Antifungal Activity of <a id="__tag_701835439" class="tag_hotlink" href="/nuccore/LY303366" ref="/nuccore/LY303366"><span class="tag-json" style="display:none">{"type":"entrez-nucleotide","attrs":{"text":"LY303366","term_id":"1257625064"}}</span>LY303366</a>, a Novel Echinocandin B, in Experimental Disseminated Candidiasis in Rabbits

R Petraitiene

V Petraitis

A Groll

M Candelario

Immunocompromised Host Section, Pediatric Oncology Branch, National Cancer Institute,^{and Surgery Service, Veterinary Resources Program, Office of Research Services, National Institutes of Health,}^{Bethesda, Maryland, and Lilly Research Laboratories, Eli Lilly & Company, Indianapolis, Indiana}²

^{Corresponding author. Mailing address: Immunocompromised Host Section, Pediatric Oncology Branch, National Cancer Institute, National Institutes of Health, Building 10, Rm. 13N240, Center Dr., Bethesda, MD 20892. Phone: (301) 402-0023. Fax: (301) 402-0575. E-mail:}vog.hin.liam@thslaw.

Received 1998 Dec 8; Revisions requested 1999 Mar 20; Accepted 1999 Jun 5.

Abstract

The safety and antifungal activity of {"type":"entrez-nucleotide","attrs":{"text":"LY303366","term_id":"1257625064"}}LY303366 (LY), a new broad-spectrum semisynthetic echinocandin, were studied against disseminated candidiasis in persistently neutropenic rabbits. In vitro time-kill assays demonstrated that LY has concentration-dependent fungicidal activity. The pharmacokinetics of LY in the plasma of nonneutropenic rabbits suggested a linear relationship between dose and area under the curve (AUC). The times spent above the MIC during the experimental dosing interval of 24 h were 4 h for LY at 0.1 mg/kg of body weight/day (LY0.1), 8 h for LY at 0.25 mg/kg/day (LY0.25), 12 h for LY at 0.5 mg/kg/day (LY0.5), and 20 h for LY at 1 mg/kg/day (LY1). Antifungal therapy was administered to infected rabbits for 10 days starting 24 h after the intravenous (i.v.) inoculation of 10Candida albicans blastoconidia. Study groups consisted of untreated controls (UCs) and animals treated with amphotericin B (AmB; 1 mg/kg/day i.v.), fluconazole (FLU; 10 mg/kg/day i.v.), and LY0.1, LY0.25, LY0.5, or LY1 i.v. Rabbits treated with LY0.5, LY1, AmB, and FLU had similarly significant clearance of C. albicans from the liver, spleen, kidney, lung, vena cava, and brain in comparison to that for UCs. There was a dose-dependent clearance of C. albicans from tissues in response to LY. Among rabbits treated with LY0.1 there was a significant reduction of C. albicans only in the spleen. In animals treated with LY0.25 there was a significant reduction in all tissues but the brain. By comparison, LY0.5 and LY1 cleared all tissues, including the brain, of C. albicans. These in vivo findings were consistent with the results of in vitro time-kill assays. A dose-dependent effect of altered cell wall morphology was observed among UCs and animals treated with LY0.1, and LY0.25, with a progressive transition from hyphal structure to disrupted yeast forms. Serum creatinine levels were higher and serum potassium levels were lower in AmB-treated rabbits than in UCs and LY- and FLU-treated rabbits. LY0.5 and LY1 were well tolerated, displayed predictable pharmacokinetics in plasma, and had activities comparable to those of AmB and FLU in the treatment of disseminated candidiasis in persistently neutropenic rabbits.

Abstract

Invasive candidiasis is an important cause of nosocomial infection in immunocompromised patients (2, 6, 23, 42). Despite recent advances in antifungal therapy, candidiasis is the most common hospital-acquired mycosis. Conventional amphotericin B (AmB), which binds to ergosterol and disrupts membrane integrity, remains the mainstay of therapy for serious Candida infections; however, its clinical utility may be thwarted by dose-limiting nephrotoxicity (12, 35). The advent of fluconazole provides new options for the treatment and prevention of invasive candidiasis (1, 15, 19, 32, 36, 41). However, the emergence of resistance to antifungal azoles poses a new challenge to our limited therapeutic armamentarium (11, 27, 33). New agents with potent antifungal efficacy and improved safety are clearly needed.

The echinocandins are a novel class of semisynthetic lipopeptide antifungal compounds which inhibit 1,3-β-d-glucan synthase. 1,3-β-d-Glucan is a major structural polymer of fungal cell walls. Inhibition of 1,3-β-d-glucan synthesis results in disruption of fungal cell wall biosynthesis, cell wall damage, and ultimately, cell death (7, 13, 22). Cilofungin or {"type":"entrez-nucleotide","attrs":{"text":"LY121019","term_id":"1257467818"}}LY121019 (N-p-octyloxybenzoylechinocandin B nucleus) was the first echinocandin B developed for clinical trials. This early echinocandin had excellent in vitro activity against Candida spp. and was highly effective in animal models of disseminated candidiasis (16, 25, 28, 40); however, clinical development of cilofungin was discontinued because of toxicity due to the carrier vehicle (39).

During the past several years, a new generation of echinocandins has emerged. {"type":"entrez-nucleotide","attrs":{"text":"LY303366","term_id":"1257625064"}}LY303366 (LY), a terphenyl-substituted echinocandin B, demonstrates potent and non-cross-resistant in vitro antifungal activity against Candida species and Pneumocystis carinii (3, 9, 10, 20, 21, 30). The antifungal activity of LY against other fungi such as Aspergillus fumigatus, Blastomyces dermatitidis, and Histoplasma capsulatum has also been observed (29, 43, 44). LY was well tolerated by healthy human volunteers (31).

Little is known, however, about the in vivo activity of LY in the treatment of disseminated candidiasis in immunocompromised hosts. We therefore investigated the efficacy and safety of LY in a persistently neutropenic rabbit model of disseminated candidiasis.

ACKNOWLEDGMENTS

We thank Joanne Peter for performing in vitro antifungal susceptibility studies and Robert L. Schaufele for technical assistance in those experiments. We also thank the staffs of the Veterinary Resources Branch and the National Cancer Institute Office of the Laboratory Animal Science for laboratory animal care.

ACKNOWLEDGMENTS

REFERENCES

References

1. Anaissie E, Bodey G P, Kantarjian H, David C, Barnett K, Bow E, Defelice R, Downs N, File T, Karam G, et al Fluconazole therapy for chronic disseminated candidiasis in patients with leukemia and prior amphotericin B therapy. Am J Med. 1991;91:142–150.[PubMed][Google Scholar]
2. Anaissie E J, Rex J H, Uzun O, Vartivarian SPredictors of adverse outcome in cancer patients with candidemia. Am J Med. 1998;104:238–245.[PubMed][Google Scholar]
3. Bartlett M S, Current W L, Goheen M P, Boylan C J, Lee C H, Shaw M M, Queener S F, Smith J WSemisynthetic echinocandins affect cell wall deposition of Pneumocystis carinii in vitro and in vivo. Antimicrob Agents Chemother. 1996;40:1811–1816.[Google Scholar]
4. Cole G T, Seshan K R, Phaneuf M, Lynn K TChlamydospore-like cells of Candida albicans in the gastrointestinal tract of infected, immunocompromised mice. Can J Microbiol. 1991;37:637–646.[PubMed][Google Scholar]
5. Committee on the Care and Use of Laboratory Animals of the Institute of Laboratory Animal Resources, Commission on Life Sciences, National Research Council. Guide for the care and use of laboratory animals. Washington, D.C: National Academy Press; 1996. [PubMed]
6. De Bock REpidemiology of invasive fungal infections in bone marrow transplantation. Bone Marrow Transplant. 1994;14(Suppl. 5):S1–S2.[PubMed][Google Scholar]
7. Debono M, Gordee R SAntibiotics that inhibit fungal cell wall development. Annu Rev Microbiol. 1994;48:471–497.[PubMed][Google Scholar]
8. Eli Lilly & Company. LY303366 Clinical investigator’s Brochure. Eli Lilly & Company, Indianapolis, Ind.; 1996. [PubMed]
9. Ernst M E, Klepser M E, Wolfe E J, Pfaller M AAntifungal dynamics of LY303366, an investigational echinocandin B analog, against Candida spp. Diagn Microbiol Infect Dis. 1996;26:125–131.[PubMed][Google Scholar]
10. Fromtling R ALY303366. Drugs Future. 1994;19:338–342.[PubMed][Google Scholar]
11. Frosco M B, Barret J FImportance of antifungal drug-resistance: clinical significance and need for novel therapy. Exp Opin Invest Drugs. 1998;7:175–197.[PubMed][Google Scholar]
12. Gallis H A, Drew R H, Pickard W WAmphotericin B: 30 years of clinical experience. Rev Infect Dis. 1990;12:308–329.[PubMed][Google Scholar]
13. Georgopapadakou N H, Tkacz J SThe fungal cell wall as a drug target. Trends Microbiol. 1995;3:98–104.[PubMed][Google Scholar]
14. Gibaldi M, Perrier D Pharmacokinetics. 2nd ed. New York, N.Y: Dekker; 1982. pp. 455–459. [PubMed][Google Scholar]
15. Goodman J L, Winston D J, Greenfield R A, Chandrasekar P H, Fox B, Kaizer H, Shadduck R K, Shea T C, Stiff P, Friedman D JA controlled trial of fluconazole to prevent fungal infections in patients undergoing bone marrow transplantation. N Engl J Med. 1992;326:845–851.[PubMed][Google Scholar]
16. Gordee R S, Zeckner D J, Howard L C, Alborn W E, Jr, Debono MAnti-Candida activity and toxicology of LY121019, a novel semisynthetic polypeptide antifungal antibiotic. Ann N Y Acad Sci. 1988;544:294–309.[PubMed][Google Scholar]
17. Jafari H S, Saez-LLorens X, Severien C, Parras F, Friedland I, Rinderknecht S, Ehrett S, Olsen K D, Abramowsky C, McCracken G H., Jr Effects of antifungal therapy on inflammation, sterilization, and histology in experimental Candida albicans meningitis. Antimicrob Agents Chemother. 1994;38:83–89.
18. Jafari H S, Saez-LLorens X, Grimprel E, Argyle J C, Olsen K D, McCracken G H., Jr Characteristics of experimental Candida albicans infection of the central nervous system in rabbits. J Infect Dis. 1991;164:389–395.[PubMed]
19. Kauffman C A, Bradley S F, Ross S C, Weber D RHepatosplenic candidiasis: successful treatment with fluconazole. Am J Med. 1991;91:137–141.[PubMed][Google Scholar]
20. Klepser M E, Ernst E J, Ernst M E, Messer S A, Pfaller M AEvaluation of endpoints for antifungal susceptibility determinations with LY303366. Antimicrob Agents Chemother. 1998;42:1387–1391.[Google Scholar]
21. Krishnarao T V, Galgiani N JComparison of the in vitro activities of the echinocandin LY303366, the pneumocandin MK-0991, and fluconazole against Candida species and Cryptococcus neoformans. Antimicrob Agents Chemother. 1997;41:1957–1960.[Google Scholar]
22. Kurtz M B, Douglas C MLipopeptide inhibitors of fungal glucan synthase. J Med Vet Mycol. 1997;35:79–86.[PubMed][Google Scholar]
23. Lecciones J A, Lee J W, Navarro E E, Witebsky F G, Marshall D, Steinberg S M, Pizzo P A, Walsh T JVascular catheter-associated fungemia in patients with cancer: analysis of 155 episodes. Rev Infect Dis. 1992;14:875–883.[PubMed][Google Scholar]
24. Lee J W, Amantea M A, Francis P A, Navarro E E, Bacher J, Pizzo P A, Walsh T JPharmacokinetics and safety of a unilamellar liposomal formulation of amphotericin B (AmBisome) in rabbits. Antimicrob Agents Chemother. 1993;38:713–718.[Google Scholar]
25. Morrison C J, Stevens D AComparative effects of cilofungin and amphotericin B on experimental murine candidiasis. Antimicrob Agents Chemother. 1990;34:746–750.[Google Scholar]
26. National Committee for Clinical Laboratory Standards. Reference method for broth dilution antifungal susceptibility testing of yeasts. Tentative standard. NCCLS document M27-T. Wayne, Pa: National Committee for Clinical Laboratory Standards; 1997. [PubMed]
27. Nguyen M H, Peacock J E, Jr, Morris A J, Tanner D C, Nguyen M L, Snydman D R, Wagener M M, Rinaldi M G, Yu V LThe changing face of candidemia: emergence of non-Candida albicans species and antifungal resistance. Am J Med. 1996;100:617–623.[PubMed][Google Scholar]
28. Perfect J R, Hobbs M M, Wright K A, Durack D TTreatment of experimental disseminated candidiasis with cilofungin. Antimicrob Agents Chemother. 1989;33:1811–1812.[Google Scholar]
29. Pfaller M A, Marco F, Messer S A, Jones R NIn vitro activity of two echinocandin derivatives, LY303366 and MK-0991 (L-743,872), against clinical isolates of Aspergillus, Fusarium, Rhizopus, and other filamentous fungi. Diagn Microbiol Infect Dis. 1998;30:251–255.[PubMed][Google Scholar]
30. Pfaller M A, Messer S A, Coffman SIn vitro susceptibilities of clinical yeast isolates to a new echinocandin derivative, LY303366, and other antifungal agents. Antimicrob Agents Chemother. 1997;41:763–766.[Google Scholar]
31. Rajman I, Desante K, Hatcher B, Hemingway J, Lachno R, Brooks S, Turik M Program and abstracts of the 37th Interscience Conference on Antimicrobial Agents and Chemotherapy. Washington, D.C: American Society for Microbiology; 1997. LY303366 single intravenous dose pharmacokinetics and safety in healthy volunteers, abstr. F-74; p. 158. [PubMed][Google Scholar]
32. Rex J H, Bennet J E, Sugar A MA randomized trial comparing fluconazole with amphotericin B for the treatment of candidemia in patients without neutropenia. N Engl J Med. 1994;331:1325–1330.[PubMed][Google Scholar]
33. Rex J H, Rinaldi M G, Pfaller M AResistance of Candida species to fluconazole. Antimicrob Agents Chemother. 1995;39:1–8.[Google Scholar]
34. Roilides E, Sein T, Gonzalez C, Lyman C, Walsh T J Program and abstracts of the 37th Interscience Conference on Antimicrobial Agents and Chemotherapy. Washington, D.C: American Society for Microbiology; 1997. Antifungal activity of splenic, liver and pulmonary macrophages against Candida albicans and modulation by macrophage colony-stimulating factor (M-CSF), abstr. G-79; p. 280. [PubMed][Google Scholar]
35. Sarosi G AAmphotericin B: still the ‘gold standard’ for antifungal therapy. Postgrad Med. 1990;88:151–152. , 155–161, 165–166. [[PubMed][Google Scholar]
36. Slavin M A, Osborne B, Adams R, Levenstein M J, Schoch H G, Feldman A R, Meyers J D, Bowden R AEfficacy and safety of fluconazole prophylaxis for fungal infections after marrow transplantation—a prospective, randomized, double-blind study. J Infect Dis. 1995;171:1545–1552.[PubMed][Google Scholar]
37. Walsh T J, McEntee C, Dixon D MTissue homogenization with sterile reinforced polyethylene bags for quantitative culture of Candida albicans. J Clin Microbiol. 1987;25:931–932.[Google Scholar]
38. Walsh T J, Bacher J, Pizzo P AChronic silastic central venous catheterization for induction, maintenance, and support of persistent granulocytopenia in rabbits. Lab Anim Med. 1988;38:467–470.[PubMed][Google Scholar]
39. Walsh T J, Lee J W, Roilides E, Francis P, Backer J, Lyman C A, Pizzo P AExperimental antifungal chemotherapy in granulocytopenic animal models of disseminated candidiasis: approaches to understanding investigational antifungal compounds for patients with neoplastic diseases. Clin Infect Dis. 1992;14(Suppl. 1):139–147.[PubMed][Google Scholar]
40. Walsh T J, Lee J W, Kelly P, Bacher J, Lecciones J, Thomas V, Lyman C, Coleman D, Gordee R, Pizzo P AAntifungal effects of the nonlinear pharmacokinetics of cilofungin, a 1,3-β-glucan synthetase inhibitor, during continuous and intermittent intravenous infusions in treatment of experimental disseminated candidiasis. Antimicrob Agents Chemother. 1991;35:1321–1328.[Google Scholar]
41. Walsh T J, Aoki S, Mechinaud F, Backer J, Lee J, Rubin M, Pizzo P AEffects of preventive, early, and late antifungal chemotherapy with fluconazole in different granulocytopenic models of experimental disseminated candidiasis. J Infect Dis. 1990;161:755–760.[PubMed][Google Scholar]
42. Wright W L, Wenzel R PNosocomial Candida. Epidemiology, transmission, and prevention. Infect Dis Clin N Am. 1997;11:411–425.[PubMed][Google Scholar]
43. Zeckner D, Butler T, Boylan C, Boyll B, Lin Y, Rabb P, Schmidtke J, Current W Program and abstracts of the 33rd Interscience Conference on Antimicrobial Agents and Chemotherapy. Washington, D.C: American Society for Microbiology; 1993. LY303366, activity against systemic aspergillosis and histoplasmosis in murine models, abstr. 364; p. 186. [PubMed][Google Scholar]
44. Zhanel G G, Karlowsky J A, Harding G A, Balko T V, Zelenitsky S A, Friesen M, Kabani A, Turik M, Hoban D JIn vitro activity of a new semisynthetic echinocandin, LY-303366, against systemic isolates of Candida species, Cryptococcus neoformans, Blastomyces dermatitidis, and Aspergillus species. Antimicrob Agents Chemother. 1997;41:863–865.[Google Scholar]