Evaluation of the pharmacokinetics of liposomal amphotericin B and analysis of the relationship between pharmacokinetics, efficacy and safety in patients with hematological diseases.

INTRODUCTION: This study aimed to identify factors responsible for changes in blood concentrations of a liposomal formulation of amphotericin B (AMPH-B, L-AMB) and analyze the relationships between blood concentrations and efficacy or toxicity. METHODS: L-AMB was administered to 30 patients being treated for hematological diseases. AMPH-B plasma concentrations were determined right before the initiation (Cmin) and at the end (Cmax) of infusion on at least 1 day, beginning on Day 3 of L-AMB treatment. The relationships of Cmin divided by dose (C/D ratio) to body weight, age, hepatic function, renal function, serum albumin, C-reactive protein (CRP), response, hypokalemia, and renal impairment were evaluated. RESULTS: C/D ratio was not correlated with age, hepatic function, renal function, or serum albumin. Body weight adjusted C/D ratio was negatively correlated with CRP. Cmax and Cmin were compared between responders and non-responders, those with or without hypokalemia, and those with or without renal impairment. A higher Cmax in patients with hypokalemia was the only significant difference seen. CONCLUSIONS: The negative correlation between CRP and plasma concentrations was likely caused by higher distribution of L-AMB from the blood to infected tissue in patients with a greater degree of infection, with a resulting decrease in plasma concentrations. AMPH-B plasma concentrations were not related to response. Higher Cmax of AMPH-B were observed in patients with hypokalemia, but no relationship between plasma concentration and renal toxicity was observed, suggesting that AMPH-B plasma concentrations appear to be minimally related to PD when used as L-AMB.

Intraocular penetration of liposomal amphotericin B after intravenous injection in inflamed human eyes.

PURPOSE: To determine the intraocular penetration of amphotericin B (AMPH-B) after an intravenously injection of liposomal amphotericin B (L-AMB) in inflamed human eyes. METHODS: Seven eyes of 5 patients with fungal eye diseases (endophthalmitis in 6 eyes and keratitis in 1 eye) were treated with intravenous injections of 100-250 mg/day of L-AMB. Samples of blood, corneal button, aqueous humor, and vitreous humor were collected and assessed for AMPH-B. RESULTS: The AMPH-B level in the cornea (604.0 µg/g) of the case with fungal keratitis exceeded the minimum inhibitory concentration. However, the levels in the aqueous and vitreous humors of the cases with fungal endophthalmitis were lower, e.g., 0.02 ± 0.01 µg/ml (0.09% of serum level) in the aqueous humor and 0.05 ± 0.08 µg/ml (0.17% of serum level) in the vitreous humor. CONCLUSIONS: The AMPH-B levels administered intravenously were very low in the aqueous and vitreous humors. Our findings indicate that intravenous L-AMB can be considered only for patients with mild endogenous fungal endophthalmitis, e.g., isolated chorioretinitis without vitreous extensions.

Effective plasma concentrations of itraconazole and its active metabolite for the treatment of pulmonary aspergillosis.

BACKGROUND: Itraconazole (ITCZ) is used to treat pulmonary aspergillosis, but findings regarding the range of effective plasma concentrations are often contradictory. This study attempted to determine effective plasma concentrations of ITCZ and its active metabolite hydroxyitraconazole (OH-ITCZ) by retrospectively analyzing their relationships to clinical efficacy. METHODS: The study included 34 patients with pulmonary aspergillosis treated using ITCZ (mean age, 70 years). Each patient was treated with 200 mg ITCZ once daily (mean duration of treatment: 384 days). Plasma concentrations of ITCZ and OH-ITCZ at trough levels from 7 to 889 days after the start of treatment were determined using high-performance liquid chromatography. Clinical efficacy was assessed through the improvement clinical symptoms. RESULTS: Fifteen patients were classified as effective group and the other 19 patients as non-effective group. Mean (±standard deviation) ITCZ trough plasma concentration was significantly higher in effective group (1254 ± 924 ng/mL) than in non-effective group (260 ± 296 ng/mL). Mean OH-ITCZ plasma concentration was significantly higher in effective group (1830 ± 1031 ng/mL) than in non-effective group (530 ± 592 ng/mL). Receiver operating characteristic curve analysis revealed the optimal cutoff for ITCZ trough plasma concentration was 517 ng/mL, and 86.7% of effective group showed concentrations exceeding this value. The optimal cutoff for total ITCZ + OH-ITCZ plasma concentration was 1025 ng/mL, and 93.3% of effective group showed a concentration exceeding this value. CONCLUSIONS: Our findings indicate that effective plasma concentration ranges for the treatment of pulmonary aspergillosis begin at an ITCZ trough plasma concentration of 500 ng/mL and a total ITCZ + OH-ITCZ plasma concentration of 1000 ng/mL.

In vitro Evaluation of Linezolid and Doripenem Clearance with Different Hemofilters.

INTRODUCTION: Renal replacement therapy (RRT) is widely used in the treatment of septic acute kidney injury. However, little is known about how the adsorption properties of hemofilters used in RRT affect antibiotic concentration. Because a cytokine-adsorption membrane is frequently used in RRT, it is important to determine the antibiotic adsorption capacity of this membrane. OBJECTIVE: The present study aimed to investigate the antibiotic adsorption capacity of different hemofilter membranes by in vitro experiments using 2 antibacterial agents (linezolid and doripenem). METHODS: We performed experimental hemofiltration in vitro using polyacrylonitrile (AN69ST), polymethylmethacrylate (PMMA), and polysulfone (PS) hemofilters for 1,440 min. The test solution was a 1,000-mL substitution fluid containing 30 µg/mL linezolid and 120 µg/mL doripenem. We measured drug concentrations at the inlet, outlet, and filtrate ports of the hemofilters for 1,440 min and calculated the sieving coefficient (SC) and adsorption rate (Ra) of the drugs onto the hemofilters. RESULTS: The amount of linezolid adsorbed onto AN69ST, PMMA, and PS membranes was decreased relative to that in the control group at 15 min (p < 0.05). However, no SC for linezolid was obtained thereafter. The Ra of linezolid onto AN69ST, PMMA, and PS membranes was higher than that in the control group (p < 0.05). In contrast, no significant differences were observed in the concentrations and Ra values of doripenem adsorbed onto AN69ST, PMMA, and PS membranes compared with those in the control group. CONCLUSIONS: Doripenem was not adsorbed onto PMMA, PS, and AN69ST membranes. Linezolid was adsorbed onto PMMA, PS, and AN69ST membranes, but only temporarily, and this did not affect drug bioavailability.

Essential human resources for antimicrobial stewardship teams in Japan: Estimates from a nationwide survey conducted by the Japanese Society of Chemotherapy.

Implementation of antimicrobial stewardship programs (ASPs) with multidisciplinary antimicrobial stewardship teams (ASTs) is critical for appropriate antimicrobial use at healthcare facilities. Although the Japanese medical reimbursement system was revised to allow fees for ASP implementation, several concerns remain, including understaffing and enforcement of the recommendations on ASTs and ASPs in practice. Furthermore, there are no recommendations on full-time equivalents (FTEs) of the core members in ASTs in Japan. This committee report presents our recommendations on ASTs based on an analysis of the nationwide survey on implemented ASPs and staff FTEs at 1358 healthcare facilities conducted by the Japanese Society of Chemotherapy. Our report provides a directive for structural and financial support of ASTs and should aid in planning for the enhancement of AST practices and the organization of new ASTs.

Breakthrough Exophiala dermatitidis infection during prophylactic administration of micafungin during second umbilical cord blood transplantation after graft failure.

Exophiala dermatitidis infections in patients with hematological malignancies are very rare. Our patient had a blood stream infection caused by E. dermatitidis following the second umbilical cord blood transplantation (UCBT) after graft failure during the first UCBT. To our knowledge, this is the first report describing a breakthrough fungal infection caused by E. dermatitidis during the prophylactic administration of micafungin (MCFG). Therefore, MCFG-treated patients should be monitored for breakthrough E. dermatitidis infection during hematopoietic stem cell transplantation.

Cyst infection in autosomal dominant polycystic kidney disease: penetration of meropenem into infected cysts.

BACKGROUND: Cyst infection is a common and serious complication of autosomal dominant polycystic kidney disease (ADPKD) that is often refractory. Carbapenems are frequently needed to treat to patients with refractory cyst infection, but little is known about the penetration of newer water-soluble carbapenems into cysts. This study investigated the penetration of meropenem (MEPM) into infected cysts in patients with ADPKD. METHODS: Between August 2013 and January 2014, 10 ADPKD patients (14 infected cysts) receiving MEPM at Toranomon Hospital underwent drainage of infected cysts and definite cyst infection was confirmed through detection of neutrophils by cyst fluid analysis. The serum concentration of MEPM was measured just after intravenous administration and was compared with that in fluid aspirated from infected cysts. RESULTS: In the patients undergoing cyst drainage, the mean serum MEPM concentration was 35.2 ± 12.2 µg/mL (range: 19.7 to 59.2 µg/mL, while the mean cyst fluid concentration of MEPM in the drained liver cysts (n = 12) or kidney cysts (n = 2) was 3.03 ± 2.6 µg/mL (range: 0 to 7.3 µg/mL). In addition, the mean cyst fluid/serum MEPM concentration ratio was 9.46 ± 7.19% (range: 0 to 18.8%). There was no relationship between the cyst fluid concentration of MEPM and the time until drainage after MEPM administration or between the cyst fluid/serum MEPM concentration ratio and the time until drainage. CONCLUSION: These findings suggest that MEPM shows poor penetration into infected cysts in ADPKD patients. TRIAL REGISTRATION: This study was registered with the University Hospital Medical Information Network (UMIN) as "Penetration of meropenem into cysts in patients with autosomal dominant polycystic kidney disease (ADPKD)", UMIN ID 000011292 on July 26th, 2013.

Clinical Application of the Dried Blood Spot Method in the Measurement of Blood Busulfan Concentration.

The dried blood spot (DBS) method, which is a simple technique for blood sample processing involving the placement of a drop of whole blood onto filter paper, has been used recently in clinical pharmacology to determine blood concentrations of various drugs. This study examined the feasibility of the clinical application of the DBS method for individual busulfan dose adjustments. Pharmacokinetic (PK) parameters of blood samples for busulfan measurements determined using the DBS method were compared with those using plasma separation (the conventional method). Blood samples were collected from patients receiving i.v. busulfan as a conditioning regimen before allogeneic hematopoietic stem cell transplantation at Toranomon Hospital, Japan. Samples collected 2, 4, and 6 hours after the start of the first drip infusion were processed by DBS or the conventional method. The area under the blood concentration-time curve (AUC) and other PK parameters were calculated to compare the 2 methods. Divergence of <20% in each parameter was considered acceptable. The divergence range for each parameter was as follows: blood concentration at 2 hours after the start of drip infusion, .6 to 8.2%; at 4 hours, .3 to 10.0%; at 6 hours, .3 to 14.2%; and AUC0-∞, .0 to 10.3%. None of the PK parameters showed a divergence between the DBS method and the conventional method exceeding 20%, suggesting that both methods are well correlated. The clinical application of blood sample processing with the DBS method in the measurement of blood busulfan concentration may therefore be feasible, but further studies are needed to confirm these findings.

Significance of monitoring trough plasma concentration levels for invasive fungal infection prophylaxis with itraconazole oral solution in patients with hematological malignancies: a prospective study.

In this prospective study, we examined the prophylactic effect of itraconazole oral solution (ITCZ-OS) against invasive fungal disease in hematologic malignancy patients. The participants were 36 patients, at least 16 years of age, with hematologic malignancies treated at our hospital. ITCZ-OS 200 mg/day was administered orally twice a day with a target trough plasma concentration of 350 ng/ml. If the patient did not achieve the target trough plasma concentration, the dose was increased. The success rate of achieving the target trough plasma concentration of ITCZ with a dose of 200 mg/day was 63.9%. During the observation period, 2 patients (5.6%) were diagnosed with possible invasive fungal disease according to the EORTC/MSG 2008 criteria. Adverse events were observed in 2 patients (5.6%). The results showed administration of ITCZ-OS while monitoring ITCZ trough plasma concentrations to be effective for preventing invasive fungal disease, and no serious adverse events occurred. Since predicting trough levels in response to ITCZ administrations is difficult, its measurement is necessary to maintain the prophylactic effect of ITCZ.

Chronic invasive sinus and intracerebral aspergillosis controlled by combination therapy with micafungin and a daily dose of 400 mg itraconazole oral solution.

Chronic invasive aspergillosis of the sinus is frequently fatal in the absence of early surgical and chemotherapeutic intervention because of its invasion of vascular tissue. We attempted to control a case of inoperable invasive aspergillosis of the sinus with micafungin and itraconazole oral solution. We prescribed a daily oral dose of 400 mg of itraconazole, which is twice the usual dose, and monitored the serum concentration of the drug. Finally, we were able to control the spread of the lesion. This case indicates that combination therapy with micafungin and a daily dose of 400 mg itraconazole oral solution is an alternative treatment strategy for inoperable invasive aspergillosis of the sinus.

[Invasive Aspergillosis Accompanied by a Subcutaneous Nodular Lesion].

We report herein on a case of invasive aspergillosis accompanied by a subcutaneous nodular lesion. A 74-years-old male with myelodysplastic syndrome was hospitalized due to high fever and a painful subcutaneous nodule on the left thigh. Chest radiography and CT scans showed multiple nodular lesions of both lungs, and bacterial pneumonia was initially suspected. He was treated with meropenem, but the symptoms did not subside. Three days after admission, we found that ß-D-glucan levels were elevated at 52.6 pg/mL. He was treated with liposomal amphotericin B (L-AMB) for invasive fungal pneumonia, and the symptoms regressed thereafter. Excisional biopsy of the nodular lesion showed a cluster of septated and branching hyphae. Serum Aspergillus antigen tests and sputum fungal culture were negative, and the fungal species could not be identified. Thus, we performed in situ hybridization (ISH) and polymerase chain reaction (PCR) with the excised subcutaneous specimens, and as a result Aspergillus fumigatus infection was diagnosed. Invasive aspergillosis with a subcutaneous lesion is a rare case, and we found that treatment with L-AMB was effective. ISH, PCR and measurement of serum trough concentration of AMPH-B are useful in diagnosis and treatment.

Efficacy and safety of meropenem (3 g daily) in Japanese patients with refractory respiratory infections.

INTRODUCTION: Pneumonia is the third leading cause of mortality in Japan. In 2011, the use of meropenem (MEPM) at 3 g daily was approved to treat refractory infections in Japan. However, little has been reported on the clinical efficacy and safety of this regimen in Japanese patients with refractory infections. OBJECTIVES: This study prospectively assessed the clinical efficacy and safety of MEPM (3 g daily) in Japanese patients with refractory pneumonia and/or intrapleural infections. METHODS: This study was performed at our university hospital and affiliated hospitals. The plasma concentrations of MEPM before and one and four hours after MEPM administration were also evaluated. RESULTS: A total of 48 patients were enrolled for the efficacy and safety evaluations. The response rate to MEPM (3 g daily) treatment was 90.9% (40/44). Adverse drug reactions were observed in 17 of the 48 patients (20.8%), and all improved after the cessation of MEPM. The plasma MEPM concentration one hour after administering 1 g of MEPM was 44.9 ± 12.0 µg/ml. A pharmacokinetic analysis revealed that the percentage of time above the MIC/24 h for an MIC of 4 µg/ml or 8 µg/ml was more than 50% in 12 of 13 (92%) and in nine of the 13 patients (69%), respectively, indicating sufficient efficacy of 3 g daily of MEPM. CONCLUSION: Treatment with MEPM (3 g daily) in Japanese patients with refractory pneumonia and/or intrapleural infections is effective, with sufficient plasma concentrations of MEPM, and the treatment has a relatively good safety profile.

[Sudden blast crisis of chronic myeloid leukemia after a 13-year durable remission following allogeneic bone marrow transplantation and donor lymphocyte infusion].

We describe a rare case of sudden blast crisis of chronic myeloid leukemia that occurred after a 13-year durable remission, following allogeneic bone marrow transplantation and donor lymphocyte infusion. A 55-year-old Japanese man was diagnosed with chronic-phase chronic myeloid leukemia 24 years previously. He underwent allogeneic bone marrow transplantation 2 years after diagnosis. Although the disease recurred 6 years after transplantation, the patient achieved remission again by a donor lymphocyte infusion. Despite a 13-year durable remission, the disease later relapsed into a sudden blast crisis. Prednisolone and vincristine combined with imatinib mesylate effectively achieved a major molecular response. However, the disease relapsed repeatedly with central nervous system infiltration. Dasatinib and intrathecal methotrexate, cytarabine, and dexamethasone administration via the Ommaya reservoir controlled disease progression. Nevertheless, the disease became refractory to treatment with the emergence of a T315I Bcr-Abl gene mutation. The patient eventually died 43 months post crisis.

Association between Extended Meropenem Regimen and Achievement of Aggressive PK/PD in Patients Receiving Continuous Renal Replacement Therapy for Septic AKI.

Aggressive pharmacokinetic (PK)/pharmacodynamic (PD) targets have shown better microbiological eradication rates and a lower propensity to develop resistant strains than conservative targets. We investigated whether meropenem blood levels, including aggressive PK/PD, were acceptable in terms of efficacy and safety using a meropenem regimen of 1 g infusion every 8 h over 3 h in patients undergoing continuous renal replacement therapy (CRRT) for septic acute kidney injury (AKI). Aggressive PK/PD targets were defined as the percentage of time that the free concentration (%fT) > 4 × minimal inhibitory concentration (MIC), the toxicity threshold was defined as a trough concentration >45 mg/L, and the percentage of achievement at each MIC was evaluated. The 100% fT > 4 × MIC for a pathogen with an MIC of 0.5 mg/L was 89%, and that for a pathogen with an MIC of 2 mg/L was 56%. The mean steady-state trough concentration of meropenem was 11.9 ± 9.0 mg/L and the maximum steady-state trough concentration was 29.2 mg/L. Simulations using Bayesian estimation showed the probability of achieving 100% fT > 4 × MIC for up to an MIC of 2 mg/L for the administered administration via continuous infusion at 3 g/24 h. We found that an aggressive PK/PD could be achieved up to an MIC of 0.5 mg/L with a meropenem regimen of 1 g infused every 8 h over 3 h for patients receiving CRRT for septic AKI. In addition, the risk of reaching the toxicity range with this regimen is low. In addition, if the MIC was 1-2 mg/L, the simulation results indicated that aggressive PK/PD can be achieved by continuous infusion at 3 g/24 h without increasing the daily dose.

Dasatinib maintenance therapy after allogeneic hematopoietic stem cell transplantation for an isolated central nervous system blast crisis in chronic myelogenous leukemia.

A 22-year-old male with Ph-positive chronic myelogenous leukemia (CML) was started on treatment with imatinib. After 12 months of therapy, he achieved a complete cytogenetic response (CCyR). Although the CCyR persisted in his bone marrow, he developed an isolated CML blast crisis in his central nervous system (CNS) after 29 months of therapy. He underwent allogeneic hematopoietic stem cell transplantation (HSCT) following combination therapy with dasatinib, intrathecal chemotherapy and cranial irradiation. Subsequently, 168 days after allogeneic HSCT, he was started on dasatinib maintenance therapy to prevent a CNS relapse. Thirty-eight months after allogeneic HSCT, he has sustained a complete molecular response in both bone marrow and CNS. We believe dasatinib has the potential to prevent CNS relapse if used for maintenance therapy after allogeneic HSCT.

Pharmacokinetics and elimination efficiency of linezolid during dialysis.

Linezolid (LZD) is an option for treating infections caused by multi-resistant Gram-positive bacteria. The protein-binding rate of LZD markedly influences its elimination by dialysis, with limited data suggesting that LZD is cleared by intermittent hemodialysis. Here, we investigated the protein-binding rate and elimination efficiency of LZD in a sepsis patient receiving dialysis. The oral administration of LZD at 600 mg/day resulted in protein-binding and free rates of the drug of 20.4% and 79.6%, respectively, 24 h after administration. By comparing the LZD concentration before and after dialysis, the elimination efficiency of free LZD as a result of dialysis was found to be 40.6%. Our sepsis patient showed higher plasma concentrations of LZD at trough after hemodialysis than the reported concentrations in normal renal function patients. However, it is not clear from our present findings if a relationship exists between myelosuppression and plasma LZD concentration.

Correlation between serum linezolid concentration and the development of thrombocytopenia.

We evaluated the possible association between trough linezolid (LZD) concentrations and platelet counts using a dose-response curve with a logit model equation. We demonstrated that trough LZD concentrations correlated with platelet counts. A significant decrease in platelet count was observed in patients with trough LZD concentrations higher than 22.1 µg/ml.

Evaluation of the pharmacokinetics of linezolid in an obese Japanese patient.

We evaluated the pharmacokinetics of linezolid in the case of an obese Japanese patient (body weight 116 kg; body mass index 37 kg/m(2)). Linezolid was administered at a dose of 600 mg by intravenous drip infusion for 60-90 min at 12-h intervals. The results showed increased clearance of linezolid and a reduced serum concentration compared to population pharmacokinetic parameters, with trough levels below the 90% minimum inhibitory concentration. However, linezolid was effective for improving lung infection and inflammation in our patient, which may be due to its particularly effective transfer into lung tissues. Linezolid undergoes slow non-enzymatic oxidation in vivo that may be increased in obese patients, and this may account for the greater clearance. Our findings are useful for the planning of linezolid therapy in obese patients.