Results from multi-country trials, presented at The Union World Conference on Lung Health, demonstrate the safety profile, tolerability and factors affecting adherence to WHO-recommended treatments for multidrug-resistant tuberculosis (MDR-TB)
- Research collaboration between University College London, UK and Stellenbosch University, South Africa demonstrates the safety profile of Levofloxacin in children and adults with MDR-TB
- Results from TBCHAMP Trial demonstrate good overall adherence to Levofloxacin in children
- Results from the CATALYST Trial demonstrate higher-mean QTcF for children taking a combination regime of moxifloxacin, clofazimine and bedaquiline, indicating that this combination should be avoided if alternatives are available
Bali, Indonesia; November 18, 2024: New research presented at The Union World Conference on Lung Health has revealed critical insight into the safety, tolerability and adherence profiles of key treatments used in WHO-recommended regimes for multidrug-resistant TB (MDR-TB).
Results from TBCHAMP, a phase 3 double-blind multi-site randomised trial in South Africa led by University College London (UCL), UK and Stellenbosch University, South Africa, and assessing Levofloxacin as preventative treatment for multidrug resistant TB in children and adolescents aged 0 – 17 years.
The study found that, of the 155 (17%) children who prematurely discontinued treatment, 70 stopped for clinical reasons, compared to 85 who stopped on non-clinical grounds. Among 818 children who were provided with information on treatment adherence, and who had not stopped treatment prematurely for clinical reasons, 61 (7%) had poor adherence.
While the study found that adherence to Levofloxacin was good overall, the researchers have emphasised the importance of identifying approaches to improve adherence, including counselling and support for caregivers.
Researchers from UCL and Stellenbosch University have also presented data from TBCHAMP alongside VQUIN, an independent phase 3 trial enrolling mostly adults in Vietnam. Individual participant data was pooled across trials.
The studies showed no evidence of serious safety concerns with Levofloxacin as a preventative treatment for MDR-TB. However, the researchers noted that low-grade adverse events (AEs) affected treatment tolerability. This resulted in treatment discontinuation, in particular among adults.
Researchers from Stellenbosch University also presented results from CATALYST, a multi-country pharmacokinetic, safety and acceptability trial of child-friendly formulations of clofazimine (CFZ) and moxifloxacin (MFX), including combination regimes of CFZ, MFX and bedaquiline (BDQ) both of which are key components of WHO-recommended regimens for rifampicin-resistant TB (RR-TB).
The study found that children taking combinations of MFX, CFZ and BDQ showed higher mean QTcF (a measure of the length of a heartbeat’s ‘resting’ phase on an electrocardiogram [ECG]), resulting in a need for additional clinical visits and the switching of drugs.
The researchers concluded that, where alternatives are available, the MFX, CFZ and BDQ combination should be avoided. Careful ECG monitoring is also recommended.
Speaking from Bali, Dr. Cassandra Kelly-Cirino, Executive Director of The International Union Against Tuberculosis and Lung Disease (The Union) said: “Multidrug resistance in TB represents a severe threat, both to those living with the disease and to global health. Treatment regimes which emphasise both safety and adherence are paramount in addressing this threat”.
“The new research presented at the Union Conference this week represents a crucial progress for these regimes, in particular in those targeted at children”.
Note: Full abstracts below
ENDS
Notes to editors:
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ANNEX – Abstract Summaries
Safety profile of levofloxacin preventive treatment for multidrug-resistant tuberculosis: a meta-analysis of the VQUIN and TB-CHAMP trials
Background: WHO recently recommended tuberculosis preventive treatment (TPT) with levofloxacin for individuals exposed to multidrug-resistant (MDR)-TB. Better understanding of the risk of adverse events (AEs), and how that varies with age, is important
Design/Methods: VQUIN and TB-CHAMP were independent phase 3 trials evaluating levofloxacin MDR-TPT. Following MDR-TB household exposure, V-QUIN enrolled mainly adults in Vietnam; TB-CHAMP enrolled mainly young children in South Africa. Randomization in both trials was 1:1 at household-level to daily levofloxacin or placebo for 6-months. Individual participant data were pooled across trials. For each pre-defined safety endpoint, the risk ratio comparing the proportion of participants experiencing the relevant endpoint between treatment groups was estimated using modified Poisson regression.
Results: Overall, 2843 (96%) of 2963 participants who commenced study treatment were included; 1922 from VQUIN and 921 TB-CHAMP. Median age was 40 years (IQR 28-52) in VQUIN and 2.8 years (1.3-4.2) in TB-CHAMP. No association was observed between levofloxacin and grade≥3 AEs, risk ratio (RR) 1.07 (95%CI 0.70-1.65); see Table. Grade≥3 AEs at least possibly related to study drug occurred in more participants in the levofloxacin-group than placebo-group in VQUIN (10 (1.0%) versus 2 (0.2%), respectively), but not in TB-CHAMP. Levofloxacin was associated with musculoskeletal events (RR 6.36, 4.30-9.42), although not among children
Conclusions: There was no evidence observed of serious safety concerns with levofloxacin MDR-TPT in either adults or children. However, low grade AEs affected treatment tolerability, resulting in treatment discontinuation, particularly in adults.
Treatment adherence to an adult levofloxacin formulation in children on multidrugresistant TB preventive treatment within the TB-CHAMP trial
Background: WHO recently recommended levofloxacin as tuberculosis (TB) preventive treatment (TPT) for contacts of multidrug-resistant (MDR)-TB. Although formulations designed for children are a priority, adult levofloxacin formulations are affordable and still used widely.
Design/Methods: TB-CHAMP was a double-blind multi-site randomised trial in South Africa assessing levofloxacin MDR-TPT. Initially children aged 0-4 years, and later also those 5-17 years who were Mycobacterium tuberculosis-infected or HIV-positive, with household exposure to an adult with bacteriologically-confirmed MDR-TB, were enrolled. Households were randomized 1:1 to 24-weeks daily levofloxacin (adult 250mg tablets) vs placebo. Competing risk methods were used to assess factors associated with premature treatment discontinuation. Factors associated with poor adherence, defined as taking
Results: Overall, 922 children were randomised, 452 to levofloxacin and 470 to placebo. Median age was 2.8 (IQR 1.3-4.2) years.
155 (17%) children discontinued treatment prematurely; 70 stopped for clinical reasons (including 7 for adverse events), and 85 for non-clinical reasons (Table). The likelihood of stopping treatment for non-clinical reasons was similar between treatment groups. In adjusted analyses, baseline factors associated with premature treatment discontinuation for non-clinical reasons were previous receipt of herbal/traditional medicine and having ≥2 typical symptoms of TB (TB already excluded). Children who slept in the same room as the index patient were less likely to discontinue treatment for non-clinical reasons than those who did not.
Among 818 children with information on treatment adherence who had not stopped treatment prematurely for clinical reasons, 61 (7%) had poor adherence. The proportion of children with poor adherence was similar between treatment groups. Younger age was associated with poor adherence.
Conclusions: Adherence to levofloxacin MDR-TPT was good overall among paediatric household contacts. It is important to identify approaches to improve adherence, including counselling and support for caregivers.
QT-interval prolongation in children receiving clofazimine and moxifloxacin for treatment of rifampicin-resistance tuberculosis: a multi-country study
Background: Clofazimine (CFZ) and moxifloxacin (MFX) are key components of shorter WHO-recommended regimens for rifampicin-resistant tuberculosis (RR-TB) treatment in children; both can cause QT prolongation. CATALYST was a pharmacokinetic, safety and acceptability trial of new child-friendlier formulations of CFZ and MFX. We present QT data from children over time, by combination of QT-prolonging drugs received.
Design/Methods: CATALYST enrolled children on RR-TB treatment for 480ms required interruption of QT-prolonging drugs and close follow-up. A repeated measures MANOVA was done to assess if serial QTcF differed by combination of QT-prolonging drugs and post-hoc analysis was with Wilk’s λ multivariate test.
Results: Thirty-six children were enrolled, median age 4.8 years (IQR 2.4, 8.1). RR-TB treatment regimens included three combinations of QT-prolonging drugs: CFZ/MFX n=12, 33%, CFZ/MFX with bedaquiline (BDQ) n=15, 42% and CFZ/MFX with delamanid (DLM) n=9, 25%. Mean QTcF over follow-up was higher in children on CFZ/MFX/BDQ than in children on CFZ/MFX or CFZ/MFX/DLM (F(9, 23)=6.98, p=0.0001; Wilk’s λ=0.268 and F(9, 23)=3.08, p=0.0141; Wilk’s λ=0.453, respectively). Seven children (19%) had ≥1 episode of QTcF >480ms (n=3 >500ms); 6/7 were taking CFZ/MFX/BDQ. No children developed arrhythmia or cardiac symptoms; MFX was discontinued in five children, and CFZ in one child.
Conclusions: Children taking MFX/CFZ/BDQ for treatment of RR-TB had higher mean QTcF, and a higher proportion had QTcF≥480ms compared to children taking MFX/CFZ or MFX/CFZ/DLM. This necessitated additional clinical visits and switching of drugs, in some. In routine programmatic care, the MFX/CFZ/BDQ combination should be avoided if alternatives are available and careful ECG monitoring is recommended.