Bedaquiline: how better to use it

Pediatric Tuberculosis Management: A Global Challenge or Breakthrough?

Managing pediatric tuberculosis (TB) remains a public health problem requiring urgent and long-lasting solutions as TB is one of the top ten causes of ill health and death in children as well as adolescents universally. Minors are particularly susceptible to this severe illness that can be fatal post-infection or even serve as reservoirs for future disease outbreaks. However, pediatric TB is the least prioritized in most health programs and optimal infection/disease control has been quite neglected for this specialized patient category, as most scientific and clinical research efforts focus on developing novel management strategies for adults. Moreover, the ongoing coronavirus pandemic has meaningfully hindered the gains and progress achieved with TB prophylaxis, therapy, diagnosis, and global eradication goals for all affected persons of varying age bands. Thus, the opening of novel research activities and opportunities that can provide more insight and create new knowledge specifically geared towards managing TB disease in this specialized group will significantly improve their well-being and longevity.

Treatment of Multidrug-Resistant and Extensively Drug-Resistant Tuberculosis in Children: The Role of Bedaquiline and Delamanid

Multidrug-resistant (MDR) tuberculosis (TB) has been emerging at an alarming rate over the last few years. It has been estimated that about 3% of all pediatric TB is MDR, meaning about 30,000 cases each year. Although most children with MDR-TB can be successfully treated, up to five years ago effective treatment was associated with a high incidence of severe adverse effects and patients with extensively drug-resistant (XDR) TB had limited treatment options and no standard regimen. The main objective of this manuscript is to discuss our present knowledge of the management of MDR- and XDR-TB in children, focusing on the characteristics and available evidence on the use of two promising new drugs: bedaquiline and delamanid. PubMed was used to search for all of the studies published up to November 2020 using key words such as "bedaquiline" and "delamanid" and "children" and "multidrug-resistant tuberculosis" and "extensively drug-resistant tuberculosis". The search was limited to articles published in English and providing evidence-based data. Although data on pediatric population are limited and more studies are needed to confirm the efficacy and safety of bedaquiline and delamanid, their use in children with MDR-TB/XDR-TB appears to have good tolerability and efficacy. However, more evidence on these new anti-TB drugs is needed to better guide their use in children in order to design effective shorter regimens and reduce adverse effects, drug interactions, and therapeutic failure.

Cycloserine for treatment of multidrug-resistant tuberculosis: a retrospective cohort study in China

PURPOSE

Cycloserine has been used in multidrug-resistant tuberculosis (MDR-TB) treatment since the 1950s. We evaluated the efficacy and safety of cycloserine and sought to clarify the role of cycloserine for treatment of simple MDR-TB, pre-extensively drug-resistant tuberculosis (pre-XDR-TB), and extensively drug-resistant tuberculosis (XDR-TB).

MATERIALS AND METHODS

A retrospective observational study was performed in Zhejiang Province, China. We enrolled 144 cycloserine-treated and 181 cycloserine-nontreated patients consecutively and determined the treatment outcome as the primary outcome. The proportion of patients with sputum culture conversion and the frequency of adverse drug reactions were also assessed.

RESULTS

One-hundred (69.4%) out of 144 patients in the cycloserine group successfully completed treatment. The HR of any unfavorable treatment outcome after the introduction of cycloserine was 0.58 (95% CI: 0.38-0.86, P=0.008). Subgroup analysis showed that cycloser-ine could benefit simple MDR-TB cases reducing the risk of unfavorable treatment outcomes (HR: 0.43, 95% CI: 0.24-0.76, P=0.004), but not pre-XDR-TB (HR: 0.65, 95% CI: 0.30-1.38, P=0.263) or XDR-TB (HR: 0.73, 95% CI: 0.22-2.37, P=0.589). The culture conversion rate at the intensive phase was similar whether cycloserine was administered or not (P=0.703). Of the 144 patients treated with cycloserine, a total of 16 (11.1%) patients experienced side effects attributed to cycloserine.

CONCLUSION

Cycloserine is an attractive agent for the treatment of MDR-TB, and its safety profile warrants its use in most MDR-TB cases. Cycloserine significantly improved the chance of a favorable outcome for patients with simple MDR-TB but not pre-XDR-TB and XDR-TB. Thus, more aggressive regimens might be required for pre-XDR-TB or XDR-TB patients.

Bedaquiline and delamanid in the treatment of multidrug-resistant tuberculosis: Promising but challenging

Improving treatment outcomes in multidrug‐resistant tuberculosis (MDR‐TB) is partly hampered by inadequate effective antitubercular agents. Development of bedaquiline and delamanid has potentially changed the treatment landscape for MDR‐TB. This review provides an update on the progress of these novel antitubercular agents. We review published studies aimed at evaluating clinical efficacy and effectiveness of bedaquiline and delamanid. Five prospective clinical studies and seven retrospective studies on bedaquiline showed that patients treated with a bedaquiline‐containing regimen had a high culture conversion rate ranging from 65 to 100% and a satisfactory treatment outcome. The combined use with linezolid might add to the effectiveness of bedaquiline. Controversies about bedaquiline resistance are discussed. Three clinical trials have reported outcomes on delamanid and showed that introducing delamanid to a background regimen improved culture conversion rate at 2 months from 29.6% to more than 40%. A higher favorable treatment rate was also observed among patients who received delamanid for more than 6 months, but about a quarter of patients defaulted in the control group. Seven retrospective studies were summarized and found a treatment benefit as well. More reliable evidence from randomized clinical trials reporting on the treatment outcomes is needed urgently to support a strong recommendation for the use of delamanid. Advances in the combined use of bedaquiline and delamanid are also reviewed, and the combination may be well tolerated but requires electrocardiograph monitoring.