HTIDE 2018, Venice 26 October 2018 The antifungal formulary What are we missing? Russell Lewis Associate Professor, Infectious Diseases Infectious Diseases Hospital, S.Orsola-Malpighi Department of Medical Sciences and Surgery University of Bologna
If many drugs are used for a disease, none are sufficient Sir William Osler, M.D. 1849 1919
The antifungal pipeline past, present and future? Number of available antifungals 20 isavuconazole posaconazole anidulafungin micafungin voriconazole 15 L-AMB ABCD ABLC 10 ketoconazole miconazole 5 CD-101, rezafungin (Cidara) SCY-078, ibrexafungerp (Scynexis) caspofungin VT-1161 (Viamet) VT-1129 (Viamet) VT-1598 (Viamet) terbinafine itraconazole fluconazole F901318 (F2G) APX001 (Amplex) VL-2397 (Vical) griseofulvin 5-FC amphotericin B nystatin 0 1940 1960 1980 Year 2000 On the horizon? 2020
What are we missing? Novel mechanism of action Emerging resistance
MDR Candida auris Simultaneously emerged on three continents Can colonize patient skin for months Can survive on hospital surfaces for months Associated with hospital outbreaks similar to MRSA or Acinetobacter spp. (horizontal patient transmission) Frequently misidentified by standard microbiological methods Frequently resistant to multiple antifungal classes and increasingly echinocandins Lockhart SR, et al. Clin Infect Dis 2017; 64:134 140.
Countries from which Candida auris cases have been reported, as of August 31, 2018 In some hospitals C. auris has accounted for up to 40% of isolates Source: CDC Jeffery-Smith A, et al.. Clin Microbiol Rev 2018; 31
MDR Aspergillus fumigatus Shaded areas showing countries that have reported TR34/L98H and TR46/Y121F/T289A resistance mechanism White- no data Aspergillus fumigatus isolate from Italy that only grows in the presence of voriconazole Image: P. Verweij, Radbound Univ Verweij, Chowdhary, Melchers & Meis. Clin Infect Dis 2016;62:362-368.
5 year, multicenter, retrospective study in Netherlands n=196 patients (2011-2015) 21% higher mortality at day +42 Voriconazolesensitive Voriconazoleresistant Lestrade PP, et al. Clin Infect Dis 2018; advance access published
Not just Aspergillus fumigatus 65 y/o female with AML, fever, severe respiratory difficulty, ANC 250 BAL grew H1N1 influenzae, A. terreus, GM 3.1 Case courtesy of Marta Stanzani, M.D., Ph.D: Antifungal MIC EUCAST Interp. Amphotericin B 4 mg/l R Anidulafungin >4 mg/l R Caspofungin >4 mg/l R Micafungin >4 mg/l R Isavuconazole 2 mg/l R Voriconazole 1 mg/l S Posaconazole 0.06 S
Limited treatment options, high mortality Resistant Aspergillus Mucorales Fusarium spp. Scedosporium apiospermum Lomentospora prolificans
What are we missing? Novel mechanism of action Emerging resistance Adequate PK
DALI Study Defining antibiotic levels in the ICU Prospective, multicentre PK point-prevalence study in 68 ICUs across 10 European countries Blood samples Peak, mid-dose, and trough to measure antibiotic exposure Data for fluconazole, caspofungin, anidulafungin Considerable inter-individual variability in PK One-third of fluconazole treated patients did not achieve minimum recommended PK/PD dosing target Echinocandin dose optimization needed to reduce variability Sinnollareddy, M., et al. Int. J. Antimicrob. Agents 39, 1 10 (2012).
Can we do better with echinocandin dosing? Distributions of free drug AUCs for caspofungin (14 daily doses) 70mg 50mg Currently licensed echinocandin dosing regimens may result in suboptimal PK/PD exposures early in the course of therapy and during the treatment of less susceptible pathogens Free-drug Plasma AUC0-24: MIC Ratio 100 50 Target AUC/MIC C. glabrata MIC90 1 7 Days of Therapy 14 Median exposures and 5% and 95% percentile for FDA-approved dosing Bader JC et al. J Antimicrob Chemother 2018; 73:i44 i50.
Acquired resistance and the gastrointestinal tract Another sign of inadequate dosing? Esophagus and oral mucosa Buccal swabs post antifungal treatment (n=93 pts)1 21.6% anidulafungin-resistant C. glabrata Intraabdominal candidiasis; Biliary tract Intraabdominal candidiasis2 FKS mutant Candida isolates were recovered from 24% (6/25) of abdominal candidiasis patients exposed to echinocandin 1-Jensen RH, Johansen HK, Soes LM, et al. Antimicrob Agents Chemother. 2016;60(3):1500-1508. 2-Shields RK, Antimicrob Agents Chemother 2014; 58:7601 7605.
A person who takes medicine must recover twice, once from the disease and once from the medicine Sir William Osler, M.D. 1849 1919
Common antifungal toxicities Hepatic toxicity All azoles Amphotericin B 5FC Echinocandins Rash/ photosensitivity Voriconazole (SCC) all azoles Renal toxicity Amphotericin B Cyclodextrans? (IV voriconazole, posaconazole, itraconazole) CNS Photopsia Voriconazole Voriconazole Peripheral neuropathy Periostitis Itraconazole, posaconazole, Voriconazole, isavuconazole? Voriconazole GI intolerance Cardiac Infusion reactions Bone marrow/ Anemia Itraconazole Posaconazole 5FC Itraconazole (all azoles-drug interactions) Amphotericin B Echinocandins 5FC Amphotericin B (EPO suppression) Lewis RE. Mayo Clinic Reviews 2011;86:805-17. Adrenal effects All triazoles, esp. Itraconazole, posaconazole
Posaconazole-associated hypertension and hypokalemia (iatrogenic cushing syndrome) Mechanism: Posaconazole-inhibits 11 β-hydroxylase enzyme resulting in elevated levels of the mineralocorticoid receptor activator deoxycorticosterone Possible relationship with elevated posaconazole levels In clinical studies, hypokalemia 30% and incident hypertension 18% All patients on posaconazole therapy should be routinely screened for hypertension and hypokalemia Barton K, Davis TK, Marshall B, Elward A, White NH. Clin Kidney J 2018; 11:691 693. Mahmood M, Abu Saleh O, Sohail MR. Antimicrob Agents Chemother 2017;61:1-4
Trimethoprim-sulfamethoxazole toxicities N eurological effects (aspetic meningitis, tremor, delirium gait disturbances) O xygen capacity decreased (methemoglobinemia, blood dyscrasia, bone marrow suppression, thrombocytopenia) T oxic epidermal necrolysis or cutaneous reactions (drug hypersensitivity, fever, rash, exanthema) R eproductive toxicity (neural tube defects, cardiovascular and oral cleft urinary tract defects) Up to 55% of patients must discontinue prophylaxis I interactions with other drugs (inhibition of CPY2C8, 2C9, renal OATP, OCTP) S ugar (hypoglycemia especially with oral hypoglycemics) K Hyperkalemia and other kidney effects (hyperkalemia, interstitial nephritis, obstructive tubulopathy, hyponatremia Y? Why not consider an alternative antimicrobial? Tomblyn M, et al. Biol Blood Marrow Transplant 2009; 15:1143 1238. Ho JM-W, Juurlink DN. CMAJ 2011; 183:1851 1858.
What are we missing? Novel mechanism of action Toxicities Emerging resistance Drug interactions Adequate PK
How big of problem are drug interactions? Therapeutic Index of Drug (>10,000 real or theoretical interactions with triazoles) High No concern Caution Low Limited Concern Serious Concern 50% of medications used in oncology or transplant populations are metabolized by 3A4; many have narrow therapeutic index Small Large Magnitude of interaction caused by perpetrator drug Brüggemann RJM, et al. Clin Infect Dis 2009; 48:1441 1458.
Gene FLT3 (ITD, TKD) Prognostic relevance of integrated genomic profiling in acute myelogenous leukemia an explosion of new drugs under investigation NPM1 DNMT3A NRAS CEBPα TET2 WT1 IDH2 IDH1 KIT RUNX1 MLL-PTD ASXL1 PHF6 KRAS PTEN TP53 HRAS EZH2 Overall Frequency, % 37 (30, 7) 29 23 10 9 8 8 8 7 6 5 5 3 3 2 2 2 0 0 Patel JP et al. N Engl J Med. 2012;366:1079-1089. 58% of new therapies in Phase I-III clinical trials at our institute have relative or absolute contraindications use with triazoles (CYP 3A4, QTc prolongation) Slide: Cristina Papayannidis & Dimitrios P. Kontoyiannis
What are we missing? Novel mechanism of action Toxicities Emerging resistance Drug interactions Adequate PK Dosing flexibility
Antifungal checklist approved therapies Novel Activity in mechanism of emerging action resistance Optimized PK/PD Dosing flexibility Limited or no toxicity Few serious drug interactions Amphoter. B Fluconazole Itraconazole Voriconazole Posaconazole Isavuconazole Caspofungin Anidulafungin Micafungin
Antifungal checklist looking to the future Novel mechanism of action Activity in emerging resistance Adequate PK exposures Dosing flexibility Limited or no toxicity Few serious drug interactions Rezafungin? Ibrexafungerp?? VT-1161????? VT-1129????? VT-1598????? F091318???? APX001??? VL-2397????
Summary We still have important gaps in the spectrum, PK/PD and safety of systemic antifungal therapy Emerging resistance is raising concerns about the future viability of current antifungals A number of investigational agents currently under development show some promise, especially for MDR pathogens