Get your patient on Posaconazole - Posaconazole tablet, Delayed Release (Posaconazole)

Posaconazole delayed-release tablets are indicated for the prophylaxis of invasive Aspergillus and Candida infections in patients who are at high risk of developing these infections due to being severely immunocompromised, such as hematopoietic stem cell transplant (HSCT) recipients with graft-versus-host disease (GVHD) or those with hematologic malignancies with prolonged neutropenia from chemotherapy as follows:

Posaconazole delayed-release tablets: adults and pediatric patients 2 years of age and older who weigh greater than 40 kg.

Non-substitutable

Noxafil ^® oral suspension is not substitutable with posaconazole delayed-release tablets or Noxafil ^® powdermix for delayed-release oral suspension due to the differences in the dosing of each formulation. Therefore, follow the specific dosage recommendations for each of the formulations [see Dosage and Administration (2.2 , 2.3 ).

Posaconazole delayed-release tablets

• Swallow tablets whole. Do not divide, crush, or chew.
• Administer with or without food [see Dosage and Administration (2.7 ) and Clinical Pharmacology (12.3 )] .
• For patients who cannot eat a full meal, Posaconazole delayed-release tablets should be used instead of Noxafil ^® oral suspension for the prophylaxis indication. Posaconazole delayed-release tablets generally provide higher plasma drug exposures than Noxafil ^® oral suspension under both fed and fasted conditions.

The recommended dosage of Posaconazole delayed-release tablets in adult patients for the prophylaxis of invasive Aspergillus and Candida infections in patients who are at high risk of developing these infections due to being severely immunocompromised is shown in Table 1 [see Dosage and Administration (2.7 , 2.9 ) and Clinical Pharmacology (12.3 )] .

The recommended dosage of Posaconazole delayed-release tablets in pediatric patients 2 years of age and older who weigh greater than 40 kg for the prophylaxis of invasive Aspergillus and Candida infections is shown in Table 2 [see Dosage and Administration (2.7 ) and Clinical Pharmacology (12.3 )].

Posaconazole delayed-release tablets are not recommended for use in pediatric patients who weigh 40 kg or less because the recommended dosage cannot be achieved with this dosage form.

• Swallow the posaconazole delayed-release tablets whole. Do not divide, crush, or chew.
• Administer posaconazole delayed-release tablets orally with or without food. [see Clinical Pharmacology (12.3 )].

Posaconazole oral suspension is not substitutable with posaconazole delayed-release tablets or posaconazole powdermix for delayed-release oral suspension due to the differences in the dosing of each formulation. Therefore, follow the specific dosage recommendations for each of the formulations [see Dosage and Administration (2.2 , 2.3 )] .

The recommended dosage of posaconazole delayed-release tablets is the same in patients with renal impairment compared to those with normal renal function.

Risk Summary

Based on findings from animal data, posaconazole may cause fetal harm when administered to pregnant women. Available data for use of posaconazole in pregnant women are insufficient to establish a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. In animal reproduction studies, skeletal malformations were observed when posaconazole was dosed orally to pregnant rats during organogenesis at doses ≥1.4 times the 400 mg twice daily oral suspension regimen based on steady-state plasma concentrations of posaconazole in healthy volunteers. In pregnant rabbits dosed orally during organogenesis, (see Data) . Based on animal data, advise pregnant women of the potential risk to a fetus.

The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.

Data

Animal Data

Posaconazole resulted in maternal toxicity (reduced food consumption and reduced body weight gain) and skeletal malformations (cranial malformations and missing ribs) when given orally to pregnant rats during organogenesis (Gestational Days 6 through 15) at doses ≥27 mg/kg (≥1.4 times the 400 mg twice daily oral suspension regimen based on steady-state plasma concentrations of drug in healthy  volunteers). The no-effect dose for malformations and maternal toxicity in rats was 9 mg/kg, which is 0.7 times the exposure achieved with the 400 mg twice daily oral suspension regimen. No malformations were seen in rabbits dosed during organogenesis (Gestational Days 7 through 19) at doses up to 80 mg/kg (5 times the exposure achieved with the 400 mg twice daily oral suspension regimen). In the rabbit, the no-effect dose was 20 mg/kg, while high doses of 40 mg/kg and 80 mg/kg (3 or 5 times the clinical exposure) caused an increase in resorptions. In rabbits dosed at 80 mg/kg, a reduction in body weight gain of females and a reduction in litter size were seen.

Risk Summary

There are no data on the presence of posaconazole in human milk, the effects on the breastfed infant, or the effects on milk production. Posaconazole is excreted in the milk of lactating rats. When a drug is present in animal milk, it is likely that the drug will be present in human milk. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for posaconazole and any potential adverse effects on the breastfed child from posaconazole or from the underlying maternal condition.

Prophylaxis of Invasive Aspergillus and Candida Infections

The safety and effectiveness of posaconazole delayed-release tablets have been established for the prophylaxis of invasive Aspergillus and Candida infections in pediatric patients 2 years of age and older who are at high risk of developing these infections due to being severely immunocompromised.

Use of posaconazole for these pediatric indications is supported by adequate and well controlled studies of posaconazole in adults and pediatric patients aged 13 years of age and older and additional PK and safety data in pediatric patients 2 years of age and older [see Clinical Pharmacology (12.3 ) and Clinical studies (14 )] .

The safety and effectiveness of posaconazole have not been established in pediatric patients less than 2 years of age.

No overall differences in the safety or effectiveness of posaconazole delayed-release tablets have been observed between geriatric patients and younger adult patients in the clinical trials; therefore, the recommended dosage in geriatric patients is the same as that for younger adult patients. No clinically meaningful differences in posaconazole pharmacokinetics were observed in posaconazole-treated geriatric patients compared to posaconazole-treated younger adult patients during clinical trials [see Clinical Pharmacology (12.3 )] .

• Of the 230 patients treated with posaconazole delayed-release tablets, 38 (17%) patients were >65 years of age.

Posaconazole Delayed-Release Tablets

No dosage adjustment is required for patients with eGFR 20 mL/minute/1.73 m ² or higher. Due to variability in posaconazole exposure, closely monitor patients with eGFR less than 20 mL/minute/1.73 m ² for breakthrough fungal infections [see Clinical Pharmacology (12.3 )] .

No dosage adjustment is recommended for posaconazole delayed-release tablets in patients with mild, moderate, or severe hepatic impairment (Child-Pugh Class A, B, or C, respectively) [see Clinical Pharmacology (12.3 )] .

However, a specific hepatic impairment study has not been conducted with posaconazole delayed-release tablets.

No adjustment in the dosage of posaconazole is necessary based on sex.

No adjustment in the dosage of posaconazole is necessary based on race.

Pharmacokinetic modeling suggests that patients who weigh greater than 120 kg may have lower posaconazole plasma drug exposure. Therefore, consider closely monitoring for breakthrough fungal infections [see Clinical Pharmacology (12.3 )] .

Posaconazole is contraindicated in persons with known hypersensitivity to posaconazole or other azole antifungal agents.

Posaconazole is contraindicated with sirolimus. Concomitant administration of posaconazole with sirolimus increases the sirolimus blood concentrations by approximately 9-fold and can result in sirolimus toxicity [see Drug Interactions (7.2 ) and Clinical Pharmacology (12.3 )] .

Posaconazole is contraindicated with CYP3A4 substrates that prolong the QT interval. Concomitant administration of posaconazole with the CYP3A4 substrates, pimozide and quinidine may result in increased plasma concentrations of these drugs, leading to QTc prolongation and cases of torsades de pointes [see Warnings and Precautions (5.2 ) and Drug Interactions (7.2 )] .

Coadministration with the HMG-CoA reductase inhibitors that are primarily metabolized through CYP3A4 (e.g., atorvastatin, lovastatin, and simvastatin) is contraindicated since increased plasma concentration of these drugs can lead to rhabdomyolysis [see Drug Interactions (7.2 ) and Clinical Pharmacology (12.3 )] .

Posaconazole may increase the plasma concentrations of ergot alkaloids (ergotamine and dihydroergotamine) which may lead to ergotism [see Drug Interactions (7.2 )] .

Coadministration of Posaconazole with venetoclax at initiation and during the ramp-up phase is contraindicated in patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) due to the potential for increased risk of tumor lysis syndrome [see Warnings and Precautions (5.11 ) and Drug Interactions (7.2 ).

Concomitant administration of posaconazole with cyclosporine or tacrolimus increases the whole blood trough concentrations of these calcineurin-inhibitors [see Drug Interactions (7.2 ) and Clinical Pharmacology (12.3 )] . Nephrotoxicity and leukoencephalopathy (including deaths) have been reported in clinical efficacy studies in patients with elevated cyclosporine or tacrolimus concentrations. Frequent monitoring of tacrolimus or cyclosporine whole blood trough concentrations should be performed during and at discontinuation of posaconazole treatment and the tacrolimus or cyclosporine dose adjusted accordingly.

Some azoles, including posaconazole, have been associated with prolongation of the QT interval on the electrocardiogram. In addition, cases of torsades de pointes have been reported in patients taking posaconazole.

Results from a multiple time-matched ECG analysis in healthy volunteers did not show any increase in the mean of the QTc interval. Multiple, time-matched ECGs collected over a 12-hour period were recorded at baseline and steady-state from 173 healthy male and female volunteers (18-85 years of age) administered posaconazole oral suspension 400 mg twice daily with a high-fat meal. In this pooled analysis, the mean QTc (Fridericia) interval change from baseline was –5 msec following administration of the recommended clinical dose. A decrease in the QTc(F) interval (–3 msec) was also observed in a small number of subjects (n=16) administered placebo. The placebo-adjusted mean maximum QTc(F) interval change from baseline was <0 msec (–8 msec). No healthy subject administered posaconazole had a QTc(F) interval ≥500 msec or an increase ≥60 msec in their QTc(F) interval from baseline.

Posaconazole should be administered with caution to patients with potentially proarrhythmic conditions. Do not administer with drugs that are known to prolong the QTc interval and are metabolized through CYP3A4 [see Contraindications (4.3 ) and Drug Interactions (7.2 )] .

Electrolyte disturbances, especially those involving potassium, magnesium or calcium levels, should be monitored and corrected as necessary before and during posaconazole therapy.

Pseudoaldosteronism, manifested by the onset of hypertension or worsening of hypertension, and abnormal laboratory findings (hypokalemia, low serum renin and aldosterone, and elevated 11-deoxycortisol), has been reported with posaconazole use in the postmarket setting. Monitor blood pressure and potassium levels and manage as necessary. Management of pseudoaldosteronism may include discontinuation of posaconazole treatment, substitution with an appropriate antifungal drug that is not associated with pseudoaldosteronism, or use of aldosterone receptor antagonists.

Hepatic reactions (e.g., mild to moderate elevations in alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, total bilirubin, and/or clinical hepatitis) have been reported in clinical trials. The elevations in liver tests were generally reversible on discontinuation of therapy, and in some instances these tests normalized without drug interruption. Cases of more severe hepatic reactions including cholestasis or hepatic failure including deaths have been reported in patients with serious underlying medical conditions (e.g., hematologic malignancy) during treatment with posaconazole. These severe hepatic reactions were seen primarily in subjects receiving the posaconazole oral suspension 800 mg daily (400 mg twice daily or 200 mg four times a day) in clinical trials.

Liver tests should be evaluated at the start of and during the course of posaconazole therapy. Patients who develop abnormal liver tests during posaconazole therapy should be monitored for the development of more severe hepatic injury. Patient management should include laboratory evaluation of hepatic function (particularly liver tests and bilirubin). Discontinuation of posaconazole must be considered if clinical signs and symptoms consistent with liver disease develop that may be attributable to posaconazole.

Due to the variability in exposure with Posaconazole delayed-release tablets, patients with severe renal impairment should be monitored closely for breakthrough fungal infections [see Dosage and Administration (2.11 ) and Use in Specific Populations (8.6 )].

Concomitant administration of posaconazole with midazolam increases the midazolam plasma concentrations by approximately 5-fold. Increased plasma midazolam concentrations could potentiate and prolong hypnotic and sedative effects. Patients must be monitored closely for adverse effects associated with high plasma concentrations of midazolam and benzodiazepine receptor antagonists must be available to reverse these effects [see Drug Interactions (7.2 ) and Clinical Pharmacology (12.3 )] .

Concomitant administration of azole antifungals, including posaconazole, with vincristine has been associated with neurotoxicity and other serious adverse reactions, including seizures, peripheral neuropathy, syndrome of inappropriate antidiuretic hormone secretion, and paralytic ileus. Reserve azole antifungals, including posaconazole, for patients receiving a vinca alkaloid, including vincristine, who have no alternative antifungal treatment options [see Drug Interactions (7.2 )].

Patients who have severe diarrhea or vomiting should be monitored closely for breakthrough fungal infections when receiving posaconazole delayed-release tablets.

Concomitant administration of posaconazole, a strong CYP3A4 inhibitor, with venetoclax may increase venetoclax toxicities, including the risk of tumor lysis syndrome (TLS), neutropenia, and serious infections. In patients with CLL/SLL, administration of posaconazole during initiation and the ramp-up phase of venetoclax is contraindicated [see Contraindications (4.6 )] . Refer to the venetoclax labeling for safety monitoring and dose reduction in the steady daily dosing phase in CLL/SLL patients.

For patients with acute myeloid leukemia (AML), dose reduction and safety monitoring are recommended across all dosing phases when coadministering posaconazole with venetoclax [see Drug Interactions (7.2 )] . Refer to the venetoclax prescribing information for dosing instructions.

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in clinical trials of posaconazole cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Clinical Trial Experience with Posaconazole Delayed-Release Tablets for Prophylaxis of Invasive Aspergillus and Candida Infections

The safety of posaconazole delayed-release tablets has been assessed in 230 patients in clinical trials. Patients were enrolled in a non-comparative pharmacokinetic and safety trial of posaconazole delayed-release tablets when given as antifungal prophylaxis (Posaconazole Delayed-Release Tablet Study). Patients were immunocompromised with underlying conditions including hematological malignancy, neutropenia post-chemotherapy, GVHD, and post HSCT. This patient population was 62% male, had a mean age of 51 years (range 19-78 years, 17% of patients were ≥65 years of age), and were 93% White and 16% Hispanic. Posaconazole therapy was given for a median duration of 28 days . In this study, 20 adult patients received 200 mg daily dosage (this is not a recommended dosage [see Dosage and Administration (2.2 )] ) and 210 adult patients received 300 mg daily dosage (following twice daily dosing on Day 1 in each cohort). Table 9 presents adverse reactions (incidence of ≥10%) observed in patients treated with posaconazole delayed-release tablets 300 mg daily dosage in the Posaconazole Delayed-Release Tablet Study.

The most frequently reported adverse reactions (>25%) in patients treated with posaconazole delayed-release tablets 300 mg once daily were diarrhea, pyrexia, and nausea. The most common adverse reaction leading to discontinuation of posaconazole delayed-release tablets 300 mg once daily was nausea (2%).

The following adverse reaction has been identified during the post-approval use of posaconazole. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Endocrine Disorders: Pseudoaldosteronism

Posaconazole is primarily metabolized via UDP-glucuronosyltransferase and is a substrate of p-glycoprotein (P-gp) efflux. Therefore, inhibitors or inducers of these clearance pathways may affect posaconazole plasma concentrations. Concomitant use of posaconazole with drugs that can decrease the plasma posaconazole concentrations should generally be avoided unless the benefit outweighs the risk. If such drugs are necessary, patients should be monitored closely for breakthrough fungal infections.

Posaconazole is a strong CYP3A4 inhibitor. Therefore, concomitant use of posaconazole may increase plasma concentrations of drugs that are CYP3A4 substrates [see Clinical Pharmacology (12.3)] .

Additional clinical studies demonstrated that no clinically important effects on zidovudine, lamivudine, indinavir, or caffeine were observed when administered with posaconazole 200 mg once daily; therefore, no dose adjustments are required for these drugs when coadministered with posaconazole 200 mg once daily.

No clinically relevant effects on the pharmacokinetics of posaconazole delayed-release tablets were observed during concomitant use with antacids, H2-receptor antagonists and proton pump inhibitors, and metoclopramide [see Clinical Pharmacology (12.3 )] . No dosage adjustment of posaconazole delayed-release tablets is required during concomitant use with these drugs.

Posaconazole is an azole antifungal agent [see Clinical Pharmacology (12.4 )] .

Exposure Response Relationship: Prophylaxis of invasive Aspergillus and Candida Infections in Adults Who Are at High Risk of Developing These Infections Due to Being Severely Immunocompromised

In clinical studies of neutropenic patients who were receiving cytotoxic chemotherapy for acute myelogenous leukemia (AML) or myelodysplastic syndromes (MDS) or hematopoietic stem cell transplant (HSCT) recipients with Graft versus Host Disease (GVHD), a wide range of plasma posaconazole exposures was noted following administration of posaconazole oral suspension. A pharmacokinetic-pharmacodynamic analysis of patient data revealed an apparent association between average posaconazole concentrations (Cavg) and prophylactic efficacy (Table 18).  A lower Cavg may be associated with an increased risk of treatment failure, defined as treatment discontinuation, use of empiric systemic antifungal therapy (SAF), or occurrence of breakthrough invasive fungal infections.

General Pharmacokinetic Characteristics

Posaconazole delayed-release tablets exhibit dose proportional pharmacokinetics after single and multiple dosing up to 300 mg. The mean pharmacokinetic parameters of posaconazole at steady state following administration of posaconazole delayed-release tablets 300 mg twice daily on Day 1, then 300 mg once daily thereafter in healthy volunteers and in neutropenic patients who are receiving cytotoxic chemotherapy for AML or MDS or HSCT recipients with GVHD are shown in Table 21 .

Absorption:

When given orally in healthy volunteers, posaconazole delayed-release tablets are absorbed with a median T _max of 4 to 5 hours. Steady-state plasma concentrations are attained by Day 6 at the 300 mg dose (once daily after twice daily loading dose at Day 1). The absolute bioavailability of the oral delayed-release tablet is approximately 54% under fasted conditions. The Cmax and AUC of posaconazole following administration of posaconazole delayed-release tablets are increased 16% and 51%, respectively, when given with a high fat meal compared to a fasted state (see Table 23 ).

Distribution:

Posaconazole is highly bound to human plasma proteins (>98%), predominantly to albumin.

Metabolism:

Posaconazole primarily circulates as the parent compound in plasma. Of the circulating metabolites, the majority are glucuronide conjugates formed via UDP glucuronidation (phase 2 enzymes). Posaconazole does not have any major circulating oxidative (CYP450 mediated) metabolites. The excreted metabolites in urine and feces account for ~17% of the administered radiolabeled dose.

Posaconazole is a substrate for p-glycoprotein (P-gp) efflux.

In vitro studies with human hepatic microsomes and clinical studies indicate that posaconazole is an inhibitor primarily of CYP3A4.

Distribution:

Posaconazole is highly bound to human plasma proteins (>98%), predominantly to albumin.

Metabolism:

Posaconazole primarily circulates as the parent compound in plasma. Of the circulating metabolites, the majority are glucuronide conjugates formed via UDP glucuronidation (phase 2 enzymes). Posaconazole does not have any major circulating oxidative (CYP450 mediated) metabolites. The excreted metabolites in urine and feces account for ~17% of the administered radiolabeled dose. Posaconazole is a substrate for p-glycoprotein (P-gp) efflux.

In vitro studies with human hepatic microsomes and clinical studies indicate that posaconazole is an inhibitor primarily of CYP3A4.

Excretion:

Following administration of Noxafil® oral suspension, posaconazole is predominantly eliminated in the feces (71% of the radiolabeled dose up to 120 hours) with the major component eliminated as parent drug (66% of the radiolabeled dose). Renal clearance is a minor elimination pathway, with 13% of the radiolabeled dose excreted in urine up to 120 hours (<0.2% of the radiolabeled dose is parent drug).

Posaconazole delayed-release tablet is eliminated with a mean half-life (t½) ranging between 26 to 31 hours.

Specific Populations:

No clinically significant differences in the pharmacokinetics of posaconazole were observed based on age, sex, renal impairment, and indication (prophylaxis).

Patients with Renal Impairment:

After posaconazole oral administration, there were no significant differences in the posaconazole pharmacokinetics in patients with eGFR 20 mL/minute/1.73 m ² or higher compared to those with eGFR>80 mL/minute/1.73 m ² . Although the mean posaconazole plasma exposure (AUC) was similar in patients with eGFR less than 20 mL/minute/1.73 m ² treated with Noxafil® oral suspension to those with eGFR >80 mL/minute/1.73 m ² treated with Noxafil® oral suspension, the range of the AUC estimates was highly variable (CV=96%) in patients with eGFR less than 20 mL/minute/1.73 m ² compared to those with eGFR>80 mL/minute/1.73 m2 (CV<40%). Similar posaconazole pharmacokinetic results are expected after administration of posaconazole delayed-release tablets [see Use in Specific Populations (8.6 )] .

Patients with Hepatic Impairment:

After a single oral dose of Noxafil® oral suspension 400 mg, the mean AUC was 43%, 27%, and 21% higher in subjects with mild (Child-Pugh Class A, N=6), moderate (Child-Pugh Class B, N=6), or severe (Child-Pugh Class C, N=6) hepatic impairment, respectively, compared to subjects with normal hepatic function (N=18). Compared to subjects with normal hepatic function, the mean C _max was 1% higher, 40% higher, and 34% lower in subjects with mild, moderate, or severe hepatic impairment, respectively [see Use in Specific Populations (8.7 )] .

Race/Ethnicity:

In a population pharmacokinetic analysis of posaconazole, AUC was found to be 25% higher in Chinese patients relative to patients from other races/ethnicities. This higher exposure is not expected to be clinically relevant given the expected variability in posaconazole exposure [see Use in Specific Populations (8.9 )] .

Patients Weighing More Than 120 kg:

Weight has a clinically significant effect on posaconazole clearance. Relative to 70 kg patients, the Cavg is decreased by 25% in patients greater than 120 kg. Patients administered posaconazole weighing more than 120 kg may be at higher risk for lower posaconazole plasma concentrations compared to lower weight patients [see Use in Specific Populations (8.10 )] .

Pediatric Patients:

A total of 12 patients 13 to 17 years of age received 600 mg/day (200 mg three times a day) of Noxafil® oral suspension for prophylaxis of invasive fungal infections. Based on pharmacokinetic data in 10 of these pediatric patients, the mean steady-state Cav was similar between these patients and adults (≥18 years of age). In a study of 136 neutropenic pediatric patients 11 months to less than 18 years treated with Noxafil® oral suspension, the exposure target of steady-state posaconazole Cavg between 500 ng/mL and less than 2500 ng/mL was attained in approximately 50% of patients instead of the pre-specified 90% of patients.

Drug Interaction Studies:

Posaconazole is primarily metabolized via UDP glucuronidation (phase 2 enzymes) and is a substrate for p-glycoprotein (P-gp) efflux. Therefore, inhibitors or inducers of these clearance pathways may affect posaconazole plasma concentrations. A summary of drugs studied clinically with the oral suspension or another tablet formulation, which affect posaconazole concentrations, is provided in Table 28.

Table 30 include a summary of the drug effects of concomitant medications that may impact the absorption of posaconazole when administered as either the oral suspension or delayed-release tablets.

A clinical study in healthy volunteers also indicates that posaconazole is a strong CYP3A4 inhibitor as evidenced by a >5-fold increase in midazolam AUC. Therefore, plasma concentrations of drugs predominantly metabolized by CYP3A4 may be increased by posaconazole. A summary of the drugs studied clinically, for which plasma concentrations were affected by posaconazole, is provided in Table 31 [see Contraindications (4 ) and Drug Interactions (7.2 ) including recommendations] .

Effects of Other Drugs on Posaconazole

Posaconazole Delayed-Release Tablets: Concomitant administration of posaconazole delayed-release tablets with drugs affecting gastric pH or gastric motility did not demonstrate any significant effects on posaconazole pharmacokinetic exposure (see Table 30 ).

Effects of Posaconazole on Other Drugs:

Mechanism of Action

Posaconazole blocks the synthesis of ergosterol, a key component of the fungal cell membrane, through the inhibition of cytochrome P-450 dependent enzyme lanosterol 14α-demethylase responsible for the conversion of lanosterol to ergosterol in the fungal cell membrane. This results in an accumulation of methylated sterol precursors and a depletion of ergosterol within the cell membrane thus weakening the structure and function of the fungal cell membrane. This may be responsible for the antifungal activity of posaconazole.

Resistance

Clinical isolates of Candida albicans and Candida glabrata with decreased susceptibility to posaconazole were observed in oral swish samples taken during prophylaxis with posaconazole and fluconazole, suggesting a potential for development of resistance. These isolates also showed reduced susceptibility to other azoles, suggesting cross-resistance between azoles. The clinical significance of this finding is not known.

Antimicrobial Activity

Posaconazole has been shown to be active against most isolates of the following microorganisms, both in vitro and in clinical infections [see Indications and Usage (1 )] .

Microorganisms

Aspergillus spp. and Candida spp.

Susceptibility Testing

For specific information regarding susceptibility test interpretive criteria and associated test methods and quality control standards recognized by FDA for this drug, please see:

https://www.fda.gov/STIC.

Carcinogenesis

No drug-related neoplasms were recorded in rats or mice treated with posaconazole for 2 years at doses higher than the clinical dose. In a 2 year carcinogenicity study, rats were given posaconazole orally at doses up to 20 mg/kg (females), or 30 mg/kg (males). These doses are equivalent to 3.9- or 3.5 times the exposure achieved with a 400 mg twice daily oral suspension regimen, respectively, based on steady-state AUC in healthy volunteers administered a high-fat meal (400 mg twice daily oral suspension regimen). In the mouse study, mice were treated at oral doses up to 60 mg/kg/day or 4.8 times the exposure achieved with a 400 mg twice daily oral suspension regimen.

Mutagenesis

Posaconazole was not genotoxic or clastogenic when evaluated in bacterial mutagenicity (Ames), a chromosome aberration study in human peripheral blood lymphocytes, a Chinese hamster ovary cell mutagenicity study, and a mouse bone marrow micronucleus study.

Impairment of Fertility

Posaconazole had no effect on fertility of male rats at a dose up to 180 mg/kg (1.7 x the 400 mg twice daily oral suspension regimen based on steady-state plasma concentrations in healthy volunteers) or female rats at a dose up to 45 mg/kg (2.2 x the 400 mg twice daily oral suspension regimen).

Two randomized, controlled studies were conducted using posaconazole as prophylaxis for the prevention of invasive fungal infections (IFIs) among patients at high risk due to severely compromised immune systems.

The first study (Noxafil ^® Oral Suspension Study 1) was a randomized, double-blind trial that compared Noxafil ^® oral suspension (200 mg three times a day) with fluconazole capsules (400 mg once daily) as prophylaxis against invasive fungal infections in allogeneic hematopoietic stem cell transplant (HSCT) recipients with Graft versus Host Disease (GVHD). Efficacy of prophylaxis was evaluated using a composite endpoint of proven/probable IFIs, death, or treatment with systemic antifungal therapy (patients may have met more than one of these criteria). This assessed all patients while on study therapy plus 7 days and at 16 weeks post-randomization. The mean duration of therapy was comparable between the 2 treatment groups (80 days, posaconazole; 77 days, fluconazole). Table 34 contains the results from Noxafil ^® Oral Suspension Study 1.

The second study (Noxafil ^® Oral Suspension Study 2) was a randomized, open-label study that compared Noxafil ^® oral suspension (200 mg 3 times a day) with fluconazole suspension (400 mg once daily) or itraconazole oral solution (200 mg twice a day) as prophylaxis against IFIs in neutropenic patients who were receiving cytotoxic chemotherapy for AML or MDS. As in Noxafil ^® Oral Suspension Study 1, efficacy of prophylaxis was evaluated using a composite endpoint of proven/probable IFIs, death, or treatment with systemic antifungal therapy (Patients might have met more than one of these criteria). This study assessed patients while on treatment plus 7 days and 100 days postrandomization. The mean duration of therapy was comparable between the 2 treatment groups (29 days, posaconazole; 25 days, fluconazole or itraconazole). Table 35 contains the results from Noxafil ^® Oral Suspension Study 2.

In summary, 2 clinical studies of prophylaxis were conducted with the Noxafil ^® oral suspension. As seen in the accompanying tables ( Tables 34 and 35 ), clinical failure represented a composite endpoint of breakthrough IFI, mortality and use of systemic antifungal therapy. In Noxafil ^® Oral Suspension Study 1 ( Table 34 ), the clinical failure rate of posaconazole (33%) was similar to fluconazole (37%), (95% CI for the difference posaconazole–comparator -11.5% to 3.7%) while in Noxafil ^® Oral Suspension Study 2 ( Table 35 ) clinical failure was lower for patients treated with posaconazole (27%) when compared to patients treated with fluconazole or itraconazole (42%), (95% CI for the difference posaconazole–comparator -22.9% to -7.8%).

All-cause mortality was similar at 16 weeks for both treatment arms in Noxafil ^® Oral Suspension Study 1 [POS 58/301 (19%) vs. FLU 59/299 (20%)]; all-cause mortality was lower at 100 days for posaconazole-treated patients in Noxafil ^® Oral Suspension Study 2 [POS 44/304 (14%) vs. FLU/ITZ 64/298 (21%)]. Both studies demonstrated fewer breakthrough infections caused by Aspergillus species in patients receiving posaconazole prophylaxis when compared to patients receiving fluconazole or itraconazole.

Posaconazole delayed-release tablets are yellow-coated, capsule shaped tablets, debossed with "100P" on one side and plain on the other side containing 100 mg of posaconazole. Bottles with child-resistant closures of 60 delayed-release tablets (NDC 70748-258-07).

Store at 20 to 25°C (68 to 77°F), excursions permitted to 15 to 30°C (59 to 86°F) [see USP Controlled Room Temperature].