Pharmacotherapeutic group: antimycotics for systemic use, other antimycotics for systemic use, ATC code: J02AX06
Mechanism of action
Anidulafungin is a semi-synthetic echinocandin, a lipopeptide synthesised from a fermentation product of Aspergillus nidulans.
Anidulafungin selectively inhibits 1,3-β-D-glucan synthase, an enzyme present in fungal cells but not in mammalian cells. This leads to inhibition of the formation of 1,3-β-D-glucan, an essential component of the fungal cell wall. Anidulafungin exhibits fungicidal activity against Candida species and activity against regions of active cell growth of Aspergillus fumigatus hyphae.
In vitro efficacy
Anidulafungin is active in vitro against Candida species C. albicans, C. glabrata, C. parapsilosis, C. krusei, and C. tropicalis. The clinical relevance of these findings is described in the section "Clinical efficacy and safety".
Isolates with mutations in hot spot regions of the target gene have been associated with clinical treatment failure or breakthrough infections. Most clinical cases involved caspofungin treatment. However, in animal studies these mutations confer cross-resistance to all three echinocandins, and therefore these isolates are classified as echinocandin-resistant until further clinical experience with anidulafungin is available.
The in vitro efficacy of anidulafungin against Candida species is not uniform. Specifically, for C. parapsilosis, anidulafungin MIC values are higher than for other Candida species. The standardised susceptibility testing procedure for Candida species against anidulafungin, as well as the corresponding interpretive breakpoints, have been established by the European Committee on Antimicrobial Susceptibility Testing (EUCAST).
Susceptibility testing breakpoints
The European Committee on Antimicrobial Susceptibility Testing (EUCAST) has established the following minimum inhibitory concentration (MIC) interpretive criteria for anidulafungin susceptibility testing: https://www.ema.europa.eu/documents/other/minimum-inhibitory-concentration-mic-breakpoints_en.xlsx
In vivo efficacy
Parenterally administered anidulafungin was effective against Candida species in immunocompetent and immunocompromised mouse and rabbit models. Treatment with anidulafungin prolonged survival and also reduced Candida species organ burden when anidulafungin therapy was initiated within a 24- to 96-hour interval after the last treatment.
Experimental infections included disseminated C. albicans infection in neutropenic rabbits, oesophageal/oral infection in neutropenic rabbits with a fluconazole-resistant strain of C. albicans, and disseminated infection in neutropenic mice with a fluconazole-resistant strain of C. glabrata.
Clinical efficacy and safety
Candidaemia and other forms of invasive candidiasis
The safety and efficacy of anidulafungin were evaluated in a pivotal randomised, double-blind, multicentre, multinational phase 3 study primarily in non-neutropenic patients with candidaemia and in a limited number of patients with deep-tissue Candida infection or abscess-forming infection. Patients with Candida endocarditis, osteomyelitis, or meningitis, or with infection caused by C. krusei were excluded from the study. Randomised patients received anidulafungin i.v. (200 mg loading dose followed by 100 mg daily), or fluconazole i.v. (800 mg loading dose followed by 400 mg daily). Patients were stratified by APACHE II score (≤20 and >20) and the presence or absence of neutropenia. Treatment was administered for at least 14 days and no longer than 42 days.
Patients in both study arms could switch to oral fluconazole after at least 10 days of intravenous therapy, provided they were able to tolerate oral medicinal products, had been afebrile for at least the previous 24 hours, and the last blood cultures were Candida-negative.
Patients who received at least one dose of study medication and who had a positive culture for Candida species from a normally sterile site prior to study enrolment were included in the MITT (modified intent-to-treat) population. In the primary efficacy analysis of global response in the MITT population at the end of intravenous therapy, anidulafungin was compared with fluconazole in a pre-specified two-step statistical comparison (non-inferiority followed by superiority). Successful global response required clinical improvement and microbiological eradication. Patients were followed for 6 weeks after end of treatment.
Two hundred and fifty-six patients (aged 16–91 years) were randomised and received at least one dose of study medication. The most frequently isolated species at baseline were C. albicans (63.8% anidulafungin, 59.3% fluconazole), followed by C. glabrata (15.7%; 25.4%), C. parapsilosis (10.2%; 13.6%), and C. tropicalis (11.8%; 9.3%), with 20, 13, and 15 isolates of the last 3 species respectively in the anidulafungin group. The majority of patients had an APACHE II score of 20 or less and very few were neutropenic.
Efficacy data, overall and by subgroup, are presented in Table 3.
Table 3. Global success in the MITT population: primary and secondary endpoints
Anidulafungin
Fluconazole
Treatment difference
a
(95% CI)
End of i.v. therapy (primary endpoint)
96/127 (75.6%)
71/118 (60.2%)
15.42 (3.9; 27.0)
Candidaemia only
88/116 (75.9%)
63/103 (61.2%)
14.7 (2.5; 26.9)
Other sterile sites
b
8/11 (72.7%)
8/15 (53.3%)
-
Peritoneal fluid/IA
c
abscess
6/8
5/8
Other
2/3
3/7
C. albicans
d
60/74 (81.1%)
38/61 (62.3%)
-
Non-albicans species
d
32/45 (71.1%)
27/45 (60.0%)
-
APACHE II score ≤20
82/101 (81.2%)
60/98 (61.2%)
-
APACHE II score >20
14/26 (53.8%)
11/20 (55.0%)
-
Non-neutropenic (ANC, cells/mm
3
>500)
94/124 (75.8%)
69/114 (60.5%)
-
Neutropenic (ANC, cells/mm
3
≤500)
2/3
2/4
-
Other endpoints
End of all therapy
94/127 (74.0%)
67/118 (56.8%)
17.24 (2.9; 31.6)
e
2-week follow-up
82/127 (64.6%)
58/118 (49.2%)
15.41 (0.4; 30.4)
e
6-week follow-up
71/127 (55.9%)
52/118 (44.1%)
11.84 (-3.4; 27.0)
e
a Calculated as anidulafungin minus fluconazole
b With or without concurrent candidaemia
c Intra-abdominal
d Data presented for patients with a single baseline pathogen
e
98.3% confidence intervals adjusted post hoc for multiple comparisons of secondary endpoints
Mortality rates in both the anidulafungin and fluconazole arms are presented in Table 4.
Table 4. Mortality
Anidulafungin
Fluconazole
Overall study mortality
29/127 (22.8%)
37/118 (31.4%)
Mortality during study therapy
10/127 (7.9%)
17/118 (14.4%)
Mortality attributed to Candida infection
2/127 (1.6%)
5/118 (4.2%)
Additional data in neutropenic patients
The efficacy of anidulafungin (200 mg intravenous loading dose followed by 100 mg intravenous daily dose) in adult neutropenic patients (defined as absolute neutrophil count ≤500 cells/mm
3
, white blood cell count ≤500 cells/mm
3
, or patients classified by the investigator as having neutropenia at study entry) with microbiologically confirmed invasive candidiasis was evaluated in a pooled data analysis from 5 prospective studies (1 comparative versus caspofungin and 4 open-label, non-comparative).
Patients were treated for a minimum of 14 days. Clinically stable patients were permitted to switch to oral azole therapy after at least 5 to 10 days of anidulafungin treatment. A total of 46 patients were included in the analysis. The majority of patients had candidaemia only (84.8%; 39/46). The most common pathogens isolated at baseline were C. tropicalis (34.8%; 16/46), C. krusei (19.6%; 9/46), C. parapsilosis (17.4%; 8/46), C. albicans (15.2%; 7/46), and C. glabrata (15.2%; 7/46). The successful global response rate at the end of intravenous therapy (primary endpoint) was 26/46 (56.5%) and at the end of all therapy was 24/46 (52.2%). All-cause mortality up to the end of the study (6-week follow-up visit) was 21/46 (45.7%).
The efficacy of anidulafungin in adult neutropenic patients (defined as absolute neutrophil count ≤500 cells/mm
3
at study entry) with invasive candidiasis was evaluated in a prospective, double-blind, randomised clinical trial. Eligible patients received either anidulafungin (200 mg intravenous loading dose followed by 100 mg intravenous daily dose) or caspofungin (70 mg intravenous loading dose followed by 50 mg intravenous daily dose) (2:1 randomisation). Patients were treated for a minimum of 14 days. Clinically stable patients were permitted to switch to oral azole therapy after at least 10 days of study treatment. A total of 14 neutropenic patients with microbiologically confirmed invasive candidiasis (MITT population) were enrolled (11 received anidulafungin, 3 caspofungin). The majority of patients had candidaemia only. The most common pathogens isolated at baseline were C. tropicalis (4 anidulafungin, 0 caspofungin), C. parapsilosis (2 anidulafungin, 1 caspofungin), C. krusei (2 anidulafungin, 1 caspofungin), and C. ciferrii (2 anidulafungin, 0 caspofungin). The successful global response rate at the end of intravenous therapy (primary endpoint) was 8/11 (72.7%) for anidulafungin and 3/3 (100.0%) for caspofungin (difference -27.3, 95% CI -80.9, 40.3). The successful global response rate at the end of all therapy was 8/11 (72.7%) for anidulafungin and 3/3 (100.0%) for caspofungin (difference -27.3, 95% CI -80.9, 40.3). All-cause mortality up to the 6-week follow-up visit was 4/11 (36.4%) for anidulafungin (MITT population) and 2/3 (66.7%) for caspofungin.
Patients with microbiologically confirmed invasive candidiasis (MITT population) and neutropenia were identified in a pooled data analysis from 4 studies with a similar design in a prospective, open-label clinical trial without a comparator. The efficacy of anidulafungin (200 mg intravenous loading dose followed by 100 mg intravenous daily dose) was evaluated in 35 adult neutropenic patients, defined as absolute neutrophil count ≤500 cells/mm
3
in 22 patients, or white blood cell count ≤500 cells/mm
3
in 13 patients classified by the investigator as having neutropenia at study entry. Patients were treated for a minimum of 14 days. Clinically stable patients were permitted to switch to oral azole therapy after at least 5 to 10 days of anidulafungin treatment. The majority of patients had candidaemia only (85.7%). The most common pathogens isolated at baseline were C. tropicalis (12 patients), C. albicans (7 patients), C. glabrata (7 patients), C. krusei (7 patients), and C. parapsilosis (6 patients). The successful global response rate at the end of intravenous therapy (primary endpoint) was 18/35 (51.4%) and at the end of all therapy was 16/35 (45.7%). All-cause mortality at day 28 was 10/35 (28.6%). The successful global response rate at the end of intravenous therapy and at the end of all therapy was 7/13 (53.8%) in the 13 patients with neutropenia as assessed by the investigator at study entry.
Additional data in patients with deep-tissue infections
The efficacy of anidulafungin (200 mg intravenous loading dose followed by 100 mg intravenous daily dose) in adult patients with microbiologically confirmed deep-tissue candidiasis was evaluated in a pooled data analysis from 5 prospective studies (1 comparative and 4 open-label). Patients were treated for a minimum of 14 days. In the 4 open-label studies, clinically stable patients were permitted to switch to oral azole therapy after at least 5 to 10 days of anidulafungin treatment. A total of 129 patients were included in the analysis. Twenty-one (16.3%) had concurrent candidaemia. The mean APACHE II score was 14.9 (range 2–44). The most common sites of infection included the peritoneal cavity (54.3%; 70 of 129), biliary tract (7.0%; 9 of 129), pleural cavity (5.4%; 7 of 129), and kidneys (3.1%; 4 of 129). The most common pathogens isolated from deep tissues at baseline included C. albicans (64.3%; 83 of 129), C. glabrata (31.0%; 40 of 129), C. tropicalis (11.6%; 15 of 129), and C. krusei (5.4%; 7 of 129). The successful global response rate at the end of intravenous therapy (primary endpoint) and at the end of all therapy, and all-cause mortality up to the 6-week follow-up visit are presented in Table 5.
Table 5. Successful global response rate
a
and all-cause mortality in patients with deep-tissue candidiasis – pooled analysis
MITT population n/N (%)
Successful global response at EOIVT
b
Total
102/129 (79.1)
Peritoneal cavity
51/70 (72.9)
Biliary tract
7/9 (77.8)
Pleural cavity
6/7 (85.7)
Kidneys
3/4 (75.0)
Successful global response at EOT
b
94/129 (72.9)
All-cause mortality
40/129 (31.0)
a Successful global response was defined as clinical and microbiological success of treatment.
b EOIVT, End of Intravenous Treatment; EOT, End of All Treatment
Paediatric population
In a prospective, open-label, non-comparative, multinational study, the safety and efficacy of anidulafungin were evaluated in 68 paediatric patients aged 1 month to <18 years with invasive candidiasis including candidaemia (ICC). Patients were stratified by age (1 month to <2 years, 2 years to <5 years, and 5 years to <18 years) and received anidulafungin intravenously once daily for up to 35 days (loading dose of 3.0 mg/kg on day 1 followed by a maintenance dose of 1.5 mg/kg daily), after which patients could be switched to oral fluconazole (6–12 mg/kg/day, maximum 800 mg/day). Follow-up visits were conducted at 2 and 6 weeks after EOT.
Of 68 patients who received anidulafungin, 64 patients had microbiologically confirmed Candida infection and efficacy was evaluated in the MITT (modified intent-to-treat) population. A total of 61 patients (92.2%) had a Candida pathogen isolated from blood only.
The most frequently isolated pathogens were Candida albicans (25 [39.1%] patients), Candida parapsilosis (17 [26.6%] patients), and Candida tropicalis (9 [14.1%] patients). Successful global response was defined as successful clinical response (cure or improvement) and successful microbiological response (eradication or presumed eradication). Successful global response rates in the MITT population are presented in Table 6.
Table 6. Summary of successful global response by age, MITT population
Successful global response, n (%)
Endpoint
Global
1 month to <2 years
2 years to
5 years to <18 years
Total
response
(N = 16) n (n/N, %)
<5 years (N = 18) n (n/N, %)
(N = 30) n (n/N, %)
(N = 64) n (n/N, %)
EOIVT
successful
11 (68.8)
14 (77.8)
20 (66.7)
45 (70.3)
95% CI
(41.3; 89.0)
(52.4; 93.6)
(47.2; 82.7)
(57.6; 81.1)
EOT
successful
11 (68.8)
14 (77.8)
21 (70.0)
46 (71.9)
95% CI
(41.3; 89.0)
(52.4; 93.6)
(50.6; 85.3)
(59.2; 82.4)
2-week follow-up
successful
11 (68.8)
13 (72.2)
22 (73.3)
46 (71.9)
95% CI
(41.3; 89.0)
(46.5; 90.3)
(54.1; 87.7)
(59.2; 82.4)
6-week follow-up
successful
11 (68.8)
12 (66.7)
20 (66.7)
43 (67.2)
95% CI
(41.3; 89.0)
(41.0; 86.7)
(47.2; 82.7)
(54.3; 78.4)
95% CI = confidence interval for the binomial distribution parameter using the Clopper-Pearson method; EOIVT = End of Intravenous Treatment; EOT = End of All Treatment; FU = follow-up; MITT = modified intent-to-treat; N = number of subjects in the population; n = number of responding subjects
⚠️ Warnings
Anidulafungin Accord has not been studied in patients with Candida endocarditis, osteomyelitis, or meningitis.
The efficacy of Anidulafungin Accord has been evaluated only in a limited number of neutropenic patients (see section 5.1).
Paediatric population
Treatment with ECALTA is not recommended in neonates (<1 month). When treating neonates, therapy for disseminated candidiasis involving the central nervous system (CNS) should be considered.
Non-clinical models of infection indicate that higher doses of anidulafungin are required for adequate CNS penetration (see section 5.3), which also leads to higher doses of the excipient polysorbate 80. According to the literature, high doses of polysorbates are associated with potentially life-threatening toxicity in neonates.
There are no clinical data supporting the efficacy and safety of higher doses of anidulafungin than those recommended in section 4.2.
Effects on the liver
Elevated liver enzymes have been observed in healthy volunteers and patients treated with anidulafungin. Clinically significant liver test abnormalities occurred in some patients with serious underlying medical conditions who were receiving concomitant medications with anidulafungin. Cases of significant hepatic dysfunction, hepatitis, and hepatic failure were uncommon in clinical studies. Patients who develop elevated liver enzymes during anidulafungin therapy should be carefully monitored for signs of worsening hepatic function and the benefit/risk of continuing anidulafungin therapy should be evaluated.
Anaphylactic reactions
Anaphylactic reactions, including shock, have been reported with the use of anidulafungin. If such reactions occur, anidulafungin should be discontinued and appropriate treatment administered.
Infusion-related reactions
Infusion-related reactions have been reported with the use of anidulafungin, including rash, urticaria, flushing, pruritus, dyspnoea, bronchospasm, and hypotension. Infusion-related reactions are infrequent when the rate of infusion of anidulafungin does not exceed 1.1 mg/min.
Exacerbation of infusion-related reactions upon concomitant administration of anaesthetics was observed in a non-clinical study in rats (see section 5.3). The clinical significance of this finding is unknown. However, caution should be exercised when anidulafungin is administered concomitantly with anaesthetics.
Fructose content
Anidulafungin Accord contains fructose.
This medicinal product must not be given to patients with hereditary fructose intolerance unless strictly necessary.
In infants and young children (below 2 years of age), hereditary fructose intolerance (HFI) may not yet be diagnosed. Medicinal products (containing fructose) given intravenously may be life-threatening and must be contraindicated in this population, unless there is an overwhelming clinical need and no alternatives are available.
A detailed history with respect to symptoms of HFI should be obtained from each patient before administration of this medicinal product.
Sodium content
Anidulafungin Accord contains less than 1 mmol sodium (23 mg) per vial. Patients on a controlled sodium diet may be informed that this medicinal product is essentially "sodium-free".
Anidulafungin Accord may be diluted with sodium-containing solutions (see section 6.6); this should be taken into account in relation to total sodium content from all sources that will be administered to the patient.