Medical and Pathogenic Mycology Fungal ABC’s

Medical and Pathogenic Mycology

Fungal ABC’s

Medical Mycology: Clinical Classification

• Yeasts Systemic disease, pulmonary disease absent or

subclinical• Dimorphic fungi Primary pulmonary disease with dissemination

prominent part of disease• Molds Primary pulmonary disease with dissemination

less common

• Immunosuppressed patients only• Pulmonary infection by inhalation of airborne

spores with subsequent dissemination• Very aggressive, destructive• Aspergillus most common (>80%) Aspergillus fumigatus most common species

• Others Rhizopus, Absidia, Mucor (Zygomycetes) Penicilllium Pseudallescheria boydii

Invasive Mold Infections

Aspergillus fumigatus

• Ubiquitous mold• Found on decaying

material • Produces large

amount of airborne conidia

• On average at 100 to 1000 conidia are inhaled daily

A

B C D

E

Flow

G

H

I KJ L

F

Flow

G

H

I KJ L

FFlow

G

H

I KJ L

F

Flow

G

H

I KJ L

F

Alveolar Infection

Angioinvasion

Dissemination

18%63%

12%

7%BMT/HemeSOTAIDS/ImmunePulm

Marr KA et al. Blood 2002;100:4358-66; Lin SJ et al. Clin Infect Dis. 2001;32:358-66.

SOT = solid organ transplant

• Hematologic malignancy• HSCT (especially allogeneic)

Host variables (age, underlying disease) Transplant factors (source of stem cells) Late complications (GVHD, corticosteroids, secondary neutropenia)

• Solid-organ transplant• Advanced HIV disease

Invasive Aspergillosis Risk Groups - Risk Factors

PG Pappas: Transplant Associated Infection Surveillance Network

Time to Onset of IFI After HSCT

0

20

40

60

80

100

120

Early Onset (0-30 days) Intermediate Onset (30-60 days) Late Onset (90+ days)

IACandidiasisFusariumOther mouldPCPUnspec. mouldZygomycetes

# of

UFU

’s

0.0

0.2

0.4

0.6

1981 1986 1991 1996

CandidiasisAspergillosisOther Mycoses

Rat

e pe

r 100

,000

pop

ulat

ion

McNeil MM et al. Clin Infect Dis. 2001;33:641-7.

Invasive Mycotic Diseases 1980 – 1997 Trends in Mortality

Year

Aspergillosis+357%

Candidiasis

Other Mycoses+329%

Invasive Aspergillosis in CanadaEmerging Epidemiology:

Ascioglu S et al. Clin Infect Dis. 2002;34:7-14.

The Diagnostic Challenge – IA

Proven• Histopathology and/or• Growth in culture from tissue biopsy or aspirate from a

sterile site

Probable

• Presence of 1 host factor criterion, 1 clinical feature and microbiological evidence (includes galactomannan)

• Culture from sputum or BAL in immunocompromised patient with clinical evidence of infection

“The problem of uncertainty cannot be disregarded as if it does not exist…”

EORTC International Consensus

Possible

• At least 1 host factor criterion Neutropenia Persistent fever despite antibiotics in high-risk patients Signs and symptoms of GVHD Prolonged corticosteroid use

Ante Mortem Screening: (1) Regular galactomannan testing (2) CT scans

Sinko et al. Transpl Infect Dis 2008: 10: 106 -109

Autopsy-Proven IFD ConfirmsUnder-Diagnosis of IFD

•Two-site autopsy study of 97 allogeneic stem cell recipients

4

3

1

0

10

6

2 2

0

2

4

6

8

10

12

Total Aspergillosis Candidiasis Mucromycosis

Ante MortemPost Mortem

IFI D

eath

s

Perlroth J et al. Med Mycol. 2007;45:321-46.

Diagnostic MethodsCT Scan Nodules or patchy consolidations Halo sign: attenuated area around a nodule

Specific to IA? - in the setting of immunocompromise

Sensitivity varies with timing relative to diagnosis (high early)

(1,3)-ß-D-glucan assay Excellent negative predictive value False positives:

Albumin Immunoglobulin Hemodialysis

Galactomannan assay Sensitivity 0.73, specificity 0.81 (proven IA) False positives:

Lowered threshold for test positivity Bifidobacterium lipoglycan Concurrent use of ß-lactam antibiotics,

particularly piperacillin-tazobactam

PCR detection of fungal DNA Sensitivity 100% for IA (preceding

symptoms by a median of 2 days) Requires further standardization

and validation

Galactamannan (GM) Assay

• GM is a carbohydrate constituent of the fungal cell wall and is released during hyphal growth

• Commercial, FDA approved sandwich EIA for detection of circulating A. fumigatus GM

• Can be used on serum or BAL fluid• Cutoff for positive is an index of 0.5 (serum)• May be detected 5-8 days before symptoms

Utility and Limitations • Serum FDA literature - Sensitivity 80.7%, Specificity 89.2% Meta analysis - Sensitivity 73% and Specificity 81% Most useful in serial sampling Highest sensitivity in neutropenic patients

• BAL Cutoff 0.5 – Sensitivity 100%, Specificity 78% Cutoff 2.0 – Sensitivity 100%, Specificity 93.2% GM > 2 associated with a 4.68 CHR of death

Protocol for MUHC

1. Presumptive diagnosis of IA:• Testing on request of adult inpatients with at least one risk

factor for IA and at least one clinical criteria consistent with IA 2. Pre-emptive screening:• Routine screening of all high risk inpatients on hematology

wards• Sera will be collected three times per week (Mon-Wed-Fri)• Assays will be run twice weekly (Tues-Thurs).

Case51 year old womanApril 2010 AML Induced with FLAG-IDA CR

March 2011 Allo HSCT from brother

CaseSeveral complications GVHD (Grade III) – liver skin and bowel CMV positive April 2011 until Dec 2011

Multiple antivirals used including gancyclovir, foscarnet and cidofivir

EBV PCR positive April 2011, Rituximab given Dec 2011

Case Admitted Dec 2011 with fevers 7 d after

rituximab S. bovis bacteremia (Rx Ceftriaxone) RSV + in nasal swab – (Rx Ribivarin) HHV-6 PCR positive on blood CMV colitis

Relative stable by Jan 1 2012 and afebrile

Days4

Days

Voriconazole

Inci

denc

e of

IA

McGill University: Incidence of IAAML and Allogeneic Stem Cell Transplant patients Pre-galactoamman

Inci

denc

e of

IA

McGill University: Incidence of IAAML and Allogeneic Stem Cell Transplant patients Post-galactomannan

Rates of Invasive Aspergillosis

Centre Population IA Incidence (%)

Maisonneuve Rosemont Hospital

Allogeneic HSCT 15

Acute Leukemia 8.9

Vancouver General Hospital Allogeneic HSCT 18.8

Hotel Dieu Quebec AML 17.8

Invasive Fungal InfectionManagement

Azoles

ß-1, 3 glucanpolysaccharide

Cell MembranePhospholipid bilayer

Ergosterol

Antifungal Agents - Sites of Action

EchinocandinsAmpho B

Adapted from Metcalf SC, Dockrell DH. J Infect. 2007;55:287-99.

Drug Classes and Agents

Polyenes• Amphotericin B (AMB)• Lipid-based formulations

ABLC ABCD L-AMB

Expanded-spectrum azoles• Voriconazole• Posaconazole• Ravuconazole*

Azoles• Fluconazole• Itraconazole

Echinocandins• Caspofungin• Micafungin• Anidulafungin

*Not yet approvedABLC = Amphotericin B lipid complex; ABCD = Amphotericin B colloidal dispersion; L-AMB: Liposomal amphotericin B

Metcalf SC, Dockrell DH. J Infect 2007;55:287-299; Petrikkos G, Skiada A. Internat J Antimicrob Agents 2007;30:108-117

Wingard JR. Best Pract Res Clin Haematol 2007;20:99-107; Bow EJ. Hematol. 2006;1:361-7.

IFI Management

Nodisease

Markers

Signs & symptoms

Full-blown disease

Sequelae

Dis

ease

pro

gres

sion Prophylactic

Preemptive

Therapy

Empirical

Asymptomatic high-risk patient

Asymptomatic + colonization OR novel diagnostic

High risk: Antibiotic + fever

Evidence of infection+ clinical disease

0

20

40

60

80

100

0 2 4 6 8 10 12

Herbrecht R et al. N Engl J Med. 2002;347:408-15.

70.8%

57.9%

Survival at 12 weeks

Voriconazole vs. Amphotericin BIA Primary Therapy

Pat

ient

s S

urvi

ving

(%)

WeeksNo. at Risk

Voriconazole 144 131 125 117 111 107 102Amphotericin B 133 117 99 87 84 80 77

P=0.02

Siwek GT et al. Clin Infect Dis. 2004;39:584-7; Scott LJ, Simpson D. Drugs 2007;67:269-298

Voriconazole

Caveats No activity against

Zygomycetes Erratic

pharmacokinetics Drug interactions Hepatotoxicity Visual toxicity

0

2

4

6

8

10

12

Pre-Voriconazole

Post-Voriconazole

AspergillusZygomycetes

Cum

ulat

ive

Inci

denc

e (%

)

Maertens J et al. Clin Infect Dis. 2004;39:1563-71.

IA Salvage TherapyCaspofungin 83 evaluable patients

refractory to or intolerant of Ampho B, lipid formulations or triazoles 86% refractory, 15% intolerant 48% hematologic malignancy, 25% HSCT

45% favourable response, including 50% with pulmonary aspergillosis 23% with disseminated aspergillosis

Excellent safety profile

Early Intervention is Associated with Lower Mortality

Von Eiff et al. Respiration. 1995;62:341-347.

Retrospective analysis of the timing of empiric antifungal treatment for 33 cases of invasive aspergillosis between 1987 and 1992

0102030405060708090

Mor

talit

y, %

<10 days >11 daysTime from onset of pneumonia to initiation of

antifungal therapy

Morrell M et al. Antimicrob Agents Chemother. 2005;49:3640-5.

Initiation of Therapy

Early Therapy Better Outcomes

"Clinical trial data indicate rapidity of therapy initiation is an important and independent determinant of outcome."

M. Morrell

Bow EJ. Hematol. 2006;1:361-7.

IFI Management

Nodisease

Markers

Signs & symptoms

Full-blown disease

Sequelae

Dis

ease

pro

gres

sion Prophylactic

Preemptive

Therapy

Empirical

Asymptomatic high-risk patient

Asymptomatic + colonization OR novel diagnostic

High risk: Antibiotic + fever

Evidence of infection+ clinical disease

Wingard JR. Best Pract Res Clin Haematol 2007;20:99-107; Bow EJ. Hematol 2006;1:361-367; Pizzo Am J Med. 1982:72;101-11; EORTC Am J Med. 1989;86:668-72.

• Treat all neutropenic patients with persistent fever despite broad-spectrum antibiotics

Empirical Therapy

Pros High mortality Difficulties in diagnosis Treat undetected infection May reduce systemic

mycoses (Pizzo) May reduce mortality

(EORTC)

Cons Over-treatment Fever is non-specific Side-effects and cost Difficulties in diagnosis

Infected patients: too little treatment

Uninfected patients: too much treatment

Early Trials• Pizzo Am J Med 1982 First comparative evaluation of empiric

antifungal therapy Enrollment Criteria

Fever for 7d after antimicrobials started, PMN<500 Predominately pediatric population (mean age 16)

Randomized to stopping all abts, no change or 0.5mg/kg/d AmB

Pizzo - Outcomes

No Δ +AmB D/C Rx

# pts 16 18 16

Candida 4(3) 0 1

Mold 2 1 1

Infectious Complications 7(6) 2 9

Survival 11 15 11

Time to defervesce 7-8 3-5d 11-12d

* Minimal renal toxicity

EORTC Trial

• Larger study of empiric AmB use in febrile neutropenics

• Enrollment Adult population Fever for 4 days after antibacterials started PMN<1000

• Randomized to empiric AmB 0.6mg/kg/d or 1.2mg/kg/2d

EORTC - Outcomes

No Δ +AmB

# pts 64 68

Candida 4 1

Mold 2 0

Survival 79% 84%

Response (fever) 53 69

Walsh T et al. N Engl J Med. 2002;346:225-35; N Engl J Med. 2004;351:1391-1402.

Empirical Therapy

VORN=415

L-AMBN=422

Point Estimate for Percent Difference

(95% CI)Overall responseno. (%)

108 (26%)

129 (30.6%)

-4.5 (-10.6 to 1.6)P=NS

Breakthroughfungal infection

8(1.9%)

21(5.0%) P=0.02

Voriconazole or Caspofungin vs L-AMB

CASN=556

L-AMBN=539

Point Estimate for Percent Difference

(95% CI)Overall responseno. (%)

190 (33.9%)

181 (33.7%)

0.2 (-5.6 to 6.0)Non-inferiority

Absence of breakthroughfungal infection

29 (5.2%)

24 (4.5%)

P=0.56

Empiric therapy - summary

Cons• Original evidence for efficacy is weak• Fever is not specific and not sensitive in hematology

population• 50% of GM+ patients are afebrile• Institution of highly active mold prophylaxis

reduces mortality, pulmonary infiltrates but NOT fever

• Overall success in high risk patients is sub-optimal

• So what else can we do?

Bow EJ. Hematol. 2006;1:361-7.

IFI Management

Nodisease

Markers

Signs & symptoms

Full-blown disease

Sequelae

Dis

ease

pro

gres

sion Prophylactic

Preemptive

Therapy

Empirical

Asymptomatic high-risk patient

Asymptomatic + colonization OR novel diagnostic

High risk: Antibiotic + fever

Evidence of infection+ clinical disease

Thoracic CT scan (± CT sinus)

Maertens J et al. Clin Infect Dis. 2005;41:1242-50.

Incorporation of Diagnostic TestsPreemptive Therapy

High-risk hematology patients (all received Candida prophylaxis, fluconazole 400 mg/day)

Daily GM monitoring and clinical evaluation

>5 days of unexplainedneutropenic fever

refractory toantibiotics or relapsing

Characteristic of invasivemycosis: ‘halo-sign’

Broad-spectrumantifungal therapy

OD index2 x ≥ 0.5

Bronchoscopy with BAL

Positive culture or microscopy (molds)

New infiltrate onchest X-ray or

signs/symptoms ofinvasive mycosis

Atypical lesion

Normal

Continued monitoringNo antifungal therapy

ThoracicCT&

BAL

+ -

9.0%

*2.7%

0%

5%

10%

15%

20%

Empirical, n=150 Pre-emptive, n=143

% o

f pat

ient

s

*p<0.02

97.0% 95.0%

0%

20%

40%

60%

80%

100%

Empirical, n=150 Pre-emptive, n=143

% o

f pat

ient

s

p=ns

Overall survival Proven and probable IFI

Cordonnier et al. CID 2009

Empirical vs Preemptive antifungal therapy in high risk neutropenic patients

Preemptive Therapy Does Not Reduce IA Mortality

If earlier is better…

Is prevention best?

Bow EJ. Hematol. 2006;1:361-7.

IFI Management

Nodisease

Markers

Signs & symptoms

Full-blown disease

Sequelae

Dis

ease

pro

gres

sion Prophylactic

Preemptive

Therapy

Empirical

Asymptomatic high-risk patient

Asymptomatic + colonization OR novel diagnostic

High risk: Antibiotic + fever

Evidence of infection+ clinical disease

0.00

0.25

0.50

0.75

1.00

0 1 2 3 4 5 6 7 8 9

Placebo

Fluconazole 400 mg/d

Sur

viva

l Pro

babi

lity

Years After TransplantMarr KA, et al. Blood. 2000;96:2055-2061.

Related and Unrelated Donor Transplants

P = .0018

HSCT indicates hematopoietic stem cell transplant.

Fluconazole Prophylaxis in HSCT•Evidence for Long-term Survival

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0 10 20 30 40 50 60 70

Adapted from van Burik JA, et al: Clin Infect Dis 2004; 39(10):1407-16.

Pro

porti

on o

f pat

ient

s w

ith tr

eatm

ent s

ucce

ss

Time to treatment failure (days since first dose of study drug)

micafungin (n = 425)Fluconazole (n = 457)

P = 0.025, by the log rank test

Overall Treatment Success•Micafungin vs. Fluconazole

Voriconazole vs. Fluconazole

*Proven + probable + presumptiveAdapted from Wingard JR, et al: Blood epub 2010

Subjects: 600 standard-risk allogeneic blood and marrow transplant patients

p=0.12

p=0.49

Voriconazole vs. Itraconazole: Improvit489 allogeneic stem cell transplant patients

N = 602 Chemotherapy& prophylaxis

Chemotherapy & prophylaxis (if needed)

Day 100postrandomization

Posaconazole (n = 304)

Fluconazole or Itraconazole (n = 298)

Primary end point time period

Secondary end point time period

Cornely OA et al. N Engl J Med 2007;356:348-59.

Study Design

Antifungal Prophylaxis: NeutropeniaPosaconazole vs Fluconazole / Itraconazole

4 (1%)

(5%) 14

2 (1%)

(2%) 7

(9%) 26

33 (11%)

(7%) 20

25 (8%)

0

5

10

15

20

25

30

35

40

All IFIs* Aspergillosis All IFIs Aspergillosis†

* P<0.001; † P= 0.003

Treatment Phase 100 Day Period After Randomization

Primary Endpoint: Prevention of IFI

Posaconazole vs Flu/Itra

Cornely OA et al. N Engl J Med 2007;356:348-59.

Fluconazole n=304Posaconazole n=298

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 20 40 60 80 100

Pro

babi

lity

of D

eath

Days After Randomization

P = .04*

PosaconazoleFluconazole or Itraconazole

Death From Any Cause

*Estimated using log-rank statistics.Censoring time is the minimum of the last contact date and day 100.

Cornely OA, et al. N Engl J Med 2007;356:348-359

21%

14%

33% relative reduction in

mortality

Antifungal Prophylaxis: Neutropenia

N = 600Firstdose

Lastdose

Last dose+ 7 days

Posaconazole

(n = 301)

(n = 299)

Fluconazole

Secondary end point time periodPrimary end point time period

Day112

Day 112+2 months

Follow-up

Ullmann AJ et al. New Engl J Med. 2007;356:335-47.

Posaconazole vs Fluconazole

Antifungal Prophylaxis: GVHD

Study Design

* P=0.07; † P= 0.006; ‡ P=0.004; § P=0.001

Ullmann AJ et al. New Engl J Med. 2007;356:335-47.

Antifungal Prophylaxis: GVHD

†

Fixed Treatment Period Exposure Period

Num

ber o

f IFI

(Pro

ven/

Pro

babl

e)

‡ §

(5%) 16

7 (2%) (2%) 7

3 (1%)

27 (9%)

(7%) 21 22 (8%)

(6%) 17

0

5

10

15

20

25

30

35

40

All IFIs* Aspergillosis All IFIs Aspergillosis

Fluconazole n=304Posaconazole n=298

Primary Endpoint: Prevention of IFI

Deaths - By Cause

39

42 2

31

37

12 11

1

33

0

5

10

15

20

25

30

35

40

45

Adverse Event IFI - InfectionComplications

Proven or ProbableInfection

Possible Infection Progression ofUnderlying Disease

or GVHD

Fluconazole (N=301)Posaconazole (N=299)

**

*

Ullmann AJ et al. New Engl J Med. 2007;356:335-47.

Antifungal Prophylaxis: GVHD

*

Comparative Efficacy in ProphylaxisRetrospective review: 573 AML inductions over 12 years

Ananda-Rajah et al; Hematologica 2012;97(3)

De Pauw BE. N Engl J Med. 2007;356:409-11.

Prophylaxis:

What are the trade-offs in the long-term? Cost and potential resistance Incidence within an institution (number-needed-

to-treat)

ResistanceIntrinsic barrier to resistance for molds Infections acquired in the community Not transmitted person to person No selection pressure on the environmental

reservoir

Breakthroughs in 3 years of posaconazole prophylaxis

• Intrinsic resistance only 1 case of MDR Fusarium 1 case of Aspergillus calidoustus

Costs Costs

Prophylactic agent Benefits

Reduced empiric antifungal use or screening protocols

Reduction in associated costs (ICU stay, other drugs/fever workup)

Reduction in mortality Sensitive to NNT – linked to local epidemiology

FUNGAL PROPHYLAXIS

AML/MDS induction

Stem cell transplant GVHD

FLUCONAZOLE Allo transplant: 400 mg PO/IV QD

Autologous transplant: 200 mg IV/PO QD GVHD: 200-400 mg PO/IV QD

(adjust with renal function, check for interactions)

POSACONAZOLE 200 mg PO TID

(Check for interactions, optimize absorption**)

AML/MDS Induction

(this is the only indication for

posaconazole)

YES

NO **Absorption: Avoid acid suppressants; give with or after high

fat meal or with nutritional supplement

MUHC Algorithm – Prophylaxis

MUHC Algorithm – PreemptiveAutologous HSCT, Consolidation, Allo HSCT pre-engraftment