Isavuconazole for treatment of refractory coccidioidal meningitis with concomitant cerebrospinal fluid and plasma therapeutic drug monitoring.

Coccidioidal meningitis (CM) is a life-threatening infection with limited treatment options. Small series have reported success with isavuconazole; however, limited data exist on cerebrospinal fluid (CSF) penetration. Paired plasma and CSF isavuconazole concentrations were measured. Eleven CSF levels were tested, (7 ventricular, 4 lumbar) in three CM patients. Ventricular CSF levels were undetectable despite detectable plasma levels. All lumbar CSF levels were detectable (mean 1.00 µg/ml). Three pairs of lumbar CSF/plasma concentrations taken within 1 h of each other yielded a mean CSF/plasma ratio of 0.31. Isavuconazole was detectable in lumbar but not ventricular CSF in three patients treated for refractory CM. LAY SUMMARY: Isavuconazole is a triazole antifungal that has been used as salvage therapy in the treatment of coccidioidal meningitis (CM). Few data exist characterizing its concentration in the cerebrospinal fluid (CSF). We report tandem plasma and CSF concentrations of isavuconazole in three patients with CM.

Evaluation of single and multiple doses of a novel mGlu2 agonist, a potential antipsychotic therapy, in healthy subjects.

AIMS: The safety, tolerability, pharmacokinetics (PK) and pharmacodynamics of single and multiple doses of a novel mGlu2 agonist were assessed in healthy males. METHODS: In two, Phase 1 investigator- and subject-blind, placebo-controlled studies, oral doses of prodrug LY2979165 were evaluated: single doses (20-150 mg, N = 30) and multiple once-daily (QD) doses (20-400 mg; N = 84), using a titration regimen. The plasma and urine PK of LY2979165 and active moiety, 2812223, were measured. Cerebrospinal fluid (CSF) was collected to determine PK and neurotransmitter levels. Safety parameters were assessed throughout. RESULTS: Nausea and vomiting were dose limiting following single doses; dose titration allowed higher doses to be tested over 14 days. The most common adverse events related to LY2979165 were dizziness, vomiting, nausea, somnolence and headache. The plasma PK of 2812223 were approximately linear with minimal accumulation with QD dosing. Conversion of LY2979165 to 2812223 was extensive, with minimal LY2979165 measurable in plasma. There was no effect of food on the PK of LY2979165 and 2812223. After 60 mg LY2979165 single-dose, 2812223 exposure in CSF was approximately 2-6% and plasma exposure and peak concentrations were approximately four-fold higher than the mGlu2 agonist in vitro EC50 value. No consistent effects were observed on CSF neurotransmitter levels. CONCLUSIONS: Oral doses of LY2979165 up to 60 mg as a single dose and up to 400 mg given as multiple QD doses, using a titration regimen, were well tolerated with linear PK. Overall, these data support further clinical evaluation of LY2979165.

A reference laboratory experience of clinically achievable voriconazole, posaconazole, and itraconazole concentrations within the bloodstream and cerebral spinal fluid.

Interest in antifungal therapeutic-drug monitoring has increased due to studies demonstrating associations between concentrations and outcomes. We reviewed the antifungal drug concentration database at our institution to gain a better understanding of achievable triazole drug levels. Antifungal concentrations were measured by high-performance liquid chromatography (HPLC), ultraperformance liquid chromatography and single-quadrupole mass spectrometry (UPLC/MS), or a bioassay. For this study, only confirmed human bloodstream (serum or plasma) and cerebral spinal fluid (CSF) concentrations of voriconazole, posaconazole, and itraconazole were analyzed. The largest numbers of bloodstream and CSF samples were found for voriconazole (14,370 and 173, respectively). Voriconazole bloodstream concentrations within the range of 1 to 5.5 µg/ml represented 50.6% of samples. Levels below the lower limit of quantification (0.2 µg/ml) were observed in 14.6% of samples, and 10.4% of samples had levels of ≥5.5 µg/ml. CSF voriconazole levels ranged from undetectable to 15.3 µg/ml and were <0.2 µg/ml in 11% of samples. Posaconazole bloodstream concentrations were ≥0.7 and ≥1.25 µg/ml in 41.6% and 18.9% of samples, respectively. Posaconazole was detected in only 4 of 22 CSF samples (undetectable to 0.56 µg/ml). Itraconazole levels, as measured by UPLC/MS, were ≥0.5 µg/ml in 43.3% and were undetectable in 33.9% of bloodstream samples. In contrast, when measured by a bioassay, itraconazole/hydroxyitraconazole bloodstream concentrations were ≥1.0 µg/ml in 72.9% of samples and were undetectable in 18% of samples. These results indicate that there is marked variability in bloodstream concentrations achieved with these three azoles. In addition, many levels within the bloodstream for each azole and for voriconazole and posaconazole in the CSF were undetectable or below thresholds associated with efficacy.

Measurement of antifungal drug levels in cerebrospinal fluid for cryptococcal meningoencephalitis.

We report a rare case of cryptococcal meningoencephalitis in which antifungal therapy was monitored by measuring the cerebrospinal fluid (CSF) levels of the antifungal drugs. A 78-year-old man with diabetes mellitus being treated with oral agents. He had no history of human immunodeficiency virus infection. The patient showed abnormal behavior and fever (>38°C) on November 20, 2009, and was admitted for disturbance of consciousness on November 24. CSF examination showed an increased cell count, and a yeast-like fungus, suggesting cryptococcal meningoencephalitis, was observed by India ink staining. Initial treatment was liposomal amphotericin B (L-AMB) plus flucytosine. Cryptococcus neoformans was isolated by CSF culture on day 2. MIC was 0.25 µg/ml for amphotericin B (AMPH-B), 4 µg/ml for flucytosine, 4 µg/ml for fluconazole (FLCZ), and 0.03 µg/ml for voriconazole (VRCZ). Despite treatment, his disturbance of consciousness persisted. The CSF level of AMPH-B was ≤0.05 µg/ml on day 8. Therefore, L-AMB was switched to fosfluconazole. The CSF level of FLCZ was sufficient (22.6 µg/ml) on day 25, but there was a decrease in glucose and the fungus could still be detected in CSF smears. Consequently, FLCZ was switched to VRCZ. On day 47, CSF level of VRCZ was 1.97 µg/ml, exceeding its MIC, so treatment was continued. On day 77, the patient was generally lucid, and CSF smears did not detect any fungi. The patient was then transferred for rehabilitation. On day 84, voriconazole was discontinued, with no evidence of fungal recurrence.

Lower than expected maraviroc concentrations in cerebrospinal fluid exceed the wild-type CC chemokine receptor 5-tropic HIV-1 50% inhibitory concentration.

To measure maraviroc total cerebrospinal fluid (CSF) concentrations and compare them with total and unbound plasma concentrations. Total maraviroc was measured by reverse-phase high-performance liquid chromatography with tandem mass spectrometry, whereas ultrafiltration was used for unbound maraviroc. Maraviroc was detected in all nine CSF/plasma pairs with a median CSF total concentration of 2.4 ng/ml. CSF concentrations exceeded the 50% inhibitory concentration of wild-type CC chemokine receptor 5-tropic HIV-1 in all specimens. CSF concentrations are lower than expected based on plasma concentrations and physicochemical characteristics. Unbound maraviroc plasma concentrations may be informative in estimating concentrations in CSF.

An LC-MS-MS method for quantitative determination of maraviroc (UK-427,857) in human plasma, urine and cerebrospinal fluid.

Maraviroc is a first-in-class CCR5 antagonist that shows potent anti-HIV-1 activity in vitro and in vivo and is well tolerated in both healthy volunteers and HIV-1-infected patients. The method for determination of maraviroc (UK-427,857) and its major metabolite (UK-408,027) in human plasma consists of a protein-precipitation procedure and analysis by liquid chromatography/tandem mass spectrometry using positive ion TurboIonSpray® ionization and multiple reaction monitoring. The assay has been validated over a concentration range of 0.500-500 ng/mL for both analytes. The determinations of maraviroc in human cerebrospinal fluid (0.500-500 ng/mL) and in urine (5.00-5000 ng/mL) have also been validated but do not include measurement of the metabolite. The validations included extraction recovery, intra-assay and inter-assay precision and accuracy, stability of stock and spiking solutions, freeze-thaw stability, matrix stability, processed-extract stability, and evaluation of potential interferences from selected medications in plasma or urine.

Maraviroc concentrations in cerebrospinal fluid in HIV-infected patients.

OBJECTIVE: To determine maraviroc (MVC) concentrations in cerebrospinal fluid (CSF) in HIV-infected patients. METHODS: Twelve CCR5+ HIV-1 adult antiretroviral-experienced patients receiving MVC-containing regimens for at least 1 month were enrolled. Both CSF and blood samples were taken around 12 hours after the last MVC dose. liquid chromatography tandem mass spectrometry was used to determine MVC concentrations, and HIV-1 viral load was determined by real-time polymerase chain reaction, (LOD, 40 copies/mL). RESULTS: Twelve blood and 12 CSF samples were collected. Median CD4 count was 281(120-759) cells per microliter, and median HIV-1 viral load was <40 copies per milliliter. Median time on MVC was 13.5 weeks (4-60). Nucleoside analogues (tenofovir/didanosine) were given in only 1 case. Median MVC concentrations in plasma were 124.75 (7.3-517) ng/mL. In all except one, CSF sample-receiving an erroneous MVC dose while taking concomitantly nevirapine-MVC concentrations [2.58 (<0.5-7.22) ng/mL] were within the EC(90) range (0.06-10.70). Median MVC CSF: plasma ratio was 0.022 (0.004-0.17), and when the free MVC plasma concentration was used, 0.094 (2.58-27.44). CSF viral load was <40 copies per milliliter in all 9 patients with undetectable plasma viral load. CONCLUSIONS: MVC achieves concentrations within the EC(90) range in CSF. All patients with undetectable plasma viral load although receiving nucleoside-sparing regimens including new drugs showed viral suppression in CSF.

Cerebrospinal fluid maraviroc concentrations in HIV-1 infected patients.

In order to assess the penetration of maraviroc to the central nervous system, we measured maraviroc concentrations in cerebrospinal fluid (CSF) and plasma. Concentrations were determined by liquid chromatography tandem mass spectrometry (lower limit of quantitation 1.25 ng/ml) in seven paired CSF and plasma samples. The median plasma maraviroc concentration was 94.9 ng/ml (range 21.4-478.0) and the median CSF concentration was 3.63 ng/ml (range 1.83-12.2). CSF samples exceeded the median EC90 for maraviroc (0.57 ng/ml) by at least three-fold. The CSF levels of maraviroc found in this study likely contribute to viral suppression in the CSF.

Cerebral aspergillosis: tissue penetration is the key.

Cerebral aspergillosis is increasingly recognized in severely immunocompromised patients and, until recently, this type of fungal infection was associated with a mortality approaching 100%. The central nervous system is a protected environment and penetration of drugs across the blood-brain barrier is mainly limited by their molecular size and physicochemical properties, as well as drug interaction with transporter systems (e.g., P-glycoprotein) at the blood-brain barrier. Most antifungal agents are large molecules (>700 Da), which makes sufficient penetration into the central nervous system unlikely. In fact, the available data indicate low levels of most antifungal agents in cerebrospinal fluid and brain tissue, except for fluconazole and voriconazole. Concentrations of voriconazole exceeding inhibitory concentrations for Aspergillus species were found repeatedly in cerebrospinal fluid and brain tissue, including brain abscess material. A recent retrospective study confirmed that voriconazole treatment resulted in improved response and survival rates in patients with cerebral aspergillosis. Data from animal models, which explored escalated doses or combinations of antifungal agents in experimental neuroaspergillosis, suggest that selected combination or dose-escalated therapies might further improve the still unsatisfactory prognosis in this particular type of Aspergillus infection.

Inhibition of voriconazole metabolism by chloramphenicol in an adolescent with central nervous system aspergillosis.

For an adolescent with bacterial meningitis and subsequent cerebral aspergillosis, intravenous voriconazole dose requirements substantially decreased during coadministration with intravenous chloramphenicol and considerably rose after discontinuation of the antibiotic. In agreement with in vitro evidence, these data suggest that chloramphenicol is a rather significant inhibitor of hepatic CYP3A4 and/or CYP2C19.

CNS pharmacokinetics of antifungal agents.

The goal in treatment of infections is to achieve a beneficial effect while minimizing toxicity. It is widely recognized that the principles of pharmacokinetics and pharmacodynamics are critical to determining an adequate dose-response relationship. There has been an increased involvement of the CNS to infection from opportunistic and endemic fungi over the last several decades due to establishment of solid-organ and bone marrow transplantation as well as immunosuppression from HIV. In this regard it has become critical to define optimal dosing regimens by an understanding of the processes which govern delivery of an antifungal agent to the targeted CNS site of involvement. The objective of this review is to: i) summarize published experimental and clinical antifungal pharmacokinetics; and ii) examine the relationship between CNS antifungal pharmacokinetics and efficacy. Examination of these studies reveal marked variability among antifungal drugs with regard to cerebrospinal fluid and brain parenchymal penetration. Formal examination of the relationship between CNS antifungal pharmacokinetics and efficacy are limited. The few experimental studies available suggest that brain parenchymal kinetics is a superior predictor of antifungal efficacy than cerebrospinal fluid concentrations.

Successful treatment with voriconazole of Aspergillus brain abscess in a boy with medulloblastoma.

Invasive aspergillosis is an increasing problem in immuno-incompetent patients after prolonged steroid therapy, cancer radio-chemotherapy, and bone marrow or solid organ transplantation. Cerebral aspergillosis is a well-described complication of the invasive aspergillosis but only in rare cases, the brain is the sole site of infection. Despite increasing availability of antifungal drugs, the prognosis of cerebral aspergillosis is poor. We report on an 11-year-old boy with medulloblastoma in the area of the fourth ventricle. Following tumor surgery and radio-chemotherapy, several abscess-like structures occurred in the operating field. After incomplete abscess, resection histology and culture confirmed a localized Aspergillus fumigatus infection. The initial treatment of the Aspergillus fumigatus infection with conventional amphotericin B failed, and treatment with the triazole voriconazole was started. Intravenous treatment with voriconazole resulted in a reduction of the Aspergillus fumigatus abscess. After switching to oral ambulatory therapy, the Aspergillus fumigatus abscess increased in size. To improve treatment, voriconazole dosage was adapted to reach drug concentrations in cerebrospinal fluid (CSF) above the minimal fungicidal concentration and plasma specimens. During the concentration-controlled voriconazole therapy for a period of 18 months, a complete response was achieved.

Voriconazole concentrations in the cerebrospinal fluid and brain tissue of guinea pigs and immunocompromised patients.

We characterized voriconazole concentrations in the cerebrospinal fluid (CSF) of immunocompetent guinea pigs and patients with invasive fungal infections. In animals, after receipt of oral doses of 4 or 10 mg/kg every 8 h, the mean ratios of CSF to plasma total and free drug concentration were 0.68 and 1.3, respectively. In humans, 1-10 h after receipt of voriconazole, the CSF concentrations ranged from 0.08 to 3.93 microg/mL, and the ratio of CSF to plasma concentration ranged from 0.22 to 1.0 (median, 0.46).

Determination of SCH 39304 by megabore capillary gas-liquid chromatography.

A gas-liquid chromatographic procedure for determination of SCH 39304 at low nanogram concentrations in serum, cerebrospinal fluid, and urine is presented. The methodology combines a high selectivity and sensitivity nitrogen-specific detector, a gas chromatograph equipped with a capillary "megabore" column, and an internal standard that is very similar in chemical structure to the drug being assayed. This method is suitable for both pharmacokinetic studies as well as for monitoring drug levels in patients receiving SCH 39304 for antifungal treatment.

Penetration of SCH-39304, a new antifungal triazole, into cerebrospinal fluid of primates.

We characterized the cerebrospinal fluid (CSF) penetration and pharmacokinetics of SCH-39304 in adult rhesus monkeys receiving a single oral dose of SCH-39304 (2.0 mg/kg of body weight). The mean CSF-to-plasma area under the curve ratio was 0.63 (+/- 0.18, standard error of the mean); maximum concentrations were 1.34 micrograms/ml (+/- 0.18) in CSF and 1.96 micrograms/ml (+/- 0.43) in plasma. The mean plasma half-life was 45.7 h (+/- 11), and mean CSF half-life was 38.7 h (+/- 3.5). The mean levels of SCH-39304 at 24 h were 1.48 micrograms/ml (+/- 0.3) in plasma and 0.96 microgram/ml (+/- 0.12) in CSF. We conclude that SCH-39304 effectively penetrates into CSF and achieves concentrations considered active against many opportunistic yeasts and that these concentrations are sustained in CSF for greater than or equal to 24 h.

[Clinical evaluation of fluconazole].

Clinical evaluation of fluconazole was performed on 12 cases of mycotic infections (7 cases of Candida esophagitis; one each case of cryptococcal meningitis with AIDS, Candida tropicalis fungemia and disseminated cryptococcosis in kidney transplant patient; 2 cases of Candida pneumonia). Satisfactory responses were obtained except 1 case of Candida pneumonia in which clinical efficacy could not be evaluated. Hiccup was noted in 1 case during the fluconazole treatment. No other adverse reaction was observed. When 150 mg and 200 mg of fluconazole were administered orally to a patient with hemodialysis (HD) after HD on separate occasions, concentrations of the drug in serum at 20 hours after ingestion were 5.9 micrograms/ml and 11.6 micrograms/ml, respectively, and in cerebrospinal fluid (CSF) were 3.5 micrograms/ml and 9.2 micrograms/ml, respectively. Two clinical benefits were obtained in our studies. First, it was possible to treat the AIDS-patient as an outpatient with Candida esophagitis using orally administered fluconazole. Second, it was possible to treat the case of cryptococcal meningitis, in which relapse often occurs, to complete the therapy when the cryptococcal antigen in serum and CSF diminished to an undetectable level and to maintain the therapy preventing relapse without severe adverse effects. Ongoing and future clinical trials will define the specific roles of fluconazole more clearly in the treatment of systemic mycosis.

Fluconazole penetration into cerebrospinal fluid in humans.

One hour after intravenous doses of 50 mg/d fluconazole for 6 days or 100 mg/d for seven days to healthy subjects, the cerebrospinal fluid concentrations of fluconazole were 1.26 mg/L and 2.74 mg/L, respectively. These values were approximately 52% and 62% those of serum. Four patients with an initial clinical diagnosis of meningitis also had significant concentrations of fluconazole in the cerebrospinal fluid.

Treatment of two cases of cryptococcal meningitis with fluconazole.

Two patients with cryptococcal meningitis were treated with the investigational triazole drug fluconazole (UK-49,858). Cerebrospinal fluid (CSF) levels of fluconazole were between 3.0 and 5.4 mg/l 2 h after an oral dose of 50 mg daily in the first patient and between 7.9 and 9.0 mg/l after an oral dose of 100 mg daily in the second patient. These levels were in the same range as plasma levels. The first patient, a 46-year-old renal transplant patient, was both clinically and microbiologically cured after 28 weeks of therapy (follow-up 14 months). In the second patient, a 15-year-old girl with chronic mucocutaneous candidiasis, fluconazole led to clinical cure of the meningitis, but failed to eradicate cryptococci from the CSF. These cases illustrate that fluconazole is useful for the treatment of cryptococcal meningitis, especially when prolonged treatment is indicated as in patients with immunodeficiencies.