Short-course, oral flubendazole does not mediate significant efficacy against Onchocerca adult male worms or Brugia microfilariae in murine infection models.

The Onchocerca ochengi adult implant and Brugia malayi microfilariemic Severe-Combined Immunodeficient (SCID) mouse models are validated screens to measure macrofilaricidal and microfilaricidal activities of candidate onchocerciasis drugs. The purpose of this study was to assess whether 5 daily sub-cutaneous (s.c.) injections of standard flubendazole (FBZ) suspension (10mg/kg), a single s.c. injection (10mg/kg) or 5 daily repeated oral doses of FBZ amorphous solid dispersion (ASD) formulation (0.2, 1.5 or 15mg/kg) mediated macrofilaricidal efficacy against O. ochengi male worms implanted into SCID mice. The direct microfilaricidal activity against circulating B. malayi microfilariae of single dose FBZ ASD formulation (2 or 40 mg/kg) was also evaluated and compared against the standard microfilaricide, ivermectin (IVM). Systemic exposures of FBZ/FBZ metabolites achieved following dosing were measured by pharmacokinetic (PK) bioanalysis. At necropsy, five weeks following start of FBZ SC injections, there were significant reductions in burdens of motile O. ochengi worms following multiple injections (93%) or single injection (82%). Further, significant proportions of mice dosed following multiple injections (5/6; 83%) or single injection (6/10; 60%) were infection negative (drug-cured). In comparison, no significant reduction in recovery of motile adult O. ochengi adult worms was obtained in any multiple-oral dosage group. Single oral-dosed FBZ did not mediate any significant microfilaricidal activity against circulating B. malayi mf at 2 or 7 days compared with >80% efficacy of single dose IVM. In conclusion, multiple oral FBZ formulation doses, whilst achieving substantial bioavailability, do not emulate the efficacy delivered by the parenteral route in vivo against adult O. ochengi. PK analysis determined FBZ efficacy was related to sustained systemic drug levels rather than achievable Cmax. PK modelling predicted that oral FBZ would have to be given at low dose for up to 5 weeks in the mouse model to achieve a matching efficacious exposure profile.

Efficacy of subcutaneous doses and a new oral amorphous solid dispersion formulation of flubendazole on male jirds (Meriones unguiculatus) infected with the filarial nematode Brugia pahangi.

River blindness and lymphatic filariasis are two filarial diseases that globally affect millions of people mostly in impoverished countries. Current mass drug administration programs rely on drugs that primarily target the microfilariae, which are released from adult female worms. The female worms can live for several years, releasing millions of microfilariae throughout the course of infection. Thus, to stop transmission of infection and shorten the time to elimination of these diseases, a safe and effective drug that kills the adult stage is needed. The benzimidazole anthelmintic flubendazole (FBZ) is 100% efficacious as a macrofilaricide in experimental filarial rodent models but it must be administered subcutaneously (SC) due to its low oral bioavailability. Studies were undertaken to assess the efficacy of a new oral amorphous solid dispersion (ASD) formulation of FBZ on Brugia pahangi infected jirds (Meriones unguiculatus) and compare it to a single or multiple doses of FBZ given subcutaneously. Results showed that worm burden was not significantly decreased in animals given oral doses of ASD FBZ (0.2-15 mg/kg). Regardless, doses as low as 1.5 mg/kg caused extensive ultrastructural damage to developing embryos and microfilariae (mf). SC injections of FBZ in suspension (10 mg/kg) given for 5 days however, eliminated all worms in all animals, and a single SC injection reduced worm burden by 63% compared to the control group. In summary, oral doses of ASD formulated FBZ did not significantly reduce total worm burden but longer treatments, extended takedown times or a second dosing regimen, may decrease female fecundity and the number of mf shed by female worms.

Macrofilaricidal efficacy of single and repeated oral and subcutaneous doses of flubendazole in Litomosoides sigmodontis infected jirds.

Flubendazole (FBZ) is highly efficacious against filarial nematodes after parenteral administration and presents a promising macrofilaricidal drug candidate for the elimination of onchocerciasis and other filariae. In the present study the efficacy of a newly developed bioavailable amorphous solid dispersion (ASD) oral formulation of FBZ was investigated in the Litomosoides sigmodontis jird model. FBZ was administered to chronically infected, microfilariae-positive jirds by single (40mg/kg), repeated (2, 6 or 15mg/kg for 5 or 10 days) oral (OR) doses or single subcutaneous (SC) injections (2 or 10mg/kg). Jirds treated with 5 SC injections at 10mg/kg served as positive controls, with untreated animals used as negative controls. After OR doses, FBZ is rapidly absorbed and cleared and the exposures increased dose proportionally. SC administered FBZ was slowly released from the injection site and plasma levels remained constant up to necropsy eight weeks after treatment end. Increasing single SC doses caused less than dose-proportional exposures. At necropsy, all animals receiving 1x or 5x 10mg/kg SC FBZ had cleared all adult worms and the 1x 2mg/kg SC treatment had reduced the adult worm burden by 98%. 10x 15mg/kg OR FBZ reduced the adult worm burden by 95%, whereas 1x 40mg/kg and 5x 15mg/kg OR reduced the worm burden by 85 and 84%, respectively. Microfilaremia was completely cleared at necropsy in all animals of the SC treatment regimens, while all oral FBZ treatment regimens reduced the microfilaremia by >90% in a dose and duration dependent manner. In accordance, embryograms from female worms revealed a FBZ dose and duration dependent inhibition of embryogenesis. Histological analysis of the remaining female adult worms showed that FBZ had damaged the body wall, intestine and most prominently the uterus and uterine content. Results of this study demonstrate that single and repeated SC injections and repeated oral administrations of FBZ have an excellent macrofilaricidal effect.

Efficacy and Safety of a Single-Dose Mebendazole 500 mg Chewable, Rapidly-Disintegrating Tablet for Ascaris lumbricoides and Trichuris trichiura Infection Treatment in Pediatric Patients: A Double-Blind, Randomized, Placebo-Controlled, Phase 3 Study.

This randomized, double-blind, placebo-controlled study evaluated the efficacy and safety of a new chewable, rapidly-disintegrating mebendazole (MBZ) 500 mg tablet for Ascaris lumbricoides and Trichuris trichiura infection treatment. Pediatric patients (1-15 years; N = 295; from Ethiopia and Rwanda) excreting A. lumbricoides and/or T. trichiura eggs were enrolled. The study had a screening phase (3 days), a double-blind treatment phase (DBP, 19 days), and an open-label phase (OLP, 7 days). Patients received MBZ or placebo on day 1 of DBP and open-label MBZ on day 19 ± 2 after stool sample collection. Cure rates (primary endpoint), defined as species-specific egg count of 0 at the end of DBP, were significantly higher in the MBZ group than placebo for A. lumbricoides (83.7% [72/86; 95% CI: 74.2%; 90.8%] versus 11.1% [9/81; 95% CI: 5.2%; 20.1%], P < 0.001) and for T. trichiura (33.9% [42/124; 95% CI: 25.6%; 42.9%] versus 7.6% [9/119; 95% CI: 3.5%; 13.9%], P < 0.001). Egg reduction rates (secondary endpoint) were significantly higher in the MBZ group than placebo for A. lumbricoides (97.9% [95% CI: 94.4; 99.9] versus 19.2% [95% CI: -5.9; 41.5]; P < 0.001) and T. trichiura (59.7% [95% CI: 33.9; 78.8] versus 10.5% [95% CI: -16.8; 32.9]; P = 0.003). Treatment-emergent adverse events (TEAEs) in MBZ group occurred in 6.3% (9/144) of patients during DBP and 2.5% (7/278) during OLP. No deaths, serious TEAEs, or TEAEs leading to discontinuations were reported. A 500 mg chewable MBZ tablet was more efficacious than placebo for the treatment of A. lumbricoides and T. trichiura infections in pediatric patients, and no safety concerns were identified.

Virological analysis of once-daily and twice-daily darunavir/ritonavir in the ODIN trial of treatment-experienced patients.

BACKGROUND: The aim of this analysis was to characterize viral resistance in the Phase III, randomized ODIN trial, which demonstrated non-inferiority of once-daily darunavir/ritonavir (DRV/r) 800/100 mg to DRV/r 600/100 mg twice daily, each combined with an optimized background regimen in treatment-experienced patients with no DRV resistance-associated mutations (RAMs) at screening. METHODS: Virological failure (VF) was defined as never achieving or losing confirmed virological suppression after week 12, with patients being classed as 'never suppressed' (never achieved HIV-1 RNA<50 copies/ml) or 'rebounders' (achieved two consecutive HIV-1 RNA<50 copies/ml but then ≥ 50 copies/ml). Phenotypes and genotypes of plasma HIV-1 viruses, using population-based sequencing and Antivirogram(®), were determined at screening/baseline and on samples from VFs with HIV-1 RNA ≥ 50 copies/ml. RESULTS: Mean baseline HIV-1 RNA was 4.16 log10 copies/ml and 53.9% of patients were protease inhibitor (PI)-experienced at enrolment. VF rate was similar in both arms. A similar proportion of virologically failing patients in both arms developed PI RAMs (11.7% versus 9.5%, respectively) or nucleoside reverse transcriptase inhibitor RAMs (6.7% versus 7.1%). One patient with VF (once-daily arm) developed four primary PI mutations, three of which were also DRV RAMs. This patient was also the only VF to lose susceptibility to DRV. Loss of susceptibility to other PIs (once daily 3.4%; twice daily 0%) and nucleoside reverse transcriptase inhibitors (once daily 13.6%; twice daily 9.8%) in VF patients was infrequent and comparable between treatment arms. CONCLUSIONS: These analyses showed once-daily DRV/r 800/100 mg was associated with similar rates of VF and emergence of resistance as DRV/r 600/100 mg twice daily in treatment-experienced patients with no DRV RAMs.

Efficacy and safety of TMC125 (etravirine) in treatment-experienced HIV-1-infected patients in DUET-2: 24-week results from a randomised, double-blind, placebo-controlled trial.

BACKGROUND: TMC125 (etravirine) is a non-nucleoside reverse-transcriptase inhibitor (NNRTI) with activity against NNRTI-resistant HIV-1 in phase IIb trials. The aim of DUET-2 is to examine the efficacy, tolerability, and safety of TMC125 in treatment-experienced patients. METHODS: In this continuing randomised, double-blind, placebo-controlled, phase III trial, HIV-1-infected patients on failing antiretroviral therapy with evidence of resistance to currently available NNRTIs and at least three primary protease inhibitor mutations were eligible for enrolment if on stable (8 weeks unchanged) antiretroviral therapy with plasma HIV-1 RNA greater than 5000 copies per mL. Patients were randomly assigned to receive either TMC125 (200 mg) or placebo, each given twice daily with darunavir-ritonavir, investigator-selected nucleoside/nucleotide reverse transcriptase inhibitors, and optional enfuvirtide. The primary endpoint was the proportion of patients with confirmed viral load below 50 copies per mL at week 24 (FDA time-to-loss of virological response algorithm). Analyses were by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00255099. FINDINGS: 591 patients were randomised and treated (295 patients in the TMC125 group and 296 in the placebo group). By week 24, 51 (17%) patients in the TMC125 group and 73 (25%) in the placebo group had discontinued, mainly because of virological failure. 183 (62%) patients in the TMC125 group and 129 (44%) in the placebo group achieved confirmed viral load below 50 copies per mL at week 24 (difference 18%, 95% CI 11-26; p=0.0003). The type and frequency of adverse events were much the same in the two groups. INTERPRETATION: In treatment-experienced patients, treatment with TMC125 led to better virological suppression at week 24 than did placebo. The safety and tolerability profile of TMC125 was generally comparable with placebo.