CLINICAL PHARMACOLOGY
Mechanism Of Action
Posaconazole is an azole
antifungal agent [see Microbiology].
Pharmacodynamics
Exposure Response Relationship
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 exposures to posaconazole was noted following
administration of Noxafil oral suspension. A pharmacokinetic-pharmacodynamic
analysis of patient data revealed an apparent association between average
posaconazole concentrations (Cavg) and prophylactic efficacy (Table 12). 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.
Table 12: Noxafil Oral
Suspension Exposure Analysis (Cavg) in Prophylaxis Trials
|
Prophylaxis in AML/MDS* |
Prophylaxis in GVHD† |
Cavg Range (ng/mL) |
Treatment Failure‡ (%) |
Cavg Range (ng/mL) |
Treatment Failure‡ (%) |
Quartile 1 |
90-322 |
54.7 |
22-557 |
44.4 |
Quartile 2 |
322-490 |
37.0 |
557-915 |
20.6 |
Quartile 3 |
490-734 |
46.8 |
915-1563 |
17.5 |
Quartile 4 |
734-2200 |
27.8 |
1563-3650 |
17.5 |
Cavg = the average posaconazole concentration when measured at steady state
* Neutropenic patients who were receiving cytotoxic chemotherapy for AML or MDS
† HSCT recipients with GVHD
‡Defined as treatment discontinuation, use of empiric systemic antifungal therapy (SAF), or occurrence of breakthrough invasive fungal infections |
Pharmacokinetics
General Pharmacokinetic
Characteristics
Posaconazole Injection
Posaconazole injection exhibits
dose proportional pharmacokinetics after single doses between 200 and 300 mg in
healthy volunteers and patients. The mean pharmacokinetic parameters after
single doses with posaconazole injection in healthy volunteers and patients are
shown in Table 13.
Table 13: Summary of Mean
Pharmacokinetic Parameters (%CV) in Healthy Volunteers (30 minute infusion via
peripheral venous line) and Patients (90 minute infusion via central venous
line) after Dosing with Posaconazole Injection on Day 1
|
Dose (ma) |
n |
AUC0-∞ (na•hr/mL) |
AUC0-12 (na•hr/mL) |
Cmax (na/mL) |
t½ (hr) |
CL (L/hr) |
Healthy Volunteers |
200 |
9 |
35400 (50) |
8840 (20) |
2250 (29) |
23.6 (23) |
6.5 (32) |
300 |
9 |
46400 (26) |
13000 (13) |
2840 (30) |
24.6 (20) |
6.9 (27) |
Patients |
200 |
30 |
N/D |
5570 (32) |
954 (44) |
N/D |
N/D |
300 |
22 |
N/D |
8240 (26) |
1590 (62) |
N/D |
N/D |
AUC0-∞ = Area under the plasma concentration-time
curve from time zero to infinity; AUC0-12 = Area under the plasma
concentration-time curve from time zero to 12 hr after the first dose on Day 1;
Cmax = maximum observed concentration; t½ = terminal phase half-life; CL =
total body clearance; N/D = Not Determined |
Table 14 displays the pharmacokinetic parameters of posaconazole in
patients following administration of posaconazole injection 300 mg taken once a
day for 10 or 14 days following BID dosing on Day 1.
Table 14: Arithmetic Mean
(%CV) of PK Parameters in Serial PK-Evaluable Patients Following Dosing of
Posaconazole Injection (300 mg)*
Day |
N |
Cmax (na/mL) |
Tmax† (hr) |
AUC024 (na*hr/mL) |
Cav (na/mL) |
Cmin (na/mL) |
10/14 |
49 |
3280 (74) |
1.5 (0.98-4.0) |
36100 (35) |
1500 (35) |
1090 (44) |
AUC0-24 = area under the concentration-time curve over
the dosing interval (i.e. 24 hours); Cav= time-averaged concentrations (i.e.,
AUC0-24h/24hr);
Cmin = POS trough level immediately before a subject received the dose of POS
on the day specified in the protocol; Cmax = observed maximum plasma
concentration; CV = coefficient of variation, expressed as a percent (%); Day =
study day on treatment; Tmax = time of observed maximum plasma concentration.
* 300 mg dose administered over 90 minutes once a day following BID dosing on
Day 1
† Median (minimum-maximum) |
Posaconazole Delayed-Release
Tablets
Noxafil 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 Noxafil delayed-release tablets 300 mg twice daily
(BID) on Day 1, then 300 mg once daily (QD) 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 15.
Table 15: Arithmetic Mean
(%CV) of Steady State PK Parameters in Healthy Volunteers and Patients
Following Administration of Posaconazole Delayed-Release Tablets (300 mg)*
|
N |
AUC0-24 hr (na•hr/mL) |
Cav† (na/mL) |
Cmax (na/mL) |
Cmin (na/mL) |
Tmax‡ (hr) |
t½ (hr) |
CL/F (L/hr) |
Healthy Volunteers |
12 |
51618 (25) |
2151 (25) |
2764 (21) |
1785 (29) |
4 (3-6) |
31 (40) |
7.5 (26) |
Patients |
50 |
37900 (42) |
1580 (42) |
2090 (38) |
1310 (50) |
4 (1.3-8.3) |
- |
9.39 (45) |
CV = coefficient of variation expressed as a percentage (%CV);
AUC0-T = Area under the plasma concentration-time curve from time zero to 24
hr; Cmax = maximum observed concentration; Cmin = minimum observed plasma
concentration; Tmax = time of maximum observed concentration; t½ = terminal
phase half-life; CL /F = Apparent total body clearance
*300 mg BID on Day 1, then 300 mg QD thereafter
† Cav = time-averaged concentrations (i.e., AUC0-24 hr/24hr)
‡ Median (minimum-maximum) |
Posaconazole Oral Suspension
Dose-proportional increases in
plasma exposure (AUC) to posaconazole oral suspension 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 in healthy volunteers. No further
increases in exposure were observed when the dose of the oral suspension
increased from 400 mg BID to 600 mg BID in febrile neutropenic patients or
those with refractory invasive fungal infections.
The mean (%CV) [min-max]
posaconazole oral suspension average steady-state plasma concentrations (Cavg)
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 16.
Table 16: The Mean (%CV)
[min-max] Posaconazole Steady-State Pharmacokinetic Parameters in Patients
Following Oral Administration of Posaconazole Oral Suspension 200 mg TID and
400 mg BID
Dose* |
Cavg (ng/mL) |
AUC† (ng•hr/mL) |
CL/F (L/hr) |
V/F (L) |
t½ (hr) |
200 mg TID‡ (n=252) |
1103 (67) [21.5-3650] |
ND§ |
ND§ |
ND§ |
ND§ |
200 mg TID¶ (n=215) |
583 (65) |
15,900 (62) |
51.2 (54) |
2425 (39) |
37.2 (39) |
[89.7-2200] |
[4100-56,100] |
[10.7-146] |
[828-5702] |
[19.1-148] |
400 mg BID# (n=23) |
723 (86) |
9093 (80) |
76.1 (78) |
3088 (84) |
31.7 (42) |
[6.70-2256] |
[1564-26,794] |
[14.9-256] |
[407-13,140] |
[12.4-67.3] |
Cavg = the average posaconazole concentration when
measured at steady state
* Oral suspension administration
† AUC (0-24 hr) for 200 mg TID and AUC (0-12 hr) for 400 mg BID
‡ HSCT recipients with GVHD
§ Not done
¶ Neutropenic patients who were receiving cytotoxic chemotherapy for acute
myelogenous leukemia or myelodysplastic syndromes
# Febrile neutropenic patients or patients with refractory invasive fungal
infections, Cavg n=24 The variability in average plasma posaconazole
concentrations in patients was relatively higher than that in healthy subjects. |
Absorption
Posaconazole Delayed-Release
Tablets
When given orally in healthy
volunteers, posaconazole delayed-release tablets are absorbed with a median Tmax
of 4 to 5 hours. Steady-state plasma concentrations are attained by Day 6 at
the 300 mg dose (QD after BID 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 is increased 16% and 51%, respectively,
when given with a high fat meal compared to a fasted state (see Table 17). In
order to enhance the oral absorption of posaconazole and optimize plasma
concentrations, posaconazole delayed-release tablets should be administered
with food.
Table 17: Statistical
Comparison of Plasma Pharmacokinetics of Posaconazole Following Single Oral
Dose Administration of 300 mg Posaconazole Delayed-Release Tablet to Healthy
Subjects under Fasting and Fed Conditions
Pharmacokinetic Parameter |
Fasting Conditions |
Fed Conditions (High Fat Meal)* |
Fed/Fasting |
N |
Mean (%CV) |
N |
Mean (%CV) |
GMR (90% CI) |
Cmax (na/mL) |
14 |
935 (34) |
16 |
1060 (25) |
1.16 (0.96, 1.41) |
AUC0-72hr (hrng/mL) |
14 |
26200 (28) |
16 |
38400 (18) |
1.51 (1.33, 1.72) |
Tmax† (hr) |
14 |
5.00 (3.00, 8.00) |
16 |
6.00 (5.00, 24.00) |
N/A |
GMR=Geometric least-squares mean ratio; CI=Confidence
interval
* 48.5 g fat
† Median (Min, Max) reported for Tmax |
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 18).
Table 18: The Effect of
Concomitant Medications that Affect the Gastric pH and Gastric Motility on the
Pharmacokinetics of Posaconazole Delayed-Release Tablets in Healthy Volunteers
Coadministered Drug |
Administration Arms |
Change in Cmax (ratio estimate*; 90% CI of the ratio estimate) |
Change in AUC0-last (ratio estimate*; 90% CI of the ratio estimate) |
Mylanta® Ultimate strenath liquid (Increase in aastric pH) |
25.4 meq/5 mL, 20 mL |
↑6%
(1.06; 0.90 -1.26)↑ |
↑4%
(1.04; 0.90 -1.20) |
Ranitidine (Zantac®) (Alteration in aastric pH) |
150 ma (mornina dose of 150 ma Ranitidine BID) |
↑4%
(1.04; 0.88 -1.23)↑ |
↓3%
(0.97; 0.84 -1.12) |
Esomeprazole (Nexium®) (Increase in aastric pH) |
40 ma (QAM 5 days, day -4 to 1) |
↑2%
(1.02; 0.88-1.17)↑ |
↑5%
(1.05; 0.89 -1.24) |
Metoclopramide (Realan®) (Increase in aastric motility) |
15 ma four times daily durina 2 days (Day -1 and 1) |
↓14%
(0.86, 0.73,1.02) |
↓7%
(0.93, 0.803,1.07) |
* Ratio Estimate is the ratio of coadministered drug plus
posaconazole to posaconazole alone for Cmax or AUC0-last. |
Posaconazole Oral Suspension
Posaconazole oral suspension is
absorbed with a median Tmax of ~3 to 5 hours. 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 the oral suspension is 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 posaconazole oral suspension 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 19).
In addition, the effects of varying gastric administration conditions on the Cmax
and AUC of posaconazole oral suspension in healthy volunteers have been
investigated and are shown in Table 20.
In order to assure attainment
of adequate plasma concentrations, it is recommended to administer Noxafil oral
suspension during or immediately following a full meal. In patients who cannot
eat a full meal, Noxafil oral suspension should be taken with a liquid
nutritional supplement or an acidic carbonated beverage (e.g., ginger ale).
Table 19: The Mean (%CV) [min-max] Posaconazole
Pharmacokinetic Parameters Following Single-Dose Oral Suspension Administration
of 200 mg and 400 mg Under Fed and Fasted Conditions
Dose (mg) |
Cmax (ng/mL) |
Tmax* (hr) |
AUC (I) (ng•hr/mL) |
CL/F (L/hr) |
t½ (hr) |
200 mg fasted (n=20)† |
132 (50) [45-267] |
3.50 [1.5-36‡] |
4179 (31) [2705-7269] |
51 (25) [28-74] |
23.5 (25) [15.3-33.7] |
200 mg nonfat (n=20)† |
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)† |
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)§ |
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)§ |
355 (43) [145-720] |
5 [4-8] |
11,295 (40) [3865-20,592] |
43 (56) [19-103] |
26.0 (19) [18.2-35.0] |
* Median [min-max].
† n=15 for AUC (I), CL/F, and t ½
‡ 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).
§ n=10 for AUC (I), CL/F, and t ½ |
Table 20: The Effect of
Varying Gastric Administration Conditions on the Cmax and AUC of Posaconazole
Oral Suspension in Healthy Volunteers*
Study Description |
Administration Arms |
Change in Cmax (ratio estimate†; 90% CI of the ratio estimate) |
Change in AUC (ratio estimate†; 90% CI of the ratio estimate) |
400-mg single dose with a high-fat meal relative to fasted state (n=12) |
5 minutes before high-fat meal |
↑96% (1.96; 1.48-2.59) |
↑111% (2.11; 1.60-2.78) |
During high-fat meal |
↑339% (4.39; 3.32-5.80) |
↑382% (4.82; 3.66-6.35) |
20 minutes after high-fat meal |
↑333% (4.33; 3.28-5.73) |
↑387% (4.87; 3.70-6.42) |
400 mg BID and 200 mg QID for 7 days in fasted state and with liquid nutritional supplement (BOOST®) (n=12) |
400 mg BID with BOOST |
↑65% (1.65; 1.29-2.11) |
↑66% (1.66; 1.30-2.13) |
200 mg QID with BOOST |
No Effect |
No Effect |
Divided daily dose from 400 mg BID to 200 mg QID for 7 days regardless of fasted conditions or with BOOST (n=12) |
Fasted state |
1↑136% (2.36; 1.84-3.02) |
↑161% (2.61; 2.04-3.35) |
With BOOST |
↑137% (2.37; 1.86-3.04) |
↑157% (2.57; 2.00-3.30) |
400-mg single dose with carbonated acidic beverage (ginger ale) and/or proton pump inhibitor (esomeprazole) (n=12) |
Ginger ale |
↑92% (1.92; 1.51-2.44) |
↑70% (1.70; 1.43-2.03) |
Esomeprazole |
↓32% (0.68; 0.53-0.86) |
↓30% (0.70; 0.59-0.83) |
400-ma sinale dose with a prokinetic aaent (metoclopramide 10 ma TID for 2 days) + BOOST or an antikinetic aaent (loperamide 4-ma sinale dose) + BOOST (n=12) |
With metoclopramide + BOOST |
↓21% (0.79; 0.72-0.87) |
↓19% (0.81; 0.72-0.91) |
With loperamide + BOOST |
↓3% (0.97; 0.88-1.07) |
↑11% (1.11; 0.99-1.25) |
400-ma sinale dose either orally with BOOST or via an NG tube with BOOST (n=16) |
Via NG tube‡ |
↓19% (0.81; 0.71-0.91) |
↓23% (0.77; 0.69-0.86) |
* 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 increased risk of treatment failure.
† Ratio Estimate is the ratio of coadministered drug plus posaconazole to
coadministered drug alone for Cmax or AUC.
‡ NG = nasogastric |
Concomitant administration of
posaconazole oral suspension with drugs affecting gastric pH or gastric
motility results in lower posaconazole exposure. (See Table 21.)
Table 21: The Effect of
Concomitant Medications that Affect the Gastric pH and Gastric Motility on the
Pharmacokinetics of Posaconazole Oral Suspension in Healthy Volunteers
Coadministered Drug (Postulated Mechanism of Interaction) |
Coadministered Drug Dose/Schedule |
Posaconazole Dose/Schedule |
Effect on Bioavailability of Posaconazole |
Change in Mean Cmax (ratio estimate*; 90% CI of the ratio estimate) |
Change in Mean AUC (ratio estimate*; 90% CI of the ratio estimate) |
Cimetidine (Alteration of aastric pH) |
400 ma BID x 10 days |
200 ma (tablets) QD x 10 days† |
↓39% (0.61; 0.53-0.70) |
↓ 39% (0.61; 0.54-0.69) |
Esomeprazole (Increase in aastric pH)‡ |
40 ma QAM x 3 days |
400 ma (oral suspension) sinale dose |
↓46% (0.54; 0.43-0.69) |
↓32% (0.68; 0.57-0.81) |
Metoclopramide (Increase in aastric motility)‡ |
10 ma TID x 2 days |
400 ma (oral suspension) sinale dose |
↓21% (0.79; 0.72-0.87) |
↓19% (0.81; 0.72-0.91) |
* Ratio Estimate is the ratio of coadministered drug plus
posaconazole to coadministered drug alone for Cmax or AUC.
† The tablet refers to a non-commercial tablet formulation without polymer.
‡ The drug interactions associated with the oral suspension are also relevant
for the delayed-release tablet with the exception of Esomeprazole and
Metoclopramide. |
Distribution
The mean volume of distribution
of posaconazole after intravenous solution administration was 261 L and ranged
from 226-295 L between studies and dose levels.
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 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 an early tablet
formulation, which affect posaconazole concentrations, is provided in Table 22.
Table 22: Summary of the Effect of Coadministered
Drugs on Posaconazole in Healthy Volunteers
Coadministered Drug (Postulated Mechanism of Interaction) |
Coadministered Drug Dose/Schedule |
Posaconazole Dose/Schedule |
Effect on Bioavailability of Posaconazole |
Change in Mean Cmax (ratio estimate*; 90% CI of the ratio estimate) |
Change in Mean AUC (ratio estimate*; 90% CI of the ratio estimate) |
Efavirenz (UDP-G Induction) |
400 ma QD x 10 and 20 days |
400 ma (oral suspension) BID x 10 and 20 days |
↓45% (0.55; 0.47-0.66) |
↓50% (0.50; 0.43-0.60) |
Fosamprenavir (unknown mechanism) |
700 ma BID x 10 days |
200 ma QD on the 1st day, 200 ma BID on the 2nd day, then 400 ma BID x 8 Days |
↓21% 0.79 (0.71-0.89) |
↓23% 0.77 (0.68-0.87) |
Rifabutin (UDP-G Induction) |
300 ma QD x 17 days |
200 ma (tablets) QD x 10 days† |
↓43% (0.57; 0.43-0.75) |
↓49% (0.51; 0.37-0.71) |
Phenytoin (UDP-G Induction) |
200 ma QD x 10 days |
200 ma (tablets) QD x 10 days† |
↓41% (0.59; 0.44-0.79) |
↓50% (0.50; 0.36-0.71) |
* Ratio Estimate is the ratio of coadministered drug plus
posaconazole to posaconazole alone for Cmax or AUC.
† The tablet refers to a non-commercial tablet formulation without polymer. |
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 23 [see
CONTRAINDICATIONS and DRUG INTERACTIONS including
recommendations].
Table 23: Summary of the Effect of Posaconazole on Coadministered Drugs in Healthy Volunteers and Patients
Coadministered Drug (Postulated Mechanism of Interaction is Inhibition of CYP3A4by posaconazole) |
Coadministered Drug Dose/Schedule |
Posaconazole Dose/ Schedule |
Effect on Bioavailability of Coadministered Drugs |
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 |
2-ma sinale oral dose |
400 ma (oral suspension) BID x 16 days |
↑ 572% (6.72; 5.62-8.03) |
↑788% (8.88; 7.26-10.9) |
Cyclosporine |
Stable maintenance dose in heart transplant recipients |
200 ma (tablets) QD x 10 days† |
↑cyclosporine whole blood trouah concentrations Cyclosporine dose reductions of up to 29% were required |
Tacrolimus |
0.05-ma/ka sinale oral dose |
400 ma (oral suspension) BID x 7 days |
↑121% (2.21; 2.01-2.42) |
↑358% (4.58; 4.03-5.19) |
Simvastatin |
40-mg single oral dose |
100 mg (oral suspension) QD x 13 days |
Simvastatin ↑ 841% (9.41, 7.13-12.44) Simvastatin Acid ↑817% (9.17, 7.36-11.43) |
Simvastatin ↑931% (10.31, 8.40-12.67) Simvastatin Acid ↑634% (7.34, 5.82-9.25) |
200 mg (oral suspension) QD x 13 days |
Simvastatin ↑1041% (11.41, 7.99-16.29) Simvastatin Acid ↑851% (9.51, 8.15-11.10) |
Simvastatin↑960% (10.60, 8.63-13.02) Simvastatin Acid ↑748% (8.48, 7.04-10.23) |
Midazolam |
0.4-mg single intravenous dose‡ |
200 mg (oral suspension) BID x 7 days |
↑30% (1.3; 1.13-1.48) |
↑362% (4.62; 4.02-5.3) |
0.4-mg single intravenous dose‡ |
400 mg (oral suspension) BID x 7 days |
↑62% (1.62; 1.41-1.86) |
↑524% (6.24; 5.43-7.16) |
2-mg single oral dose‡ |
200 mg (oral suspension) QD x 7 days |
↑169% (2.69; 2.46-2.93) |
↑ 470% (5.70; 4.82-6.74) |
2-mg single oral dose‡ |
400 mg (oral suspension) BID x 7 days |
↑138% (2.38; 2.13-2.66) |
↑397% (4.97; 4.46-5.54) |
Rifabutin |
300 mg QD x 17 days |
200 mg (tablets) QD x 10 days† |
↑ 31% (1.31; 1.10-1.57) |
↑72% (1.72;1.51-1.95) |
Phenytoin |
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) |
Ritonavir |
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) |
Atazanavir Atazanavir/ ritonavir boosted regimen |
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) |
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 coadministered drug plus
posaconazole to coadministered drug alone for Cmax or AUC.
† The tablet refers to a non-commercial tablet formulation without polymer.
‡ The mean terminal half-life of midazolam was increased from 3 hours to 7 to
11 hours during coadministration with posaconazole. |
Additional clinical studies
demonstrated that no clinically significant effects on zidovudine, lamivudine,
indinavir, or caffeine were observed when administered with posaconazole 200 mg
QD; therefore, no dose adjustments are required for these coadministered drugs
when coadministered with posaconazole 200 mg QD.
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 injection is
eliminated with a mean terminal half-life (t½) of 27 hours and a total body
clearance (CL) of 7.3 L/h.
Posaconazole delayed-release
tablet is eliminated with a mean half-life (t½) ranging between 26 to 31 hours.
Posaconazole oral suspension is
eliminated with a mean half-life (t½) of 35 hours (range: 2066 hours).
Microbiology
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].
Microorganisms
Aspergillus spp. and Candida
spp.
Susceptibility Testing
Posaconazole interpretive
criteria (breakpoints) have not been established.
Animal Toxicology And/Or Pharmacology
In a nonclinical study using intravenous administration
of posaconazole in very young dogs (dosed from 2 to 8 weeks of age), an
increase in the incidence of brain ventricle enlargement was observed in
treated animals as compared with concurrent control animals. No difference in
the incidence of brain ventricle enlargement between control and treated
animals was observed following the subsequent 5month treatment-free period.
There were no neurologic, behavioral or developmental abnormalities in the dogs
with this finding, and a similar brain finding was not seen with oral
posaconazole administration to juvenile dogs (4 days to 9 months of age).
The clinical significance of this finding is unknown;
therefore, the use of posaconazole injection to patients under 18 years of age
is not recommended.
Clinical Studies
Prophylaxis Of Aspergillus And Candida Infections With Posaconazole
Oral Suspension
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 (Oral Suspension 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). 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 24 contains the results from Oral Suspension Study
1.
Table 24: Results from Blinded Clinical Study in
Prophylaxis of IFI in All Randomized Patients with Hematopoietic Stem Cell
Transplant (HSCT) and Graft-vs.-Host Disease (GVHD): Oral Suspension Study 1
|
Posaconazole
n=301 |
Fluconazole
n=299 |
On therapy plus 7 days |
Clinical Failure* |
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 Proven/probable funaal infection prior to death |
22 (7%) 2 (<1%) |
24 (8%) 6 (2%) |
SAF† |
27 (9%) |
25 (8%) |
Through 16 weeks |
Clinical Failure*,‡ |
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 funaal infection prior to death |
10 (3%) |
16 (5%) |
SAF† |
26 (9%) |
30 (10%) |
Event free lost to follow-up§ |
24 (8%) |
30 (10%) |
* Patients may have met more than one criterion defining
failure.
† Use of systemic antifungal therapy (SAF) criterion is based on protocol
definitions (empiric/IFI usage >4 consecutive days).
‡ 95% confidence interval (posaconazole-fluconazole) = (-11.5%, +3.7%).
§ 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 (Oral
Suspension Study 2) was a randomized, open-label study that compared
posaconazole 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 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 25 contains the results from Oral
Suspension Study 2.
Table 25: Results from
Open-Label Clinical Study 2 in Prophylaxis of IFI in All Randomized Patients
with Hematologic Malignancy and Prolonged Neutropenia: Oral Suspension Study 2
|
Posaconazole
n=304 |
Fluconazole/Itraconazole
n=298 |
On therapy plus 7 days |
Clinical Failure*† |
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 %) |
SAF‡ |
67 (22%) |
98 (33%) |
Through 100 days postrandomization |
Clinical Failure† |
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%) |
SAF‡ |
98 (32%) |
125 (42%) |
Event free lost to follow-up§ |
34 (11%) |
24 (8%) |
* 95% confidence interval
(posaconazole-fluconazole/itraconazole) = (-22.9%, -7.8%).
† Patients may have met more than one criterion defining failure.
‡ Use of systemic antifungal therapy (SAF) criterion is based on protocol
definitions (empiric/IFI usage >3 consecutive days).
§ 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, 2 clinical studies
of prophylaxis were conducted with the posaconazole oral suspension. As seen in
the accompanying tables (Tables 24 and 25), clinical failure represented a
composite endpoint of breakthrough IFI, mortality and use of systemic antifungal
therapy. In Oral Suspension Study 1 (Table 24), 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 Oral Suspension Study 2 (Table
25) 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 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 Oral Suspension 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.
Treatment Of Oropharyngeal
Candidiasis With Posaconazole Oral Suspension
Posaconazole Oral Suspension
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 1 dose of study medication and had
a positive oral swish culture of Candida species at baseline were included in
the analyses (see Table 26). 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 (see Table 26).
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 26).
Table 26: Posaconazole Oral Suspension 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 posttreatment 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.
Posaconazole Oral Suspension
Treatment Of Oropharyngeal Candidiasis Refractory To Treatment With Fluconazole
Or Itraconazole
Posaconazole Oral Suspension
Study 4 was a noncomparative 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 greater than or equal to 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, 89 subjects met these strict criteria for refractory
infection.
Forty-five subjects with
refractory OPC were treated with posaconazole oral suspension 400 mg BID for 3
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 28 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).