AAC Accepted Manuscript Posted Online 20 April 2015 Antimicrob. Agents Chemother. doi:10.1128/AAC.00234-15 Copyright © 2015, American Society for Microbiology. All Rights Reserved.
1 2
Antifungal Activity of SCY-078 (MK-3118) and Standard Antifungal Agents against Clinical non-Aspergillus Mold Isolates
3
Frédéric Lamoth1,2,3,4 and Barbara D. Alexander1,2 *
4 5
1
6
University Medical Center, Durham, North Carolina, USA
7
2
8
Durham, North Carolina, USA
9
3
Division of Infectious Diseases and International Health, Department of Medicine, Duke
Clinical Microbiology Laboratory, Department of Pathology, Duke University Medical Center,
Infectious Diseases Service, Department of Medicine, Lausanne University Hospital,
10
Lausanne, Switzerland
11
4
Institute of Microbiology, Lausanne University Hospital, Lausanne, Switzerland
12 13
Running title: SCY-078 against non-Aspergillus molds
14 15
Keywords: Mucoromycotina, Fusarium, Scedosporium, Paecilomyces, antifungal activity, betaglucan synthase inhibitor, echinocandins, amphotericin B, voriconazole, posaconazole
16
Word count: 1147 (text), 74 (abstract)
17 18 19
* Corresponding author:
20 21 22 23 24 25 26 27
Barbara Alexander Division of Infectious Diseases and International Health Box 102359 Duke University Medical Center Durham, NC 27710 Phone: (919) 668-0789 Fax: (919) 684-8902 E-mail: [email protected]
1
28
ABSTRACT
29
The limited armamentarium of active and oral antifungal drugs against emerging non-
30
Aspergillus molds is of particular concern. Current antifungal agents and the new orally
31
available beta-1,3-D-glucan synthase inhibitor, SCY-078, were tested in vitro against 135
32
clinical non-Aspergillus mold isolates. Akin to echinocandins, SCY-078 showed no or poor
33
activity against Mucoromycotina and Fusarium spp. However, SCY-078 was highly active
34
against Paecilomyces variotii and was the only compound displaying some activity against
35
notoriously pan-resistant Scedosporium prolificans.
2
36
TEXT
37
Invasive mold infections are a major threat for patients with chemotherapy-induced neutropenia
38
or long-term immunosuppressive therapy following allogeneic hematopoietic stem cell or solid-
39
organ transplantation. While Aspergillus spp. account for the majority of cases, invasive mold
40
infections due to non-Aspergillus molds are increasing and are associated with a particularly
41
high mortality rate (1, 2). Mucoromycotina (previously referred to as zygomycetes), Fusarium
42
spp., Scedosporium spp., Paecilomyces spp. and Scopulariopsis spp. are well-recognized
43
opportunistic fungal pathogens that often exhibit high MICs in vitro and clinical resistance to
44
currently available antifungal drugs (3-7). Amphotericin B, whilst not active against all of these
45
species, often remains the only therapeutic choice, but is associated with toxicity. The lack of
46
oral formulations is another major problem in the management of these infections which require
47
prolonged courses of antifungal treatment.
48 49
SCY-078 (formerly MK-3118) is a semi-synthetic derivative of the natural product enfumafungin,
50
a potent inhibitor of fungal beta-1,3-D-glucan synthases (8, 9). This compound is structurally
51
different from the echinocandins and has the advantage of having oral bioavailability. Its in vitro
52
activity against Candida spp. and Aspergillus spp. was recently demonstrated (10-12).
53 54
We retrospectively tested the in vitro antifungal activity of standard antifungal agents
55
(amphotericin B, voriconazole, itraconazole, posaconazole, caspofungin, micafungin and
56
anidulafungin) and SCY-078 against a collection of 135 selected clinical isolates representing
57
the most clinically relevant non-Aspergillus fungal pathogens including Rhizopus spp. (16),
58
Mucor spp. (7), Rhizomucor spp. (2), Cunninghamella spp. (4), Lichtheimia spp. (previously
59
Absidia spp.) (4), Fusarium spp. (35), Scedosporium apiospermum / Pseudallescheria boydii
60
complex (19), Scedosporium prolificans (5), Purpureocillium lilacinum (previously Paecilomyces
61
lilacinus) (30), Paecilomyces variotii (5), and Scopulariopsis spp. (8). All isolates were recovered 3
62
from clinical specimens at Duke University Hospital (Durham, NC, USA) between 2009 and
63
2013. The ATCC strain Paecilomyces variotii MYA3630 was used as control strain. Antifungal
64
susceptibility testing was performed by microbroth dilution method according to the Clinical and
65
Laboratory Standards (CLSI) M38-A2 procedure (13). SCY-078 powder was provided by the
66
manufacturer (Scynexis Inc., Durham, NC). According to CLSI recommendations, the minimal
67
inhibitory concentration (MIC, concentration at which no hyphal growth was detected) was
68
assessed for amphotericin B and azole compounds and the minimal effective concentration
69
(MEC, concentration at which hyphal growth was significantly altered with formation of blunted
70
colonies) was determined for echinocandins and SCY-078 (13); reading was performed at 24h
71
or 48h according to genus (13). MIC(MEC)50 and MIC(MEC)90 (i.e. concentrations that inhibit
72
50% and 90% isolates, respectively) were determined for each species. The study was
73
approved by the Duke Hospital Institutional Review Board.
74 75
The origin of isolates and characteristics of patients from whom they were obtained are shown
76
in Table 1. MIC(MEC)50 and MIC(MEC)90 of all fungal species are represented in Table 2.
77
Predictably, amphotericin B was the only drug displaying good universal activity against the
78
Mucoromycotina. Notably, posaconazole, the other agent with known clinical activity against this
79
group of organisms, displayed better activity against Cunninghamella and Lichtheimia spp. (7/8
80
had MIC 16 µg/ml for
81
56% and 71% of strains tested, respectively. Similarly, amphotericin B was the only active drug
82
against most Fusarium spp., although relatively high MICs (≥4 µg/ml) were observed in 40% of
83
cases. The echinocandins and SCY-078 had little activity against the Mucoromycotina or
84
Fusarium spp.
85 86
SCY-078 and the echinocandins had negligible effect against P. lilacinum but were very active
87
against P. variotii (MEC 16
Mucormycotina (33) Rhizopus spp. (16) Mucor spp. (7) Rhizomucor spp. (2) Lichtheimia spp. (4) Cunninghamella spp. (4)
Fusarium spp. (35)
Purpureocillium lilacinum (30) Paecilomyces variotii (5) Scopulariopsis spp. (8)
16 / 16
>16 / >16
>16 / >16
>16 / >16
0.5 / 2
16 / >16
>16 / >16
(16 - >16)
(>16)
(>16)
(>16)
(0.125 – 2)
(8 - >16)
(0.5 - >16)
(2 - >16)
16 / >16
>16 / >16
>16 / >16
>16 / >16
0.5 / 1
>16 / >16
>16 / >16
>16 / >16
(8 - >16)
(>16)
(>16)
(8 - >16)
(0.125 – 4)
(8 - >16)
(1 - >16)
(2 - >16)
16 - >16
>16
>16
8 - >16
0.25 – 1
>16
2 - >16
>16
8 / 16
>16 / >16
>16 / >16
8 / 16
1/2
>16 / >16
1 / >16
>16 / >16 (2 - >16)
(8 – 16)
(>16)
(>16)
(8 – 16)
(0.5 – 2)
(>16)
(1 - >16)
16 / 16
>16 / >16
>16 / >16
16 / 16
4/4
>16 / >16
1/2
4 / >16
(16)
(>16)
(>16)
(8 – 16)
(2 – 4)
(16 - >16)
(1 – 2)
(4 - >16) >16 / >16
8 / 16
>16 / >16
>16 / >16
>16 / >16
2/4
>16 / >16
>16 / >16
(8 – 16)
(8 - >16)
(2 - >16)
(8 - >16)
(1 - >16)
(2 - >16)
(2 - >16)
(>16)
>16 / >16
>16 / >16
>16 / >16
>16 / >16
>16 / >16
0.25 / 0.5
1/1
>16 / >16
(2 - >16)
(0.25 - >16)
(0.06 - >16)
(0.06 - >16)
(16 - >16)
(0.125 – 0.5)
(0.25 – 2)
(4 - >16)
16 / >16
(16)
4/8
0.5 / 8
1 / >16
8 / >16
8 / >16
>16 / >16
>16 / >16
>16 / >16
(4 – 8)
(0.25 – 16)
(16)
(16)
(2 - >16)
(16 - >16)
(>16)
(>16)
Scedosporium apiospermum /
2/4
0.5 / 1
1/2
8/8
8 / >16
1/1
>16 / >16
>16 / >16
Pseudoallescheria boydii (19)
(1 – 8)
(0.06 - >16)
(0.25 - >16)
(2 – 16)
(2 - >16)
(0.5 – 2)
(2 - >16)
(>16)
4/4
16 / 16
>16 / >16
8 / 16
>16 / >16
>16 / >16
>16 / >16
>16 / >16
(4)
(16)
(>16)
(8 – 16)
(8 - >16)
(>16)
(>16)
(>16)
Scedosporium prolificans (5)
12
221
Caspofungin (CSP), micafungin (MCF), anidulafungin (AND), amphotericin B (AMB), voriconazole (VCZ), posaconazole (POS),
222
itraconazole (ITZ).
223
1
224
to 16 µg/ml (11).
225
2
226
inhibit 50% and 90% isolates, respectively.
All drugs were tested via Clinical Laboratory Standards Institute microbroth dilution method within concentrations ranging from 0.02
Minimal inhibitory concentration (MIC), minimal effective concentration (MEC); MIC(MEC)50 and MIC(MEC)90, concentrations that
227
13
1 2
Antifungal Activity of SCY-078 (MK-3118) and Standard Antifungal Agents against Clinical non-Aspergillus Mold Isolates
3
Frédéric Lamoth1,2,3,4 and Barbara D. Alexander1,2 *
4 5
1
6
University Medical Center, Durham, North Carolina, USA
7
2
8
Durham, North Carolina, USA
9
3
Division of Infectious Diseases and International Health, Department of Medicine, Duke
Clinical Microbiology Laboratory, Department of Pathology, Duke University Medical Center,
Infectious Diseases Service, Department of Medicine, Lausanne University Hospital,
10
Lausanne, Switzerland
11
4
Institute of Microbiology, Lausanne University Hospital, Lausanne, Switzerland
12 13
Running title: SCY-078 against non-Aspergillus molds
14 15
Keywords: Mucoromycotina, Fusarium, Scedosporium, Paecilomyces, antifungal activity, betaglucan synthase inhibitor, echinocandins, amphotericin B, voriconazole, posaconazole
16
Word count: 1147 (text), 74 (abstract)
17 18 19
* Corresponding author:
20 21 22 23 24 25 26 27
Barbara Alexander Division of Infectious Diseases and International Health Box 102359 Duke University Medical Center Durham, NC 27710 Phone: (919) 668-0789 Fax: (919) 684-8902 E-mail: [email protected]
1
28
ABSTRACT
29
The limited armamentarium of active and oral antifungal drugs against emerging non-
30
Aspergillus molds is of particular concern. Current antifungal agents and the new orally
31
available beta-1,3-D-glucan synthase inhibitor, SCY-078, were tested in vitro against 135
32
clinical non-Aspergillus mold isolates. Akin to echinocandins, SCY-078 showed no or poor
33
activity against Mucoromycotina and Fusarium spp. However, SCY-078 was highly active
34
against Paecilomyces variotii and was the only compound displaying some activity against
35
notoriously pan-resistant Scedosporium prolificans.
2
36
TEXT
37
Invasive mold infections are a major threat for patients with chemotherapy-induced neutropenia
38
or long-term immunosuppressive therapy following allogeneic hematopoietic stem cell or solid-
39
organ transplantation. While Aspergillus spp. account for the majority of cases, invasive mold
40
infections due to non-Aspergillus molds are increasing and are associated with a particularly
41
high mortality rate (1, 2). Mucoromycotina (previously referred to as zygomycetes), Fusarium
42
spp., Scedosporium spp., Paecilomyces spp. and Scopulariopsis spp. are well-recognized
43
opportunistic fungal pathogens that often exhibit high MICs in vitro and clinical resistance to
44
currently available antifungal drugs (3-7). Amphotericin B, whilst not active against all of these
45
species, often remains the only therapeutic choice, but is associated with toxicity. The lack of
46
oral formulations is another major problem in the management of these infections which require
47
prolonged courses of antifungal treatment.
48 49
SCY-078 (formerly MK-3118) is a semi-synthetic derivative of the natural product enfumafungin,
50
a potent inhibitor of fungal beta-1,3-D-glucan synthases (8, 9). This compound is structurally
51
different from the echinocandins and has the advantage of having oral bioavailability. Its in vitro
52
activity against Candida spp. and Aspergillus spp. was recently demonstrated (10-12).
53 54
We retrospectively tested the in vitro antifungal activity of standard antifungal agents
55
(amphotericin B, voriconazole, itraconazole, posaconazole, caspofungin, micafungin and
56
anidulafungin) and SCY-078 against a collection of 135 selected clinical isolates representing
57
the most clinically relevant non-Aspergillus fungal pathogens including Rhizopus spp. (16),
58
Mucor spp. (7), Rhizomucor spp. (2), Cunninghamella spp. (4), Lichtheimia spp. (previously
59
Absidia spp.) (4), Fusarium spp. (35), Scedosporium apiospermum / Pseudallescheria boydii
60
complex (19), Scedosporium prolificans (5), Purpureocillium lilacinum (previously Paecilomyces
61
lilacinus) (30), Paecilomyces variotii (5), and Scopulariopsis spp. (8). All isolates were recovered 3
62
from clinical specimens at Duke University Hospital (Durham, NC, USA) between 2009 and
63
2013. The ATCC strain Paecilomyces variotii MYA3630 was used as control strain. Antifungal
64
susceptibility testing was performed by microbroth dilution method according to the Clinical and
65
Laboratory Standards (CLSI) M38-A2 procedure (13). SCY-078 powder was provided by the
66
manufacturer (Scynexis Inc., Durham, NC). According to CLSI recommendations, the minimal
67
inhibitory concentration (MIC, concentration at which no hyphal growth was detected) was
68
assessed for amphotericin B and azole compounds and the minimal effective concentration
69
(MEC, concentration at which hyphal growth was significantly altered with formation of blunted
70
colonies) was determined for echinocandins and SCY-078 (13); reading was performed at 24h
71
or 48h according to genus (13). MIC(MEC)50 and MIC(MEC)90 (i.e. concentrations that inhibit
72
50% and 90% isolates, respectively) were determined for each species. The study was
73
approved by the Duke Hospital Institutional Review Board.
74 75
The origin of isolates and characteristics of patients from whom they were obtained are shown
76
in Table 1. MIC(MEC)50 and MIC(MEC)90 of all fungal species are represented in Table 2.
77
Predictably, amphotericin B was the only drug displaying good universal activity against the
78
Mucoromycotina. Notably, posaconazole, the other agent with known clinical activity against this
79
group of organisms, displayed better activity against Cunninghamella and Lichtheimia spp. (7/8
80
had MIC 16 µg/ml for
81
56% and 71% of strains tested, respectively. Similarly, amphotericin B was the only active drug
82
against most Fusarium spp., although relatively high MICs (≥4 µg/ml) were observed in 40% of
83
cases. The echinocandins and SCY-078 had little activity against the Mucoromycotina or
84
Fusarium spp.
85 86
SCY-078 and the echinocandins had negligible effect against P. lilacinum but were very active
87
against P. variotii (MEC 16
Mucormycotina (33) Rhizopus spp. (16) Mucor spp. (7) Rhizomucor spp. (2) Lichtheimia spp. (4) Cunninghamella spp. (4)
Fusarium spp. (35)
Purpureocillium lilacinum (30) Paecilomyces variotii (5) Scopulariopsis spp. (8)
16 / 16
>16 / >16
>16 / >16
>16 / >16
0.5 / 2
16 / >16
>16 / >16
(16 - >16)
(>16)
(>16)
(>16)
(0.125 – 2)
(8 - >16)
(0.5 - >16)
(2 - >16)
16 / >16
>16 / >16
>16 / >16
>16 / >16
0.5 / 1
>16 / >16
>16 / >16
>16 / >16
(8 - >16)
(>16)
(>16)
(8 - >16)
(0.125 – 4)
(8 - >16)
(1 - >16)
(2 - >16)
16 - >16
>16
>16
8 - >16
0.25 – 1
>16
2 - >16
>16
8 / 16
>16 / >16
>16 / >16
8 / 16
1/2
>16 / >16
1 / >16
>16 / >16 (2 - >16)
(8 – 16)
(>16)
(>16)
(8 – 16)
(0.5 – 2)
(>16)
(1 - >16)
16 / 16
>16 / >16
>16 / >16
16 / 16
4/4
>16 / >16
1/2
4 / >16
(16)
(>16)
(>16)
(8 – 16)
(2 – 4)
(16 - >16)
(1 – 2)
(4 - >16) >16 / >16
8 / 16
>16 / >16
>16 / >16
>16 / >16
2/4
>16 / >16
>16 / >16
(8 – 16)
(8 - >16)
(2 - >16)
(8 - >16)
(1 - >16)
(2 - >16)
(2 - >16)
(>16)
>16 / >16
>16 / >16
>16 / >16
>16 / >16
>16 / >16
0.25 / 0.5
1/1
>16 / >16
(2 - >16)
(0.25 - >16)
(0.06 - >16)
(0.06 - >16)
(16 - >16)
(0.125 – 0.5)
(0.25 – 2)
(4 - >16)
16 / >16
(16)
4/8
0.5 / 8
1 / >16
8 / >16
8 / >16
>16 / >16
>16 / >16
>16 / >16
(4 – 8)
(0.25 – 16)
(16)
(16)
(2 - >16)
(16 - >16)
(>16)
(>16)
Scedosporium apiospermum /
2/4
0.5 / 1
1/2
8/8
8 / >16
1/1
>16 / >16
>16 / >16
Pseudoallescheria boydii (19)
(1 – 8)
(0.06 - >16)
(0.25 - >16)
(2 – 16)
(2 - >16)
(0.5 – 2)
(2 - >16)
(>16)
4/4
16 / 16
>16 / >16
8 / 16
>16 / >16
>16 / >16
>16 / >16
>16 / >16
(4)
(16)
(>16)
(8 – 16)
(8 - >16)
(>16)
(>16)
(>16)
Scedosporium prolificans (5)
12
221
Caspofungin (CSP), micafungin (MCF), anidulafungin (AND), amphotericin B (AMB), voriconazole (VCZ), posaconazole (POS),
222
itraconazole (ITZ).
223
1
224
to 16 µg/ml (11).
225
2
226
inhibit 50% and 90% isolates, respectively.
All drugs were tested via Clinical Laboratory Standards Institute microbroth dilution method within concentrations ranging from 0.02
Minimal inhibitory concentration (MIC), minimal effective concentration (MEC); MIC(MEC)50 and MIC(MEC)90, concentrations that
227
13
