Evaluating the effectiveness and safety of a short and all-oral treatment regimen for the management of rifampicin-resistant tuberculosis in Cameroon

Background: Rifampicin-resistant tuberculosis (RR-TB) remains a global treat and a major cause of ill health in low and middle incomes countries. Attempts to reduce the length of RR-TB treatment has been ongoing since several years using combination of drugs which are tolerable and effective. Since November 2021, and following the World Health Organization recommendation, Cameroon has been implementing the all-oral short regimen known as “ShORRT” with bedaquiline replacing the injectable in the “Bangladesh regimen”. 

Methods: All RR-TB patients diagnosed using Xpert MTB/Rif assay were initiated on the ShORRT in the existing eleven treatment centres of the country. Patients with proven baseline resistance to quinolones were switched to an individualized regimen with bedaquiline as core drug following national guidelines. Sputum samples were sent to the supranational laboratory to test for bedaquiline resistance using next generation sequencing: Deeplex. Proportions were presented with their percentage, and median with the interquartile range [IQR]. 

Results: Of 70 patients initiated on the ShORRT, 47 (67.1%) were males. The median age was 35 [25,45] years old among which 27 (38.6%) were new cases of tuberculosis. 21 (30%) were co-infected with HIV and on anti-retroviral therapy. The baseline bacillary load was high in 50 (73.5%) patients and the baseline second line probe assay results was reported in 19 (27.1%) patients with none presenting a fluoroquinolone resistance. The median time to smear conversion was 56 [30-63] days and we had two (3%) patients who died within the first month of treatment. Moreover two (3%) patients presented grade 3 prolongation of the QTC of more than 500 ms for which we had to stop and replace bedaquiline and moxifloxacin to amikacin and levofloxacin. 

Conclusion: Nationwide roll-out of the ShORRT in Cameroon has shown early sputum conversion. For two patients we had to replace bedaquiline and moxifloxacin in the regimen due to grade 3 cardiotoxicity at month two of treatment. Final reporting of the ShORRT will include definitive outcome for those who experience treatment failure or relapse, description of the safety profile of the regimen and the proportion of acquired drug resistance to group A TB drugs used in the regimen.