1
|
Rosser SPA, Lee S, Kohli S, Keogh SJ, Chung J, O'Brien T, Fraser C, McLachlan AJ, Shaw PJ, Nath CE. Evaluation of treosulfan cumulative exposure in paediatric patients through population pharmacokinetics and dosing simulations. Br J Clin Pharmacol 2023; 89:1413-1424. [PMID: 36369677 DOI: 10.1111/bcp.15599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 09/14/2022] [Accepted: 11/06/2022] [Indexed: 11/15/2022] Open
Abstract
AIM To investigate the pharmacokinetics (PK) of intravenous treosulfan in paediatric patients undergoing haematopoietic stem cell transplantation (HSCT) for a broad range of diseases and to explore the impact of different dosing regimens on treosulfan exposure (area under the concentration-time curve, AUC0→∞ ) through dosing simulations. METHODS A prospective multicentre PK study was conducted using treosulfan concentration data (n = 423) collected from 53 children (median age 3.5, range 0.2-17.0 years) receiving three daily age-guided doses (10-14 g/m2 ). Population PK modelling was performed using NONMEM software, utilising a stepwise forward selection backward elimination method and likelihood-ratio test for screening covariates to describe PK variability. Monte Carlo simulation was used to generate patient PK data for 10 000 virtual paediatric patients and cumulative AUC0→∞ values were evaluated using age, body surface area (BSA) and model-based dosing regimens, targeting 4800 mg*h/L. RESULTS Treosulfan concentration data were described using a one-compartment PK model with first-order elimination. Population mean (95% CI) estimates for clearance (CL) and volume of distribution (V) were 16.3 (14.9-18.1) L/h and 41.9 (38.8-45.1) L, respectively. Allometrically scaled body weight was the best covariate descriptor for CL and V, and maturational age further explained variability in CL. Dosing simulations indicated that in young patient groups (<2 years), a model-based dosing regimen more accurately achieved the target AUC0→∞ (58.3%) over the age (42.6%) and BSA-based (51.3%) regimens. CONCLUSION Treosulfan disposition was described through allometric body weight and maturational age descriptors. Model-informed dosing is recommended for patients under 2 years. Treosulfan PK parameters and AUC0→∞ were not influenced by patient disease.
Collapse
Affiliation(s)
- Sebastian P A Rosser
- The Children's Hospital at Westmead Clinical School, University of Sydney, Sydney, Australia.,Department of Biochemistry, The Children's Hospital at Westmead, Sydney, Australia.,Cancer Centre for Children, The Children's Hospital at Westmead, Sydney, Australia
| | - Samiuela Lee
- Department of Biochemistry, The Children's Hospital at Westmead, Sydney, Australia.,School of Chemical and Biomedical Engineering, University of Sydney, Sydney, Australia
| | - Shruti Kohli
- Cancer Centre for Children, The Children's Hospital at Westmead, Sydney, Australia
| | - Steven J Keogh
- Cancer Centre for Children, The Children's Hospital at Westmead, Sydney, Australia
| | - Jason Chung
- The Children's Hospital at Westmead Clinical School, University of Sydney, Sydney, Australia.,Department of Biochemistry, The Children's Hospital at Westmead, Sydney, Australia
| | - Tracey O'Brien
- Kids Cancer Centre, Sydney Children's Hospital at Randwick, Randwick, Australia.,School of Women and Children's Health, Faculty of Medicine, University of New South Wales, Randwick, Australia
| | | | - Andrew J McLachlan
- Sydney Pharmacy School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Peter J Shaw
- The Children's Hospital at Westmead Clinical School, University of Sydney, Sydney, Australia.,Cancer Centre for Children, The Children's Hospital at Westmead, Sydney, Australia
| | - Christa E Nath
- Department of Biochemistry, The Children's Hospital at Westmead, Sydney, Australia.,Cancer Centre for Children, The Children's Hospital at Westmead, Sydney, Australia.,Sydney Pharmacy School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| |
Collapse
|
2
|
Rosser SPA, McLachlan AJ, Hempel G, Chung J, Shaw PJ, Keogh SJ, Nath CE. Validation of a liquid chromatography-tandem mass spectrometry method for simultaneous quantification of N,N-dimethylacetamide and N-monomethylacetamide in pediatric plasma. J Sep Sci 2023; 46:e2201003. [PMID: 36879545 DOI: 10.1002/jssc.202201003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/07/2023] [Accepted: 03/04/2023] [Indexed: 03/08/2023]
Abstract
N,Na-dimethylacetamide is an excipient used in intravenous busulfan formulations, a drug used in hematopoietic stem cell transplantation conditioning. The aim of this study was to develop and validate a liquid chromatography-tandem mass spectrometry method for simultaneous quantification of N,N-dimethylacetamide, and its metabolite N-monomethylacetamide in plasma from children receiving busulfan. A 4 μl aliquot of patient plasma was extracted using 196 μl 50% methanol solution and quantified against calibrators prepared in the extraction solvent given negligible matrix effects across three concentrations. 9 [H2 ]-N,N-dimethylacetamide was used as an internal standard. Separation of N,N-dimethylacetamide and N-monomethylacetamide was achieved using a Kinetex EVO C18 stationary phase (100 mm × 2.1 mm × 2.6 μm) running an isocratic mobile phase of 30% methanol containing 0.1% formic acid at a flow of 0.2 ml/min over 3.0 min. The injection volume was 1 μl. Calibration curves for N,N-dimethylacetamide and N-monomethylacetamide were linear up to 1200 and 200 μg/L, respectively, with a lower limit of quantification 1 μg/L for both analytes. Calibrator accuracy and precision were within ± 10% of the test parameters across four concentration levels. Analytes were stable over 14 days at three different storage conditions. This method was successfully applied to measure N,N-dimethylacetamide and N-monomethylacetamide concentrations in a total of 1265 plasma samples from 77 children.
Collapse
Affiliation(s)
- Sebastian P A Rosser
- The Children's Hospital at Westmead Clinical School, University of Sydney, Sydney, Australia.,Department of Biochemistry, The Children's Hospital at Westmead, Sydney, Australia.,Cancer Centre for Children, The Children's Hospital at Westmead, Sydney, Australia
| | - Andrew J McLachlan
- Sydney Pharmacy School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Georg Hempel
- Institute for Pharmaceutical and Medicinal Chemistry and Clinical Pharmacy, University of Münster, Sydney, Germany
| | - Jason Chung
- The Children's Hospital at Westmead Clinical School, University of Sydney, Sydney, Australia.,Department of Biochemistry, The Children's Hospital at Westmead, Sydney, Australia
| | - Peter J Shaw
- The Children's Hospital at Westmead Clinical School, University of Sydney, Sydney, Australia.,Cancer Centre for Children, The Children's Hospital at Westmead, Sydney, Australia
| | - Steven J Keogh
- Cancer Centre for Children, The Children's Hospital at Westmead, Sydney, Australia
| | - Christa E Nath
- Department of Biochemistry, The Children's Hospital at Westmead, Sydney, Australia.,Cancer Centre for Children, The Children's Hospital at Westmead, Sydney, Australia.,Sydney Pharmacy School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| |
Collapse
|
3
|
Rosser SPA, Atkinson C, Nath CE, Fletcher JI. Quantification of vincristine and tariquidar by LC-MS/MS in mouse whole blood using volumetric absorptive microsampling for pharmacokinetic applications. J Sep Sci 2022; 45:2508-2519. [PMID: 35567751 DOI: 10.1002/jssc.202101013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 03/31/2022] [Accepted: 05/10/2022] [Indexed: 11/07/2022]
Abstract
A liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous quantification of vincristine and tariquidar in 10 μL of mouse whole blood using volumetric absorptive microsampling devices. Samples were extracted from the devices and quantified against calibrators prepared in a human blood plasma matrix. Separation of vincristine and tariquidar was achieved using a Shimpack XR ODS III C18 stationary phase and H2 O and methanol mobile phase solvents containing 0.1% formic acid, running a gradient elution at a flow rate 0.2 mL/min over 6.0 min. The method was linear up to 1200 ng/mL (R2 > 0.99 for both analytes), with calibrator accuracy within ± 15% of the nominal concentrations and analyte coefficient of variance < 15% for both vincristine and tariquidar. Pharmacokinetic assessment of both analytes was successfully applied in mice as both single agent therapy and combination therapy over a 24-hour period, and a 2.3-fold increase in vincristine drug exposure was observed in combination with tariquidar. This study validates the use of this approach for longitudinal analysis of drug exposure in animal studies. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
| | - Caroline Atkinson
- Children's Cancer Institute, Lowy Cancer Research Centre, UNSW Sydney, NSW, Australia.,School of Women's and Children's Health, UNSW Sydney, Sydney, NSW, Australia
| | - Christa E Nath
- Department of Biochemistry, The Children's Hospital at Westmead, NSW, Australia
| | - Jamie I Fletcher
- Children's Cancer Institute, Lowy Cancer Research Centre, UNSW Sydney, NSW, Australia.,School of Women's and Children's Health, UNSW Sydney, Sydney, NSW, Australia
| |
Collapse
|
4
|
Ben Hassine K, Nava T, Théoret Y, Nath CE, Daali Y, Kassir N, Lewis V, Bredius RGM, Shaw PJ, Bittencourt H, Krajinovic M, Uppugunduri CRS, Ansari M. Precision dosing of intravenous busulfan in pediatric hematopoietic stem cell transplantation: Results from a multicenter population pharmacokinetic study. CPT Pharmacometrics Syst Pharmacol 2021; 10:1043-1056. [PMID: 34453497 PMCID: PMC8452291 DOI: 10.1002/psp4.12683] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 05/14/2021] [Accepted: 06/11/2021] [Indexed: 12/13/2022]
Abstract
Busulfan (Bu) is a common component of conditioning regimens before hematopoietic stem cell transplantation (HSCT) and is known for high interpatient pharmacokinetic (PK) variability. This study aimed to develop and externally validate a multicentric, population PK (PopPK) model for intravenous Bu in pediatric patients before HSCT to first study the influence of glutathione‐s‐transferase A1 (GSTA1) polymorphisms on Bu's PK in a large multicentric pediatric population while accounting for fludarabine (Flu) coadministration and, second, to establish an individualized, model‐based, first‐dose recommendation for intravenous Bu that can be widely used in pediatric patients. The model was built using data from 302 patients from five transplantation centers who received a Bu‐based conditioning regimen. External model validation used data from 100 patients. The relationship between body weight and Bu clearance (CL) was best described by an age‐dependent allometric scaling of a body weight model. A stepwise covariate analysis identified Day 1 of Bu conditioning, GSTA1 metabolic groups based on GSTA1 polymorphisms, and Flu coadministration as significant covariates influencing Bu CL. The final model adequately predicted Bu first‐dose CL in the external cohort, with 81% of predicted area under the curves within the therapeutic window. The final model showed minimal bias (mean prediction error, −0.5%; 95% confidence interval [CI], −3.1% to 2.0%) and acceptable precision (mean absolute prediction error percentage, 18.7%; 95% CI, 17.0%–20.5%) in Bu CL prediction for dosing. This multicentric PopPK study confirmed the influence of GSTA1 polymorphisms and Flu coadministration on Bu CL. The developed model accurately predicted Bu CL and first doses in an external cohort of pediatric patients.
Collapse
Affiliation(s)
- Khalil Ben Hassine
- CANSEARCH Research Platform in Pediatric Oncology and Hematology, Department of Pediatrics, Gynecology and Obstetrics, University of Geneva, Geneva, Switzerland.,Division of Pediatric Oncology and Hematology, Department of Pediatrics, Gynecology and Obstetrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Tiago Nava
- CANSEARCH Research Platform in Pediatric Oncology and Hematology, Department of Pediatrics, Gynecology and Obstetrics, University of Geneva, Geneva, Switzerland.,Division of Pediatric Oncology and Hematology, Department of Pediatrics, Gynecology and Obstetrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Yves Théoret
- Charles-Bruneau Cancer Center, Sainte-Justine University Health Center (SJUHC), Montreal, Quebec, Canada.,Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada.,Clinical Pharmacology Unit, Sainte-Justine University Health Center (SJUHC), Montreal, Quebec, Canada.,Department of Pediatrics, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Christa E Nath
- Department of Biochemistry, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.,The Cancer Centre for Children, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Children's Hospital at Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Youssef Daali
- Clinical Pharmacology and Toxicology Division, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.,Faculty of Medicine & Sciences, University of Geneva, Geneva, Switzerland
| | - Nastya Kassir
- Genentech/Roche, Clinical Pharmacology, South San Francisco, California, USA
| | - Victor Lewis
- Department of Pediatrics, Alberta Children's Hospital, Calgary, Alberta, Canada
| | - Robbert G M Bredius
- Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands
| | - Peter J Shaw
- The Cancer Centre for Children, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Children's Hospital at Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Henrique Bittencourt
- Charles-Bruneau Cancer Center, Sainte-Justine University Health Center (SJUHC), Montreal, Quebec, Canada.,Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada.,Clinical Pharmacology Unit, Sainte-Justine University Health Center (SJUHC), Montreal, Quebec, Canada.,Department of Pediatrics, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Maja Krajinovic
- Charles-Bruneau Cancer Center, Sainte-Justine University Health Center (SJUHC), Montreal, Quebec, Canada.,Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada.,Clinical Pharmacology Unit, Sainte-Justine University Health Center (SJUHC), Montreal, Quebec, Canada.,Department of Pediatrics, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Chakradhara Rao Satyanarayana Uppugunduri
- CANSEARCH Research Platform in Pediatric Oncology and Hematology, Department of Pediatrics, Gynecology and Obstetrics, University of Geneva, Geneva, Switzerland.,Division of Pediatric Oncology and Hematology, Department of Pediatrics, Gynecology and Obstetrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Marc Ansari
- CANSEARCH Research Platform in Pediatric Oncology and Hematology, Department of Pediatrics, Gynecology and Obstetrics, University of Geneva, Geneva, Switzerland.,Division of Pediatric Oncology and Hematology, Department of Pediatrics, Gynecology and Obstetrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| |
Collapse
|
5
|
Lee S, Nath CE, Balzer BWR, Lewis CR, Trahair TN, Anazodo AC, Shaw PJ. An HPLC–PDA method for determination of alectinib concentrations in the plasma of an adolescent. ACTA CHROMATOGR 2020. [DOI: 10.1556/1326.2019.00578] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Alectinib is a central nervous system-active small molecule anaplastic lymphoma kinase (ALK) inhibitor that is effective in the treatment of patients with ALK positive tumors, including advanced non-small cell lung cancers and lymphomas. A simple, isocratic high-performance liquid chromatography–photo diode array detection (HPLC–PDA) assay for measurement of alectinib in human plasma is described. Alectinib is extracted from the plasma matrix by addition of methanol, followed by centrifugation and acidification with 0.1% formic acid. It elutes with a run time of 4.6 min using a 250 mm × 4.6 mm RP-C18 column with 0.1% aqueous formic acid and methanol (35:65, v/v) and a flow rate of 1 mL/min. Detection was at 339 nm. Linear calibration plots were achieved in the range of 0.1–20 μg/mL for alectinib (r2 = 0.9996). With limits of detection and quantification of 0.05 and 0.1 μg/mL, respectively, and excellent precision (%CV < 10%), accuracy (bias < ±12%), and recovery (>97%) within the 1–20 μg/mL concentration range, this assay was suitable for measuring pre-dose alectinib concentrations in an adolescent receiving 600-mg doses twice daily.
Collapse
Affiliation(s)
- Samiuela Lee
- 1 Department of Biochemistry, The Children’s Hospital at Westmead, Australia
| | - Christa E. Nath
- 1 Department of Biochemistry, The Children’s Hospital at Westmead, Australia
- 2 Faculty of Pharmacy, University of Sydney, Australia
| | - Ben W. R. Balzer
- 3 Sydney Children's Hospital, Randwick NSW 2031, Australia
- 4 School of Women's and Children's Health, University of New South Wales, Randwick NSW 2031, Australia
| | - Craig R. Lewis
- 5 Nelune Comprehensive Cancer Centre, Prince of Wales Hospital, Randwick NSW 2031, Australia
- 6 Prince of Wales Clinical School, University of New South Wales, Randwick NSW 2031, Australia
| | - Toby N. Trahair
- 4 School of Women's and Children's Health, University of New South Wales, Randwick NSW 2031, Australia
- 7 Kids Cancer Centre, Sydney Children's Hospital, Randwick NSW 2031, Australia
| | - Antoinette C. Anazodo
- 4 School of Women's and Children's Health, University of New South Wales, Randwick NSW 2031, Australia
- 5 Nelune Comprehensive Cancer Centre, Prince of Wales Hospital, Randwick NSW 2031, Australia
- 7 Kids Cancer Centre, Sydney Children's Hospital, Randwick NSW 2031, Australia
| | - Peter J. Shaw
- 8 Cancer Centre for Children, The Children's Hospital at Westmead, Australia
- 9 Discipline of Child and Adolescent Health, University of Sydney, Australia
| |
Collapse
|
6
|
Duong JK, Veal GJ, Nath CE, Shaw PJ, Errington J, Ladenstein R, Boddy AV. Population pharmacokinetics of carboplatin, etoposide and melphalan in children: a re-evaluation of paediatric dosing formulas for carboplatin in patients with normal or mild impairment of renal function. Br J Clin Pharmacol 2018; 85:136-146. [PMID: 30261554 DOI: 10.1111/bcp.13774] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 08/01/2018] [Accepted: 09/08/2018] [Indexed: 01/13/2023] Open
Abstract
AIMS Carboplatin dosage is calculated by using the estimated glomerular filtration rate (GFR) to achieve a target plasma area under the plasma concentration-time curve (AUC). The aims of the present study were to investigate factors that influence the pharmacokinetics of carboplatin in children with high-risk neuroblastoma, and whether target exposures for carboplatin were achieved using current treatment protocols. METHODS Data on children receiving high-dose carboplatin, etoposide and melphalan for neuroblastoma were obtained from two study sites [European International Society for Paediatric Oncology (SIOP) Neuroblastoma study, Children's Hospital at Westmead; n = 51]. A population pharmacokinetic model was built for carboplatin to evaluate various dosing formulas. The pharmacokinetics of etoposide and melphalan was also investigated. The final model was used to simulate whether target carboplatin AUC (16.4 mg ml-1 ·min) would be achieved using the paediatric Newell formula, modified Calvert formula and weight-based dosing. RESULTS Allometric weight was the only significant, independent covariate for the pharmacokinetic parameters of carboplatin, etoposide and melphalan. The paediatric Newell formula and modified Calvert formula were suitable for achieving the target AUC of carboplatin for children with a GFR <100 ml min-1 1.73 m-2 but not for those with a GFR ≥100 ml min-1 1.73 m-2 . A weight-based dosing regimen of 50 mg kg-1 achieved the target AUC more consistently than the other formulas, regardless of renal function. CONCLUSIONS GFR did not appear to influence the pharmacokinetics of carboplatin after adjusting pharmacokinetic parameters for weight. This model-based approach validates the use of weight-based dosing as an appropriate alternative for carboplatin in children with either mild renal impairment or normal renal function.
Collapse
Affiliation(s)
- J K Duong
- Faculty of Pharmacy, University of Sydney, Sydney, NSW, Australia
| | - G J Veal
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
| | - C E Nath
- Faculty of Pharmacy, University of Sydney, Sydney, NSW, Australia.,Departments of Biochemistry and Oncology, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - P J Shaw
- BMT Services, The Children's Hospital at Westmead, Westmead, NSW, Australia.,Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - J Errington
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
| | - R Ladenstein
- Children's Cancer Research Institute, St Anna Children's Hospital, Vienna, Austria
| | - A V Boddy
- Faculty of Pharmacy, University of Sydney, Sydney, NSW, Australia
| |
Collapse
|
7
|
Balzer BWR, Loo C, Wegner EA, Nath CE, Lee S, Smith C, Lewis CR, Trahair TN, Anazodo AC. Alectinib is effective, safe and tolerable in an adolescent with stage IVB ALK-rearranged adenocarcinoma of the lung. Pediatr Hematol Oncol 2018; 35:415-421. [PMID: 30526220 DOI: 10.1080/08880018.2018.1541492] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Anaplastic lymphoma kinase (ALK) inhibitors such as crizotinib and alectinib have been shown to have significant activity in ALK-rearranged non-small cell lung cancers (NSCLC). There are no data for alectinib's safety or efficacy in younger patients, though it is superior to crizotinib in adult trials. We present a 14-year old girl diagnosed with stage IV-B ALK-positive adenocarcinoma of the lung after presenting with cough and fever. She was commenced on alectinib at adult dose and has had sustained complete metabolic remission for 9 months. She is the youngest patient with lung adenocarcinoma to be treated with alectinib.
Collapse
Affiliation(s)
- Ben W R Balzer
- a Sydney Children's Hospital , Randwick , New South Wales , Australia.,b School of Women's and Children's Health , University of New South Wales , Randwick , New South Wales , Australia
| | - Christine Loo
- c Department of Anatomical Pathology , NSW Health Pathology, Prince of Wales Hospital , Randwick , New South Wales , Australia
| | - Eva A Wegner
- d Department of Nuclear Medicine and PET , Prince of Wales Hospital , Randwick , New South Wales , Australia.,e Prince of Wales Clinical School , University of New South Wales , Randwick , New South Wales , Australia
| | - Christa E Nath
- f Department of Biochemistry , The Children's Hospital at Westmead , Westmead , New South Wales , Australia.,g Faculty of Pharmacy , University of Sydney , Camperdown , New South Wales , Australia
| | - Samiuela Lee
- f Department of Biochemistry , The Children's Hospital at Westmead , Westmead , New South Wales , Australia
| | - Chantelle Smith
- h Pharmacy Department , Sydney Children's Hospital , Randwick , New South Wales , Australia
| | - Craig R Lewis
- e Prince of Wales Clinical School , University of New South Wales , Randwick , New South Wales , Australia.,i Department of Medical Oncology , Prince of Wales Hospital , Randwick , New South Wales , Australia
| | - Toby N Trahair
- a Sydney Children's Hospital , Randwick , New South Wales , Australia.,b School of Women's and Children's Health , University of New South Wales , Randwick , New South Wales , Australia.,j Sydney Children's Hospital , Kids Cancer Centre , Randwick , New South Wales , Australia
| | - Antoinette C Anazodo
- a Sydney Children's Hospital , Randwick , New South Wales , Australia.,b School of Women's and Children's Health , University of New South Wales , Randwick , New South Wales , Australia.,j Sydney Children's Hospital , Kids Cancer Centre , Randwick , New South Wales , Australia.,k Prince of Wales Hospital , Nelune Comprehensive Cancer Centre , Randwick , New South Wales , Australia
| |
Collapse
|
8
|
Cendana M, Lee S, Upadhyay PJ, Byrne JA, Shaw PJ, Earl J, Nath CE. An HPLC-UV method for determining plasma dimethylacetamide concentrations in patients receiving intravenous busulfan. Biomed Chromatogr 2016; 31. [PMID: 27925250 DOI: 10.1002/bmc.3906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 11/02/2016] [Accepted: 11/27/2016] [Indexed: 11/06/2022]
Abstract
Dimethylacetamide (DMA) is a solvent used in the preparation of intravenous busulfan, an alkylating agent used in blood or marrow transplantation. DMA may contribute to hepatic toxicity, so it is important to monitor its clearance. The aim of this study was to develop an HPLC-UV assay for measurement of DMA in human plasma. After precipitation of plasma proteins with acetonitrile followed by dilution (1:4) with water, the extract was injected onto the HPLC and detected at 195 nm. Separation was performed using a Cogent-HPS 5 μm C18 column (250 × 4.6 mm) preceded by a Brownlee 7 μm RP18 , pre-column (1.5 cm × 3.2 mm). The mobile phase was 25 mm sodium phosphate buffer (pH 3), containing 2.5% (v/v) acetonitrile and 0.0005% (v/v) sodium-octyl-sulfonate. Using a flow rate of 1 mL/min, the retention times of DMA and the internal standard (IS), 2-chloroacetamide, were 9.5 and 3.5 min, respectively. Peak area ratio (DMA:IS) was a linear function of concentration from 1 to 1000 μg/mL. There was excellent intraday precision (<5% for 5-700 μg/mL DMA), accuracy (<3% deviation from the true concentration) and recovery (74-98%). The limits of detection and quantification were 1 and 5 μg/mL, respectively. In eight children who received intravenous busulfan, DMA concentrations ranged from 110 to 438 μg/mL.
Collapse
Affiliation(s)
- Mildred Cendana
- Department of Biochemistry, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Samiuela Lee
- Department of Biochemistry, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Parth J Upadhyay
- The Cancer Centre for Children, The Children's Hospital at Westmead, Westmead, NSW, Australia.,Faculty of Pharmacy, University of Sydney, NSW, Australia
| | - Jennifer A Byrne
- Children's Cancer Research Unit, The Children's Hospital at Westmead, Westmead, NSW, Australia.,Discipline of Child and Adolescent Health, Faculty of Medicine, University of Sydney, NSW, Australia
| | - Peter J Shaw
- The Cancer Centre for Children, The Children's Hospital at Westmead, Westmead, NSW, Australia.,Discipline of Child and Adolescent Health, Faculty of Medicine, University of Sydney, NSW, Australia
| | - John Earl
- Department of Biochemistry, The Children's Hospital at Westmead, Westmead, NSW, Australia.,Discipline of Child and Adolescent Health, Faculty of Medicine, University of Sydney, NSW, Australia
| | - Christa E Nath
- Department of Biochemistry, The Children's Hospital at Westmead, Westmead, NSW, Australia.,The Cancer Centre for Children, The Children's Hospital at Westmead, Westmead, NSW, Australia.,Faculty of Pharmacy, University of Sydney, NSW, Australia
| |
Collapse
|
9
|
Nath CE, Trotman J, Tiley C, Presgrave P, Joshua D, Kerridge I, Kwan YL, Gurney H, McLachlan AJ, Earl JW, Nivison-Smith I, Zeng L, Shaw PJ. High melphalan exposure is associated with improved overall survival in myeloma patients receiving high dose melphalan and autologous transplantation. Br J Clin Pharmacol 2016; 82:149-59. [PMID: 26879446 DOI: 10.1111/bcp.12906] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 02/01/2016] [Accepted: 02/09/2016] [Indexed: 11/28/2022] Open
Abstract
AIM High dose melphalan (HDM) and autologous stem cell transplantation (ASCT) retains a central role in the treatment of myeloma. The aim of this study was to determine whether HDM exposure (area under the concentration vs. time curve, AUC), is significantly associated with transplant outcomes. METHODS Melphalan concentrations were measured in six to 11 plasma samples collected after HDM (median 192 mg m(-) (2) ) to determine melphalan AUC for a total of 114 patients. Binary logistic regression was used to assess whether melphalan AUC was associated with severe (≥ grade 3) oral mucositis. Multivariate Cox regression was used to assess whether melphalan AUC was significantly associated with time to progression, progression-free survival and overall survival (OS). RESULTS Melphalan AUC ranged from 4.9 to 24.6 mg l(-1) h, median 12.84 mg l(-1) h. Melphalan AUC above the median was a risk factor for severe mucositis (HR 1.21, 95% CI 1.06, 1.38, P = 0.004) but was also associated with significantly improved overall survival (OS) (HR 0.40, 95% CI 0.20, 0.81, P = 0.001), with an estimated median survival of 8.50 years vs. 5.38 years for high vs. low AUC groups. Multivariate analysis did not identify melphalan AUC as being significantly associated with time to progression or progression-free survival. CONCLUSIONS This large scale pharmacodynamic analysis of HDM demonstrates that high melphalan exposure is associated with improved survival, with an acceptable increase in transplant toxicity. These results suggest studies targeting a higher AUC are warranted in patients undergoing HDM and ASCT for myeloma.
Collapse
Affiliation(s)
- Christa E Nath
- The Children's Hospital at Westmead, Hawkesbury Rd, Westmead, 2145
| | - Judith Trotman
- Concord Hospital, Hospital Road, Concord, NSW, 2139.,University of Sydney, Sydney, NSW, 2006
| | - Campbell Tiley
- Gosford Hospital, Holden St, Gosford, NSW, 2250.,University of Newcastle, University Dr, Callaghan, NSW, 2308
| | - Peter Presgrave
- Wollongong Hospital, Loftus St, Wollongong, NSW, 2500.,University of Wollongong, Northfields Ave, Wollongong, NSW, 2522
| | - Douglas Joshua
- University of Sydney, Sydney, NSW, 2006.,Royal Prince Alfred Hospital, Missenden Rd, Camperdown, NSW, 2050
| | - Ian Kerridge
- University of Sydney, Sydney, NSW, 2006.,Westmead Hospital, Hawkesbury Rd, Westmead, NSW, 2145
| | - Yiu Lam Kwan
- Concord Hospital, Hospital Road, Concord, NSW, 2139
| | - Howard Gurney
- University of Sydney, Sydney, NSW, 2006.,Westmead Hospital, Hawkesbury Rd, Westmead, NSW, 2145
| | - Andrew J McLachlan
- Concord Hospital, Hospital Road, Concord, NSW, 2139.,University of Sydney, Sydney, NSW, 2006
| | - John W Earl
- The Children's Hospital at Westmead, Hawkesbury Rd, Westmead, 2145.,University of Sydney, Sydney, NSW, 2006
| | - Ian Nivison-Smith
- Australasian Bone Marrow Transplant Recipient Registry, 370 Victoria Street, Darlinghurst, NSW, 2010, Australia
| | - Lihua Zeng
- The Children's Hospital at Westmead, Hawkesbury Rd, Westmead, 2145
| | - Peter J Shaw
- The Children's Hospital at Westmead, Hawkesbury Rd, Westmead, 2145.,University of Sydney, Sydney, NSW, 2006
| |
Collapse
|
10
|
Koyyalamudi SR, Kuzhiumparambil U, Nath CE, Byrne JA, Fraser CJ, O'Brien TA, Earl JW, Shaw PJ. Development and Validation of a High Pressure Liquid Chromatography-UV Method for the Determination of Treosulfan and Its Epoxy Metabolites in Human Plasma and Its Application in Pharmacokinetic Studies. J Chromatogr Sci 2015; 54:326-33. [PMID: 26433392 DOI: 10.1093/chromsci/bmv145] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Indexed: 11/12/2022]
Abstract
Treosulfan (l-threitol-1,4-di-methanesulfonate) is a prodrug of a bifunctional alkylating agent that is being used increasingly in pediatric bone marrow transplantation regimens. The activation pathway is a complex reaction, which consists of two consecutive reactions leading to epoxybutane derivatives which are responsible for DNA alkylation. A simple, sensitive high performance liquid chromatography method for the determination of the sum of treosulfan and its epoxy metabolites by UV detection after derivatization with sodium diethyldithiocarbamate in human plasma was developed and validated. Plasma samples containing treosulfan and epoxy metabolites were converted into thiocarbamate derivative with 10% sodium diethyldithiocarbamate. Dinitrobiphenyl was used as an internal standard. The analysis was carried out using a reversed phase C18 column with a mobile phase consisting of methanol-water (65:35, v/v) at a flow rate of 1 mL/min. The eluent was monitored at 254 nm. The standard calibration curve was established between 2.5 and 50 µg/mL, with a correlation coefficient of 0.9987. Intra- and interday precision and accuracy of the method was <8% and met the analytical criteria. Pharmacokinetic parameters were determined in six children who received intravenous treosulfan (dose range 12-24 g/m(2)) in combination with fludarabine prior to blood or marrow transplantation.
Collapse
Affiliation(s)
- Sundar R Koyyalamudi
- Department of Biochemistry, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia Department of Oncology, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia Discipline of Paediatrics and Child Health, The University of Sydney, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia
| | | | - Christa E Nath
- Department of Biochemistry, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia Department of Oncology, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia
| | - Jennifer A Byrne
- Discipline of Paediatrics and Child Health, The University of Sydney, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia Children's Cancer Research Unit, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia
| | | | - Tracey A O'Brien
- Kids Cancer Centre, Sydney Children's Hospital, Randwick, NSW 2031, Australia Women's & Children's Health, Faculty of Medicine, University of New South Wales, Kensington, NSW 2052, Australia
| | - John W Earl
- Department of Biochemistry, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia Discipline of Paediatrics and Child Health, The University of Sydney, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia
| | - Peter J Shaw
- Department of Oncology, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia Discipline of Paediatrics and Child Health, The University of Sydney, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia
| |
Collapse
|
11
|
Bartelink IH, Boelens JJ, Bredius RGM, Egberts ACG, Wang C, Bierings MB, Shaw PJ, Nath CE, Hempel G, Zwaveling J, Danhof M, Knibbe CAJ. Body weight-dependent pharmacokinetics of busulfan in paediatric haematopoietic stem cell transplantation patients: towards individualized dosing. Clin Pharmacokinet 2012; 51:331-45. [PMID: 22455797 DOI: 10.2165/11598180-000000000-00000] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND OBJECTIVES The wide variability in pharmacokinetics of busulfan in children is one factor influencing outcomes such as toxicity and event-free survival. A meta-analysis was conducted to describe the pharmacokinetics of busulfan in patients from 0.1 to 26 years of age, elucidate patient characteristics that explain the variability in exposure between patients and optimize dosing accordingly. PATIENTS AND METHODS Data were collected from 245 consecutive patients (from 3 to 100 kg) who underwent haematopoietic stem cell transplantation (HSCT) in four participating centres. The inter-patient, inter-occasion and residual variability in the pharmacokinetics of busulfan were estimated with a population analysis using the nonlinear mixed-effects modelling software NONMEM VI. Covariates were selected on the basis of their known or theoretical relationships with busulfan pharmacokinetics and were plotted independently against the individual pharmacokinetic parameters and the weighted residuals of the model without covariates to visualize relations. Potential covariates were formally tested in the model. RESULTS In a two-compartment model, body weight was the most predictive covariate for clearance, volume of distribution and inter-compartmental clearance and explained 65%, 75% and 40% of the observed variability, respectively. The relationship between body weight and clearance was characterized best using an allometric equation with a scaling exponent that changed with body weight from 1.2 in neonates to 0.55 in young adults. This implies that an increase in body weight in neonates results in a larger increase in busulfan clearance than an increase in body weight in older children or adults. Clearance on the first day was 12% higher than that of subsequent days (p < 0.001). Inter-occasion variability on clearance was 15% between the 4 days. Based on the final pharmacokinetic-model, an individualized dosing nomogram was developed. CONCLUSIONS The model-based individual dosing nomogram is expected to result in predictive busulfan exposures in patients ranging between 3 and 65 kg and thereby to a safer and more effective conditioning regimen for HSCT in children.
Collapse
Affiliation(s)
- Imke H Bartelink
- Department of Clinical Pharmacy, University Medical Center Utrecht, Utrecht, the Netherlands.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Zeng L, Blair EYL, Nath CE, Shaw PJ, Earl JW, Stephen K, Montgomery K, Coakley JC, Hodson E, Stormon M, McLachlan AJ. Population pharmacokinetics of mycophenolic acid in children and young people undergoing blood or marrow and solid organ transplantation. Br J Clin Pharmacol 2011; 70:567-79. [PMID: 20840448 DOI: 10.1111/j.1365-2125.2010.03734.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
AIMS To characterize the population pharmacokinetics of mycophenolic acid (MPA) and evaluate dose regimens using a simulation approach and accepted therapeutic drug monitoring targets in children and young people undergoing blood or marrow, kidney and liver transplantation. METHODS MPA concentration-time data were collected using an age specific sampling protocol over 12h. Some patients provided randomly timed but accurately recorded blood samples. Total and unbound MPA were measured by HPLC. NONMEM was employed to analyze MPA pharmacokinetic data. Simulations (n= 1000) were conducted to assess the suitability of the MPA dose regimens to maintain total MPA AUC(0,12h) within the range 30 and 60mg l(-1) h associated with optimal outcome. RESULTS A two-compartment pharmacokinetic model with first-order elimination best described MPA concentration-time data. Population mean estimates of MPA clearance, inter-compartmental clearance, volumes of distribution in the central and peripheral compartments, absorption rate constant and bioavailability were 6.42 l h(-1) , 3.74 l h(-1) , 7.24 l, 16.8l, 0.39h(-1) and 0.48, respectively. Inclusion of bodyweight and concomitant ciclosporin reduced the inter-individual variability in CL from 54.3% to 31.6%. Children with a bodyweight of 10kg receiving standard MPA dose regimens achieve an MPA AUC below the target range suggesting they may be at a greater risk of acute rejection. CONCLUSIONS The population pharmacokinetic model for MPA can be used to explore dosing guidelines for safe and effective immunotherapy in children and young people undergoing transplantation.
Collapse
Affiliation(s)
- Lihua Zeng
- Faculty of Pharmacy Department of Paediatrics and Child Health, University of Sydney, Sydney
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Nath CE, Shaw PJ, Trotman J, Zeng L, Duffull SB, Hegarty G, McLachlan AJ, Gurney H, Kerridge I, Kwan YL, Presgrave P, Tiley C, Joshua D, Earl J. Population pharmacokinetics of melphalan in patients with multiple myeloma undergoing high dose therapy. Br J Clin Pharmacol 2010; 69:484-97. [PMID: 20573084 PMCID: PMC2856049 DOI: 10.1111/j.1365-2125.2010.03638.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Accepted: 01/08/2010] [Indexed: 12/22/2022] Open
Abstract
AIMS To i) investigate the pharmacokinetics of total and unbound plasma melphalan using a population approach, ii) identify clinical factors that affect melphalan disposition and iii) evaluate the role of melphalan exposure in melphalan-related toxicity and disease response. METHODS Population pharmacokinetic modelling (using NONMEM) was performed with total and unbound concentration-time data from 100 patients (36-73 years) who had received a median 192 mg m(-2) melphalan dose. Model derived estimates of total and unbound melphalan exposure (AUC) in patients with serious melphalan toxicity and those who had a good disease response (>or=90% decrease in paraprotein concentrations) were compared using the Mann-Whitney test. RESULTS A two compartment model generated population mean estimates for total and unbound melphalan clearance (CL) of 27.8 and 128 l h(-1), respectively. Estimated creatinine clearance, fat free mass and haematocrit were important determinants of total and unbound CL, reducing the inter-individual variability in total CL from 34% to 27% and in unbound CL from 42% to 30%. Total AUC (range 4.9-24.4 mg l(-1) h) and unbound AUC (range 1.0-6.5 mg l(-1) h) were significantly higher in patients who had oral mucositis (>or=grade 3) and long hospital admissions (P < 0.01). Patients who responded well had significantly higher unbound AUC (median 3.2 vs. 2.8 mg l(-1) h, P < 0.05) when assessed from diagnosis to post-melphalan and higher total AUC (median 21.3 vs. 13.4 mg l(-1) h, P= 0.06), when assessed from pre- to post-melphalan. CONCLUSIONS Creatinine clearance, fat free mass and haematocrit influence total and unbound melphalan plasma clearance. Melphalan exposure is related to melphalan toxicity while the association with efficacy shows promising trends that will be studied further.
Collapse
Affiliation(s)
- Christa E Nath
- The Children's Hospital at Westmead, Sydney, NSW, Australia.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Nath CE, Dallapozza L, Eslick AE, Misra A, Carr D, Earl JW. An isocratic fluorescence HPLC assay for the monitoring of l-asparaginase activity and l-asparagine depletion in children receivingE.colil-asparaginase for the treatment of acute lymphoblastic leukaemia. Biomed Chromatogr 2009; 23:152-9. [DOI: 10.1002/bmc.1096] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
15
|
Nath CE, Earl JW, Pati N, Stephen K, Shaw PJ. Variability in the pharmacokinetics of intravenous busulphan given as a single daily dose to paediatric blood or marrow transplant recipients. Br J Clin Pharmacol 2008; 66:50-9. [PMID: 18341668 DOI: 10.1111/j.1365-2125.2008.03166.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
AIM To examine inter- and intrapatient variability in the pharmacokinetics of intravenous (i.v.) busulphan given as a single daily dose to children with malignant (n = 19) and nonmalignant (n = 21) disease. METHODS Busulphan (120 mg m(-2), 130 mg m(-2) or 3.2 mg kg(-1)) was administered over median 2.1 h. Blood samples (4-10) were collected after the first dose, busulphan concentrations were measured and pharmacokinetic parameters, including clearance (CL) and area under the concentration-time curve (AUC), were determined using the Kinetica software (Innaphase). Interpatient variability was assessed as percent coefficient of variation (% CV). Intrapatient variability was assessed by calculating percent differences between observed full dose AUC and AUC predicted from an initial 65 mg m(-2) dose in 13 children who had busulphan pharmacokinetic monitoring. RESULTS Clearance of i.v. busulphan in 40 children was 4.78 +/- 2.93 l h(-1) (% CV 61%), 0.23 +/- 0.08 l h(-1) kg(-1) (% CV 35%) and 5.79 +/- 1.59 l h(-1) m(-2) (% CV 27%). Age correlated significantly (p < 0.001) with CL (l h(-1)) and CL (l h(-1) kg(-1)), but not with CL (l h(-1) m(-2)). AUC normalized to the 130 mg m(-2) dose ranged from 14.1 to 56.3 mg l(-1) x h (% CV 37%) and also did not correlate with age. Interpatient variability in CL (l h(-1) m(-2)) was highest in six children with immune deficiencies (60%) and lowest in seven children with solid tumours (14%). Intrapatient variability was <13% for nine (of 13) children, but between 20 and 44% for four children. CONCLUSIONS There is considerable inter- and intrapatient variability in i.v. busulphan CL (l h(-1) m(-2)) and exposure that is unrelated to age, especially in children with immune deficiencies. These results suggest that monitoring of i.v. busulphan pharmacokinetics is required.
Collapse
Affiliation(s)
- Christa E Nath
- Departments of Biochemistry, The Children's Hospital at Westmead, Locked Bag 4001, Westmead, NSW 2145, Australia.
| | | | | | | | | |
Collapse
|
16
|
|
17
|
Abstract
AIM To develop a population pharmacokinetic model for melphalan in children with malignant diseases and to evaluate limited sampling strategies for melphalan. METHODS Melphalan concentration data following a single intravenous dose were collected from 59 children with malignant diseases aged between 0.3 and 18 years. The data were split into two sets: the model development dataset (39 children, 571 concentration observations) and the model validation dataset (20 children, 277 concentration observations). Population pharmacokinetic modelling was performed with the NONMEM software. Stepwise multiple linear regression was used to develop a limited sampling model for melphalan. RESULTS A two-compartment model was fitted to the concentration-vs.-time data. The following covariate population pharmacokinetic models were obtained: (i) Clearance (l h(-1)) = 0.34.WT - 3.17.CPT + 0.0377.GFR, where WT = weight (kg), CPT = prior carboplatin therapy (0 = no, 1 = yes), and GFR = glomerular filtration rate (ml min(-1) 1.73 m(-2)); (ii) Volume of distribution (l) = 1.12 + 0.178.WT. Interpatient variability (coefficient of variation) was 27.3% for clearance and 33.8% for volume of distribution. There was insignificant bias and imprecision between observed and model-predicted melphalan concentrations in the validation dataset. A three-sample limited sampling model was developed which adequately predicted the area under the concentration-time curve (AUC) in the development and validation datasets. CONCLUSIONS A population pharmacokinetic model for melphalan has been developed and validated and may now be used in conjunction with pharmacodynamic data to develop safe and effective dosing guidelines in children with malignant diseases.
Collapse
Affiliation(s)
- Christa E Nath
- Department of Biochemistry, The Children's Hospital at Westmead, NSW, Australia.
| | | | | | | |
Collapse
|
18
|
Nath CE, McLachlan AJ, Shaw PJ, Coakley JC, Earl JW. Amphotericin B dose optimization in children with malignant diseases. Chemotherapy 2007; 53:142-7. [PMID: 17310120 DOI: 10.1159/000100013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Accepted: 01/17/2006] [Indexed: 11/19/2022]
Abstract
In this study, rational dosing guidelines for amphotericin B-deoxycholate (AmB) are proposed for children. AmB steady-state trough concentrations (C(ss,trough)) and plasma creatinine concentrations (C(creat)) were measured in 83 children (age: 10 months to 18 years) receiving prophylactic AmB therapy (1 mg/kg/day). Maximum tolerable AmB C(ss,trough) were identified by determining the probability of large (>24%, 75th percentile) increases in C(creat) after 6 days of AmB for a series of C(ss,trough) ranges. Dose requirements were determined using a concentration-targeting approach. The 0.76-1.05 mg/l C(ss,trough) range provided the maximum concentrations that still had a low probability (p < 0.29) of adverse renal effects. 1 mg/kg/day AmB produces C(ss,trough) within this range for children weighing 25-45 kg. Lighter children (10-25 kg) require higher AmB doses (1.25-1.5 mg/kg/day) to achieve target C(ss,trough), while heavier children (45-55 kg) require lower doses (0.75 mg/kg/day). These starting dose guidelines may require individualization and prospective evaluation.
Collapse
Affiliation(s)
- Christa E Nath
- Department of Biochemistry, The Children's Hospital at Westmead, Westmead, Australia.
| | | | | | | | | |
Collapse
|
19
|
Hong Y, Shaw PJ, Tattam BN, Nath CE, Earl JW, Stephen KR, McLachlan AJ. Plasma protein distribution and its impact on pharmacokinetics of liposomal amphotericin B in paediatric patients with malignant diseases. Eur J Clin Pharmacol 2006; 63:165-72. [PMID: 17180621 DOI: 10.1007/s00228-006-0240-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Accepted: 11/17/2006] [Indexed: 10/23/2022]
Abstract
OBJECTIVE This study investigates the association of liposomal amphotericin B (L-AmB) with plasma proteins and its impact on the pharmacokinetics of L-AmB in paediatric patients with malignant diseases. METHODS Paediatric oncology patients (n = 39) who received multiple-doses of L-AmB were recruited into this study. The association of the drug with plasma lipoprotein was investigated using single vertical spin density gradient ultracentrifugation and quantitated with a validated HPLC assay. The unbound amphotericin B (AmB) in the plasma was separated by ultrafiltration and determined with a validated LC/MS/MS assay. RESULTS The ex vivo lipoprotein distribution of L-AmB found that 68.3 +/- 11.8% of the drug was associated with the high density lipoprotein (HDL) fraction, which demonstrated a significant inverse correlation with posterior Bayesian estimates of L-AmB clearance (r = -0.690, p < 0.01). The average of unbound fraction of AmB in plasma of patients administered with L-AmB was 0.005, but its relationship with L-AmB clearance did not reach a statistical significance. CONCLUSION L-AmB displays different lipoprotein distribution profile from that of the conventional AmB formulation, with L-AmB preferentially associated with HDL in plasma. The inverse correlation of L-AmB clearance to its HDL distribution contributes to the difference in the pharmacokinetic profile of L-AmB.
Collapse
Affiliation(s)
- Ying Hong
- Faculty of Pharmacy, University of Sydney, Pharmacy Building (A15), Sydney, NSW 2006, Australia
| | | | | | | | | | | | | |
Collapse
|
20
|
Hong Y, Shaw PJ, Nath CE, Yadav SP, Stephen KR, Earl JW, McLachlan AJ. Population pharmacokinetics of liposomal amphotericin B in pediatric patients with malignant diseases. Antimicrob Agents Chemother 2006; 50:935-42. [PMID: 16495254 PMCID: PMC1426421 DOI: 10.1128/aac.50.3.935-942.2006] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A population pharmacokinetic model of liposomal amphotericin B (L-AmB) in pediatric patients with malignant diseases was developed and evaluated. Blood samples were collected from 39 pediatric oncology patients who received multiple doses of L-AmB with a dose range from 0.8 to 5.9 mg/kg of body weight/day. The patient cohort had an average age of 7 years (range, 0.2 to 17 years) and weighed an average of 28.8 +/- 19.8 kg. Population pharmacokinetic analyses were performed with NONMEM software. Pharmacokinetic parameters, interindividual variability (IIV), between-occasion variability (BOV), and intraindividual variability were estimated. The influence of patient characteristics on the pharmacokinetics of L-AmB was explored. The final population pharmacokinetic model was evaluated by using a bootstrap sampling technique. The L-AmB plasma concentration-time data was described by a two-compartment pharmacokinetic model with zero-order input and first-order elimination. The population mean estimates of clearance (CL) and volume of distribution in the central compartment (V1) were 0.44 liters/h and 3.12 liters, respectively, and exhibited IIV (CL, 10%) and significant BOV (CL, 46% and V1, 56%). The covariate models were CL (liters/h) = 0.44 . e(0.0152.(WT-21)) and V1 (liters) = 3.12.e(0.0241.(WT-21)), where WT is the patient's body weight (kg) centered on the study population cohort median of 21 kg. Model evaluation by the bootstrap procedure indicated that the full pharmacokinetic model was robust and parameter estimates were accurate. In conclusion, the pharmacokinetics of L-AmB in pediatric oncology patients were adequately described by the developed population model. The model has been evaluated and can be used in the design of rational dosing strategies for L-AmB antifungal therapy in this special population.
Collapse
Affiliation(s)
- Ying Hong
- Faculty of Pharmacy, Pharmacy Building (A15), Camperdown Campus, University of Sydney, Sydney, NSW 2006, Australia
| | | | | | | | | | | | | |
Collapse
|
21
|
Nath CE, Shaw PJ, Montgomery K, Earl JW. Melphalan pharmacokinetics in children with malignant disease: influence of body weight, renal function, carboplatin therapy and total body irradiation. Br J Clin Pharmacol 2005; 59:314-24. [PMID: 15752378 PMCID: PMC1884786 DOI: 10.1111/j.1365-2125.2004.02319.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
AIM To analyse the pharmacokinetics of melphalan in 52 children (0.3-18 years) and determine whether any clinical factors affect the pharmacokinetic parameters Additionally, to examine whether a test melphalan dose can predict the pharmacokinetics of a full dose, when there are 5 intervening days of carboplatin therapy. METHODS Melphalan concentrations were measured in 14 blood samples collected from each child following doses ranging from 30 to 180 mg m(-2). The pharmacokinetics were analysed with Kinetica 4.0. RESULTS Children who did not have carboplatin (n = 27) had median melphalan clearance (CL) of 15.5 l h(-1) m(-2) (interquartile range: 12.4-19.9 l h(-1) m(-2)) and steady state volume of distribution (Vss) of 14.9 l m(-2) (interquartile range: 12.7-18.3 l m(-2)). Children who had carboplatin (n = 25) had 34% lower median CL (10.2 l h(-1) m(-2)) and 18% lower median Vss (12.2 l m(-2)) (P < 0.001). Melphalan elimination was impaired in a separate group of three children given concomitant carboplatin and etoposide. Stepwise multiple linear regression indicated that weight, carboplatin, glomerular filtration rate (GFR) and total body irradiation (TBI) significantly affected CL, while weight and carboplatin influenced Vss. A test dose (10 mg m(-2)) tended to underpredict the area-under-the-concentration-vs.-time-curve for a full (180 mg m(-2)) dose in 19 individuals given carboplatin. CONCLUSIONS In children, melphalan CL is influenced by weight, carboplatin, TBI and GFR. Vss is influenced by weight and carboplatin.
Collapse
Affiliation(s)
- Christa E Nath
- Department of Biochemistry and Oncology, The Children's Hospital at Westmead, NSW, Australia.
| | | | | | | |
Collapse
|
22
|
Abstract
AIMS To construct a population pharmacokinetic model for the antifungal agent, amphotericin B (AmB), in children with malignant diseases. METHODS A two compartment population pharmacokinetic model for AmB was developed using concentration-time data from 57 children aged between 9 months and 16 years who had received 1 mg kg(-1) day(-1) doses in either dextrose (doseform=1) or lipid emulsion (doseform=2). P-Pharm (version 1.5) was used to estimate the basic population parameters, to identify covariates with significant relationships with the pharmacokinetic parameters and to construct a Covariate model. The predictive performance of the Covariate model was assessed in an independent group of 26 children (the validation group). RESULTS The Covariate model had population mean estimates for clearance (CL), volume of distribution into the central compartment (V) and the distributional rate constants (k12 and k21) of 0.88 l h(-1), 9.97 l, 0.27 h(-1) and 0.16 h(-1), respectively, and the intersubject variability of these parameters was 19%, 49%, 55% and 48%, respectively. The following covariate relationships were identified: CL (l h(-1)) = 0.053 + 0.0456 weight (0.75) (kg) + 0.242 doseform and V (l) = 7.11 + 0.107 weight (kg). Our Covariate model provided unbiased and precise predictions of AmB concentrations in the validation group of children: the mean prediction error was 0.0089 mg l(-1) (95% confidence interval: -0.0075, 0.0252 mg l(-1)) and the root mean square prediction error was 0.1245 mg l(-1) (95% confidence interval: 0.1131, 0.1349 mg l(-1)). CONCLUSIONS A valid population pharmacokinetic model for AmB has been developed and may now be used in conjunction with AmB toxicity and efficacy data to develop dosing guidelines for safe and effective AmB therapy in children with malignancy.
Collapse
Affiliation(s)
- C E Nath
- Department of Biochemistry, The Children's Hospital at Westmead, NSW, Australia.
| | | | | | | | | |
Collapse
|
23
|
Abstract
Fourteen children, aged between 5 and 17 years, with stable renal graft function and stable cyclosporin A (CSA) trough levels (Cmin) were studied. They had been taking CSA 12-hourly since their transplant 1.5-9 years previously, with the average dose of Neoral being 6.4 (range 4.4-8.4) mg/kg per day. CSA whole blood levels were measured at 0, 20, and 40 min, and at 1, 1.5, 2, 2.5, 3, 4, 6, and 8 h following the morning dose using the Abbott TDx fluorescence polarization immunoassay. The area under the concentration time curve (AUC), clearance adjusted for bioavailability (CL/F), and steady-state volume of distribution adjusted for bioavailability (Vss/F) were determined using model-independent pharmacokinetic analysis. Delay time (Tdel), peak concentration (Cmax), time to peak concentration (Tmax), and Cmin were also determined and correlated with AUC and other parameters. The Tdel in absorption varied from 0.3 to 1.6 (mean 0.73) h, resulting in a similarly variable time to Tmax of 1-2.4 h (mean 1.59). Tmax was related to the age of the patient (Tmax = 0.027 age + 1.41, r2 = 0.56, P < 0.005). The AUC showed good correlation with Cmax (Cmax = 0.25 AUC + 423.32, r2 = 0.96, P < 0.0005). Cmax appears to be a more-suitable measure of exposure to CSA than Cmin. Prediction of Tmax from the age of the child may help to overcome the problem of when to collect blood for peak levels.
Collapse
Affiliation(s)
- J C Tam
- Centre for Kidney Research, Royal Alexandra Hospital for Children, PO Box 3515, Parramatta, NSW Australia 2124
| | | | | | | | | | | | | |
Collapse
|
24
|
Nath CE, Shaw PJ, Gunning R, McLachlan AJ, Earl JW. Amphotericin B in children with malignant disease: a comparison of the toxicities and pharmacokinetics of amphotericin B administered in dextrose versus lipid emulsion. Antimicrob Agents Chemother 1999; 43:1417-23. [PMID: 10348763 PMCID: PMC89289 DOI: 10.1128/aac.43.6.1417] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In a prospective, randomized clinical trial, the toxicity of 1 mg of amphotericin B (AmB) per kg of body weight per day infused in 5% dextrose was compared with that of AmB infused in lipid emulsion in children with malignant disease. In an analysis of 82 children who received a full course of 6 days or more of AmB (117 courses), it was shown that there were significant increases in plasma urea and creatinine concentrations and in potassium requirement after 6 days of therapy with both AmB infused in dextrose and AmB infused in lipid emulsion, with there being no difference between the two methods of AmB administration. An intent-to-treat comparison of the numbers of courses affected by acute toxicity (fever, rigors) and chronic toxicity (nephrotoxicity) also indicated that there was no significant difference between AmB infused in dextrose (78 courses) and AmB infused in lipid emulsion (84 courses). The pharmacokinetics of AmB were investigated in 20 children who received AmB in dextrose and 15 children who received AmB in lipid emulsion. Blood samples were collected up to 24 h after administration of the first dose, and the concentration of AmB in plasma was analyzed by a high-performance liquid chromatography assay. The clearance (CL) of AmB in dextrose (0.039 +/- 0.016 liter. h-1. kg-1) was significantly lower (P < 0.005) than the CL of AmB in lipid emulsion (0.062 +/- 0. 024 liter. h-1. kg-1). The steady-state volume of distribution for AmB in dextrose (0.83 +/- 0.33 liter. kg-1) was also significantly lower (P < 0.005) than that for AmB in lipid emulsion (1.47 +/- 0.77 liter. kg-1). Although AmB in lipid emulsion is apparently cleared faster and distributes more widely than AmB in dextrose, this study did not reveal any significant advantage with respect to safety and tolerance in the administration of AmB in lipid emulsion compared to its administration in dextrose in children with malignant disease.
Collapse
Affiliation(s)
- C E Nath
- Department of Biochemistry, New Children's Hospital, Westmead, NSW, Australia.
| | | | | | | | | |
Collapse
|
25
|
Abstract
Fetal oxygen saturation (FSpO2) was recorded during labour to determine the relationship between FSpO2 and indicators of fetal well-being, including umbilical blood gases, xanthine (X), hypoxanthine (Hx) and Apgar scores. This is one of the largest reported series of fetal pulse oximetry, with 118 fetuses monitored for over 329 hours. Mean FSpO2 for all cases was 46.9% (SD = 9.1%). There was no correlation between FSpO2 during the last 10 minutes of monitoring and arterial pH, Hx or X. A mean FSpO2 > or = 30% was associated with a 5 minute Apgar score of > or = 7 in the majority of cases. One fetus had a mean FSpO2 < 30% during the final 10 minutes of monitoring and an umbilical arterial pH < 7.20, while there were 10 fetuses with an umbilical arterial pH < 7.20, and mean FSpO2 > or = 30%. As these numbers are small, a larger series is necessary to further characterize the small number of fetuses who are significantly hypoxic.
Collapse
Affiliation(s)
- C E East
- Perinatal Research Centre, Royal Women's Hospital, Herston, Queensland
| | | | | | | | | |
Collapse
|
26
|
Shaw PJ, Atkins MC, Nath CE, Earl JW. ATRA administration in the critically ill patient. Leukemia 1995; 9:1288. [PMID: 7630206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
|