Table 5.
Recommended drug regimens and predicted effectivity for XDR AA1SA strains
| 2018 WHO-recommended grouping of MDR-TB drugs [64] | Effectivity in AA1SA strains | ||
|---|---|---|---|
| WHO grouping | Anti-tuberculous drug | Clade A1 | Clade B |
| % cases that would benefit | % cases that would benefit | ||
| Group A: include all three medicines where possible | Levofloxacin OR moxifloxacin | 27%* | 22%* |
| Bedaquiline | 98% | 96% | |
| Linezolid | 100% | 100% | |
| Group B: add one or both medicines | Clofazimine | 98% | 96% |
| Cycloserine OR terizidone | 100% | 40% | |
| Group C: add to complete the regimen and when medicines from Groups A and B cannot be used | Ethambutol | 0% | 0% |
| Delamanid | 100% | 100% | |
| Pyrazinamide | 0% | 0% | |
| Imipenem-cilastatin OR meropenem, with clavulanic acid | Unknown | ||
| Amikacin OR streptomycin | AMK 2%; SM 0% | AMK 5%; SM 0% | |
| Ethionamide OR prothionamide | 0% | 0% | |
| p-Aminosalicylic acid | 80%** | 80%** | |
An all-oral regimen should comprise all three group A agents and at least one group B agent, such that at least four likely effective drugs are included in the initial phase of treatment. If only one or two group A agents are used, both group B agents should be included in the regimen. Group C agents should be used when an effective regimen (four likely effective agents) cannot be constituted with group A and B drugs. Further information and specifications can be found in [64]
*An additional 5% of strains have emerging fluoroquinolone resistance, which is not reflected by this number
**Based on phenotypic resistance observed in an overlapping cohort [4]