Drug-Drug Interaction Study of Benznidazole and E1224 in Healthy Male Volunteers.

E1224 is a prodrug of ravuconazole (RVZ), an antifungal drug with promising anti-Trypanosoma cruzi activity, the causative organism of Chagas disease (CD). This study was designed to assess the pharmacokinetics (PK) and safety interactions of benznidazole (BNZ), the drug of choice for treatment of CD, and E1224 in healthy volunteers. This open-label, single-center, sequential, single- and multiple-oral-dose study enrolled 28 healthy male subjects. These subjects received BNZ (2.5 mg/kg) once daily on days 1 and 9 and twice daily from day 12 to day 15 and E1224 once daily from day 4 to day 15 (loading dose of 400 mg for 3 days and maintenance dose of 100 mg for 9 days). The maximum concentration (Cmax) and area under the concentration curve from zero to infinity for BNZ were comparable, whether BNZ was given alone or with E1224 at steady state, with ratios of geometric means for BNZ-RVZ to BNZ of 0.96 and 0.83 and corresponding 90% confidence intervals (CIs) of 0.91 to 1.10 and 0.80 to 0.87, respectively. However, RVZ Cmax and area under the concentration curve from zero to 24 h increased by about 35% when concomitantly administered with BNZ at steady state (ratio of geometric means for RVZ-BNZ/RVZ of 1.31 and 1.36 and corresponding 90% CIs of 1.23 to 1.39 and 1.31 to 1.41, respectively). Both compounds were well tolerated. There were no clinically relevant safety interactions between E1224 and BZN. Given these results, coadministration of RVZ and BNZ should not require any adaptation of E1224 dosing.

Effects of Dihydroartemisinin-Piperaquine Phosphate and Artemether-Lumefantrine on QTc Interval Prolongation.

QT/QTc interval prolongation reflects delayed cardiac repolarization which can lead to Torsade de Pointes and sudden death. Many antimalarial drugs prolong QT/QTc interval. However, due to confounding factors in patients with malaria, the precise extent of this effect has been found to be highly variable among studies. We compared the effects of dihydroartemisinin-piperaquine phosphate (DHA-PQP) and artemether-lumefantrine (A-L) on QT interval duration in healthy volunteers. In this randomized, parallel groups, active moxifloxacin- and placebo-controlled study, prolongation of the QT/QTc interval following treatment with DHA-PQP in fasted and fed condition and A-L in fed state was investigated in healthy subjects (n = 287; Clinicaltrials.gov: NCT01103830). DHA-PQP resulted in significant mean (95% confidence interval (CI)) maximum increases in QTc Fridericia (QTcF) of 21.0 ms (15.7, 26.4) for DHA-PQP fasted, 35.9 ms (31.1, 40.6) for DHA-PQP high-fat/low-caloric and 46.0 ms (39.6, 52.3) for DHA-PQP high-fat/high-caloric breakfast. For A-L, the largest difference from baseline relative to placebo was 9.9 ms (95% CI: 6.8, 12.9). Increases in QTcF related to maximum plasma concentrations of piperaquine. Moxifloxacin demonstrated assay sensitivity. Increases in QTcF following DHA-PQP and A-L were clinically relevant. Food increased piperaquine exposure and QTcF interval prolongation emphasizing the need to administer DHA-PQP in the fasting state.

Determination of an optimal dosing regimen for fexinidazole, a novel oral drug for the treatment of human African trypanosomiasis: first-in-human studies.

BACKGROUND AND OBJECTIVES: Fexinidazole is a 5-nitroimidazole recently included in a clinical efficacy trial as an oral drug for the treatment of human African trypanosomiasis (HAT). Preclinical studies showed it acts as a pharmacologically active pro-drug with two key active metabolites: sulfoxide and sulfone (the most active metabolite). The present studies aimed to determine the best dose regimen for the treatment of stage 2 sleeping sickness patients, which could eventually also treat stage 1 patients. METHODS: Fexinidazole was assessed in 154 healthy adult male subjects of sub-Saharan African origin. Three initial first-in-human studies and two additional studies assessed a single ascending dose and multiple ascending doses (both under fasted conditions), tablet versus suspension formulation and food effect (fasted vs. high-fat meal and field-adapted food), and multiple ascending doses with a loading dose regimen under fed conditions. RESULTS: Fexinidazole was well-tolerated in a single dose from 100 to 3,600 mg, with quick absorption of the parent drug and rapid metabolism into sulfoxide [time to maximum concentration (t max) 2-5 h] and sulfone (t max 18-24 h). The tablet formulation was approximately 25 % less bioavailable than the suspension, and food intake increased drug absorption and plasma concentrations of fexinidazole and its two metabolites by approximately 200 %. Fourteen-day multiple ascending dosing administered up to 3,600 mg/day in fasted conditions showed that fexinidazole was generally well-tolerated (mild to moderate, spontaneously reversible drug-related adverse events). Following the high-fat food effect finding, another study was conducted to evaluate the impact of a low-fat regimen closer to that of the target population, showing that the type of meal does not influence fexinidazole absorption. The last study showed that a loading dose of 1,800 mg/day for 4 days followed by a 1,200 mg/day regimen for 6 days with a normal meal provided the desired exposure of fexinidazole and its metabolites, particularly sulfone, with good tolerability. Based on preclinical evidence from a chronic infection mouse model, systemic drug concentrations obtained are expected to be clinically effective in stage 2 HAT. CONCLUSIONS: These studies show that fexinidazole can be safely assessed in patients as a potential oral cure for both stages of HAT.

A single centre, open-label, cross-over study of pharmacokinetics comparing topical zinc/clindamycin gel (Zindaclin) and topical clindamycin lotion (Dalacin T) in subjects with mild to moderate acne.

Zinc/clindamycin gel (Zindaclin 1%) gel, is a new once-daily topical acne treatment (Strakan Ltd) containing clindamycin phosphate equivalent to 1% clindamycin and zinc acetate in a formulation, which leads to a reduced systemic absorption of clindamycin through the skin. The objective of the study was to compare the systemic absorption of clindamycin from zinc/clindamycin gel and clindamycin lotion (Dalacin T topical lotion, Pharmacia Ltd) after repeated twice-daily topical administration for two periods of 5 days with an intervening gap of 2 weeks in 24 subjects with mild to moderate acne. Plasma Cmax, and AUC0-12 of clindamycin measured after single and multiple applications of zinc/clindamycin gel were between 30% and 50% lower than for clindamycin lotion. As zinc/clindamycin gel is a topical treatment for acne, the lower systemic bioavailability may be beneficial because there may be a correspondingly lower risk of systemic events in zinc/clindamycin gel-treated subjects.