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Pai AA, Mohanan E, Panetta JC, Kulkarni UP, Illangeswaran RSS, Balakrishnan B, Jayaraman A, Edison ES, Lakshmi KM, Devasia AJ, Fouzia NA, Korula A, Abraham A, George B, Srivastava A, Mathews V, Standing JF, Balasubramanian P. Treosulfan Exposure Predicts Thalassemia-Free Survival in Patients with Beta Thalassemia Major Undergoing Allogeneic Hematopoietic Cell Transplantation. Clin Pharmacol Ther 2024; 115:116-125. [PMID: 37846495 PMCID: PMC7615782 DOI: 10.1002/cpt.3078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 10/09/2023] [Indexed: 10/18/2023]
Abstract
A toxicity-reduced conditioning regimen with treosulfan, fludarabine, and thiotepa in patients with high-risk β-thalassemia major has significantly improved hematopoietic stem cell transplantation (HCT) outcomes. However, complications resulting from regimen-related toxicities (RRTs), mixed chimerism, and graft rejection remain a challenge. We evaluated the dose-exposure-response relationship of treosulfan and its active metabolite S, S-EBDM, in a uniform cohort of patients with β-thalassemia major to identify whether therapeutic drug monitoring (TDM) and dose adjustment of treosulfan is feasible. Plasma treosulfan/S, S-EBDM levels were measured in 77 patients using a validated liquid chromatography with tandem mass spectrometry method, and the pharmacokinetic parameters were estimated using nlmixr2. The influence of treosulfan and S, S-EBDM exposure, and GSTA1/NQO1 polymorphisms on graft rejection, RRTs, chimerism status, and 1-year overall survival (OS), and thalassemia-free survival (TFS) were assessed. We observed that treosulfan exposure was lower in patients with graft rejection than those without (1,655 vs. 2,037 mg•h/L, P = 0.07). Pharmacodynamic modeling analysis to identify therapeutic cutoff revealed that treosulfan exposure ≥1,660 mg•hour/L was significantly associated with better 1-year TFS (97% vs. 81%, P = 0.02) and a trend to better 1-year OS (90% vs. 69%, P = 0.07). Further, multivariate analysis adjusting for known pre-HCT risk factors also revealed treosulfan exposure <1,660 mg•h/L (hazard ratio (HR) = 3.23; 95% confidence interval (CI) = 1.12-9.34; P = 0.03) and GSTA1*B variant genotype (HR = 3.75; 95% CI = 1.04-13.47; P = 0.04) to be independent predictors for inferior 1-year TFS. We conclude that lower treosulfan exposure increases the risk of graft rejection and early transplant-related mortality affecting TFS. As no RRTs were observed with increasing treosulfan exposure, TDM-based dose adjustment could be feasible and beneficial.
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Affiliation(s)
- Aswin Anand Pai
- Department of Hematology, Christian Medical College, Vellore, India
- Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, India
| | | | - John C. Panetta
- Department of Pharmaceutical Sciences, St Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Uday P. Kulkarni
- Department of Hematology, Christian Medical College, Vellore, India
| | | | | | - Agila Jayaraman
- Department of Hematology, Christian Medical College, Vellore, India
| | - Eunice S. Edison
- Department of Hematology, Christian Medical College, Vellore, India
| | | | - Anup J. Devasia
- Department of Hematology, Christian Medical College, Vellore, India
| | | | - Anu Korula
- Department of Hematology, Christian Medical College, Vellore, India
| | - Aby Abraham
- Department of Hematology, Christian Medical College, Vellore, India
| | - Biju George
- Department of Hematology, Christian Medical College, Vellore, India
| | - Alok Srivastava
- Department of Hematology, Christian Medical College, Vellore, India
| | - Vikram Mathews
- Department of Hematology, Christian Medical College, Vellore, India
| | - Joseph F. Standing
- Infection, Immunity and Inflammation, Great Ormond Street Institute of Child Health, University College London, London, UK
- Department of Pharmacy, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
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Slatter MA, Gennery AR. Treosulfan-based conditioning for inborn errors of immunity. Ther Adv Hematol 2021; 12:20406207211013985. [PMID: 34094045 PMCID: PMC8141989 DOI: 10.1177/20406207211013985] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 04/12/2021] [Indexed: 11/17/2022] Open
Abstract
Inborn errors of immunity (IEI) are inherited disorders that lead to defects in the development and/or function of the immune system. The number of disorders that can be treated by haematopoietic stem-cell transplantation (HSCT) has increased rapidly with the advent of next-generation sequencing. The methods used to transplant children with IEI have improved dramatically over the last 20 years. The introduction of reduced-toxicity conditioning is an important factor in the improved outcome of HSCT. Treosulfan has myeloablative and immunosuppressive properties, enabling engraftment with less toxicity than traditionally used doses of busulfan. It is firmly incorporated into the conditioning guidelines of the Inborn Errors Working Party of the European Society for Blood and Marrow Transplantation. Unlike busulfan, pharmacokinetically guided dosing of treosulfan is not part of routine practice, but data are emerging which indicate that further improvements in outcome may be possible, particularly in infants who have a decreased clearance of treosulfan. It is likely that individualized dosing, not just of treosulfan, but of all agents used in conditioning regimens, will be developed and implemented in the future. This will lead to a reduction in unwanted variability in drug exposure, leading to more predictable and adjustable exposure, and improved outcome of HSCT, with fewer late adverse effects and improved quality of life. Such conditioning regimens can be used as the basis to study the need for additional agents in certain disorders which are difficult to engraft or require high levels of donor chimerism, the dosing of individual cellular components within grafts, and effects of adjuvant cellular or immunotherapy post-transplant. This review documents the establishment of treosulfan worldwide, as a safe and effective agent for conditioning children with IEI prior to HSCT.
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Affiliation(s)
- Mary A Slatter
- Great North Children's Hospital, Clinical Resource Building, Floor 4, Block 2, Queen Victoria Road, Newcastle Upon Tyne NE1 4LP, UK
| | - Andrew R Gennery
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
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Romański M, Pogorzelska A, Główka FK. Kinetics of in Vitro Guanine- N7-Alkylation in Calf Thymus DNA by (2 S,3 S)-1,2-Epoxybutane-3,4-diol 4-methanesulfonate and (2 S,3 S)-1,2:3,4-Diepoxybutane: Revision of the Mechanism of DNA Cross-Linking by the Prodrug Treosulfan. Mol Pharm 2019; 16:2708-2718. [PMID: 31013419 DOI: 10.1021/acs.molpharmaceut.9b00251] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Prodrug treosulfan, originally registered for treatment of ovarian cancer, has gained a use in conditioning prior to hematopoietic stem cell transplantation. Treosulfan converts nonenzymatically to the monoepoxide intermediate (EBDM), and then to (2 S,3 S)-1,2:3,4-diepoxybutane (DEB). The latter alkylates DNA forming mainly (2' S,3' S)- N-7-(2',3',4'-trihydroxybut-1'-yl)guanine (THBG) and (2 S,3 S)-1,4-bis(guan-7'-yl)butane-2,3-diol cross-link (bis-N7G-BD) via the intermediate epoxide adduct (EHBG). It is believed that DNA cross-linking by DEB is a primary mechanism for the anticancer and myeloablative properties of treosulfan, but clear evidence is lacking. Recently, we have proved that EBDM alkylates DNA producing (2' S,3' S)- N-7-(2',3'-dihydroxy-4'-methylsulfonyloxybut-1'-yl)-guanine (HMSBG) and that free HMSBG converts to EHBG. In this paper, we investigated the kinetics of HMSBG, bis-N7G-BD, and THBG in DNA in vitro to elucidate the contribution of EBDM and DEB to treosulfan-dependent DNA-DNA cross-linking. Calf thymus DNA was exposed to ( A) 100 μM treosulfan, ( B) 200 μM treosulfan, and ( C) DEB at a concentration 100 μM, exceeding that produced by 200 μM treosulfan. Following mild acid thermal hydrolysis of DNA, ultrafiltration, and off-line HPLC purification, the guanine adducts were quantified by LC-MS/MS. Both bis-N7G-BD and THBG reached highest concentrations in the DNA in experiment B. Ratios of the maximal concentration of bis-N7G-BD and THBG to DEB (adduct Cmax/DEB Cmax) in experiments A and B were 1.7-3.0-times greater than in experiment C. EHBG converted to the bis-N7G-BD cross-link at a much higher rate constant (0.20 h-1) than EBDM and DEB initially alkylated the DNA (1.8-3.4 × 10-5 h-1), giving rise to HMSBG and EHBG, respectively. HMSBG decayed unexpectedly slowly (0.022 h-1) compared with the previously reported behavior of the free adduct (0.14 h-1), which revealed the inhibitory effect of the DNA environment on the adduct epoxidation to EHBG. A kinetic simulation based on the obtained results and the literature pharmacokinetic parameters of treosulfan, EBDM, and DEB suggested that in patients treated with the prodrug, EBDM could produce the vast majority of EHBG and bis-N7G-BD via HMSBG. In conclusion, EBDM can produce DNA-DNA lesions independently of DEB, and likely plays a greater role in DNA cross-linking after in vivo administration of treosulfan than DEB. These findings compel revision of the previously proposed mechanism of the pharmacological action of treosulfan and contribute to better understanding of the importance of EBDM for biological effects.
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Affiliation(s)
- Michał Romański
- Department of Physical Pharmacy and Pharmacokinetics , Poznan University of Medical Sciences , 6 Święcickiego Street , 60-781 Poznań , Poland
| | - Alicja Pogorzelska
- Department of Physical Pharmacy and Pharmacokinetics , Poznan University of Medical Sciences , 6 Święcickiego Street , 60-781 Poznań , Poland
| | - Franciszek K Główka
- Department of Physical Pharmacy and Pharmacokinetics , Poznan University of Medical Sciences , 6 Święcickiego Street , 60-781 Poznań , Poland
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van der Stoep MYEC, Zwaveling J, Bertaina A, Locatelli F, Guchelaar HJ, Lankester AC, Moes DJAR. Population pharmacokinetics of treosulfan in paediatric patients undergoing hematopoietic stem cell transplantation. Br J Clin Pharmacol 2019; 85:2033-2044. [PMID: 31144349 PMCID: PMC6710524 DOI: 10.1111/bcp.13995] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 05/03/2019] [Accepted: 05/15/2019] [Indexed: 12/17/2022] Open
Abstract
Aims Treosulfan is an alkylating agent increasingly used prior to haematopoietic stem cell transplantation. The aim of this study was to develop a population pharmacokinetic (PK) model of treosulfan in paediatric haematopoietic stem cell transplantation recipients and to explore the effect of potential covariates on treosulfan PK. Also, a limited sampling model (LSM) will be developed to accurately predict treosulfan exposure suitable for a therapeutic drug monitoring setting. Methods In this multicentre study, 91 patients, receiving a total dose of 30, 36 or 42 g/m2 treosulfan, administered over 3 consecutive days, were enrolled. A population PK model was developed and demographic factors, as well as laboratory parameters, were included as potential covariates. In addition, a LSM was developed using data from 28 patients. Results A 2‐compartment model with first order elimination best described the data. Bodyweight with allometric scaling and maturation function were identified as significant predictors of treosulfan clearance. Treosulfan clearance reaches 90% of adult values at 4 postnatal years. A model‐based dosing table is presented to target an exposure of 1650 mg*h/L (population median) for different weight and age groups. Samples taken at 1.5, 4 and 7 hours after start of infusion resulted in the best limited sampling strategy. Conclusions This study provides a treosulfan population PK model in children and captures the developmental changes in clearance. A 3‐point LSM allows for accurate and precise estimation of treosulfan exposure.
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Affiliation(s)
- M Y E C van der Stoep
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | - J Zwaveling
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | - A Bertaina
- Department of Paediatric Haematology and Oncology, Istituto di Ricovero e Cura a Carattere Scientifico Bambino Gesù Children's Hospital, Rome, University La Sapienza, Rome, Italy
| | - F Locatelli
- Department of Paediatric Haematology and Oncology, Istituto di Ricovero e Cura a Carattere Scientifico Bambino Gesù Children's Hospital, Rome, University La Sapienza, Rome, Italy
| | - H J Guchelaar
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | - A C Lankester
- Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands
| | - D J A R Moes
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands
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