Pharmacokinetics
Absorption
Posaconazole is absorbed with a median Tmax of ~3 to 5 hours. Dose proportional increases in plasma exposure (AUC) to posaconazole were observed following single oral doses from 50 mg to 800 mg and following multiple-dose administration from 50 mg BID to 400 mg BID. No further increases in exposure were observed when the dose was increased from 400 mg BID to 600 mg BID in febrile neutropenic patients or those with refractory invasive fungal infections. Steady-state plasma concentrations are attained at 7 to 10 days following multiple-dose administration.
Following single-dose administration of 200 mg, the mean AUC and Cmax of posaconazole
are approximately 3 times higher when administered with a nonfat meal and approximately
4 times higher when administered with a high-fat meal (~50 gm fat) relative
to the fasted state. Following single-dose administration of 400 mg, the mean
AUC and Cmax of posaconazole are approximately 3 times higher when administered
with a liquid nutritional supplement (14 gm fat) relative to the fasted state
(see Table 1). In order to assure attainment of adequate plasma concentrations,
it is recommended to administer posaconazole with food or a nutritional supplement
(see DOSAGE AND ADMINISTRATION).
TABLE 1: The Mean (%CV) [min-max] Posaconazole Pharmacokinetic
Parameters Following Single-Dose Suspension Administration of 200 mg and 400
mg Under Fed and Fasted Conditions
| Dose (mg) |
Cmax
(ng/mL) |
Tmaxa
(hr) |
AUC (I)
(ng·hr/mL) |
CL/F
(L/hr) |
t½
(hr) |
200 mg fasted
(n=20)c |
132 (50)
[45-267] |
3.50
[1.5-36b] |
4179 (31)
[2705-7269] |
51 (25)
[28-74] |
23.5 (25)
[15.3-33.7] |
200 mg nonfat
(n=20)c |
378 (43)
[131-834] |
4 [3-5] |
10,753 (35)
[4579-17,092] |
21 (39)
[12-44] |
22.2 (18)
[17.4-28.7] |
200 mg high-fat
(54 gm fat)
(n=20)c |
512 (34)
[241-1016] |
5 [4-5] |
15,059 (26)
[10,341-24,476] |
14 (24)
[8.2-19] |
23.0 (19)
[17.2-33.4] |
400 mg fasted
(n=23)d |
121 (75)
[27-366] |
4 [2-12] |
5258 (48)
[2834-9567] |
91 (40)
[42-141] |
27.3 (26)
[16.8-38.9] |
400 mg with liquid nutritional supplement
(14 gm fat)
(n=23)d |
355 (43)
[145-720] |
5 [4-8] |
11,295 (40)
[3865-20,592] |
43 (56)
[19-103] |
26.0 (19)
[18.2-35.0] |
a Median [min-max]
b The subject with Tmax of 36 hrs had relatively constant plasma
levels over 36 hrs (1.7 ng/mL difference between 4 hrs and 36 hrs)
c n=15 for AUC (I), CL/F and t1/2
d n=10 for AUC (I), CL/F and t1/2 |
In 12 healthy volunteers who received a single 400 mg dose of NOXAFIL Oral
Suspension in the fasted state, 5 minutes before, during, and 20 minutes after
a high-fat meal in a 4-way crossover design, the coadministration of NOXAFIL
with a high fat meal significantly increased the extent of absorption of posaconazole
compared to in the fasted state. However, the magnitude of the food effect varied
with timing of the meals. When NOXAFIL was administered during a high-fat meal,
the mean Cmax and AUC increased by 339% and 382% compared to in the fasted state,
respectively. When NOXAFIL was administered 20 minutes after a high-fat meal,
the mean Cmax and AUC also increased by 333% and 387% compared to in the fasted
state, respectively. When NOXAFIL was administered 5 minutes before a high-fat
meal, the mean Cmax and AUC increased by 96% and 111% compared to in the fasted
state, respectively (See DOSAGE AND ADMINISTRATION).
In 12 healthy volunteers who received 400 mg BID and 200 mg QID of NOXAFIL Oral Suspension for 7 days in the fasted state and with liquid nutritional supplement (BOOST® Drink) in a 4-way crossover design, the administration of NOXAFIL 400 mg BID with BOOST increased the mean Cmax and AUC by 65% and 66%, respectively, compared to NOXAFIL 400 mg BID in the fasted state. However, when NOXAFIL 200 mg QID was administered with BOOST, the mean Cmax and AUC were not affected compared to NOXAFIL 200 mg QID in the fasted state.
In 12 healthy volunteers who received 400 mg BID and 200 mg QID of NOXAFIL
Oral Suspension for 7 days in the fasted state and with liquid nutritional supplement
(BOOST Drink) in a 4-way crossover design, the absorption of posaconazole was
significantly increased when NOXAFIL was administered by dividing the total
daily dose from 400 mg BID to 200 mg QID regardless of under fasted conditions
or with liquid nutritional supplement. In the fasted state, the mean Cmax and
AUC increased by 136% and 161%, respectively, when NOXAFIL was administered
as 200 mg QID compared to 400 mg BID. When NOXAFIL was administered as 200 mg
QID with BOOST, the mean Cmax and AUC increased by 44% and 54%, respectively,
compared to 400 mg BID with BOOST.
In 12 healthy volunteers who received a single 400 mg dose of NOXAFIL Oral
Suspension alone, or with ginger ale, or with esomeprazole, or both ginger ale
and esomeprazole in the fasted state in a 4-way crossover design, the coadministration
of NOXAFIL with ginger ale (carbonated acidic beverage) increased the mean Cmax
and AUC by 92% and 70% compared to NOXAFIL alone, respectively. The coadministration
of NOXAFIL with esomeprazole (proton pump inhibitor) decreased the mean Cmax
and AUC by 46% and 32% compared to NOXAFIL alone, respectively. The coadministration
of NOXAFIL with both ginger ale and esomeprazole decreased the mean Cmax and
AUC by 33% and 21% compared to NOXAFIL alone, respectively (See CLINICAL
PHARMACOLOGY, Drug Interactions, PRECAUTIONS: DRUG INTERACTIONS,
and DOSAGE AND ADMINISTRATION.
In 12 subjects who received single 400 mg dose of NOXAFIL Oral Suspension with
BOOST, or with a prokinetic agent (metoclopramide 10 mg TID for 2 days) and
BOOST, or with an anti-kinetic agent (loperamide 4 mg single dose) and BOOST
in a 3-way crossover design, the coadministration of NOXAFIL with metoclopramide
decreased the mean Cmax and AUC by 21% and 19%, respectively, compared to NOXAFIL
alone. When NOXAFIL was coadministered with loperamide, the mean Cmax and AUC
were decreased by 3% and increased by 11%, respectively, compared to NOXAFIL
alone (See CLINICAL PHARMACOLOGY, Drug Interactions and PRECAUTIONS:
DRUG INTERACTIONS).
In 16 healthy volunteers who received a single 400 mg dose of NOXAFIL either
orally or via an NG tube in a crossover design, the mean Cmax and AUC decreased
by 19% and 23%, respectively, when NOXAFIL was administered via an NG tube compared
to when POS was administered orally. In 5 subjects, the Cmax and AUC decreased
substantially (range -27% to -53% and -33% to -51%, respectively) when NOXAFIL
was administered via an NG tube compared to when NOXAFIL was administered orally.
It is recommended to closely monitor patients for breakthrough fungal infections
when NOXAFIL is administered via an NG tube because a lower plasma exposure
may be associated with an increase risk of treatment failure (See CLINICAL
PHARMACOLGY, Exposure Response Relationship).
Distribution
Posaconazole has an apparent volume of distribution of 1774 L, suggesting extensive extravascular distribution and penetration into the body tissues.
Posaconazole is highly protein bound ( > 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.
Excretion
Posaconazole is eliminated with a mean half-life (t½) of 35 hours (range 20 to 66 hours) and a total body clearance (CL/F) of 32 L/hr. 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).
Summary of Pharmacokinetic Parameters
The mean (%CV) [min-max] posaconazole average steady-state plasma concentrations (Cav) and steady-state pharmacokinetic parameters in patients following administration of 200 mg TID and 400 mg BID of the oral suspension are provided in Table 2.
TABLE 2. The Mean (%CV) [min-max] Posaconazole Steady-State
Pharmacokinetic Parameters in Patients Following Oral Administration of Posaconazole
200 mg TID and 400 mg BID
| Dosea |
Cav (ng/mL) |
AUCe
(ng·hr/mL) |
CL/F (L/hr) |
V/F (L) |
t1/2 (hr) |
200 mg TIDb
(n=252) |
1103 (67)
[21.5– 3650] |
NDf |
NDf |
NDf |
NDf |
| 200 mg TIDc (n=215) |
583 (65)
[89.7-2200] |
15,900 (62)
[4100-56,100] |
51.2 (54)
[10.7-146] |
2425 (39)
[828-5702] |
37.2 (39)
[19.1-148] |
| 400 mg BIDd (n=23) |
723 (86)
[6.70-2256] |
9093 (80)
[1564-26,794] |
76.1 (78)
[14.9-256] |
3088 (84)
[407-13,140] |
31.7 (42)
[12.4-67.3] |
Note: Cav based on observed data; other pharmacokinetic parameters
based on estimates from population pharmacokinetic analyses
a Oral suspension administration
bAllogeneic hematopoietic stem cell transplant (HSCT) recipients
with graft-versus-host disease
c Neutropenic patients who were receiving cytotoxic chemotherapy
for acute myelogenous leukemia or myelodysplastic syndromes
d Febrile neutropenic patients or patients with refractory invasive
fungal infections, Cav n=24
e AUC (0-24 hr) for 200 mg TID and AUC (0-12 hr) for 400 mg BID
f Not done |
The variability in average plasma posaconazole concentrations in patients was relatively higher than that in healthy subjects.
Exposure Response Relationship
In clinical studies of immunocompromised patients, a wide range of plasma exposures to posaconazole was noted. A pharmacokinetic-pharmacodynamic analysis of patient data revealed an apparent association between average posaconazole concentrations (Cav) and prophylactic efficacy. A lower Cav may be associated with an increased risk of treatment failure [defined in the study as treatment discontinuation, use of empiric systemic antifungal therapy (SAF), or invasive fungal infections (IFI)].
To enhance the oral absorption of posaconazole and optimize plasma concentrations:
- Each dose of NOXAFIL® Oral Suspension should be administered during
or immediately (i.e. within 20 minutes) following a full meal or liquid nutritional
supplement. For patients who cannot eat a full meal or tolerate an oral nutritional
supplement, alternative antifungal therapy should be considered or patients
should be monitored closely for breakthrough fungal infections.
- Patients who have severe diarrhea or vomiting should be monitored closely
for breakthrough fungal infections.
- Co-administration of drugs that can decrease the plasma concentrations
of posaconazole should generally be avoided unless the benefit outweighs the
risk. If such drugs are necessary, patients should be monitored closely for
breakthrough fungal infections (see CLINICAL PHARMACOLOGY, Drug Interactions
section)
Pharmacokinetics in Special Populations
Gender
The pharmacokinetics of posaconazole are comparable in men and women. No adjustment in the dosage of NOXAFIL is necessary based on gender.
Race
The pharmacokinetic profile of posaconazole is not significantly affected by race. No adjustment in the dosage of NOXAFIL is necessary based on race.
Geriatric
The pharmacokinetics of posaconazole are comparable in young and elderly subjects ( ≥ 65 years of age). No adjustment in the dosage of NOXAFIL is necessary in elderly patients ( ≥ 65 years of age) based on age.
Pediatric
In the prophylaxis studies, the mean steady-state posaconazole average concentration (Cav) was similar among ten adolescents (13-17 years of age) and adults ( ≥ 18 years of age). This is consistent with pharmacokinetic data from another study in which mean steady-state posaconazole Cav from 12 adolescent patients (8-17 years of age) was similar to that in the adults ( ≥ 18 years of age).
Hepatic Insufficiency
After a single oral dose of posaconazole 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), and severe (Child-Pugh Class C, N=6) hepatic insufficiency, respectively, compared to subjects with normal hepatic function (N=18). Compared to subjects with normal hepatic function, the mean Cmax was 1% higher, 40% higher, and 34% lower in subjects with mild, moderate, and severe hepatic insufficiency, respectively. The mean apparent oral clearance (CL/F) was reduced by 18%, 36% and 28% in subjects with mild, moderate, and severe hepatic insufficiency, respectively, compared to subjects with normal hepatic function. The elimination half-life (t½) was 27 hours, 39 hours, 27 hours, and 43 hours in subjects with normal hepatic function, mild, moderate, and severe hepatic insufficiency, respectively.
It is recommended that no dose adjustment of NOXAFIL is needed in patients
with mild to severe hepatic insufficiency (Child-Pugh Class A, B, and C) (See
WARNINGS and DOSAGE AND ADMINISTRATION)
Renal Insufficiency
Following single-dose administration of 400 mg of the oral suspension, there
was no significant effect of mild (CLcr: 50-80 mL/min/1.73m2, n=6)
and moderate (CLcr: 20-49 mL/min/1.73m2, n=6) renal insufficiency
on posaconazole pharmacokinetics; therefore, no dose adjustment is required
in patients with mild to moderate renal impairment. In subjects with severe
renal insufficiency (CLcr: < 20 mL/min/1.73m2), the mean plasma
exposure (AUC) was similar to that in patients with normal renal function (CLcr:
> 80 mL/min/1.73m2); however, the range of the AUC estimates was
highly variable (CV=96%) in these subjects with severe renal insufficiency as
compared to that in the other renal impairment groups (CV < 40%). Due to the
variability in exposure, patients with severe renal impairment should be monitored
closely for breakthrough fungal infections (see DOSAGE AND ADMINISTRATION).
Electrocardiogram Evaluation
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 400 mg BID 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 (see PRECAUTIONS).
Drug Interactions
Effect of Other Drugs on Posaconazole
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, which affect posaconazole concentrations,
is provided in Table 3 (see PRECAUTIONS: DRUG INTERACTIONS
section).
TABLE 3. Summary of the Effect of Co-administered Drugs on
Posaconazole in Healthy Volunteers
| Co-administered Drug (Postulated
Mechanism of Interaction) |
Co-administered Drug Dose/Schedule |
Posaconazole Dose/Schedule |
Effect on Bioavailability of Posaconazole |
Recommendations |
| Change in Mean Cmax (ratio estimate*; 90%
CI of the ratio estimate) |
Change in Mean AUC (ratio estimate*; 90%
CI ofthe ratio estimate) |
Rifabutin
(UDP-G Induction) |
300 mg QD x 17 days |
200 mg (tablets) QD × 10 days |
↓43%
(0.57;0.43-0.75) |
↓ 49%
(0.51; 0.37-0.71) |
Avoid concomitant use unless the benefit outweighs the
risks. |
Phenytoin
(UDP-G Induction) |
200 mg QD x 10 days |
200 mg (tablets) QD × 10 days |
↓ 41%
(0.59;0.44-0.79) |
↓ 50%
(0.50;0.36-0.71) |
Avoid concomitant use unless the benefit outweighs the
risks. |
Cimetidine
(Alteration of Gastric pH) |
400 mg BID × 10 days |
200 mg (tablets) QD × 10 days |
↓ 39%
(0.61; 0.53-0.70) |
↓ 39%
(0.61; 0.54-0.69) |
Avoid concomitant use unless the benefit outweighs the
risks. |
Efavirenz
(UDP-G Induction) |
400 mg QD × 10 and 20 days |
400 mg (oral suspension) BID × 10 and 20 days |
↓45%
(0.55;0.47-0.66) |
↓ 50%
(0.50; 0.43-0.60) |
Avoid concomitant use unless the benefit outweighs the
risks. |
Esomeprazole
(Increase in gastric pH) |
40 mg QAM × 3 days |
400 mg (oral suspension) single dose |
↓ 46%
(0.54; 0.43-0.69) |
↓ 32%
(0.68; 0.57-0.81) |
Monitor closely for breakthrough fungal infections |
Metoclopramide
(Increase in gastric motility) |
10 mg TID × 2 days |
400 mg (oral suspension) single dose |
↓ 21%
(0.79; 0.72-0.87) |
↓ 19%
(0.81; 0.72-0.91) |
Monitor closely for breakthrough fungal infections |
| *Ratio Estimate is the ratio of co-administered drug plus
posaconazole to posaconazole alone for Cmax or AUC. |
Co-administration of these drugs listed in Table 3 with posaconazole may result in lower plasma concentrations of posaconazole.
No clinically relevant effect on posaconazole bioavailability and/or plasma concentrations was observed when administered with an antacid, glipizide, ritonavir, loperamide, or H2 receptor antagonists other than cimetidine; therefore, no posaconazole dose adjustments are required when used concomitantly with these products.
Effect of Posaconazole on Other Drugs
In vitro studies with human hepatic microsomes and clinical studies
indicate that posaconazole is an inhibitor primarily of CYP3A4. 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 4. (see CONTRAINDICATIONS,
WARNINGS, and PRECAUTIONS: DRUG
INTERACTIONS section).
TABLE 4. Summary of the Effect of Posaconazole on Co-administered
Drugs in Healthy Volunteers and Patients
| Co-administered Drug (Postulated
Mechanism of Interaction) |
Co-administered Drug Dose/Schedule |
Posaconazole Dose/Schedule |
Effect on Bioavailability of Co-administered Drugs |
Recommendations |
| Change in Mean Cmax (ratio estimate*; 90%
CI of the ratio estimate) |
Change in Mean AUC (ratio estimate*; 90%
CI of the ratio estimate) |
Sirolimus
(Inhibition of CYP3A4 by posaconazole) |
2 mg single oral dose |
400 mg (oral suspension) BID x 16 days |
↑ 572%
(6.72; 5.62-8.03) |
↑ 788%
(8.88; 7.26-10.9) |
Co-administration of posaconazole with sirolimus is contraindicated (see
CONTRAINDICATIONS). |
Cyclosporine
(Inhibition of CYP3A4 by posaconazole) |
Stablemaintenance dose in heart transplant recipients |
200 mg (tablets) QD x 10 days |
↑ cyclosporine whole blood trough concentrations
Cyclosporine dose reductions of up to 29% were required |
At initiation of posaconazole treatment, reduce the cyclosporine dose
to approximately three-fourths of the original dose.
Frequent monitoring of cyclosporine whole blood trough concentrations should
be performed during and at discontinuation of posaconazole treatment and
the cyclosporine dose adjusted accordingly. |
Tacrolimus
(Inhibition of CYP3A4 by posaconazole) |
0.05 mg/kg single oral dose |
400 mg (oral suspension) BID × 7 days |
↑121%
(2.21; 2.01-2.42) |
↑ 358%
(4.58; 4.03-5.19) |
At initiation of posaconazole treatment, reduce the tacrolimus dose to
approximately one-third of the original dose.
Frequent monitoring of tacrolimus whole blood trough concentrations should
be performed during and at discontinuation of posaconazole treatment and
the tacrolimus dose adjusted accordingly. |
Rifabutin
(Inhibition of CYP3A4 by posaconazole) |
300 mg QD x 17 days |
200 mg (tablets) QD × 10 days |
↑ 31%
(1.31; 1.10-1.57) |
↑ 72%
(1.72; 1.51-1.95) |
Avoid concomitant use unless the benefit outweighs the risks. If the
drugs are co-administered, frequent monitoring of rifabutin adverse effects
(eg, uveitis, leukopenia) should be performed. |
Midazolam
(Inhibition of CYP3A4 by posaconazole) |
Single 30 min IV infusion of 0.05 mg/kg |
200 mg (tablets) QD x 10 days |
NA** |
↑ 83%
(1.83; 1.57-2.14) |
Frequent monitoring of adverse effects of benzodiazepines
metabolized by CYP3A4 should be performed and dose reduction of these
benzodiazepines should be considered during co-administration with posaconazole.
|
| 0.4 mg single IV dosea |
200 mg (oral suspension) BID x 7 days |
↑30%
(1.3; 1.13-1.48) |
↑362%
(4.62; 4.02-5.3) |
| 2 mg single oral dosea |
200 mg (oral suspension) BID x 7 days |
↑126%
(2.26; 2.02-2.53) |
↑362%
(4.59; 4.12-5.11) |
| 0.4 mg single IV dosea |
400 mg (oral suspension) BID x 7 days |
↑62%
(1.62; 1.41-1.86) |
↑524%
(6.24; 5.43-7.16) |
Phenytoin
(Inhibition of CYP3A4 by posaconazole) |
200 mg QD PO x 10 days |
200 mg (tablets) QD x 10 days |
↑ 16%
(1.16; 0.85-1.57) |
↑ 16%
(1.16; 0.84-1.59) |
Frequent monitoring of phenytoin concentrations should be performed while
co-administered with posaconazole and dose reduction of phenytoin should
be considered. |
Ritonavir
(Inhibition of CYP3A4 by posaconazole) |
100 mg QD x 14 days |
400 mg (oral suspension) BID x 7 days |
↑ 49%
(1.49;1.04-2.15) |
↑ 80%
(1.8;1.39-2.31) |
Frequent monitoring of adverse effects and toxicity of ritonavir should
be performed during co-administration with posaconazole. |
Atazanavir
(Inhibition of CYP3A4 by posaconazole) |
300 mg QD x 14 days |
400 mg (oral suspension) BID x 7 days |
↑ 155%
(2.55; 1.89-3.45) |
↑ 268%
(3.68; 2.89-4.70) |
Frequent monitoring of adverse effects and toxicity of Atazanavir
should be performed during co- administration with posaconazole. |
| Atazanavir/ ritonavir boosted regimen (Inhibition of CYP3A4 by posaconazole) |
300 mg/100 mg QD x 14 days |
400 mg (oral suspension) BID x 7 days |
↑ 53%
(1.53; 1.13-2.07) |
↑ 146%
(2.46; 1.93-3.13) |
*Ratio Estimate is the ratio of co-administered drug plus
posaconazole to co-administered drug alone for Cmax or AUC.
**NA: Not applicable if administered as an IV.
a The mean terminal half-life of midazolam was increased from
3 hours to 8 to 10 hours during co-administration with posaconazole. |
Additional clinical studies demonstrated that no clinically significant effects
on zidovudine, lamivudine, ritonavir, indinavir, or caffeine were observed when
administered with posaconazole 200 mg QD; therefore, no dose adjustments are
required for these co-administered drugs when co-administered with posaconazole
200 mg QD.
Posaconazole administration with glipizide does not require a dose adjustment in either drug; however, glucose concentrations decreased in some healthy volunteers administered the combination. Therefore, glucose concentrations should be monitored in accordance with the current standard of care for patients with diabetes when posaconazole is co-administered with glipizide.
Microbiology
Mechanism of Action
As a triazole antifungal agent, posaconazole blocks the synthesis of ergosterol, a key component of the fungal cell membrane, through the inhibition of the enzyme lanosterol 14α-demethylase and accumulation of methylated sterol precursors.
Activity in vitro and in vivo
Posaconazole has shown in vitro activity against Aspergillus fumigatus
and Candida albicans, including Candida albicans isolates from
patients refractory to itraconazole or fluconazole or both drugs (see Clinical
Studies and INDICATIONS).
In vitro susceptibility testing was performed according to the Clinical
and Laboratory Standards Institute (CLSI) methods (M27-A2, M27-A, M38-A, M38-P).
However, correlation between the results of susceptibility studies and clinical
outcome has not been established. Posaconazole interpretive criteria/ breakpoints
have not been established for any fungi.
In immunocompetent and/or immunocompromised mice and rabbits with pulmonary
or disseminated infection with A. fumigatus, posaconazole administered
prophylactically was effective in prolonging survival and reducing mycological
burden. Prophylactic posaconazole also prolonged survival of immunocompetent
mice challenged with C. albicans or A. flavus (see Clinical
Studies).
Drug Resistance
Clinical isolates of Candida albicans and Candida glabrata with
decreases in posaconazole susceptibility 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.
Clinical Studies
Prophylaxis of Aspergillus and Candida Infections
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 (Study 1) was a randomized, double-blind trial that compared posaconazole 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). Study 1 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 two treatment groups (80 days, posaconazole; 77 days, fluconazole). Table 5 contains the results from Study 1.
TABLE 5. Results from Blinded Clinical Study 1 in Prophylaxis
of IFI in All Randomized Patients with Hematopoietic Stem Cell Transplant (HSCT)
and Graft-vs-Host Disease (GVHD)
| |
Posaconazole
n=301 |
Fluconazole
n=299 |
| On therapy plus 7 days |
| Clinical Failurea |
50 (17%) |
55 (18%) |
| Failure due to: |
|
|
| Proven/Probable IFI |
7 (2%) |
22 (7%) |
| (Aspergillus) |
3 (1%) |
17 (6%) |
| (Candida) |
1 ( < 1%) |
3 (1%) |
| (Other) |
3 (1%) |
2 (1%) |
| All Deaths |
22 (7%) |
24 (8%) |
| Proven/probable fungal infection prior to death |
2 ( < 1%) |
6 (2%) |
| SAFb |
27 (9%) |
25 (8%) |
| Through 16 weeks |
| Clinical Failurea,c |
99 (33%) |
110 (37%) |
| Failure due to: |
|
|
| Proven/Probable IFI |
16 (5%) |
27 (9%) |
| (Aspergillus) |
7 (2%) |
21 (7%) |
| (Candida) |
4 (1%) |
4 (1%) |
| (Other) |
5 (2%) |
2 (1%) |
| All Deaths |
58 (19%) |
59 (20%) |
| Proven/probable fungal infection prior to death |
10 (3%) |
16 (5%) |
| SAFb |
26 (9%) |
30 (10%) |
| Event free lost to follow-upd |
24 (8%) |
30 (10%) |
a Patients may have met more than one criterion
defining failure.
b Use of systemic antifungal therapy (SAF) criterion is based
on protocol definitions (empiric/IFI usage > 4 consecutive days).
c 95% confidence interval (posaconazole-fluconazole) = (-11.5%,
+3.7%).
d Patients who are lost to follow-up (not observed for 112 days),
and who did not meet another clinical failure endpoint. These patients were
considered failures. |
The second study (Study 2) was a randomized, open-label study that compared
posaconazole oral suspension (200 mg three 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 acute myelogenous leukemia or myelodysplastic syndromes. As in 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). Study 2 assessed patients while on treatment
plus 7 days and 100 days post-randomization. The mean duration of therapy was
comparable between the two treatment groups (29 days, posaconazole; 25 days,
fluconazole or itraconazole). Table 6 contains the results from Study 2.
TABLE 6. Results from Open-Label Clinical Study 2 in Prophylaxis
of IFI in All Randomized Patients with Hematologic Malignancy and Prolonged
Neutropenia
| |
Posaconazole
n=304 |
Fluconazole/Itraconazole
n=298 |
| On therapy plus 7 days |
| Clinical Failurea,b |
82 (27%) |
126 (42%) |
| Failure due to: |
|
|
| Proven/Probable IFI |
7 (2%) |
25 (8%) |
| (Aspergillus) |
2 (1%) |
20 (7%) |
| (Candida) |
3 (1%) |
2 (1%) |
| (Other) |
2 (1%) |
3 (1%) |
| All Deaths |
17 (6%) |
25 (8%) |
| Proven/probable fungal infection prior to death |
1 ( < 1%) |
2 (1%) |
| SAFc |
67 (22%) |
98 (33%) |
| Through 100 days post-randomization |
| Clinical Failureb |
158 (52%) |
191 (64%) |
| Failure due to: |
|
|
| Proven/Probable IFI |
14 (5%) |
33 (11%) |
| (Aspergillus) |
2 (1%) |
26 (9%) |
| (Candida) |
10 (3%) |
4 (1%) |
| (Other) |
2 (1%) |
3 (1%) |
| All Deaths |
44 (14%) |
64 (21%) |
| Proven/probable fungal infection prior to death |
2 (1%) |
16 (5%) |
| SAFc |
98 (32%) |
125 (42%) |
| Event free lost to follow-upd |
34 (11%) |
24 (8%) |
a 95% confidence interval (posaconazole-fluconazole/itraconazole)
= (-22.9%, -7.8%).
b Patients may have met more than one criterion defining failure.
c Use of systemic antifungal therapy (SAF) criterion is based
on protocol definitions (empiric/IFI usage > 3 consecutive days).
d Patients who are lost to follow-up (not observed for 100 days),
and who did not meet another clinical failure endpoint. These patients were
considered failures. |
In summary, two clinical studies of prophylaxis were conducted. As seen in the accompanying tables (Tables 5 and 6), clinical failure represented a composite endpoint of breakthrough IFI, mortality and use of systemic antifungal therapy. In Study 1 (Table 5), 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 Study 2 (Table 6) 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 Study
1 [POS 58/301 (19%) vs FLU 59/299 (20%)]; all-cause mortality was lower at 100
days for posaconazole-treated patients in Study 2 [POS 44/304 (14%) vs FLU/ITZ
64/298 (21%)]. Both studies demonstrated substantially fewer breakthrough infections
caused by Aspergillus species in patients receiving posaconazole prophylaxis
when compared to patients receiving fluconazole or itraconazole.
For information on a pharmacokinetic/pharmacodynamic analysis of patient data
see CLINICAL PHARMACOLOGY, Exposure Response Relationship section.
Treatment of Oropharyngeal Candidiasis (OPC)
Study 3 was a randomized, controlled, evaluator-blinded study in HIV-infected patients with oropharyngeal candidiasis. Patients were treated with posaconazole or fluconazole oral suspension (both posaconazole and fluconazole were given as follows: 100 mg twice a day for 1 day followed by 100 mg once a day for 13 days).
Clinical and mycological outcomes were assessed after 14 days of treatment
and at 4 weeks after the end of treatment. Patients who received at least one
dose of study medication and had a positive oral swish culture of Candida
species at baseline were included in the analyses (Table 7). The majority of
the subjects had C. albicans as the baseline pathogen.
Clinical success at Day 14 (complete or partial resolution of all ulcers and/or plaques and symptoms) and clinical relapse rates (recurrence of signs or symptoms after initial cure or improvement) 4 weeks after the end of treatment were similar between the treatment arms (Table 7).
Mycologic eradication rates (absence of colony forming units in quantitative
culture at the end of therapy, day 14), as well as mycologic relapse rates (4
weeks after the end of treatment) were also similar between the treatment arms
(see Table 7).
TABLE 7. Clinical Success, Mycological Eradication, and Relapse
Rates in Oropharyngeal Candidiasis
| |
Posaconazole |
Fluconazole |
| Clinical Success at End of Therapy (Day 14) |
155/169 (91.7%) |
148/160 (92.5%) |
| Clinical Relapse (4 Weeks after End of Therapy) |
45/155 (29.0%) |
52/148 (35.1%) |
| Mycological Eradication (absence of CFU) at End of Therapy (Day 14) |
88/169 (52.1%) |
80/160 (50.0%) |
| Mycological Relapse (4 Weeks after End of Treatment) |
49/88 (55.6%) |
51/80 (63.7%) |
Mycologic response rates, using a criterion for success as a post-treatment quantitative culture with ≤ 20 colony forming units (CFU/mL) were also similar between the two groups (posaconazole 68.0%, fluconazole 68.1%). The clinical significance of this finding is unknown.
Treatment of Oropharyngeal Candidiasis Refractory to Treatment with Fluconazole
or Itraconazole
Study 4 was a non-comparative study of posaconazole oral suspension in HIV-infected subjects with OPC that was refractory to treatment with fluconazole or itraconazole. An episode of OPC was considered refractory if there was failure to improve or worsening of OPC after a standard course of therapy with fluconazole ≥ 100 mg/day for at least 10 consecutive days or itraconazole 200 mg/day for at least 10 consecutive days and treatment with either fluconazole or itraconazole had not been discontinued for more than 14 days prior to treatment with posaconazole. Of the 199 subjects enrolled in this study, eighty-nine subjects met these strict criteria for refractory infection.
Forty-five subjects with refractory OPC were treated with posaconazole 400 mg BID for three days, followed by 400 mg QD for 25 days with an option for further treatment during a 3-month maintenance period. Following a dosing amendment, a further 44 subjects were treated with posaconazole 400 mg BID for twenty-eight days. The efficacy of posaconazole was assessed by the clinical success (cure or improvement) rate after 4 weeks of treatment. The clinical success rate was 74.2% (66/89). The clinical success rates for both the original and the amended dosing regimens were similar (73.3% and 75.0%, respectively).
For information on a pharmacokinetic/pharmacodynamic analysis of patient data
see CLINICAL PHARMACOLOGY, Exposure Response Relationship section.
Last updated on RxList: 3/18/2009