Pharmacokinetic modelling and development of Bayesian estimators for therapeutic drug monitoring of mycophenolate mofetil in reduced-intensity haematopoietic stem cell transplantation.

International audienceBACKGROUND: Mycophenolate mofetil, a prodrug of mycophenolic acid (MPA), is used during non-myeloablative and reduced-intensity conditioning haematopoetic stem cell transplantation (HCT) to improve engraftment and reduce graft-versus-host disease (GVHD). However, information about MPA pharmacokinetics is sparse in this context and its use is still empirical. OBJECTIVES: To perform a pilot pharmacokinetic study and to develop maximum a posteriori Bayesian estimators (MAP-BEs) for the estimation of MPA exposure in HCT. PATIENTS AND METHODS: Fourteen patients administered oral mycophenolate mofetil 15 g/kg three times daily were included. Two consecutive 8-hour pharmacokinetic profiles were performed on the same day, 3 days before and 4 days after the HCT. One 8-hour pharmacokinetic profile was performed on day 27 after transplantation. For these 8-hour pharmacokinetic profiles, blood samples were collected predose and 20, 40, 60, 90 minutes and 2, 4, 6 and 8 hours post-dose. Using the iterative two-stage (ITS) method, two different one-compartment open pharmacokinetic models with first-order elimination were developed to describe the data: one with two gamma laws and one with three gamma laws to describe the absorption phase. For each pharmacokinetic profile, the Akaike information criterion (AIC) was calculated to evaluate model fitting. On the basis of the population pharmacokinetic parameters, MAP-BEs were developed for the estimation of MPA pharmacokinetics and area under the plasma concentration-time curve (AUC) from 0 to 8 hours at the different studied periods using a limited-sampling strategy. These MAP-BEs were then validated using a data-splitting method. RESULTS: The ITS approach allowed the development of MAP-BEs based either on 'double-gamma' or 'triple-gamma' models, the combination of which allowed correct estimation of MPA pharmacokinetics and AUC on the basis of a 20 minute-90 minute-240 minute sampling schedule. The mean bias of the Bayesian versus reference (trapezoidal) AUCs was 20%. AIC was systematically calculated for the choice of the most appropriate model fitting the data. CONCLUSION: Pharmacokinetic models and MAP-BEs for mycophenolate mofetil when administered to HCT patients have been developed. In the studied population, they allowed the estimation of MPA exposure based on three blood samples, which could be helpful in conducting clinical trials for the optimization of MPA in reduced-intensity HCT. However, prior studies will be needed to validate them in larger populations

Les infections après greffe de sang placentaire (à propos de 36 greffes réalisées au CHU de Besançon)

BESANCON-BU Médecine pharmacie (250562102) / SudocSudocFranceF

Détection du (1,3)-b-D-glucane sérique pour le diagnostic des infections fongiques invasives : évaluation rétrospective au CHU de Besançon

International audienc

Evaluation de 2 cibles ribosomale et mitochondriale pour le diagnostic des aspergilloses invasives par PCR en temps réel

International audienc

False-positive Aspergillus real-time PCR assay due to a nutritional supplement in a bone marrow transplant recipient with GVH disease.

International audiencePCR screening for circulating DNA, especially when combined with antigen testing, has shown promise for the definitive diagnosis of invasive aspergillosis. False positives for Aspergillus real-time PCR assays have been described in several reports, but no sources of fungal DNA contamination could be clearly identified. We report a false-positive case for both galactomannan (GM) antigenemia and Aspergillus PCR due to nutritional supplement intake in a bone marrow transplant recipient with digestive graft-versus-host disease. Our case report also suggests that fungal DNA can pass into the serum from the intestinal tract in the same way as fungal GM. Clinicians should be aware of this possibility, so that the administration of costly, unnecessary antifungal treatments with potential adverse side-effects can be avoided

Pharmacokinetics of mycophenolic acid administered 3 times daily after hematopoietic stem cell transplantation with reduced-intensity regimen.

International audienceMycophenolate mofetil (MMF) is an immunosuppressive drug used as a prophylactic agent to prevent acute graft-versus-host disease (aGVHD) after hematopoietic stem cell transplantation (HSCT). After reduced-intensity conditioning (RIC) regimen, administration of MMF orally 3 times a day (tid) seems to be more beneficial than twice a day (bid). However, information regarding the pharmacokinetic (PK) parameters of mycophenolic acid (MPA), the active metabolite of MMF, administered in this regimen are very limited. We performed a prospective study in 15 patients for whom 3 sets of sampling were performed: at the beginning of the treatment, after 1 week, and after 1 month. Two consecutive 8-hour sets of sampling were performed at day 0 (D0) and D7. Plasma concentrations of MPA were quantified and areas under the curve for 8hours (AUC(0-8)), and maximal and through concentrations were calculated. The results show that AUC(0-8) increases between the beginning of treatment and the end of the first week, but remains stable thereafter. Moreover, a trend to lower AUC(0-8) was observed for the patients who experienced GVHD > or =2 compared to those patients who did not. The other PK parameters are not associated with pharmacodynamic events. A limited sampling strategy with Bayesian estimators is currently under investigation to confirm these data and the role of D7 AUC(0-8) as a potential target of therapeutic drug monitoring (TDM)

Quantitative polymerase chain reaction detection of circulating DNA in serum for early diagnosis of mucormycosis in immunocompromised patients.

International audienceBACKGROUND: The aim of our study was to assess the detection of circulating DNA from the most common species of Mucorales for early diagnosis of mucormycosis in at-risk patients. METHODS: We retrospectively evaluated a combination of 3 quantitative polymerase chain reaction (qPCR) assays using hydrolysis probes targeting Mucor/Rhizopus, Lichtheimia (formerly Absidia), and Rhizomucor for circulating Mucorales detection. Serial serum samples from 10 patients diagnosed with proven mucormycosis (2-9 samples per patient) were analyzed. RESULTS: No cross-reactivity was detected in the 3 qPCR assays using 19 reference strains of opportunistic fungi, and the limit of detection ranged from 3.7 to 15 femtograms/10 µL, depending on the species. DNA from Mucorales was detected in the serum of 9 of 10 patients between 68 and 3 days before mucormycosis diagnosis was confirmed by histopathological examination and/or positive culture. All the qPCR results were concordant with culture and/or PCR-based identification of the causing agents in tissue (Lichtheimia species, Rhizomucor species, and Mucor/Rhizopus species in 4, 3, and 2 patients, respectively). Quantitative PCR was negative in only 1 patient with proven disseminated mucormycosis caused by Lichtheimia species. CONCLUSION: Our study suggests that using specific qPCR targeting several species of Mucorales according to local ecology to screen at-risk patients could be useful in a clinical setting. The cost and efficacy of this strategy should be evaluated. However, given the human and economic cost of mucormycosis and the need for rapid diagnosis to initiate prompt directed antifungal therapy, this strategy could be highly attractive

Early immune reconstitution and efficient graft vs tumor effect after unrelated partially matched double cord blood transplantation in refractory 8p11 syndrome.

International audienc

Epidemiology of invasive fungal infections during induction therapy in adults with acute lymphoblastic leukemia: a GRAALL-2005 study.

International audienceLittle data have been published concerning invasive fungal infections during treatment of acute lymphoblastic leukemia (ALL). Patients included between May 2006 and October 2012 in the multicenter phase III trial for newly diagnosed ALL (GRAALL-2005) were retrospectively reviewed for the occurrence of IFI using the EORTC modified criteria. These patients did not routinely receive antifungal prophylaxis. Among 969 patients included (median age 47 years), 65 (6.7%) developed IFI during induction chemotherapy: 26 (3.3%) invasive aspergillosis (IA), 33 (3.4%) invasive candidiasis (IC) and six other IFI. For IA, the median time between induction therapy and IA diagnosis was 20 days. Diagnosis was probable in 22 cases and proven in four. Aspergillus antigen in serum was tested in all cases and positive in 24. Overall 12-week mortality after diagnosis of IA was 5/26 and attributable mortality related to the infection was 4/26 (15.4%). For IC, the median time between induction therapy and diagnosis was 19 days. Diagnosis was proven in 29 episodes. Candida albicans was the major pathogen in yeast infections (16/27). Overall 12-week mortality after diagnosis of IC was 8/33 (24.2%) and attributable mortality related to the infection was 7/33. The median delay between induction chemotherapy initiation and attributable death related to IC was 15 days. These findings may help to optimize the future management of ALL patients, and as in AML advocate systematic monitoring and the development of prophylactic or preemptive antifungal treatments