In five sites in Sweden (Linköping, Norrköping, Jönköping, Kalmar and Stockholm), 40 consenting adult patients with mild to moderate drug-susceptible pulmonary TB will be recruited. The term Actual Study Start Date (stated 23rd of November 2020) refers to when the study opened for recruitment and this date will be updated once the first patient is enrolled in the trial.~The study participants are randomized to receive either 6-month standardized TB treatment (n=10) or a 4-month regimen (n=30) of rifampicin (RIF) 35 mg/kg and isoniazid (INH) 5 mg/kg complemented the first 8 weeks by pyrazinamide (PZA) 40 mg/kg and ethambutol (EMB) 15-20 mg/kg.~First-line drug concentration is determined at 0, 1, 2, 4, 6, 8, 12 and 24 h Day 1 and Week 2 and potential side effects thoroughly monitored throughout the study.~Early bactericidal activity (EBA) and sputum culture conversion are evaluated by time to culture positivity (TTP) in liquid medium system BACTEC MGIT (MGIT, mycobacteria growth indicator tube) 960 of induced sputum samples collected at day 0, 5 and at week 1, 2 and 8 after treatment initiation.~Clinical symptoms are assessed by a clinical scoring tool (TBscore II). Final treatment outcome and occurrence of relapse after the end of treatment are recorded according to World Health Organization (WHO) definitions.~Peak drug concentration (Cmax) and area under the plasma concentration-time curve (AUC) 0-24h will be estimated by non-compartmental analysis and conditions for early therapeutic drug monitoring (TDM) of high-dose RIF/PZA will be explored by model-based analysis.~Primary and main secondary outcomes in the study are the distribution of pharmacokinetics (Cmax, AUC) of high-dose PZA/RIF regimen, safety in terms of incidence of adverse event/severe adverse event (AE/SAE) probably related or related to TB treatment, and drug exposure (AUC) of high-dose PZA/RIF in relation to Mycobacterium tuberculosis (Mtb) drug-susceptibility level (MIC) compared with standard-of-care and suggested literature-derived pharmacokinetic/pharmacodynamic (PK/PD) targets.
Tuberculosis (TB) treatment is long and complex with the risk of poor treatment adherence and treatment failure. Several attempts to shorten treatment of drug-susceptible TB have been unsuccessful. However, recent data support a shortened regimen for mild and moderate pulmonary TB and simultaneous optimization of rifampicin (RIF) and pyrazinamide (PZA).~This phase II clinical study aim to investigate a strategy to shorten TB treatment by exploring safety and drug exposure of a high-dose sterilizing TB regimen.