Pharmacotherapeutic group: Antimycotics for systemic use, triazole derivatives, ATC code: J02AC04.
Mechanism of action
Posaconazole inhibits the enzyme lanosterol 14α-demethylase (CYP51), which catalyses an essential step in ergosterol biosynthesis.
Microbiology
Posaconazole has been shown in vitro to be active against the following microorganisms: Aspergillus species (Aspergillus fumigatus, A. flavus, A. terreus, A. nidulans, A. niger, A. ustus), Candida species (Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis, C. dubliniensis, C. famata, C. inconspicua, C. lipolytica, C. norvegensis, C. pseudotropicalis), Coccidioides immitis, Fonsecaea pedrosoi, and species of Fusarium, Rhizomucor, Mucor, and Rhizopus. The microbiological data suggest that posaconazole is active against Rhizomucor, Mucor, and Rhizopus; however the clinical data are currently too limited to assess the efficacy of posaconazole against these causative agents.
The following in vitro data are available, but their clinical significance is unknown. In a surveillance study of > 3,000 clinical mold isolates from 2010-2018, 90 % of non-Aspergillus fungi exhibited the following in vitro minimum inhibitory concentration (MIC): Mucorales spp (n=81) of 2 mg/L; Scedosporium apiospermum/S. boydii (n=65) of 2 mg/L; Exophiala dermatiditis (n=15) of 0.5 mg/L, and Purpureocillium lilacinum (n=21) of 1 mg/L.
Resistance
Clinical isolates with decreased susceptibility to posaconazole have been identified. The principle mechanism of resistance is the acquisition of substitutions in the target protein, CYP51.
Epidemiological Cut-off (ECOFF) Values for Aspergillus spp.
The ECOFF values for posaconazole, which distinguish the wild type population from isolates with acquired resistance, have been determined by EUCAST methodology.
EUCAST ECOFF values:
• Aspergillus flavus: 0.5 mg/L
• Aspergillus fumigatus: 0.5 mg/L
• Aspergillus nidulans: 0.5 mg/L
• Aspergillus niger: 0.5 mg/L
• Aspergillus terreus: 0.25 mg/L
There are currently insufficient data to set clinical breakpoints for Aspergillus spp. ECOFF values do not equate to clinical breakpoints.
Breakpoints
EUCAST MIC breakpoints for posaconazole [susceptible (S); resistant (R)]:
• Candida albicans: S ≤0.06 mg/L, R >0.06 mg/L
• Candida tropicalis: S ≤0.06 mg/L, R >0.06 mg/L
• Candida parapsilosis: S ≤0.06 mg/L, R >0.06 mg/L
• Candida dubliniensis: S ≤0.06 mg/L, R > 0.06 mg/L
There are currently insufficient data to set clinical breakpoints for other Candida species.
Combination with other antifungal agents
The use of combination antifungal therapies should not decrease the efficacy of either posaconazole or the other therapies; however, there is currently no clinical evidence that combination therapy will provide an added benefit.
Clinical experience
Summary of posaconazole concentrate for solution for infusion and tablet study invasive aspergillosis The safety and efficacy of posaconazole for the treatment of patients with invasive aspergillosis was evaluated in a double-blind controlled study (study-69) in 575 patients with proven, probable, or possible invasive fungal infections per EORTC/MSG criteria.
Patients were treated with posaconazole (n=288) concentrate for solution for infusion or tablet given at a dose of 300 mg QD (BID on Day 1). Comparator patients were treated with voriconazole (n=287) given IV at a dose of 6 mg/kg BID Day 1 followed by 4 mg/kg BID, or orally at a dose of 300 mg BID Day 1 followed by 200 mg BID. Median treatment duration was 67 days (posaconazole) and 64 days (voriconazole).
In the intent-to-treat (ITT) population (all subjects who received at least one dose of study drug), 288 patients received posaconazole and 287 patients received voriconazole. The full analysis set population (FAS) is the subset of all subjects within the ITT population who were classified by independent adjudication as having proven or probable invasive aspergillosis: 163 subjects for posaconazole and 171 subjects for voriconazole. The all-cause mortality and global clinical response in these two populations are presented in Table 3 and 4, respectively.
Table 3. Posaconazole invasive aspergillosis treatment study 1: all-cause mortality at Day 42 and Day 84, in the ITT and FAS populations
| | Posaconazole | Voriconazole | |
| Population | N | n (%) | N | n (%) | Difference* (95 % CI) |
| Mortality in ITT at Day 42 | 288 | 44 (15.3) | 287 | 59 (20.6) | -5.3 % (-11.6, 1.0) |
| Mortality in ITT at Day 84 | 288 | 81 (28.1) | 287 | 88 (30.7) | -2.5 % (-9.9, 4.9) |
| Mortality in FAS at Day 42 | 163 | 31 (19.0) | 171 | 32 (18.7) | 0.3% (-8.2, 8.8) |
| Mortality in FAS at Day 84 | 163 | 56 (34.4) | 171 | 53 (31.0) | 3.1% (-6.9, 13.1) |
| * Adjusted treatment difference based on Miettinen and Nurminen's method stratified by randomisation factor (risk for mortality/poor outcome), using Cochran-Mantel-Haenszel weighting scheme. |
Table 4. Posaconazole invasive aspergillosis treatment study 1: global clinical response at Week 6 and Week 12 in the FAS population
| | Posaconazole | Voriconazole | |
| Population | N | Success (%) | N | Success (%) | Difference* (95 % CI) |
| Global clinical response in the FAS at 6 weeks | 163 | 73 (44.8) | 171 | 78 (45.6) | -0.6 % (-11.2, 10.1) |
| Global clinical response in the FAS at 12 weeks | 163 | 69 (42.3) | 171 | 79 (46.2) | -3.4 % (-13.9, 7.1) |
| * Successful Global Clinical Response was defined as survival with a partial or complete response Adjusted treatment di ference based on Miettinen and Nurminen's method stratified by randomisation factor (risk for mortality/poor outcome), using Cochran-Mantel-Haenszel weighting scheme. |
Summary of posaconazole tablet bridging study
Study 5615 was a non-comparative multi-center study performed to evaluate the pharmacokinetic properties, safety, and tolerability of posaconazole tablet. Study 5615 was conducted in a similar patient population to that previously studied in the pivotal posaconazole oral suspension clinical program. The pharmacokinetics and safety data from Study 5615 were bridged to the existing data (including efficacy data) with the oral suspension.
The subject population included: 1) patients with AML or MDS who had recently received chemotherapy and had developed or were anticipated to develop significant neutropenia, or 2) patients who had undergone a HSCT and were receiving immunosuppressive therapy for prevention or treatment of GVHD. Two different dosing groups were evaluated: 200 mg twice daily on Day 1, followed by 200 mg once daily thereafter (Part IA) and 300 mg twice daily on Day 1, followed by 300 mg once daily thereafter (Part 1B and Part 2).
Serial PK samples were collected on Day 1 and at steady-state on Day 8 for all Part 1 subjects and a subset of Part 2 subjects. Moreover, sparse PK samples were collected at several days during steady state before the next dose (Cmin) for a larger subject population. Based on average Cmin concentrations, a predicted average concentration (Cav) could be calculated for 186 subjects dosed with 300 mg. PK analysis in patients of Cav found that 81 % of the subjects treated with the 300 mg once daily dose attained steady state predicted Cav between 500-2,500 ng/mL. One subject (<1 %) had a predicted Cav below 500 ng/mL and 19 % of the subjects had a predicted Cav above 2,500 ng/mL. Subjects achieved a mean predicted Cav at steady state of 1,970 ng/mL.
In Table 5 a comparison is shown of exposure (Cav) after administration of posaconazole tablet and posaconazole oral suspension at therapeutic doses in patients depicted as quartile analysis. Exposures after tablet administration are generally higher than, but overlapping with, exposures after administration of posaconazole oral suspension.
Table 5. Cav quartile analyses of pivotal patient studies with posaconazole tablet and oral suspension
| | Posaconazole tablet | Posaconazole oral suspension |
| | Prophylaxis in AML and HSCT Study 5615 | Prophylaxis in GVHD Study 316 | Prophylaxis in Neutropenia Study 1899 | Treatment - Invasive Aspergillosis Study 0041 |
| | 300 mg once daily (Day 1 300 mg twice daily)* | 200 mg three times daily | 200 mg three times daily | 200 mg four times daily (hospitalized) then 400 mg twice daily |
| Quartile | pCav Range (ng/mL) | Cav Range (ng/mL) | Cav Range (ng/mL) | Cav Range (ng/mL) |
| Q1 | 442 – 1,223 | 22 – 557 | 90 – 322 | 55 – 277 |
| Q2 | 1,240 – 1,710 | 557 – 915 | 322 – 490 | 290 – 544 |
| Q3 | 1,719 – 2,291 | 915 – 1,563 | 490 – 734 | 550 – 861 |
| Q4 | 2,304 – 9,523 | 1,563 – 3,650 | 734 – 2,200 | 877 – 2,010 |
| pCav: predicted Cav Cav = the average concentration when measured at steady state *20 patients received 200 mg once daily (Day 1 200 mg twice daily) |
Summary of posaconazole oral suspension studies
Invasive aspergillosis
Oral posaconazole suspension 800 mg/day in divided doses was evaluated for the treatment of invasive aspergillosis in patients with disease refractory to amphotericin B (including liposomal formulations) or itraconazole or in patients who were intolerant of these medicinal products in a non- comparative salvage therapy trial (Study 0041). Clinical outcomes were compared with those in an external control group derived from a retrospective review of medical records. The external control group included 86 patients treated with available therapy (as above) mostly at the same time and at the same sites as the patients treated with posaconazole. Most of the cases of aspergillosis were considered to be refractory to prior therapy in both the posaconazole group (88 %) and in the external control group (79 %).
As shown in Table 6, a successful response (complete or partial resolution) at the end of treatment was seen in 42 % of posaconazole-treated patients compared to 26 % of the external group. However, this was not a prospective, randomised controlled study and so all comparisons with the external control group should be viewed with caution.
Table 6. Overall efficacy of posaconazole oral suspension at the end of treatment for invasive aspergillosis in comparison to an external control group
| | Posaconazole oral suspension | External control group |
| Overall Response | 45/107 (42 %) | 22/86 (26 %) |
| Success by Species All mycologically confirmed Aspergillus spp.1 | 34/76 | (45 %) | 19/74 | (26 %) |
| A. fumigatus | 12/29 | (41 %) | 12/34 | (35 %) |
| A. flavus | 10/19 | (53 %) | 3/16 | (19 %) |
| A. terreus | 4/14 | (29 %) | 2/13 | (15 %) |
| A. niger | 3/5 | (60 %) | 2/7 | (29 %) |
Fusarium spp.
11 of 24 patients who had proven or probable fusariosis were successfully treated with posaconazole oral suspension 800 mg/day in divided doses for a median of 124 days and up to 212 days. Among eighteen patients who were intolerant or had infections refractory to amphotericin B or itraconazole, seven patients were classed as responders.
Chromoblastomycosis/Mycetoma
9 of 11 patients were successfully treated with posaconazole oral suspension 800 mg/day in divided doses for a median of 268 days and up to 377 days. Five of these patients had chromoblastomycosis due to Fonsecaea pedrosoi and 4 had mycetoma, mostly due to Madurella species.
Coccidioidomycosis
11 of 16 patients were successfully treated (at the end of treatment complete or partial resolution of signs and symptoms present at baseline) with posaconazole oral suspension 800 mg/day in divided doses for a median of 296 days and up to 460 days.
Prophylaxis of Invasive Fungal Infections (IFIs) (Studies 316 and 1899)
Two randomised, controlled prophylaxis studies were conducted among patients at high risk for developing invasive fungal infections.
Study 316 was a randomised, double-blind trial of posaconazole oral suspension (200 mg three times a day) versus fluconazole capsules (400 mg once daily) in allogeneic hematopoietic stem cell transplant recipients with graft-versus-host disease (GVHD). The primary efficacy endpoint was the incidence of proven/probable IFIs at 16 weeks post-randomization as determined by an independent, blinded external expert panel.
A key secondary endpoint was the incidence of proven/probable IFIs during the on-treatment period (first dose to last dose of study medicinal product + 7 days). The majority (377/600, [63 %]) of patients included had Acute Grade 2 or 3 or chronic extensive (195/600, [32.5 %]) GVHD at study start. The mean duration of therapy was 80 days for posaconazole and 77 days for fluconazole.
Study 1899 was a randomised, evaluator-blinded study of posaconazole oral suspension (200 mg three times a day) versus fluconazole suspension (400 mg once daily) or itraconazole oral solution (200 mg twice a day) in neutropenic patients who were receiving cytotoxic chemotherapy for acute myelogenous leukaemia or myelodysplastic syndromes. The primary efficacy endpoint was the incidence of proven/probable IFIs as determined by an independent, blinded external expert panel during the on-treatment period. A key secondary endpoint was the incidence of proven/probable IFIs at 100 days post-randomization. New diagnosis of acute myelogenous leukaemia was the most common underlying condition (435/602, [72 %]). The mean duration of therapy was 29 days for posaconazole and 25 days for fluconazole/itraconazole.
In both prophylaxis studies, aspergillosis was the most common breakthrough infection. See Table 7 and 8 for results from both studies. There were fewer breakthrough Aspergillus infections in patients receiving posaconazole prophylaxis when compared to control patients.
Table 7. Results from clinical studies in prophylaxis of Invasive Fungal Infections
| Study | Posaconazole oral suspension | Controla | P-Value |
| Proportion (%) of patients with proven/probable IFIs |
| On-treatment periodb |
| 1899d | 7/304 (2) | 25/298 (8) | 0.0009 |
| 316e | 7/291 (2) | 22/288 (8) | 0.0038 |
| Fixed-time periodc |
| 1899d | 14/304 (5) | 33/298 (11) | 0.0031 |
| 316 d | 16/301 (5) | 27/299 (9) | 0.0740 |
FLU = fluconazole; ITZ = itraconazole; POS = posaconazole.
a: FLU/ITZ (1899); FLU (316).
b: In 1899 this was the period from randomization to last dose of study medicinal product plus 7 days; in 316 it was the period from first dose to last dose of study medicinal product plus 7 days.
c: In 1899, this was the period from randomization to 100 days post-randomization; in 316 it was the period from the baseline day to 111 days post-baseline.
d: All randomized
e: All treated
Table 8. Results from clinical studies in prophylaxis of Invasive Fungal Infections
| Study | Posaconazole oral suspension | Controla |
| Proportion (%) of patients with proven/probable Aspergillosis |
| On-treatment periodb |
| 1899d | 2/304 (1) | 20/298 (7) |
| 316e | 3/291 (1) | 17/288 (6) |
| Fixed-time periodc |
| 1899d | 4/304 (1) | 26/298 (9) |
| 316 d | 7/301 (2) | 21/299 (7) |
FLU = fluconazole; ITZ = itraconazole; POS = posaconazole.
a: FLU/ITZ (1899); FLU (316).
b: In 1899 this was the period from randomization to last dose of study medicinal product plus 7 days; in 316 it was the period from first dose to last dose of study medicinal product plus 7 days.
c: In 1899, this was the period from randomization to 100 days post-randomization; in 316 it was the period from the baseline day to 111 days post-baseline.
d: All randomized
e: All treated
In Study 1899, a significant decrease in all cause mortality in favour of posaconazole was observed [POS 49/304 (16 %) vs. FLU/ITZ 67/298 (22 %) p= 0.048]. Based on Kaplan-Meier estimates, the probability of survival up to day 100 after randomization, was significantly higher for posaconazole recipients; this survival benefit was demonstrated when the analysis considered all causes of death (P= 0.0354) as well as IFI-related deaths (P = 0.0209).
In Study 316, overall mortality was similar (POS, 25 %; FLU, 28 %); however, the proportion of IFI- related deaths was significantly lower in the POS group (4/301) compared with the FLU group (12/299; P= 0.0413).
Paediatric population
There is limited paediatric experience for posaconazole tablets.
Three patients 14-17 years of age were treated with posaconazole concentrate for solution for infusion and tablet 300 mg/day (BID on Day 1 followed by QD thereafter) in the study of treatment of invasive aspergillosis.
The safety and efficacy of posaconazole for oral suspension have been established in paediatric patients 2 to less than 18 years of age. Use of posaconazole in these age groups is supported by evidence from adequate and well-controlled studies of posaconazole in adults and pharmacokinetic and safety data from paediatric studies (see section 5.2). No new safety signals associated with the use of posaconazole in paediatric patients were identified in the paediatric studies (see section 4.8).
Safety and efficacy in paediatric patients below the age of 2 years have not been established. No data are available.
Electrocardiogram evaluation
Multiple, time-matched ECGs collected over a 12 hour period were obtained before and during administration of posaconazole oral suspension (400 mg twice daily with high fat meals) from 173 healthy male and female volunteers aged 18 to 85 years. No clinically relevant changes in the mean QTc (Fridericia) interval from baseline were observed.
1 Includes other less common species or species unknown