de Jong, Bouke Catherine, Nourdine, Said, Bergeman, Auke Thomas, Salim, Zahara, Grillone, Silahi Halifa, Braet, Sofie Marijke, Wirdane Abdou, Mohamed, Snijders, Rian, Ronse, Maya, Hoof, Carolien, Tsoumanis, Achilleas, Ortuño-Gutiérrez, Nimer, der Werf, Christian van, Piubello, Alberto, Mzembaba, Aboubacar, Assoumani, Younoussa, and Hasker, Epco
Background: To reduce leprosy risk in contacts of patients with leprosy by around 50%, the World Health Organization (WHO) recommends leprosy post-exposure prophylaxis (PEP) using single-dose rifampicin (SDR). Results from a cluster randomized trial in the Comoros and Madagascar suggest that PEP with a double dose of rifampicin led to a similar reduction in incident leprosy, prompting the need for stronger PEP. The objective of this Phase 2 trial was to assess safety of a bedaquiline-enhanced PEP regimen (intervention arm, bedaquiline 800 mg with rifampicin 600 mg, BE-PEP), relative to the WHO recommended PEP with rifampicin 600 mg alone (control arm, SDR-PEP). Methods and findings: From July 2022 to January 2023, consenting participants were screened for eligibility, including a heart rate-corrected QT interval (QTc) <450 ms and liver enzyme tests (ALT/AST) below 3× the upper limit of normal (ULN), before they were individually randomized 1:1 in an open-label design. Recruitment was sequential, by age group. Pediatric dosages were weight adjusted. Follow-up was done at day 1 post-dose (including ECG) and day 14 (including ALT/AST), with repeat of ALT/AST on the last follow-up at day 30 in case of elevation on day 14. The primary outcome was non-inferiority of BE-PEP based on a <10 ms difference in QTc 24 h after treatment administration, both unadjusted and adjusted for baseline QTc. Of 408 screened participants, 313 were enrolled, starting with 187 adults, then 38 children aged 13 to 17 years, and finally 88 children aged 5 to 12 years, of whom 310 (99%) completed all visits. Across all ages, the mean QTc change on BE-PEP was from 393 ms to 396 ms, not significantly different from the change from 392 ms to 394 ms on SDR-PEP (difference between arms 1.8 ms, 95% CI −1.8, 5.3, p = 0.41). No individual's QTc increased by >50 ms or exceeded 450 ms after PEP administration. Per protocol, all children were analyzed together, with no significant difference in mean QTc increase for BE-PEP compared to SDR-PEP, although non-inferiority of BE-PEP in children was not demonstrated in unadjusted analysis, as the upper limit of the 95% CI of 10.4 ms exceeded the predefined margin of 10 ms. Adjusting for baseline QTc, the regression coefficient and 95% CI (3.3; −1.4, 8.0) met the 10 ms non-inferiority margin. No significant differences in ALT or AST levels were noted between the intervention and control arms, although a limitation of the study was false elevation of ALT/AST during adult recruitment due to a technical error. In both study arms, one serious adverse event was reported, both considered unlikely related to the study drugs. Dizziness, nausea, headache, and diarrhea among adults, and headaches in children, were nonsignificantly more frequently observed in the BE-PEP group. Conclusions: In this study, we observed that safety of single-dose bedaquiline 800 mg in combination with rifampicin is comparable to rifampicin alone, although non-inferiority of QTc changes was demonstrated in children only after adjusting for the baseline QTc measurements. A Phase 3 cluster randomized efficacy trial is currently ongoing in the Comoros. Trial Registration: ClinicalTrials.gov NCT05406479. Bouke C. de Jong and team assess the safety of a Bedaquiline enhanced post-exposure prophylaxis regimen in the Comoros Islands. Author summary: Why was this study done?: Worldwide, leprosy is diagnosed in 200,000 persons annually. Those living near a patient with leprosy can reduce their risk of developing leprosy by half if they take a single dose of the antibiotic rifampicin, known as "post-exposure prophylaxis," or PEP. Dual antibiotic treatment given as PEP may reduce the risk further, and bedaquiline has been shown to have a high degree of effectiveness against leprosy in animal studies, although the safety of PEP containing bedaquiline had not previously been tested. What did the researchers do and find?: In a village in the Comoros affected by leprosy, first adults and then children were invited to participate in a randomized study in which they could receive either a single dose of the regular PEP, or bedaquiline-enhanced PEP, in which regular rifampicin PEP was combined with bedaquiline. They had their heart rhythm and liver enzymes checked before and after taking PEP to screen for asymptomatic drug toxicity. There was no statistically significant difference in the heart rhythm or liver function between the 2 groups. While the analysis in children showed that the spread around the difference just exceeded the predetermined safety margin, the analysis controlled for baseline values did not show increased risk. What do these findings mean?: The findings suggest that regular PEP can safely be combined with bedaquiline, although it is not yet known if this provides stronger protection against developing leprosy. Limitations in this study include a technical error in liver function testing of adult participants, which may have hidden a low-level elevation. [ABSTRACT FROM AUTHOR]