A Caldés

Hospital Universitari de Bellvitge, l'Hospitalet de Llobregat, Catalonia, Spain

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Publications (12)35.39 Total impact

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    ABSTRACT: Several factors contribute to mycophenolic acid (MPA) between-patient variability. Here we characterize the metabolic pathways of MPA and quantify the effect of combining genetic polymorphism of multidrug-resistant-associated protein-2, demographics, biochemical covariates, co-medication (cyclosporine (CsA) vs. macrolides), and renal function on MPA, 7-O-MPA-glucuronide (MPAG), and acyl-glucuronide (AcMPAG) disposition, in renal transplant recipients, after mycophenolate mofetil. Complete pharmacokinetic profiles from 56 patients (five occasions) were analyzed. Enterohepatic circulation was modeled by transport of MPAG to the absorption site. This transport significantly decreased with increasing CsA trough concentrations (CtroughCsA). MPAG and AcMPAG plasma clearances significantly decreased with renal function. No significant influence of multidrug-resistant-associated protein-2 C24T single-nucleotide polymorphism was found. The model adequately predicted the increase in MPAG/AcMPAG exposures in CsA and macrolide patients with decreased renal function. This resulted in higher MPA exposures in macrolide patients versus CsA patients, and increased MPA exposures with renal function from 25 to 10 ml/min, in macrolide patients, owing to enhanced MPAG enterohepatic circulation. Lower-percentage enterohepatic circulation occurred with higher CtroughCsA and renal function values. The lack of MPA protein-binding modeling did not permit evaluation of the impact of renal function and CtroughCsA on MPA exposures in CsA patients. Thus, dose tailoring of covariates is recommended for target MPA exposure.Kidney International advance online publication, 8 January 2014; doi:10.1038/ki.2013.517.
    Kidney International 01/2014; 85(6). DOI:10.1038/ki.2013.517 · 8.56 Impact Factor
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    ABSTRACT: Implement a sensitive UHPLC method for the assay of ganciclovir in human plasma. We developed and validated a chromatographic method coupled to ultraviolet detection for quantification of ganciclovir, with a short run time using a small volume of human plasma. Comparison of system performance was made with respect to analysis time, efficiency and sensitivity. Correlation coefficients (r) of the calibration curves ranged from 0.999744 to 0.999784. Within-day and between-day imprecision and inaccuracy, specificity and recovery were also evaluated for validation. The method was precise and accurate and the retention time was 0.7 min. The calibration curves were linear between 0.5 and 30 μg/mL. There was a good correlation between HPLC and UHPLC techniques. We developed a method that is currently applied in a clinical study assessing GCV plasma concentration variability after ganciclovir and valganciclovir administration.
    Clinical biochemistry 03/2012; 45(4-5):309-14. DOI:10.1016/j.clinbiochem.2011.12.014 · 2.28 Impact Factor
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    ABSTRACT: Oral (p.o.) or intravenous (IV) ganciclovir (GCV) has been the first-line agent for prevention and treatment of cytomegalovirus (CMV) infection and disease in solid organ transplantation (SOT). The introduction of p.o. valganciclovir, with higher bioavailability than p.o. GCV, has proven to be a suitable approach toward outpatient p.o. therapy for CMV infection/disease. The present single-arm, exploratory pilot trial performed with 21 patients investigates the efficacy and safety of a short therapeutic course (21 days) based on an initial IV treatment with GCV (5 mg/kg twice daily, for 5 days) followed by p.o. valganciclovir (900 mg twice daily, for 16 days) for CMV infection/disease in SOT patients. In all cases, doses were adjusted for renal function. Moreover, the study allowed comparison of exposure to GCV after p.o. valganciclovir with respect to IV GCV in the same patients. Response to treatment was monitored until day 180. Viral load eradication was achieved in 66.7% of patients, on day 21. Although not statistically significant, a trend was seen toward increased persistence of viral load on day 21 for patients with donor positive/recipient negative CMV serostatus or receiving either anti-rejection therapy or polyclonal anti-thymocyte globulin. CMV clinical infection recurred in 14.3% of patients, with higher recurrence rates in patients with risk factors for persistence of viremia. Exposures to GCV after using IV GCV or p.o. valganciclovir showed comparable values (P=0.054). This short course, combining initial IV GCV and subsequent p.o. valganciclovir, may provide effective exposure and therapeutic response in the treatment of CMV infection in SOT patients with adequate drug exposure and with the additional potential benefit of shortening the length of hospital stay, which may result in cost reduction and improved patient comfort.
    Transplant Infectious Disease 12/2009; 12(3):204-12. DOI:10.1111/j.1399-3062.2009.00481.x · 2.06 Impact Factor
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    ABSTRACT: A population pharmacokinetics analysis was performed after intravenous ganciclovir and oral valganciclovir in solid organ transplant patients with cytomegalovirus. Patients received ganciclovir at 5 mg/kg of body weight (5 days) and then 900 mg of valganciclovir (16 days), both twice daily with dose adjustment for renal function. A total of 382 serum concentrations from days 5 and 15 were analyzed with NONMEM VI. Renal function given by creatinine clearance (CLCR) was the most influential covariate in CL. The final pharmacokinetic parameters were as follows: ganciclovir clearance (CL) was 7.49·(CLCR/57) liter/h (57 was the mean population value of CLCR); the central and peripheral distribution volumes were 31.9 liters and 32.0 liters, respectively; intercompartmental clearance was 10.2 liter/h; the first-order absorption rate constant was 0.895 h−1; bioavailability was 0.825; and lag time was 0.382 h. The CLCR was the best predictor of CL, making dose adjustment by this covariate important to achieve the most efficacious ganciclovir exposure.
    Antimicrobial Agents and Chemotherapy 10/2009; 53(11):4816-24. DOI:10.1128/AAC.00085-09 · 4.48 Impact Factor
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    ABSTRACT: Our aim was to study the changes in the Health Related Quality of Life (HRQoL) during the first year following liver transplantation. Among 159 patients awaiting orthotopic liver transplantation (OLT) who were prospectively studied at 4 hospitals in Catalonia, 108 actually obtained an organ. HRQoL over time, namely, before, as well as at 3 and 12 months after transplantation, was recorded using the Short Form-36 (SF-36) and the Liver Disease Quality of Life (LDQOL 1.0). After we searched medical, clinical, and sociodemographic records to examine the studied variables on the HRQoL at each moment, the significance was explored using t tests and one-way analysis of variance (ANOVA). Comparison of the SF-36 dimensions before and at 3 months after transplantation revealed almost all domains to show significant improvements (P < .01), except bodily pain, role-physical, social functioning, and PCS. Comparisons between 3 and 12 months after transplantation showed only significant improvements in role-physical, physical functioning, and PCS (P < .05). The other dimensions showed similar or slightly better scores, but the differences were not significant. For LDQOL 1.0 before and 3 months after transplantation, the dimensions with significant differences (P < .01) were: effects of liver disease on activities of daily living; concentration; health distress; sleep problems; stigmata of liver disease; and sexual function. Comparing 3 and 12 months posttransplantation, no dimension showed a significant improvement. A negative correlation existed between hypertensive patients and PCS on the SF-36 (P < .001). The clinical diagnosis of alcoholic liver disease showed better scores in some dimensions of the LDQOL than the other diagnoses. Female subjects showed significantly worse HRQoL than men (P < .001). Child-Pugh and Model for End-Stage Liver Disease (MELD) classifications were not associated with the HRQoL either before or after transplantation. The most important finding in this study was that all domains showed significant improvements in HRQoL at 3 months after transplantation with only slight improvements at 12 months.
    Transplantation Proceedings 07/2009; 41(6):2187-8. DOI:10.1016/j.transproceed.2009.06.139 · 0.98 Impact Factor
  • Transplantation 07/2008; 86(Supplement). DOI:10.1097/01.tp.0000330593.89252.b9 · 3.83 Impact Factor
  • Transplantation 07/2008; 86(Supplement). DOI:10.1097/01.tp.0000330472.26066.55 · 3.83 Impact Factor
  • Transplantation 07/2008; 86(Supplement). DOI:10.1097/01.tp.0000332647.08253.2c · 3.83 Impact Factor
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    ABSTRACT: Kidney grafts from suboptimal donors are more likely to suffer the nephrotoxic side-effects of cyclosporine than kidneys from standard donors. In an attempt to avoid the use of cyclosporine, we carried out a prospective study in low-immunological risk recipients of suboptimal kidneys, using an immunosuppressive protocol combining Thymoglobuline in induction with a bi-therapy of mycophenolate mofetil (MMF) and steroids. Patients with panel reactive antibodies (PRA) <50% receiving a first renal transplant from a suboptimal donor (age >or=50, non heart beating, arterial hypertension, or acute renal failure) or a kidney at risk of delayed graft function (DGF) because of a prolonged cold ischaemia time (CIT) of 24 h or more, were eligible for this trial. Between September 1996 and December 1999, 30 patients were enrolled for the trial and treated with MMF 2 g orally, pre-operatively, and 3 g daily, post-operatively; Thymoglobuline 2 mg/kg IV pre-operatively, 1.5 mg/kg IV the next day, and for doses of 1 mg/kg IV given on alternate days; and prednisolone 0.25 mg/kg per day, reduced progressively from the end of the first month to 0.1 mg/kg per day by 3 months post-transplant. Cyclosporine was added only if rejection grade II or higher, or a reduction in MMF below 1 g daily, occurred. Ten patients (30%) suffered from DGF, and one kidney suffered primary non function. Seven patients (24%) suffered acute rejection (six were biopsy proven, 3 grade I and 3 grade II). MMF dosage was reduced in 28 patients because of adverse events, and calcineurin inhibitors were introduced in 16 patients. There were 14 episodes of opportunistic infection (cytomegalovirus (CMV 10), Herpes zoster 2, Listeria monocytogenes 1, Pseudomonas aeuruginosa 1), and 7 malignancies (skin 2, thyroid 1, lung 1, Kaposi's sarcoma 2, post-transplantation lymphoproliferative disorder 1). Mean serum creatinine was 178, 199, 213, and 218 micromol/l at 1, 2, 3 and 5 years after transplantation, respectively. Actuarial patient and graft (after censoring for death) survival was 94% and 83% after 1 year and 79% and 65% after 5 years, respectively. These results show that with the combination of MMF, Thymoglobuline and steroids the use of cyclosporine can be delayed, and in a few cases completely avoided, with good efficacy in terms of prevention of rejection and recovery of renal function. Regardless of acceptable patient and graft survival, side-effects of MMF at the doses used in this protocol were common and led to overimmunosuppression in the long-term. Starting MMF at low dose, MPA monitoring and probably CMV prophylaxis may improve the results of this regimen.
    Transplant International 11/2003; 16(11):820-7. DOI:10.1007/s00147-003-0638-7 · 2.60 Impact Factor
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    ABSTRACT: Sirolimus (SRL) is a potent non-nephrotoxic immunosuppressant. In our unit, SRL was administered to 17 heart transplant (HT) recipients at 1770+/-1234 days' posttransplant surgery, for the following reasons: (1) calcineurin inhibitor (CI) withdrawal due to renal insufficiency (RI; n=6); (2) neurotoxicity (n=1) and pancytopenia (n=1); (3) vascular graft disease (VGD) treatment (n=5); (4) immunosuppression optimization due to lung cancer (n=2); (5) CI use was delayed due to postsurgery RI (n=2). The mean follow-up was 190+/-165 days. Mean SRL doses (mg)/concentrations (ng/mL) at 7 (n=17), 30 (n=14), and 180 (n=8) days were: 1.2+/-0.6/5.9+/-6; 1.6+/-0.8/4.8+/-3.1; and 1.7+/-1.0/5.2+/-3.7. Among group 1, CI patients were discontinued without favorable functional impact. Neurotoxicity and pancytopenia improved, but there were no major clinical events in the VGD group. One "bridge" to CI was successfully performed (postsurgery RI). Total leukocyte count fell while hemoglobin, platelet, and cholesterol profiles were not affected. Ten of 15 patients (67%) were discontinued from CI without rejection and with a dose reduction of mycophenolate mofetil. There were 8 episodes (47%) of SRL-related toxicity, leading to 4 discontinuations (23%); 8 patients (47%) have died during follow-up. This retrospective analysis of outcomes in the context of severe complicated patients suggests that more premature introduction SRL is preferable, particularly in a large patient cohort.
    Transplantation Proceedings 09/2003; 35(5):1978-80. DOI:10.1016/S0041-1345(03)00658-4 · 0.98 Impact Factor
  • Transplantation Proceedings 09/2003; 35(5):1775-7. DOI:10.1016/S0041-1345(03)00703-6 · 0.98 Impact Factor
  • Transplantation Proceedings 03/2002; 34(1):343-4. DOI:10.1016/S0041-1345(01)02791-9 · 0.98 Impact Factor