Hetty Waskin

Posaconazole Tablet Pharmacokinetics: Lack of Effect of Concomitant Medications Altering Gastric pH and Gastric Motility in Healthy Subjects

ABSTRACT Posaconazole oral suspension is an extended-spectrum triazole that should be taken with food to maximize absorption. A new posaconazole tablet formulation has demonstrated improved bioavailability over the oral suspension in healthy adults in a fasting state. This study evaluated the effects of concomitant medications altering gastric pH (antacid, ranitidine, and esomeprazole) and gastric motility (metoclopramide) on the pharmacokinetics of posaconazole tablets. This was a prospective open-label 5-way crossover study in 20 healthy volunteers. In each treatment period, a single 400-mg dose (4 100-mg tablets) of posaconazole was administered alone or with 20 ml antacid (2 g of aluminum hydroxide and 2 g of magnesium hydroxide), ranitidine (150 mg), esomeprazole (40 mg), or metoclopramide (15 mg). There was a ≥10-day washout between treatment periods. Posaconazole exposure, time to maximum concentration of drug in serum (Tmax), and apparent terminal half-life (t1/2) were similar when posaconazole was administered alone or with medications affecting gastric pH and gastric motility. Geometric mean ratios (90% confidence intervals [CIs]) of the area under the concentration-time curve from time zero to infinity (AUC0–inf) (posaconazole with medications affecting gastric pH and gastric motility versus posaconazole alone) were 1.03 (0.88–1.20) with antacid, 0.97 (0.84–1.12) with ranitidine, 1.01 (0.87–1.17) with esomeprazole, and 0.93 (0.79–1.09) with metoclopramide. Geometric mean ratios (90% CIs) of the maximum concentration of drug in serum (Cmax) were 1.06 (0.90–1.26) with antacid, 1.04 (0.88–1.23) with ranitidine, 1.05 (0.89–1.24) with esomeprazole, and 0.86 (0.73–1.02) with metoclopramide. In summary, in healthy volunteers, the pharmacokinetics of a single 400-mg dose of posaconazole tablets was not altered to a clinically meaningful extent when posaconazole was administered alone or with medications affecting gastric pH or gastric motility.

Phase 1b Study of New Posaconazole Tablet for Prevention of Invasive Fungal Infections in High-Risk Patients with Neutropenia

ABSTRACT Posaconazole tablets, a new oral formulation of posaconazole, can be effective when given as antifungal prophylaxis to neutropenic patients at high risk for invasive fungal infection (e.g., those with acute myelogenous leukemia or myelodysplastic syndrome). Such effectiveness might be specifically important to patients with poor oral intake because of nausea, vomiting, or chemotherapy-associated mucositis. This was a prospective, global study in high-risk patients to characterize the pharmacokinetics and safety profile of posaconazole tablets and to identify the dose of posaconazole tablets that would provide exposure within a predefined range of exposures (steady-state average concentration [area under the concentration-time curve/24 h] of ≥500 ng/ml and ≤2,500 ng/ml in >90% of patients). The study evaluated two sequential dosing cohorts: 200 mg posaconazole once daily (n = 20) and 300 mg posaconazole once daily (n = 34) (both cohorts had a twice-daily loading dose on day 1) taken without regard to food intake during the neutropenic period for ≤28 days. The exposure target was reached (day 8) in 15 of 19 (79%) pharmacokinetic-evaluable patients taking 200 mg posaconazole once daily and in 31 of 32 (97%) patients taking 300 mg posaconazole once daily; 300 mg posaconazole once daily achieved the desired exposure target. Posaconazole tablets were generally well tolerated in high-risk neutropenic patients. (This study has been registered at ClinicalTrials.gov under registration no. NCT01777763.)

Phase 3 pharmacokinetics and safety study of a posaconazole tablet formulation in patients at risk for invasive fungal disease

BACKGROUND Antifungal prophylaxis with a new oral tablet formulation of posaconazole may be beneficial to patients at high risk for invasive fungal disease. A two-part (Phase 1B/3) study evaluated posaconazole tablet pharmacokinetics (PK) and safety. METHODS Patients with neutropenia following chemotherapy for haematological malignancy or recipients of allogeneic HSCT receiving prophylaxis or treatment for graft-versus-host disease received 300 mg posaconazole (as tablets) once daily (twice daily on day 1) for up to 28 days without regard to food intake. Weekly trough PK sampling was performed during therapy, and a subset of patients had sampling on days 1 and 8. Cmin-evaluable subjects received ≥6 days of dosing, and were compliant with specified sampling timepoints. Steady-state PK parameters, safety, clinical failure and survival to day 65 were assessed. ClinicalTrials.gov, NCT01777763; EU Clinical Trials Register, EUDRA-CT 2008-006684-36. RESULTS Two hundred and ten patients received 300 mg posaconazole (as tablets) once daily. Among Cmin-evaluable subjects (n = 186), steady-state mean Cmin was 1720 ng/mL (range = 210-9140). Steady-state Cmin was ≥700 ng/mL in 90% of subjects with 5% (10 of 186) <500 ng/mL and 5% (10 of 186) 500-700 ng/mL. Six (3%) patients had steady-state Cmin ≥3750 ng/mL. One patient (<1%) had an invasive fungal infection. The most common treatment-related adverse events were nausea (11%) and diarrhoea (8%). There was no increase in adverse event frequency with higher posaconazole exposure. CONCLUSIONS In patients at high risk for invasive fungal disease, 300 mg posaconazole (as tablets) once daily was well tolerated and demonstrated a safety profile similar to that reported for posaconazole oral suspension: most patients (99%) achieved steady-state pCavg exposures >500 ng/mL and only one patient (<1%) had a pCavg <500 ng/mL.

Phase 1B Study of the Pharmacokinetics and Safety of Posaconazole Intravenous Solution in Patients at Risk for Invasive Fungal Disease

ABSTRACT This was a phase 1B, dose-ranging, multicenter, pharmacokinetics, and safety study of cyclodextrin-based posaconazole intravenous (i.v.) solution administered through a central line to subjects at high risk for invasive fungal disease (part 1 of a 2-part study [phase 1B/3]). Initially, the safety and tolerability of single-dose posaconazole i.v. 200 mg (n = 10) were compared with those of a placebo (n = 11). Subsequently, 2 doses were evaluated, posaconazole i.v. 200 mg once daily (q.d.) (n = 21) and 300 mg q.d. (n = 24). The subjects received twice-daily (b.i.d.) posaconazole i.v. on day 1, followed by 13 days of posaconazole i.v. q.d., then 14 days of posaconazole oral suspension 400 mg b.i.d. The steady-state (day 14) exposure target (average concentration [areas under concentration-time curve {AUCs}/24 h, average concentrations at steady state {Cavgs}], of ≥500 to ≤2,500 ng/ml in ≥90% of the subjects) was achieved by 94% of the subjects for 200 mg posaconazole q.d. and by 95% of subjects for 300 mg posaconazole q.d. The desired exposure target (mean steady-state Cavg, ∼1,200 ng/ml) was 1,180 ng/ml in the 200-mg dosing cohort and was exceeded in the 300-mg dosing cohort (1,430 ng/ml). Posaconazole i.v. was well tolerated. Posaconazole i.v. 300 mg q.d. was selected for the phase 3 study segment. (This study has been registered at ClinicalTrials.gov under registration no. NCT01075984.)

Pharmacokinetics and Safety Study of Posaconazole Intravenous Solution Administered Peripherally to Healthy Subjects

ABSTRACT This study evaluated the safety, tolerability, and pharmacokinetics of a posaconazole i.v. (intravenous) solution. This was a single-center, 2-part, randomized, rising single- and multiple-dose study in healthy adults. In part 1, subjects received 0 (vehicle), 50, 100, 200, 250, or 300 mg posaconazole in a single dose i.v. by 30-min peripheral infusion (6 cohorts of 12 subjects each [9 active and 3 placebo], making a total of 72 subjects). Blood samples were collected until 168 h postdose. In part 2, subjects were to receive 2 peripheral infusions at a 12-h interval on day 1 followed by once-daily infusion for 9 days. However, part 2 was terminated early because of high rates of infusion site reactions with multiple dosing at the same infusion site. The pharmacokinetics results for part 1 (n = 45 subjects) showed that the mean posaconazole exposure (area under the concentration-time curve from time zero to infinity [AUC0–∞]) ranged from 4,890 to 46,400 ng · h/ml (range of coefficient of variation values, 26 to 50). The dose-proportionality slope estimate (90% confidence interval) for AUC0–∞ was 1.30 (1.19 to 1.41), indicating a greater-than-dose-proportional increase. The data for safety in part 1 show that 29/72 subjects had ≥1 adverse event. Infusion site reactions were reported in 2/9 vehicle subjects, 0/18 placebo subjects, and 7/45 i.v. posaconazole subjects. The data for safety in part 2 show that infusion site reactions were reported in 1/4 (25%) placebo subjects, 3/9 (33%) vehicle control subjects, and 4/5 (80%) i.v. posaconazole (100 mg) subjects (3 posaconazole recipients subsequently developed thrombophlebitis and were discontinued from treatment). In conclusion, the posaconazole i.v. solution showed a greater-than-dose-proportional increase in exposure, primarily at doses below 200 mg. When administered peripherally at the same infusion site, multiple dosing of i.v. posaconazole led to unacceptably high rates of infusion site reactions. Intravenous posaconazole was otherwise well tolerated. Single doses of i.v. posaconazole were tolerated when given through a peripheral vein over 30 min.

Effect of a High-Fat Meal on the Pharmacokinetics of 300-Milligram Posaconazole in a Solid Oral Tablet Formulation

ABSTRACT Posaconazole in oral suspension must be taken multiple times a day with food (preferably a high-fat meal) to ensure adequate exposure among patients. We evaluated the effect of food on the bioavailability of a new delayed-release tablet formulation of posaconazole at the proposed clinical dose of 300 mg once daily in a randomized, open-label, single-dose, two-period crossover study with 18 healthy volunteers. When a single 300-mg dose of posaconazole in tablet form (3 tablets × 100 mg) was administered with a high-fat meal, the posaconazole area under the concentration-time curve from 0 to 72 h (AUC0–72) and maximum concentration in plasma (Cmax) increased 51% and 16%, respectively, compared to those after administration in the fasted state. The median time to Cmax (Tmax) shifted from 5 h in the fasted state to 6 h under fed conditions. No serious adverse events were reported, and no subject discontinued the study due to an adverse event. Six of the 18 subjects reported at least one clinical adverse event; all of these events were mild and short lasting. The results of this study demonstrate that a high-fat meal only modestly increases the mean posaconazole exposure (AUC), ∼1.5-fold, after administration of posaconazole tablets, in contrast to the 4-fold increase in AUC observed previously for a posaconazole oral suspension given with a high-fat meal.

Development of a PCR Assay to Detect Low Level Trypanosoma cruzi in Blood Specimens Collected with PAXgene Blood DNA Tubes for Clinical Trials Treating Chagas Disease

Chagas disease is caused by the parasitic infection of Trypanosoma cruzi (T. cruzi). The STOP CHAGAS clinical trial was initiated in 2011 to evaluate posaconazole in treating Chagas disease, with treatment success defined as negative qualitative PCR results of detecting the parasites in blood specimens collected post-treatment. PAXgene Blood DNA tubes were utilized as a simple procedure to collect and process blood specimens. However, the PAXgene blood specimens challenged published T. cruzi PCR methods, resulting in poor sensitivity and reproducibility. To accurately evaluate the treatment efficacy of the clinical study, we developed and validated a robust PCR assay for detecting low level T. cruzi in PAXgene blood specimens. The assay combines a new DNA extraction method with a custom designed qPCR assay, resulting in limit of detection of 0.005 and 0.01 fg/μl for K98 and CL Brener, two representative strains of two of T. cruzi’s discrete typing units. Reliable qPCR standard curves were established for both strains to measure parasite loads, with amplification efficiency ≥ 90% and the lower limit of linearity ≥ 0.05 fg/μl. The assay successfully analyzed the samples collected from the STOP CHAGAS study and may prove useful for future global clinical trials evaluating new therapies for asymptomatic chronic Chagas disease.

Pharmacokinetics and safety results from the Phase 3 randomized, open-label, study of intravenous posaconazole in patients at risk of invasive fungal disease

Objectives A two-part (Phase 1B/3), sequential, open-label, multicentre study evaluated the pharmacokinetics (PK) and safety of intravenous (iv) posaconazole given as antifungal prophylaxis to neutropenic patients with AML or myelodysplastic syndrome (MDS) or to recipients at risk of invasive fungal disease (IFD) after allogeneic HSCT. Methods Patients (N = 237) received 300 mg of posaconazole iv twice daily on day 1, followed by 300 mg of posaconazole iv once daily for 4-28 days. After at least 5 days, patients were randomly assigned to receive posaconazole oral suspension, 400 mg twice daily or 200 mg three times daily, to complete a 28 day treatment course. Primary PK parameters were steady-state average concentration over the dosing interval (Cavg) and posaconazole trough levels (Cmin). Results Mean posaconazole Cmin was 1320 ng/mL (day 6) and 1297 ng/mL (day 8); steady-state Cmin was 1090 ng/mL (day 10). Mean steady-state posaconazole Cavg was 1500 ng/mL (day 10 or 14) and was similar in HSCT recipients (1560 ng/mL) and AML/MDS patients (1470 ng/mL). The most commonly reported treatment-related adverse events were diarrhoea (8%), nausea (5%) and rash (5%). IFD was reported in 3/237 patients (1%; 2 proven, 1 probable). Conclusions Intravenous posaconazole at 300 mg was well tolerated, resulted in adequate steady-state systemic exposure and was associated with a low incidence of IFD in this population at high risk. Trial registry and number ClinicalTrials.gov, NCT01075984.