A pilot double-blind, randomized, and placebo-controlled study of orally administered IFN-alpha-n1 (Ins) in pediatric patients with measles.

To determine the safety and effectiveness of low-dose oral interferon-alpha (IFN-alpha) against measles, 30 confined pediatric patients were prospectively and randomly assigned to either a placebo or an oral IFN-alpha group and observed daily for 14 days in a double-blind manner. The IFN patients received a daily sublingual dose of 200 IU of human lymphoblastoid IFN-alpha. The IFN-treated group showed shorter average duration of malaise (3.2 vs. 10.7 days, p < 0.0001), anorexia (3.1 vs. 6.7 days, p < 0.0001), and irritability (1.1 vs. 2.2 days, p < 0.01) and shorter duration of macular/maculopapular/papular lesions (4.3 vs. 8.2 days,p < 0.0001) and branny desquamation (4.6 vs. 5.8 days, p > 0.05) and shorter time for rash to become generalized (5.5 vs. 10.3 days, p < 0.0001). No hematologic, renal, or liver toxicities were noted. It, therefore, appears that low-dose oral human lymphoblastoid IFN-alpha used in this pilot study is both safe and effective in children with measles infection.

Biochemical and pharmacological factors causing induction and suppression of germination of Trichosporon beigelii.

Trichosporon beigelii is an emerging fungal pathogen, which is morphologically characterized by blastoconidia, arthroconidia and hyphae. The non-hyphal forms of T. beigelii germinate to form hyphae in plasma in vitro and in tissues in vivo, suggesting possible pathophysiological significance of this process. Little is known, however, about the mechanisms of germination of T. beigelii. We therefore studied relevant biochemical and pharmacological factors that may regulate germination of T. beigelii. Germination was significantly enhanced by temperature at 37 degrees C, chemically defined cell culture media such as RPMI-1640, plasma, physiological pH, N-acetylglucosamine and proline. N-acetylglucosamine was equivalent to proline in inducing germination. Germination was suppressed by high concentrations of glucose, increasing inocula, low pH, and amphotericin B at achievable serum concentrations. Thus, many of the factors regulating germination of T. beigelii appear to be similar to those for Candida albicans.

Vascular catheter-associated fungemia in patients with cancer: analysis of 155 episodes.

We reviewed all 155 episodes of central venous catheter-associated fungemia among inpatients at the National Cancer Institute during a 10-year period. Candida species accounted for 98% of episodes. Fungemia was documented by culture of blood drawn through catheters in 50% of cases and by culture of both catheter-drawn and peripheral blood in 39%; mortality and the rate of dissemination were similar for these two groups. Four management strategies were used: catheter removal, antifungal therapy (with amphotericin B), both, or neither; indications for the use of both modes of treatment included fever, neutropenia, long-term indwelling catheterization, positive cultures of both catheter-drawn and peripheral blood, isolation of Candida tropicalis, and fungal isolation from two or more blood cultures. Disseminated fungal infection was documented in 82% of cases with these features but also in 35% of the less severe cases treated only with catheter removal. In addition, nine (82%) of 11 cases managed only with antifungal therapy had a negative outcome (either death from disseminated infection or the recurrence of fevers and/or fungemia), a finding suggesting that intravascular catheters should be removed in fungemia. Virtually all cases of catheter-associated fungemia in patients with cancer are clinically significant and require prompt therapy with amphotericin B.

Antifungal effects of the nonlinear pharmacokinetics of cilofungin, a 1,3-beta-glucan synthetase inhibitor, during continuous and intermittent intravenous infusions in treatment of experimental disseminated candidiasis.

Cilofungin (LY-121019) is a fungicidal cell wall-active 1,3-beta-glucan synthetase inhibitor with a short plasma half-life and saturable nonlinear plasma pharmacokinetics. To optimize the in vivo efficacy of this compound, we studied the effects of its linear and nonlinear pharmacokinetics during continuous versus intermittent intravenous infusion of cilofungin in the treatment of experimental disseminated candidiasis in persistently granulocytopenic rabbits. Six groups of rabbits were studied, untreated controls (n = 32) and five cilofungin dosage regimen groups consisting of the following: 25 mg/kg of body weight intravenously twice daily (VLoINT) (n = 9); 50 mg/kg twice daily (LoINT) (n = 9); 90 mg/kg twice daily (HiINT) (n = 11); 5 mg/kg/h for 18 h/day (LoCI) (n = 7); and 10 mg/kg/h for 18 h/day (HiCI) (n = 7). All regimens achieved plasma concentrations exceeding the MIC for Candida albicans (0.25 microgram/ml). In vitro timed kill assays found that the fungicidal activity and rate of kill by cilofungin above the MIC for C. albicans was concentration dependent. At the lower dosage regimens (VLoINT, LoINT, and LoCI), cilofungin followed linear plasma pharmacokinetics, whereas at higher doses (HiCI and HiINT), nonlinear kinetics consistent with a saturated elimination pathway(s) were observed. Only HiCI and HiINT produced a 10(3)- to 10(4)-fold reduction in CFU per gram in candidiasis of the brain (P less than or equal to 0.001). HiCI and HiINT also significantly reduced infection in the choroid (P less than or equal to 0.05). All regimens, except VLoInt, significantly (P less than or equal to 0.01) reduced tissue infections in lung, liver, spleen, and kidney. However, only the regimens with nonlinear saturation kinetics (HiCI and HiINT) produced a 10(6) reduction in the spleen and a > 10(5) reduction of C. albicans in the kidney and liver. A simple doubling of the dosage from LoCI to HiCI resulted in tissue concentrations that were 10 times higher and a 10(2)- to 10(4)-fold-greater antifungal effect. There was a direct correlation (r2 = 0.83) between tissue concentrations of cilofungin and antifungal activity. Thus, continuous and intermittent infusion dosage regimens that elicit nonlinear saturation plasma pharmacokinetics of cilofungin were associated with increased antifungal activity against experimental disseminated candidiasis.

Plasma pharmacokinetics and tissue penetration of a novel antifungal triazole, Bay R 3783, and its long-lasting active metabolite, Bay U 3625, in rabbits.

The plasma pharmacokinetics and tissue penetration of Bay R 3783 (BR), a new antifungal triazole, and one of its active metabolites, Bay U 3625 (BU), were studied in rabbits. Plasma levels of BR and BU were determined simultaneously in five rabbits for six days after a single oral dose of 20 or 40 mg/kg BR. For BR, the mean Cmax was 1.9 +/- 0.4 mg/l, the Tmax 2.0 +/- 0.7 h, the AUC alpha 7.5 +/- 1.6 mg.h/l, and the terminal plasma T1/2 2.1 +/- 0.1 h. For BU, the mean Cmax was 0.84 +/- 0.09 mg/l, the Tmax 24 +/- 4 h, the AUC alpha 61.9 +/- 6.5 mg.h/l, and the plasma T1/2 was 48 +/- 3 h. In a multi-dose study, the plasma BR clearance during wash-out gradually diminished, suggesting possible metabolite inhibition of BRs biotransformation. No hepatic or renal toxicity was seen after 28 days of dosing with BR 40 mg/kg/d. Both BR and BU penetrated well into tissues, with tissue drug concentrations over three times higher than in plasma at multiple tissue sites. Persistence of BU in plasma, however, resulted in prolonged, higher tissue levels of BU than of BR. We conclude that BR is converted to a long-lasting active metabolite BU, that persistence of BU in tissue is prolonged, and that these properties may permit BU to contribute significantly to the antifungal activity of BR.

Empiric therapy with amphotericin B in febrile granulocytopenic patients.

The early diagnosis of invasive fungal infection in granulocytopenic patients remains unreliable. Granulocytopenic patients who are persistently or recurrently febrile despite therapy with appropriate antibacterial agents are at high risk for the development of such infection. Two randomized clinical trials demonstrated that the empiric administration of amphotericin B to persistently or recurrently febrile granulocytopenic patients decreased the frequency, morbidity, and mortality of invasive fungal infection; these effects were especially marked in profoundly granulocytopenic patients who were not receiving antifungal prophylaxis. Current studies continue to indicate that prompt empiric administration of amphotericin B to persistently or recurrently febrile granulocytopenic patients ensures earlier treatment of deep mycoses. The roles of newer antifungal triazole compounds and of liposomal and lipid complexes of amphotericin B in empiric antifungal therapy must be investigated further in thoughtfully designed, randomized clinical trials.

Cilofungin (LY121019) shows nonlinear plasma pharmacokinetics and tissue penetration in rabbits.

We studied the plasma pharmacokinetics and tissue penetration of cilofungin (LY121019), a new echinocandin antifungal compound, by intermittent and continuous infusion in rabbits. Following a single intravenous dose of 50 mg/kg of body weight, the maximum concentration in plasma was 297 +/- 39 micrograms/ml, the area under the curve was 30.1 +/- 6.7 micrograms.h/ml, clearance was 30 +/- 10 ml/min/kg, volume of distribution was 0.85 +/- 0.23 liters/kg, half-life in distribution phase was 3.7 +/- 0.2 min (first 12 min postdose), and half-life in elimination phase was 12.9 +/- 0.7 min. When rabbits received cilofungin by continuous infusion (CI) at 10 mg/kg/h over 6 days, sustained concentrations in plasma of 290 +/- 56 micrograms/ml were seen, more than 50-fold higher than predicted if kinetics were linear. Similarly, at 5 mg/kg/h, high levels were also obtained. Such elevated levels in plasma would not have been predicted from the pharmacokinetic characteristics of cilofungin given as a single intravenous dose. Further pharmacokinetic study at several rates of CI suggested that cilofungin elimination follows Michaelis-Menten kinetics. Simultaneous cilofungin levels in plasma and tissue were then determined for rabbits receiving six intravenous, intermittent doses (ID) of cilofungin at 15 mg/kg every 4 min and for rabbits receiving CI as described above. After ID, the mean of the ratios of cilofungin levels in tissue to those in plasma were highest for liver and bile but very low for cerebrum and cerebellum. After CI, ratios were as much as 89 times higher than for ID and significantly greater in the brain, choroid, kidney, and bile (P less than 0.05). We conclude that following a single dose of cilofungin, the compound is rapidly cleared via first-order kinetics and does not penetrate into the central nervous system, whereas following CI, cilofungin exhibits nonlinear saturable kinetics, is slowly cleared, and significantly penetrates into central nervous system tissues.

SCH-39304 in prevention and treatment of disseminated candidiasis in persistently granulocytopenic rabbits.

To investigate the potential use of SCH-39304 for the prevention and treatment of disseminated candidiasis in granulocytopenic patients, we studied its in vivo antifungal activity as preventive, early, and late treatments in three models (acute, subacute, and chronic) of disseminated candidiasis in persistently granulocytopenic rabbits. SCH-39304 was an effective as amphotericin B alone and fluconazole alone for the prevention of disseminated candidiasis. SCH-39304 alone and fluconazole alone were as effective as amphotericin B plus flucytosine for early treatment of subacute disseminated candidiasis. When treatment was delayed for 5 days to establish chronic disseminated candidiasis, SCH-39304 was less effective than amphotericin B plus flucytosine. In comparison with different treatment regimens, SCH-39304 was more effective in early and preventive treatment. Thus, SCH-39304 was comparable to treatment control regimens in prevention and early treatment of subacute disseminated candidiasis. SCH-39304 also was most effective in granulocytopenic rabbits with disseminated candidiasis when used for prevention or early treatment.

Trichosporon beigelii, an emerging pathogen resistant to amphotericin B.

Trichosporon beigelii caused fatal disseminated infections that were resistant to amphotericin B in two granulocytopenic patients. In vitro susceptibility studies demonstrated that both index strains of T. beigelii were inhibited but not killed by amphotericin B at achievable concentrations in serum. The minimum lethal concentration for both isolates was greater than or equal to 18 micrograms/ml. Five of seven other isolates were found to have a similar pattern of amphotericin B resistance. The fact that the minimum lethal concentration of T. beigelii was many times greater than its MIC was consistent with a resistance pattern of tolerance. We concluded that T. beigelii may be resistant in vitro to amphotericin B and that this in vitro resistance was correlated with refractory, disseminated trichosporonosis in granulocytopenic patients. T. beigelii should be included in the expanding list of amphotericin B-resistant fungi.

Experimental basis for use of fluconazole for preventive or early treatment of disseminated candidiasis in granulocytopenic hosts.

To determine the potential for the use of fluconazole for prevention and treatment of disseminated candidiasis in granulocytopenic patients, we investigated its activity and pharmacokinetics in models of acute, subacute, and chronic forms of disseminated candidiasis in persistently granulocytopenic rabbits. Fluconazole was administered for systemic prophylaxis, early treatment, and delayed treatment. Single-dose and steady-state plasma pharmacokinetics, tissue penetration, and dose-response studies of the investigational compound were studied in subacutely infected granulocytopenic rabbits. Fluconazole was more effective when used for systemic prophylaxis or early treatment of disseminated candidiasis than for delayed treatment. Fluconazole was as effective as amphotericin B plus flucytosine in preventive and early treatment of disseminated candidiasis but was significantly less effective than amphotericin plus flucytosine in the treatment of chronic candidiasis. Dose-response studies demonstrated that the antifungal effect of fluconazole was dose- and time-dependent. Studies of the pharmacokinetics of fluconazole in rabbits demonstrated a long half-life in plasma and a large volume of distribution, properties that correspond to the attainment of high levels of penetration into tissues at multiple organ sites. We conclude that fluconazole is effective for prevention and early treatment of disseminated candidiasis in persistently granulocytopenic rabbits and that the evaluation of its use in preventive or early treatment of disseminated candidiasis in carefully designed clinical trials is warranted.