Activities of an intravenous formulation of itraconazole in experimental disseminated Aspergillus, Candida, and Cryptococcus infections

An intravenous (i.v.) formulation of itraconazole was evaluated in disseminated fungal infection models in guinea pigs. In acute disseminated Candida albicans and Aspergillus fumigatus infections, treatment at 5 mg/kg of body weight twice a day (b.i.d.) significantly prolonged survival. In these models and in animals with chronic disseminated cryptococcosis, itraconazole given i.v. at 2.5 and 5 mg/kg b.i.d. greatly reduced the proportions of organs with culture-detectable fungal burdens. The efficacy of i.v. itraconazole in these animal models justifies its further investigation for the treatment of life-threatening mycoses in humans.     

Efficacy of nikkomycin Z against experimental pulmonary blastomycosis.

Nikkomycin Z is a chitin synthetase inhibitor. In vitro, nikkomycin Z had good activity against Blastomyces dermatitidis, with an MIC of 0.78 microg/ml and a minimal fungicidal concentration of 3.1 microg/ml. The efficacies of various treatment durations (3, 5, or 10 days) and doses (200, 400, or 1,000 mg/kg of body weight) of nikkomycin Z given twice daily were compared with those of itraconazole at 200 mg/kg given twice daily and amphotericin B at 6.25 mg/kg in a murine model of pulmonary blastomycosis. All treatments prolonged survival compared with untreated controls (P < 0.05 to 0.01); 100% survival was achieved with 5 or 10 days of any nikkomycin Z dose or with amphotericin B. Amphotericin B and nikkomycin Z, but not itraconazole, reduced infection compared with controls. Amphotericin B and the 10-day regimens of all nikkomycin Z doses were equivalent and superior to itraconazole or nikkomycin Z for < or = 5 days at any dose (P < 0.05 to 0.01). Increased duration and/or dosage improved the efficacy of nikkomycin Z, with 10 days of each dose curing 50 to 90% of the animals. Only a 1,000-mg/kg/day dose of nikkomycin Z was curative when treatment lasted less than 10 days. In contrast, itraconazole cured no mice, while amphotericin B cured all mice. Based on the total amount of drug given, amphotericin B was estimated to be 32 times as active as nikkomycin Z and nikkomycin Z was estimated to be 3 times as active as itraconazole. Overall, nikkomycin Z given orally was well tolerated, had good activity against blastomycosis, and could result in biological cure, thus producing results equivalent to those of parenteral amphotericin B.     

A comparison of the efficacy of itraconazole, amphotericin B and 5-fluorocytosine in the treatment of Aspergillus fumigatus endocarditis in the rabbit

The efficacy of amphotericin B, 5-fluorocytosine and itraconazole was compared for the treatment of experimental rabbit Aspergillus fumigatus endocarditis. Therapy with amphotericin B or 5-fluorocytosine, at dosages of 3.0 and 35 mg/kg body weight respectively, failed to eradicate aspergillus from the cardiac vegetations in all but one of the animals tested; none of these animals survived for longer than nine treatment days. When similar doses of amphotericin and 5-fluorocytosine were administered concomittantly, 30% of the animals had sterile vegetations. Itraconazole at 2.5 and 3.5 mg/kg body weight was not successful; all the animals tested had infected vegetations and did not survive beyond nine days of therapy. In contrast, itraconazole at 5.0 mg/kg sterilised the endocardial vegetations and all these animals survived for 14 days. It is concluded that itraconazole may be useful in the treatment of aspergillus endocarditis.     

Efficacy of caspofungin and voriconazole combinations in experimental aspergillosis

Guinea pigs were infected with Aspergillus fumigatus at two challenge doses and treated for 7 days with a placebo, intraperitoneal caspofungin (1 mg/kg daily), oral voriconazole (1 mg/kg twice a day), or a combination of the caspofungin and voriconazole treatments. The combination therapy statistically significantly prolonged survival over that with the control at both challenge doses and achieved a statistically significant reduction in kidney burdens as measured by quantitative PCR. The same was true for animals given caspofungin alone at both levels of challenge and for animals treated with voriconazole alone at the lower challenge dose. However, the effects of combination therapy on prolongation of survival were greater than those of either monotherapy at both challenge doses, and the reduction in kidney burdens with combination therapy was significantly greater than that with caspofungin alone in the animals given the lower challenge dose. No synergistic interactive effects were seen for the two agents in checkerboard titration experiments in vitro. We conclude that therapy of experimental aspergillosis with caspofungin and voriconazole combined offers slight additional improvements in efficacy rather than effects of a clearly synergistic nature.     

Efficacy of ravuconazole (BMS-207147) in a guinea pig model of disseminated aspergillosis

Ravuconazole (BMS-207147, ER-30346), an oral triazole, was evaluated in an immunosuppressed temporarily neutropenic guinea pig model of invasive aspergillosis. In this model, guinea pigs were immunosuppressed with triamcinolone 20 mg/kg sc od beginning 4 days before challenge and made neutropenic with cyclophosphamide 300 mg/kg ip 1 day before challenge. Treatments of ravuconazole 5, 10 and 25 mg/kg po od were compared with itraconazole 2.5 and 5.0 mg/kg po bd and amphotericin B 1.25 mg/kg ip od. Treatment began 24 h after lethal intravenous challenge with Aspergillus fumigatus and continued for 5 days. Mortality occurred in eight of eight untreated control animals versus none of eight treated with ravuconazole 5 or 10 mg/kg/day or itraconazole 10 mg/kg/day. Mortality occurred in one of eight animals treated with ravuconazole 25 mg/kg/day, one of eight with amphotericin B and two of eight treated with itraconazole 5 mg/kg/day. Compared with controls, each of the antifungals examined significantly reduced the tissue burden in liver and brain, although only the highest doses of the azole drugs and amphotericin B significantly reduced tissue burden in the kidney. All three doses of ravuconazole improved survival and also reduced the tissue burden of ASPERGILLUS: In this model of invasive aspergillosis, ravuconazole showed significant activity and may be a useful compound in human disease.     

In vitro and in vivo antifungal activities of TAK-456, a novel oral triazole with a broad antifungal spectrum

TAK-456 is a novel oral triazole compound with potent and broad-spectrum in vitro antifungal activity and strong in vivo efficacy against Candida albicans and Aspergillus fumigatus. TAK-456 inhibited sterol synthesis of C. albicans and A. fumigatus by 50% at 3 to 11 ng/ml. TAK-456 showed strong in vitro activity against clinical isolates of Candida spp., Aspergillus spp., and Cryptococcus neoformans, except for Candida glabrata. The MICs at which 90% of the isolates tested were inhibited byTAK-456, fluconazole, itraconazole, voriconazole, and amphotericin B were 0.25, 4, 0.5, 0.13, and 0.5 microg/ml, respectively, for clinical isolates of C. albicans and 1, >64, 0.5, 0.5, and 0.5 microg/ml, respectively, for clinical isolates of A. fumigatus. Therapeutic activities of TAK-456 and reference triazoles against systemic lethal infections caused by C. albicans and A. fumigatus in mice were investigated by orally administering drugs once daily for 5 days, and efficacies of the compounds were evaluated by the prolongation of survival. In normal mice, TAK-456 and fluconazole were effective against infection caused by fluconazole-susceptible C. albicans at a dose of 1 mg/kg. In transiently neutropenic mice, therapeutic activity of TAK-456 at 1 mg/kg of body weight against infection with the same strain was stronger than those at 1 mg/kg of fluconazole. TAK-456 was effective against infections with two strains of fluconazole-resistant C. albicans at a dose of 10 mg/kg. TAK-456 also expressed activities similar to or higher than those of itraconazole against the infections caused by two strains of A. fumigatus in neutropenic mice at a dose of 10 mg/kg. These results suggest that TAK-456 is a promising candidate for development for the treatment of candidiasis and aspergillosis in humans.     

Efficacy of amphotericin B or itraconazole in a murine model of central nervous system Aspergillus infection

Given the greater than 90% lethality of clinical central nervous system (CNS) aspergillosis despite current therapies, there is a need for an animal model to study therapeutic strategies. We previously established a model of CNS aspergillosis by intracerebral infection and report here the results of treatment with the two therapies with the greatest clinical experience, i.e., treatments with amphotericin B (AMB) and itraconazole (ITZ). Mice were given cyclophosphamide to produce pancytopenia. AMB was given intraperitoneally (i.p.; 3 mg/kg of body weight) or intravenously (i.v.; 0.8 mg/kg) once daily. ITZ in cyclodextrin was given by gavage once daily at a dose of 100 mg/kg or twice daily at 50 mg/kg. Treatments were started at day 1 postinfection and given for 10 days. At day 15, survivors were euthanatized. Ninety percent of the mice given no treatment died by day 6, and 100% died by day 10. Mice treated with AMB either i.p. or i.v. had 40% survival. Mice treated with ITZ either once or twice per day had a median survival time of 10 days, compared with 4 days for control animals, but a survival rate of only 10%. AMB and ITZ prolonged survival (P, <0.0001 to <0.05) compared with controls. Brains from surviving mice had CFU of Aspergillus fumigatus. This model can be used to compare newer antifungals and to study combination therapy or immunotherapy to find better therapeutic alternatives.     

A comparative study of the in vitro susceptibilities of clinical and laboratory-selected resistant isolates of Aspergillus spp. to amphotericin B, itraconazole, voriconazole and posaconazole (SCH 56592)

We investigated the in vitro susceptibilities of clinical and laboratory-selected Aspergillus spp. to posaconazole, and compared the results with those obtained for amphotericin B, itraconazole and voriconazole. Conidial suspensions from clinical isolates (284 Aspergillus fumigatus, 66 Aspergillus niger, 31 Aspergillus flavus and 43 Aspergillus spp.) and laboratory-selected resistant A. fumigatus isolates (15 resistant to amphotericin B, 25 to itraconazole and 12 to voriconazole) were prepared and their susceptibilities to various antifungal agents determined using a previously described broth macrodilution technique. The geometric mean MICs (mg/L) of posaconazole for A. fumigatus (0.17 +/- 0.11) and non-A. fumigatus aspergilli (0.16 +/- 0.28) were significantly lower (P 0.05) than those for amphotericin B, itraconazole and voriconazole. Amphotericin B-resistant A. fumigatus isolates were as susceptible to posaconazole as the parental strain. Itraconazole- and voriconazole-resistant isolates showed low-level (two- to three-fold increase in MICs) cross-resistance to posaconazole. The minimum fungicidal concentrations (mg/L) of posaconazole for A. fumigatus (n = 58) and non-A. fumigatus aspergilli (n = 40) were 4. 45 +/- 2.70 (range 0.25-8) and 4.14 +/- 3.03 (range 0.5-8), respectively. Time-kill studies showed that the fungicidal activity of posaconazole against A. fumigatus is time- and concentration-dependent (for example, posaconazole 4 mg/L killed >99% of A. fumigatus conidia within 24 h). These results suggest that overall, posaconazole has better activity and a smaller range of MICs for Aspergillus spp., including those with reduced susceptibility to amphotericin B, itraconazole and voriconazole.     

In vitro and in vivo activity of olamufloxacin (HSR-903) against Legionella spp

The activity of the fluoroquinolone olamufloxacin (HSR-903) against Legionella spp. was studied in vitro and in vivo. The olamufloxacin MIC at which 50% of isolates are inhibited (MIC50) for 81 different Legionella spp. strains (59 type strains and 22 clinical isolates) was 0.008 mg/L, which was identical to sparfloxacin, whereas the MIC50s for erythromycin, levofloxacin and ciprofloxacin were 0.25, 0.032 and 0.032 mg/L, respectively. Olamufloxacin and sparfloxacin (at 0.008 mg/L) inhibited intracellular growth and subsequent cytotoxicity of L. pneumophila 80-045 in J774.1 macrophages, whereas levofloxacin and ciprofloxacin did not, at the same concentration. When olamufloxacin was given to the infected guinea pigs orally (5 mg/kg of body weight), peak levels in the lung were 3.02 mg/kg at 2 h post-administration, with a half-life of 3.41 h and an AUC0-12 of 12.31 mg.h/kg. The 2 day post-infection bacterial burden of the lung in the animals treated with olamufloxacin (5 and 1.25 mg/kg given orally twice a day) was much lower than in those treated with levofloxacin (same dose as olamufloxacin) or erythromycin (10 mg/kg given orally twice a day). When treated with olamufloxacin (5 mg/kg given orally twice a day) for 7 days, 11 of 12 L. pneumophila-infected guinea pigs survived for 14 days post-infection, as did all 12 guinea pigs treated with levofloxacin (5 mg/kg given orally twice a day) for 7 days. In contrast, only two of 12 animals treated with erythromycin survived and 10 of 11 died in the physiological saline group. Olamufloxacin was as effective as levofloxacin in a guinea pig model of Legionnaires' disease. These data warrant further study of whether olamufloxacin is an option for the treatment of Legionella infections.     

Efficacy of intravenous itraconazole against experimental pulmonary aspergillosis.

The efficacy of intravenous itraconazole solubilized in hydroxypropyl-beta-cyclodextrin was assessed in a rat model of Aspergillus fumigatus pneumonia. Immunosuppressed rats were infected by intratracheal inoculation of A. fumigatus conidia. Intravenous administration of various doses of itraconazole was started immediately after infection and continued once a day for 7 days. A 10-mg dose of intravenous itraconazole per kg was as effective on survival as 1 mg of amphotericin B per kg daily (a survival rate of 100% in 28 days), while treatment with 1 mg/kg did not increase the survival rate. The 50% lethal dose of intravenous itraconazole given to immunosuppressed and uninfected rats for 7 days was 24.5 mg/kg/day. A microbiological assay to estimate accumulation in tissue after five daily intravenous administrations of itraconazole at 10 mg/kg showed that itraconazole and its active metabolites were present in the lungs for at least 6 h, reaching the MIC as previously described (B. Dupont and E. Drouchet, Rev. Infect. Dis. 9(Suppl. 1):71-76, 1987; A. Espinel-Ingroff, S. Shadomy, and R. J. Gebhart, Antimicrob. Agents Chemother. 26:5-9, 1984). Intravenous itraconazole was considered to be worth evaluating in clinical trials of aspergillosis.     

Itraconazole for experimental pulmonary aspergillosis: comparison with amphotericin B, interaction with cyclosporin A, and correlation between therapeutic response and itraconazole concentrations in plasma.

Itraconazole and amphotericin B were compared by using a newly developed model of invasive pulmonary aspergillosis in rabbits immunosuppressed with methylprednisolone and cyclosporin A (CsA). Both itraconazole at 40 mg/kg (given orally) and amphotericin B at 1 mg/kg (given intravenously) had in vivo antifungal activity in comparison with controls. At these dosages, amphotericin B was more effective than itraconazole in reducing the tissue burden (log10 CFU per gram) of Aspergillus fumigatus (P < 0.05) and the number of pulmonary lesions (P < 0.01). However, there was considerable variation in the near-peak concentrations of itraconazole in plasma (median, 4.15 micrograms/ml; range, < 0.5 to 16.8 micrograms/ml) and a strong inverse correlation between concentrations of itraconazole in plasma and the tissue burden of A. fumigatus. An inhibitory sigmoid maximum-effect model predicted a significant pharmacodynamic relationship (r = 0.87, P < 0.001) between itraconazole concentrations in plasma and antifungal activity as a function of the tissue burden of A. fumigatus. This model demonstrated that levels in plasma of greater than 6 micrograms/ml were associated with a significantly greater antifungal effect. Levels in plasma of less than 6 micrograms/ml were associated with a rapid decline in the antifungal effect. Itraconazole, in comparison with amphotericin B, caused a twofold elevation of CsA levels (P < 0.01) but was less nephrotoxic (P < 0.01). This study of experimental pulmonary aspergillosis demonstrated that amphotericin B at 1 mg/kg/day was more active but more nephrotoxic than itraconazole at 40 mg/kg/day, that itraconazole increased concentrations of CsA in plasma, and that the antifungal activity of itraconazole strongly correlated with concentrations in plasma in an inhibitory sigmoid maximum-effect model. These findings further indicate the importance of monitoring concentrations of itraconazole in plasma as a guide to increasing dosage, improving bioavailability, and optimizing antifungal efficacy in the treatment of invasive pulmonary aspergillosis.     

Optimization of voriconazole dosage regimen to improve the efficacy in patients with invasive fungal disease by pharmacokinetic/pharmacodynamic analysis

Invasive fungal disease (IFD) is a significant cause of morbidity and mortality in hospitalized patients. To maximize the efficacy of voriconazole treatment, the study established the relationship between voriconazole pharmacokinetic/pharmacodynamic (PK/PD) and probability of response and optimized voriconazole dosage regimen in patients with IFD based on Monte Carlo simulation. Forty‐four patients proven with IFD were involved in this study. Among them, the overall cure rate was 75% (33/44) and there was a significant difference between C_min/MIC values in patients with lack of response (n = 11) and those with successful response (n = 33) (mean value: 1.91 vs. 11.33; P < 0.05). Logistic regression model showed a high correlation between voriconazole C_min/MIC ratio and clinical response (P = 0.044, OR = 1.349). According to Monte Carlo simulation results under different voriconazole dosing regimens, we could draw a conclusion that 200 mg voriconazole administered intravenously or orally twice daily for Candida infections and 300 mg administered orally or with 200 mg administered intravenously twice daily for Aspergillus infections were rational, which could achieve a value of the cumulative fraction of response >90%. This study built the relationship between voriconazole PK/PD and clinical response and obtained the reasonable empirical dosage regimen, which can be used to customize individual dosage regimen and improve the efficacy of voriconazole treatment.     

Comparison of the efficacies of amphotericin B, fluconazole, and itraconazole against a systemic Candida albicans infection in normal and neutropenic mice.

We compared the efficacies of the new triazole antifungal drugs fluconazole and itraconazole with that of amphotericin B in vitro and in an animal model of systemic candidiasis in normal and neutropenic mice. Antifungal treatment with fluconazole (2.5 to 20 mg/kg orally twice daily), itraconazole (10 to 40 mg/kg orally twice daily), or amphotericin B (0.1 to 4 mg/kg intraperitoneally once daily) was started 1 day after intravenous injection of 10(4) Candida albicans into normal mice or 10(3) C. albicans into neutropenic mice; the drugs were administered for 2 days. In normal mice the efficacy of treatment, which was assessed on the basis of the number of C. albicans cultured from the kidney, was greater for amphotericin B than for the triazoles. Fluconazole was more potent than itraconazole on the basis of equivalent doses, although itraconazole was more potent on the basis of the amount of free drug that was available. In neutropenic mice amphotericin B was less effective than it was in normal mice, whereas the triazoles were equally effective in normal and neutropenic mice. This was not expected, since in vitro data showed that amphotericin B was highly fungicidal, whereas both fluconazole and itraconazole had only a minimal effect on the growth of C. albicans in vitro.     

Antimycotic activity of BAY N 7133 in animal experiments

The triazole derivative BAY N 7133 has been tested for its antimycotic efficacy on oral administration in vivo and compared with ketoconazole in mice infected with Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans and in guinea pig trichophytosis. On starting administration at the same time as infection and using daily doses between 25 and 100 mg/kg, the agent protected the mice in all experimental models, even mouse aspergillosis for which ketoconazole was not adequately effective. BAY N 7133 was also effective for mouse candidosis by parenteral administration and was effective for guinea pig trichophytosis on topical application.     

Rifapentine is not more active than rifampin against chronic tuberculosis in guinea pigs

Rifamycins are key sterilizing drugs in the current treatment of active tuberculosis (TB). Daily dosing of rifapentine (P), a potent rifamycin with high intracellular accumulation, in place of rifampin (R) in the standard antitubercular regimen significantly shortens the duration of treatment needed to prevent relapse in a murine model of active TB. We undertook the current study to compare directly the activities of human-equivalent doses of P and R in a guinea pig model of chronic TB, in which bacilli are predominantly extracellular within human-like necrotic granulomas. Hartley strain guinea pigs were aerosol infected with ~200 bacilli of Mycobacterium tuberculosis H37Rv, and treatment given 5 days/week was initiated 6 weeks later. R at 100 mg/kg of body weight and P at 100 mg/kg were given orally alone or in combination with isoniazid (H) at 60 mg/kg and pyrazinamide (Z) at 300 mg/kg. Culture-positive relapse was assessed in subgroups of guinea pigs after completion of 1 and 2 months of treatment. Human-equivalent doses of R and P showed equivalent bactericidal activity when used alone and in combination therapy. In guinea pigs treated with rifampin, isoniazid, and pyrazinamide (RHZ) or PHZ, microbiological relapse occurred in the lungs of 8/10 animals treated for 1 month and in 0/10 animals treated for 2 months. Substitution of P for R in the standard antitubercular regimen did not shorten the time to cure in this guinea pig model of chronic TB. Data from ongoing clinical trials comparing the activity of these two drugs are awaited to determine the relevance of the guinea pig TB model in preclinical drug screening.     

Efficacy of intravenous itraconazole against invasive pulmonary aspergillosis in neutropenic mice

The efficacy of itraconazole (ITZ) solubilized in hydroxypropyl-β-cyclodextrin (ITZ-IV) was examined in a murine model of invasive pulmonary aspergillosis (IPA). Immunosuppressed mice were infected by the intratracheal inoculation of Aspergillus fumigatus conidia (2 × 10⁶ conidia/mouse). Their body weight rapidly decreased and they died within 6 days after infection. Intravenous administration of various doses of ITZ-IV was started 24 h after infection and was continued once a day for 4 days. ITZ-IV at daily doses of 10, 20, or 40 mg/kg was as effective as the intraperitoneal administration of amphotericin B (AMPH) at a dosage of 1 mg/kg daily in improving survival. ITZ-IV (20 mg/kg per day), as well as AMPH (1 mg/kg per day) significantly lowered the fungal burden in the pulmonary tissues. Histological improvement was seen within 2 days after the beginning of administration of ITZ-IV (20 mg/kg per day). In mice intravenously given a single dose of ITZ-IV (20 mg/kg), the blood level and pulmonary tissue level of ITZ plus its active metabolites, mainly hydroxyitraconazole (OH-ITZ), decreased gradually after the injection, but after 4 h their concentration was still between 1.4 μg/ml (ITZ) and 1.9 μg/ml (OH-ITZ), concentrations that were approximately 10 to 20 times greater than the minimum inhibitory concentration (MIC) of ITZ for challenging the strain of A. fumigatus (0.16 μg/ml). These results support the clinical usefulness of ITZ-IV for the treatment of IPA in immunocompromised patients.     

Efficacy of caspofungin alone and in combination with voriconazole in a Guinea pig model of invasive aspergillosis

The antifungal activity of caspofungin acetate (CAS) alone and in combination with voriconazole (VRC) was evaluated in an immunosuppressed transiently neutropenic guinea pig model of invasive aspergillosis. Guinea pigs were immunosuppressed with triamcinolone at 20 mg/kg of body weight/day subcutaneously beginning 4 days prior to lethal intravenous challenge with Aspergillus fumigatus and were made temporarily neutropenic with cyclophosphamide administered at 150 mg/kg intraperitoneally (i.p.) 1 day prior to challenge. Therapy with i.p. CAS at 1 and 2.5 mg/kg/day (with and without oral VRC at 5 mg/kg/day), oral VRC at 5 mg/kg/day, or i.p. amphotericin B (AMB) at 1.25 mg/kg/day was begun 24 h after challenge and was continued for 5 days. Mortality occurred in 12 of 12 untreated controls, whereas mortality occurred in 4 of 12 and 6 of 12 guinea pigs treated with CAS at 1 and 2.5 mg/kg/day, respectively, and in 3 of 12 guinea pigs treated with AMB. No mortality occurred among animals treated with CAS at 1 mg/kg/day plus VRC at 5 mg/kg/day, CAS at 2.5 mg/kg/day plus VRC at 5 mg/kg/day, or VRC at 5 mg/kg/day alone. Both CAS regimens increased the survival times and reduced the colony counts in tissue compared with those for the controls. Treatment with VRC and AMB significantly reduced the colony counts in the tissues of selected animals compared with those in the tissues of the controls. Treatment with VRC and AMB also resulted in reductions in colony counts in tissues compared with those in the tissues of animals treated with CAS (the difference was not statistically significant) and improved the survival times but did not sterilize tissues. Combination therapies with CAS plus VRC at either dose reduced colony counts in tissues 1,000-fold over those for the controls and were the only regimens that significantly reduced the numbers of positive cultures. The combinations of CAS plus VRC were highly effective in this model and should be further evaluated for use against invasive aspergillosis.     

Efficacy of D0870 compared with those of itraconazole and amphotericin B in two murine models of invasive aspergillosis.

D0870 is a novel azole antifungal compound. It was compared with conventional amphotericin B and itraconazole therapy in two murine models of invasive aspergillosis, one a systemic nonimmunocompromised mouse model and the other a temporarily neutropenic mouse respiratory model. D0870 was given orally and achieved measurable concentrations in serum approximately proportional to the daily dose with accumulation over time if it was given twice daily. Amphotericin B at 3.3 mg/kg of body weight was given intraperitoneally for four to six doses, and itraconazole was given orally in a cyclodextrin suspension at 5 to 50 mg/kg daily or twice daily (BID). The duration of therapy varied from 7 to 14 days. In the nonimmunocompromised mouse model, D0870 at 25 mg/kg BID was slightly inferior to amphotericin B and itraconazole with regard to mortality, with a median survival of 20 days for the three groups (P = 0.03 compared with amphotericin B). However, D0870 at 25 mg/kg BID was inferior to amphotericin B (but not itraconazole) with respect to renal culture (P = 0.01) and brain culture (P = 0.0001) results. Only amphotericin B was statistically superior to controls with regard to mortality. In the neutropenic mouse respiratory model, D0870 at 50 mg/kg/day was superior to amphotericin B, itraconazole, and controls with regard to mortality. D0870 at both 25 and 50 mg/kg/day was statistically superior to controls with regard to lung culture results (P = 0.004 to 0.04). A second experiment with a higher inoculum showed that no drug regimen was effective in that model. In all models low doses and concentrations of D0870 in serum were ineffective. D0870 has some efficacy for the treatment of invasive aspergillosis when it is given at modest doses.     

Comparison of itraconazole and fluconazole treatments in a murine model of coccidioidal meningitis

Coccidioidal meningitis (CM) is a devastating disease that requires long-term therapy and for which there is little hope of a cure. A model was used to compare the efficacies of itraconazole and fluconazole. CD-1 mice were infected intrathecally with 30 to 36 viable arthroconidia of Coccidioides. Oral therapy with cyclodextrin (control) or itraconazole or fluconazole at 10, 25, or 50 mg/kg of body weight twice daily (BID) was given for 12 days, from day 3 of infection. Treatment with both antifungals at all doses prolonged survival compared with that of the control treatment (P < 0.01 to 0.0001). At 50 mg/kg, itraconazole and fluconazole were equivalent, whereas itraconazole at 10 or 25 mg/kg prolonged survival compared to that achieved with fluconazole at these dosages (P < 0.05 and 0.01, respectively). Early histologic analysis (10 days of treatment) with 50 mg/kg BID itraconazole or fluconazole showed suppression of CM in all five animals per group; in quantitative cultures, three of three animals from each group had no detectable infection in the brain, spinal cord, or a site of secondary infection, the lungs. In contrast, four of seven controls showed mild to severe meningitis, with arteritis detected in three animals. In a short-term organ clearance study, 5 days of treatment with 10 or 50 mg/kg BID itraconazole or fluconazole reduced the tissue burdens in the brain and spinal cord compared to the tissue burdens in the controls (P < 0.02 to 0.0003). Fluconazole at 10 mg/kg did not reduce the fungal burden in secondary sites, the lungs and kidneys, whereas this itraconazole dose was more effective in clearing the fungi from both organs (P < 0.05 and P < 0.001, respectively). At 50 mg/kg, itraconazole and fluconazole were equivalent in clearing the fungi from the brain and kidney, but itraconazole was superior to fluconazole in clearing the fungi from the spinal cord and lungs (P < 0.05). Thus, both itraconazole and fluconazole were effective at controlling CM, but neither eliminated Coccidioides from tissues. Overall, itraconazole was more efficacious on an mg/kg basis; at high doses they were similarly effective.     

Influence of grapefruit juice on itraconazole plasma levels in mice and guinea pigs

Levels of itraconazole and its metabolite hydroxy-itraconazole were measured by HPLC in plasma samples from guinea pigs and DBA/2 and BALB/c mice after oral or intraperitoneal treatment with itraconazole/cyclodextrin solution at 5 and 20 mg/kg daily for 7 days. The animals were randomly assigned to receive grapefruit juice or drinking water in their fluid bottles, since components of grapefruit juice have been found to alter the pharmacokinetic behaviour of pharmaceuticals that interact with cytochrome P450 enzymes. The results demonstrated clear differences in itraconazole pharmacokinetics between the three animal types studied. The total levels of antifungally active azole were highest in DBA/2 mice and lowest in guinea pigs, regardless of the route of administration. Guinea pigs that drank grapefruit juice had higher plasma levels of azoles after oral administration of the drug, but the juice did not influence levels of itraconazole or its metabolite in guinea pigs treated intraperitoneally, or in either mouse strain treated orally or intraperitoneally. This result indicates that grapefruit juice effects on the pharmacokinetics of itraconazole are species dependent and confined to the gastrointestinal tract, influencing drug absorption. Differences in itraconazole pharmacokinetics between mouse strains need to be considered in the design of experiments involving itraconazole treatment of mice experimentally infected with fungi.