Understanding and maximising the community impact of seasonal malaria chemoprevention in Burkina Faso (INDIE-SMC): study protocol for a cluster randomised evaluation trial.

INTRODUCTION: Seasonal malaria chemoprevention (SMC) involves repeated administrations of sulfadoxine-pyrimethamine plus amodiaquine to children below the age of 5 years during the peak transmission season in areas of seasonal malaria transmission. While highly impactful in reducing Plasmodium falciparum malaria burden in controlled research settings, the impact of SMC on infection prevalence is moderate in real-life settings. It remains unclear what drives this efficacy decay. Recently, the WHO widened the scope for SMC to target all vulnerable populations. The Ministry of Health (MoH) in Burkina Faso is considering extending SMC to children below 10 years old. We aim to assess the impact of SMC on clinical incidence and parasite prevalence and quantify the human infectious reservoir for malaria in this population. METHODS AND ANALYSIS: We will perform a cluster randomised trial in Saponé Health District, Burkina Faso, with three study arms comprising 62 clusters of three compounds: arm 1 (control): SMC in under 5-year-old children, implemented by the MoH without directly observed treatment (DOT) for the full course of SMC; arm 2 (intervention): SMC in under 5-year-old children, with DOT for the full course of SMC; arm 3 (intervention): SMC in under 10-year-old children, with DOT for the full course of SMC. The primary endpoint is parasite prevalence at the end of the malaria transmission season. Secondary endpoints include the impact of SMC on clinical incidence. Factors affecting SMC uptake, treatment adherence, drug concentrations, parasite resistance markers and transmission of parasites will be determined. ETHICS AND DISSEMINATION: The London School of Hygiene & Tropical Medicine's Ethics Committee (29193) and the Burkina Faso National Medical Ethics Committee (Deliberation No 2023-05-104) approved this study. The findings will be presented to the community; disease occurrence data and study outcomes will also be shared with the Burkina Faso MoH. Findings will be published irrespective of their results. TRIAL REGISTRATION NUMBER: NCT05878366.

Power to identify exposure-response relationships in phase IIa pulmonary tuberculosis trials with multi-dimensional bacterial load modeling.

Adequate power to identify an exposure-response relationship in a phase IIa clinical trial for pulmonary tuberculosis (TB) is important for dose selection and design of follow-up studies. Currently, it is not known what response marker provides the pharmacokinetic-pharmacodynamic (PK-PD) model more power to identify an exposure-response relationship. We simulated colony-forming units (CFU) and time-to-positivity (TTP) measurements for four hypothetical drugs with different activity profiles for 14 days. The power to identify exposure-response relationships when analyzing CFU, TTP, or combined CFU + TTP data was determined at 60 total participants, or with 25 out of 60 participants in the lowest and highest dosing groups (unbalanced design). For drugs with moderate bactericidal activity, power was low (<59%), irrespective of the data analyzed. Power was 1.9% to 29.4% higher when analyzing TTP data compared to CFU data. Combined analysis of CFU and TTP further improved the power, on average by 4.2%. For a drug with a medium-high activity, the total sample size needed to achieve 80% power was 136 for CFU, 72 for TTP, and 68 for combined CFU + TTP data. The unbalanced design improved the power by 16% over the balanced design. In conclusion, the power to identify an exposure-response relationship is low for TB drugs with moderate bactericidal activity or with a slow onset of activity. TTP provides the PK-PD model with more power to identify exposure-response relationships compared to CFU, and combined analysis or an unbalanced dosing group study design offers modest further improvement.

Early bactericidal activity studies for pulmonary tuberculosis: A systematic review of methodological aspects.

A milestone in the development of novel antituberculosis drugs is the demonstration of early bactericidal activity (EBA) in a phase IIa clinical trial. The significant variability in measurements of bacterial load complicates data analysis in these trials. A systematic review and evaluation of methods for determination of EBA in pulmonary tuberculosis studies was undertaken. Bacterial load quantification biomarkers, reporting intervals, calculation methods, statistical testing, and handling of negative culture results were extracted. In total, 79 studies were identified in which EBA was determined. Colony-forming units on solid culture media and/or time-to-positivity in liquid media were the biomarkers used most often, reported in 72 (91%) and 34 (43%) studies, respectively. Twenty-two different reporting intervals were presented, and 12 different calculation methods for EBA were identified. Statistical testing for a significant EBA compared with no change was performed in 54 (68%) studies, and between-group testing was performed in 32 (41%) studies. Negative culture result handling was discussed in 34 (43%) studies. Notable variation was found in the analysis methods and reporting of EBA studies. A standardized and clearly reported analysis method, accounting for different levels of variability in the data, could aid the generalization of study results and facilitate comparison between drugs/regimens.

Optimized Loading Dose Strategies for Bedaquiline When Restarting Interrupted Drug-Resistant Tuberculosis Treatment.

Interruption of treatment is common in drug-resistant tuberculosis patients. Bedaquiline has a long terminal half-life; therefore, restarting after an interruption without a loading dose could increase the risk of suboptimal treatment outcome and resistance development. We aimed to identify the most suitable loading dose strategies for bedaquiline restart after an interruption. A model-based simulation study was performed. Pharmacokinetic profiles of bedaquiline and its metabolite M2 (associated with QT prolongation) were simulated for 5,000 virtual patients for different durations and starting points of treatment interruption. Weekly bedaquiline area under the concentration-time curve (AUC) and M2 maximum concentration (Cmax) deviation before interruption and after reloading were assessed to evaluate the efficacy and safety, respectively, of the reloading strategies. Bedaquiline weekly AUC and M2 Cmax deviation were mainly driven by the duration of interruption and only marginally by the starting point of interruption. For interruptions with a duration shorter than 2 weeks, no new loading dose is needed. For interruptions with durations between 2 weeks and 1 month, 1 month and 1 year, and longer than 1 year, reloading periods of 3 days, 1 week, and 2 weeks, respectively, are recommended. This reloading strategy results in an average bedaquiline AUC deviation of 1.88% to 5.98% compared with -16.4% to -59.8% without reloading for interruptions of 2 weeks and 1 year, respectively, without increasing M2 Cmax. This study presents easy-to-implement reloading strategies for restarting a patient on bedaquiline treatment after an interruption.

Pharmacokinetically-guided dosing to improve the efficacy of brigatinib in non-small cell lung cancer patients.

Brigatinib was recently approved for the treatment of anaplastic lymphoma kinase-positive non-small cell lung cancer and is dosed according to a one-dose-fits-all paradigm. We aimed to identify a pharmacokinetically-guided precision dosing strategy to improve treatment response with brigatinib through simulations using a previously published pharmacokinetic-pharmacodynamic model. Dosing strategies explored were the approved 180 mg QD; the highest tolerable dose tested in clinical trials: 240 mg QD; and two precision dosing strategies targeting the median trough concentrations following 180 mg QD, and 240 mg QD. We investigated the impact of alternative dosing regimens on progression-free survival (PFS), overall survival (OS) and the probability of developing a grade ≥2 rash or grade ≥2 amylase increase. Median PFS and OS increased by 1.6 and 7.8 months, respectively between the currently approved dosing strategy and precision dosing to the median trough concentration of the 240 mg dosing strategy, with only a minor increase in the probability of developing toxicity.

Pharmacokinetics and probability of target attainment for micafungin in normal-weight and morbidly obese adults.

OBJECTIVES: The rising pandemic of obesity means an increasing number of obese patients who require antimicrobial therapy for serious infections. Micafungin is an echinocandin drug frequently used as therapy or prophylaxis for fungal infections, predominantly with Candida species. In order to maximize the efficacy of micafungin in obese patients, the dose that corresponds to optimal exposure for each obese individual needs to be identified. METHODS: We performed a prospective study in 16 obese and 8 normal-weight healthy subjects with a weight ranging from 61.5-184 kg (ClinicalTrials.gov Identifier: NCT03102658). A population pharmacokinetic model was developed and used to simulate several dosing regimens to evaluate the PTA for relevant MICs to define the optimal dose using the pharmacokinetic/pharmacodynamic target of an AUC/MIC ratio above 5000. RESULTS: Total body weight was found to be most predictive for CL and V. Simulations showed that a 100 mg dose results in a PTA of >90% in patients weighing ≤125 kg infected with a Candida species having an MIC of 0.016 mg/L. The maintenance dose should be increased to 200 mg in patients >125 kg infected with a Candida species with an MIC of 0.016 mg/L. For an MIC of 0.032 mg/L, a 300 mg maintenance dose is recommended above 125 kg weight. Furthermore, we demonstrate that patients can benefit from a loading dose (i.e. twice the maintenance dose). CONCLUSIONS: We present easy-to-use dose recommendations for obese patients, based on both weight and target MIC, that result in adequate exposure in patients with body weight up to 190 kg.