Resistance Analyses in Highly Treatment-Experienced People With Human Immunodeficiency Virus (HIV) Treated With the Novel Capsid HIV Inhibitor Lenacapavir.

BACKGROUND: Lenacapavir (LEN) is a first-in-class inhibitor of human immunodeficiency virus type 1 (HIV-1) capsid function in clinical development for the treatment of heavily treatment-experienced (HTE) people with HIV (PWH) harboring multidrug resistance (MDR) in combination with an optimized background regimen (OBR). Here we describe resistance analyses conducted in the pivotal phase 2/3 CAPELLA study. METHODS: CAPELLA enrolled viremic HTE PWH with resistance to ≥3 of 4 of the main antiretroviral (ARV) classes and resistance to ≥2 ARV drugs per class. Baseline resistance analyses used commercial assays (HIV-1 protease, reverse transcriptase, integrase genotypic/phenotypic tests). Postbaseline resistance was evaluated in participants experiencing virologic failure. RESULTS: At baseline, 46% of participants had resistance to the 4 main ARV drug classes, with one-third of participants having exhausted all drugs from ≥3 of the 4 main ARV classes. Treatment with LEN + OBR for 26 weeks led to viral suppression in 81% of participants. Postbaseline resistance mutations to lenacapavir occurred in 8 participants (6 with M66I, 1 with K70H, 1 with Q67H + K70R) who were receiving unintended functional LEN monotherapy at the time of resistance selection. CONCLUSIONS: LEN added to OBR led to high efficacy in this HTE patient population with MDR but could select for resistance when used unintentionally as functional monotherapy.

Improving outcomes for multidrug-resistant tuberculosis: aggressive regimens prevent treatment failure and death.

BACKGROUND: Evidence is sparse regarding the optimal construction of regimens to treat multidrug-resistant (MDR) tuberculosis disease due to strains of Mycobacterium tuberculosis resistant to at least both isoniazid and rifampin. Given the low potency of many second-line antituberculous drugs, we hypothesized that an aggressive regimen of at least 5 likely effective drugs during the intensive phase, including a fluoroquinolone and a parenteral agent, would be associated with a reduced risk of death or treatment failure. METHODS: We conducted a retrospective cohort study of patients initiating MDR tuberculosis treatment between 2000 and 2004 in Tomsk, Russian Federation. We used a multivariate Cox proportional hazards model to assess whether monthly exposure to an aggressive regimen was associated with the risk of death or treatment failure. RESULTS: Six hundred fourteen individuals with confirmed MDR tuberculosis were eligible for analysis. On multivariable analysis that adjusted for extensively drug-resistant (XDR) tuberculosis-MDR tuberculosis isolates resistant to fluoroquinolones and parenteral agents-we found that monthly exposure to an aggressive regimen was significantly associated with a lower risk of death or treatment failure (hazard ratio, 0.52 [95% confidence interval, .29-.94]; P = .030). CONCLUSIONS: Receipt of an aggressive treatment regimen was a robust predictor of decreased risk of death or failure during MDR tuberculosis treatment. These findings further support the use of this regimen definition as the benchmark for the standard of care of MDR tuberculosis patients and should be used as the basis for evaluating novel therapies.

An optimized background regimen design to evaluate the contribution of levofloxacin to multidrug-resistant tuberculosis treatment regimens: study protocol for a randomized controlled trial.

BACKGROUND: Current guidelines for treatment of multidrug-resistant tuberculosis (MDR-TB) are largely based on expert opinion and observational data. Fluoroquinolones remain an essential part of MDR-TB treatment, but the optimal dose of fluoroquinolones as part of the regimen has not been defined. METHODS/DESIGN: We designed a randomized, blinded, phase II trial in MDR-TB patients comparing across levofloxacin doses of 11, 14, 17 and 20 mg/kg/day, all within an optimized background regimen. We assess pharmacokinetics, efficacy, safety and tolerability of regimens containing each of these doses. The primary efficacy outcome is time to culture conversion over the first 6 months of treatment. The study aims to determine the area under the curve (AUC) of the levofloxacin serum concentration in the 24 hours after dosing divided by the minimal inhibitory concentration of the patient's Mycobacterium tuberculosis isolate that inhibits > 90% of organisms (AUC/MIC) that maximizes efficacy and the AUC that maximizes safety and tolerability in the context of an MDR-TB treatment regimen. DISCUSSION: Fluoroquinolones are an integral part of recommended MDR-TB regimens. Little is known about how to optimize dosing for efficacy while maintaining acceptable toxicity. This study will provide evidence to support revised dosing guidelines for the use of levofloxacin as part of combination regimens for treatment of MDR-TB. The novel methodology can be adapted to elucidate the effect of other single agents in multidrug antibiotic treatment regimens. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01918397 . Registered on 5 August 2013.