomycin).
An estimated 480 000 people developed MDR-TB in 2014 and 190 000 people died as a result of it.
MDR-TB cannot be treated with the standard 6- month course of first-line medication which is effective in most TB patients.
Patients with rifampicin-resistant or MDR-TB are treated with a different combination of second-line drugs, usually for 18 months or more.
Recently, a standardized treatment regimen lasting less than 12 months has been used in a number of countries. It has shown promising results in selected MDR-TB patients
Based on data from these studies, WHO has updated its treatment guidelines for drug-resistant TB in May 2016 and included a recommendation on the use of the shorter MDR-TB regimen under specific conditions.
This new recommendation is expected to benefit the majority of MDR-TB patients worldwide; however, there are serious risks for worsening resistance if the regimen is used inappropriately (e.g. in XDR-TB patients).
The new regimen is applicable to MDR-TB patients who satisfy the following inclusion criteria:
- NO Confirmed resistance or suspected ineffectiveness to a medicine in the shorter MDR-TB regimen (except isoniazid resistance) AND
- NO Exposure to >1 second-line medicines in the shorter MDR-TB regimen for >1 month AND
- NO Intolerance to >1 medicines in the shorter MDR-TB regimen or risk of toxicity (e.g. drug-drug interactions) AND
- NO Pregnancy AND
- NO Extrapulmonary disease AND
- ALL medicines in the shorter MDR-TB regimen available in the programme
- 2nd line drug resistance
- extrapulmonary disease and
Intensive phase: 4-6 months Km-Mfx-Pto-Cfz-Z-Hhigh-dose-E
Continuation phase: 5 months Mfx-Cfz-Z-E
*Supported by selected first line TB drugs
Km=Kanamycin; Mfx=Moxifloxacin; Pto=Prothionamide; Cfz=Clofazimine; Z=Pyrazinamide; Hhigh-dose= high-dose Isoniazid; E=Ethambutol
Switch to conventional MDR-TB regimen under the following circumstances:
- FAILING REGIMEN,
- DRUG INTOLERANCE,
- RETURN AFTER INTERRUPTION >2 MONTHS,
- EMERGENCE OF ANY EXCLUSION CRITERION
Link to fact sheet providing details of the shorter MDR-TB regimen:
Link to WHO’s news release regarding the shorter MDR-TB regimen:
Link to fact sheet on Molecular Line-Probe Assay to detect second line anti-TB drug resistance: