Clinical failure and its management

David W. DenningDirector, National Aspergillosis CentreUniversity Hospital South Manchester

[Wythenshawe Hospital]The University of Manchester

Problems with antifungal therapy

1. Drug toxicity

2. Drug interactions and low blood levels

ItraconazoleNauseaAnkle swellingPeripheral neuropathyFatigue

VoriconazoleFeeling illConfusion/hallucinations/poor concentrationPhotosensitivity

Drug toxicitiesCommon reasons for stopping therapies

Itraconazole concentrations

in phase 2 studies

Denning et al, Am J Med 1994;97:135

Itraconazole concentrations in relation to timing of samples

Tucker et al, J Am Acad Dermatol 1990;23:593-601

Optimising itraconazole levels – aim between 5 and 17 mg/L

Lestner et al, Clin Infect Dis 2009; 49:928

Itraconazole for ABPA in CF

Sermet-Gaudelus, Antimicrob Ag Chemother 2001;45:1937.

Itraconazole often poorly absorbed and variable penetration

into CF sputum

Generic itraconazole (Sandoz)

Pasqualotto, Int J Antimicrob Ag 2007; 30:93

Approval of itraconazole by the FDA and Europe in 1991

Voriconazole - metabolism

98% metabolised by liverPrimarily metabolised by CYP2C19 and CYP3A4,

less by CYP2C9.

Cirrhosis / prior alcohol abuse and elderly likely predictors of slow metabolisers. Also genetic polymorphism of CYP2C19.

Low levels likely in children, oral therapy and unpredictable.

Usual dosing 150 – 300mg twice daily

Voriconazole datasheet

Random voriconazole concentrations in adults receiving 3mg/Kg BID

1

10

100

1000

10,000

100,000

0 70 140 210 280

days after first dose

Log 1

0 [

Conce

ntr

ati

on (

µg/L

)]

Data from Denning et al, Clin Infect Dis 2002;34:563

Possible toxicity

Very small children may metabolise voriconazole very fast and need dose escalation to ?7-

10mg/Kg BID or 200mg BID

Voriconazole levels in children

Pasqualotto et al, Arch Dis Child 2008;93:578

Cytochrome P450 interactionsFluc Itra Posa Vori

Inhibitor

2C19 + +++ 2C9 ++ + ++ 3A4 ++ +++ +++ ++Substrate

2C19 +++ 2C9 + 3A4 +++ +

Dodds Ashley & Alexander. Drugs Today 2006;41:393.

New section on drug interactions which you can search very quickly

Problems with antifungal therapy

1. Drug toxicity

2. Drug interactions and low blood levels

3. Azole resistance, intrinsic and acquired

32 yr old from Malawi, on HAART Rx- haemoptysis- Aspergillus precipitin titre 1/16

CT scan shows 2 large cavities with aspergillomas, with additional lesions (October 2005)

Chronic cavitary pulmonary aspergillosis (CCPA) in HIV February 2005

Surgical removal would require a pneumonectomySo treated with itraconazole

On HAART Rx, with low viral load, CD4 count >200- New haemoptysis- Aspergillus precipitin titre 1/32

CXR & CT scan showed expansion of inferior cavity

CCPA in HIV February 2007

February 2007 April 2007

MICs A. fumigatus Feb 2007Itraconazole = >8.0mg/mLVoriconazole = 0.5 mg/mLPosaconazole = 1.0 mg/mL

Itraconazole concentrationsNov 05 2.5 mg/LDec 05 3.4 mg/LMarch 06 4.5 mg/LJuly 06 6.7 mg/LFeb 07 8.4 mg/L

CCPA in HIV - low itraconazole concentrations

Do low concentrations of antifungal predispose to the development of

resistance?

microtitre,

RPMI 2% glucose

35°C 48 hrs

2x106/mL

Test inoculum

AF72 AF91

Denning et al, JAC 1997;40:401

confirmation in vivo

Denning et al, JAC 1997;40:401

Strain 5 (AF 72)G54 CYP51A mutation

Strain 6 (AF 91)M220 CYP51A mutation

controls

Itra 25mg/Kg

Itra 75mg/Kg

AmB 5mg/Kg

Itra 75mg/Kg

AmB 5mg/Kg

Development of international standards for susceptibility testing and

breakpoints

Manchester azole MIC distributions

0

50

100

150

200

250

?0.015 0.03 0.06 0.125 0.25 0.5 1 2 4 8 >8

Numb

er of

isolat

es

Itraconazole MIC (mg/L)

0

50

100

150

200

250

?0.015 0.03 0.06 0.125 0.25 0.5 1 2 4 8 >8

MIC mg/L

Numb

er of

isolat

es

Voriconazole MIC (mg/L)

0

10

20

30

40

50

?0.015 0.03 0.06 0.125 0.25 0.5 1 2 4 8 >8

Numb

er of

isolat

es

Posaconazole MIC (mg/L)

modified EUCAST method - 0.5 x 105 not 1-2.5 x 105 cfu/mL

Azole resistance in A. fumigatus in Manchester 1997-2009

Bueid, J Antimicrob Chemother 2010;65:2116. Howard et al, EID 2009; 15:1068

0

10

20

30

40

50

60

70

80

90

100

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Year

Num

ber

of

pat

ien

t ca

ses

Multi-azole resistant

Itraconazole & posaconazole resistant

Voriconazole resistant

Itraconazole resistant

Fully susceptible

0% 0%7%

3%

0%5%

5%

5%

7%

17%

0%

14%

20%

Clinical features of patients with azole resistant A. fumigatus

17 patients, 15 from UK, different cities

9 had CCPA, all with aspergilloma3 had sputum isolate, with no treatment data2 had ABPA2 had IA1 had Aspergillus bronchitis

13 of 14 patients had prior azole exposure

8 failed therapy and 5 failed to improve (12 itraconazole, 1 voriconazole)

Howard et al, EID 2009; 15:1068

http://www.hpa-standardmethods.org.uk/documents/bsop/pdf/bsop57.pdf

Molecular detection of Aspergillus spp.

in sputum

Denning et al. Clin Infect Dis 2011;

Laboratory result ABPA CPA Normals

Culture positive for A. fumigatus

0/197/42

(16.7%)0/11

qPCR positive for Aspergillus spp

15/19 (78.9%)

30/42 (71.4%)

4/11 (36.4%)

CF and Aspergillus cultures

Baxter, unpublished

Pre-sonication

Post-sonication

Routine culture cfu versus qPCR for AspergillusSputum and BAL

Kirwan, AAA 2012 Abstract

Sample BL AC PC VC JO

  culture qPCR culture qPCR culture qPCR culture qPCR culture qPCR

Sputum before 8 32.8 1 32.8 2 33.6 0 34.8

Ist trap 33 28.9 0 37.8 2 36.9 0 33.4

Ist wash (5-20mL) 0 38 0 30.3 0 33.5 2 33.5    

BAL (10-70 mL) 0 37.2 0 32.8 0 33.1        

LLL BAL             12 34    

LLL trap                 1 32.7

RML BAL                 0 neg

RUL BAL 10mL                 0 33.4

RLL (120mL)                 0 31.2

Sputum after 3 32.2 0 29.6 0 34.9 1 34.6 0 31.4

      E. dermatiditis            

Direct detection of resistance mutations in clinical specimens,

without positive cultures

Laboratory result ABPA CPA Normals

Culture positive for A. fumigatus

0/197/42

(16.7%)0/11

qPCR positive for Aspergillus spp

15/19 (78.9%)

30/42 (71.4%)

4/11 (36.4%)

A. fumigatus CYP51A mutation detected directly from qPCR positive sample 6/8 (75%)12/24 (50%) NT

Denning, Clin Infect Dis 2011;52:1123

Problems with antifungal therapy

1. Drug toxicity

2. Drug interactions and low blood levels

3. Azole resistance, intrinsic and acquired

4. Antifungal failure (without resistance/low azole blood levels etc)

5. Immune reconstitution or other ‘switching’ of immune response

Aspergillomas in CF

Turcios – www.aspergillus.ac.uk

Felton, Clin Infect Dis 2010; 51:1383.

Chishimba et al, J Asthma . In press

Second and third line antifungal therapy for ABPA and/or asthma

• 26 patients, ABPA (n = 21) or SAFS (n = 5).• All patients had failed itraconazole (n=14) or developed adverse events (n=12)

Chishimba et al, J Asthma . In press

Second and third line antifungal therapy for ABPA and/or asthma

• 26 patients, ABPA (n = 21) or SAFS (n = 5).• All patients had failed itraconazole (n=14) or developed adverse events

(AEs) (n=12)• 34 courses of therapy, 25 with voriconazole and 9 with posaconazole.

• Voriconazole responses: 17/25 (68%) at 3 months, 15/20 (75%) at 6 months and 12/16 (75%) at 12 months, • Posaconazole responses: 7/9 (78%) at 3, 6 and 12 months for posaconazole. • 18/24 (75%) discontinued oral corticosteroids, 12 of them within 3 months of starting antifungal therapy. • 6/23 (26%) patients on voriconazole had AEs requiring discontinuation before 6 months compared to none on posaconazole (p=0.15). • 4 relapsed (57%), 1 at 3 months and 3 at 12 months after discontinuation.

Inhaled amphotericin B

Dose and reconstitution

• Dose can be increased in 5mg/1ml stages up to 20mg/4mls twice a day or a maximum daily treatment dosage of 1mg/kg

• Reconstitution:– 10ml water for injection added

to 50mg yellow powder (5mg per ml)

– (2ml therefore yields 10mg dose)

– Consider residual volume of nebuliser!

Compressors• Need servicing regularly!• To drive most nebulisers an output of at

least 8 L/m is required

The Pari LC plus with exhaust filter

Nebuliser chamber

Features:

• Fill volume 2ml-8ml• Delivers approx 65% respirable dose• Can go through the dishwasher• Can survive boiling in water

Comparison of Pari LC versus other nebulisers

Another challenge – immune reconstitution

Miceli, Cancer 2007;110:112; Caillot Eur J Radiol 2010;74:e172

Day 0

Day 7

Immune reconstitution in invasive pulmonary aspergillosis, in AIDS

Patient HB Day +14, CD4 cells 84/uL

Sambatakou, Eur J Clin Microbiol Infect Dis 2005;24:628

Patient HB Day +42, after AmB and ITZ

Immune reconstitution in invasive pulmonary aspergillosis, in AIDS

Patient HB Day +64, CD4 cells 340/uL, on

VRCSambatakou, Eur J Clin Microbiol Infect Dis 2005;24:628

Patient HB Day +87, day of death

Several patients have increasing breathlessness with antifungal

therapy

Documented fall in DLCO in one patient

Deaths in others.Mechanism unclear.

Likely benefit from steroids, needs good antifungal cover.

Interferon gamma replacement

Both patients improved with γIFN

Kelleher, Eur Resp J 2006;27:1307

CPA treatment – IFN gamma?

Denning DW et al, Clin Infect Dis 2003; 37(Suppl 3):S265-80.

Management approach

1. Exclude low blood levels – be careful of large dose increases with voriconazole

2. Fungal cultures – test for resistance

3. Exclude or treat bacterial co-infection

4. Use IV therapy if patient very ill

5. Consider surgical resection, gamma IFN, inhaled AmB (if ABPA/SAFS),

6. Long term IV therapy for CPA feasible and partially effective.