High exposures to bioactivated cyclophosphamide are related to the occurrence of veno-occlusive disease of the liver following high-dose chemotherapy

Clinical features and risk factors of hepatic sinusoidal obstruction syndrome in children after hematopoietic stem cell transplantation: A single-center experience

Hepatic sinusoidal obstruction syndrome (SOS) is an illness with serious life effects that develops after hematopoietic stem cell transplantation (HSCT). We investigated the risk factors and clinical features of hepatic SOS in children following HSCT in 210 children who underwent allogeneic or autologous HSCT between 2009 and 2021 were analyzed in the context of SOS. The syndrome developed in 22 (10.4%) patients:frequently in neuroblastoma [24% (5/21)], hemophagocytic lymphohistiocytosis [57% (4/7)], and thalassemia major [22% (7/31)]. The median time from HSCT to diagnosis was 16 (6-38) days. Severe disease occurred in 8 (36%) patients, and mild/moderate in 14 (64%) and 4 patients died (18%). In univariate analyses, patient's age ≤ 2 years [odds ratio (OR)= 3.043, P = 0.028], pretransplant AST and ALT levels > 100 U/L (OR=3.576, P = 0.045), and chemotherapy/radiotherapy to abdomen before transplantation (OR = 3.162, P = 0.044) were determined as risk factors. In multivariate analysis, pre-transplant AST and ALT levels > 100 U/L (OR = 16.04, P = 0.010) and ferritin levels over 1000 mg/dl (OR=5.15, P = 0.047) were significant. The only independent risk factor on mortality was the age ≤ 2 years (P = 0.001). Although our study confirmed several risk factors for SOS, we failed to achieve some well-known risk factors. Precautions should be taken considering the factors affecting liver function before transplantation and the risk of SOS in infants receiving chemotherapy and radiotherapy before transplantation, such as neuroblastoma in which comparable results in respect to the chemotherapy only. The risk factors should be fully elucidated in multicenter studies to improve preventive and therapeutic strategies.

Integrated Electrochemical Aptasensor Array toward Monitoring Anticancer Drugs in Sweat

In the realm of clinical practice, the concurrent utilization of anticancer medications can enhance their overall therapeutic efficacy. However, it is crucial to acknowledge that the interactions among these anticancer drugs can potentially yield detrimental consequences on their intended outcomes. Consequently, the assessment of both anticancer potency and potential toxic side effects is greatly refined when multiple anticancer drugs are simultaneously detected and evaluated. Here, we designed a wearable electrochemical aptasensor array for monitoring multiple anticancer drugs in sweat. The integrated sensor array consists of three working electrodes modified with three different aptamers (Apt1, Apt2, and Apt3), a Au counter electrode, and a Ag/AgCl reference electrode. Molecular docking simulations were performed to show the binding affinities between three anticancer drugs and their corresponding aptamers. Various eigenvalues were derived from the square-wave voltammetry electrochemical signals, and these data sets were subjected to rigorous analysis through multivariate data analysis techniques. This analytical approach demonstrated exceptional performance by achieving flawless 100% accuracy in the precise identification of nine anticancer drugs consistently at uniform concentrations. Furthermore, the integrated wearable sensor array exhibited impressive capabilities, correctly recognizing all nine anticancer drugs with 100% accuracy and successfully distinguishing between these drugs in artificial sweat samples. The proposed sensor array presents good stability for 15 days. Flexibility tests showed stable device performance after 500 twisting cycles. This innovative wearable sensing array represents a novel approach for achieving real-time monitoring and precise adjustment of drug dosages. It offers invaluable insights for tailoring the treatment of anticancer drugs to individual patients, predicting both drug efficacy and potential adverse reactions within the field of clinical medicine.

Acute Liver Injury Caused by Cyclophosphamide in a Patient With Factor VIII Deficiency: A Rare Presentation

Because of the variety of drugs, herbal, and dietary supplements used in clinical practice. Drug-induced liver injury (DILI) has become an important and common cause of acute liver injury and failure. Many drugs associated with DILI have been identified, but there remains some uncertainty about others. Cyclophosphamide is a commonly used antineoplastic medication, and its association with DILI has been reported in animals and has been established in humans with the use of high-dose IV. Oral cyclophosphamide has not been clearly shown to cause acute liver injury, thus highlighting many of the unique aspects of this manuscript. Here, we report a case of cyclophosphamide-induced DILI with the aim to alert clinicians regarding this potential association.

Low-Dose Cyclophosphamide Associated With Hyponatremia and Hepatotoxicity

Cyclophosphamide (CY) is an alkylating agent often used as a chemotherapeutic agent, with increasing use as an immunosuppressant. Cyclophosphamide has many established adverse effects, including hyponatremia and limited reports of hepatotoxicity, particularly in high-dose treatment. A case of simultaneous hyponatremia and acute liver injury associated with the initiation of cyclophosphamide two weeks prior is discussed here. A 73-year-old male with acquired hemophilia A/factor VIII deficiency presented to the emergency department (ED) with four days of hip pain and was found to have jaundice and confusion. Laboratory evaluation demonstrated hyponatremia and an acute liver injury associated with his recent cyclophosphamide use. With the discontinuation of the offending agent and sodium correction, he made a full recovery. Cyclophosphamide-induced hyponatremia is likely secondary to the nephrogenic syndrome of inappropriate antidiuresis (NSIAD) and is most often associated with high-dose regimens. While the mechanism of hepatotoxicity requires further study, it is likely dose-dependent and related to excess levels of 4-hydroxycyclophosphamide (HCY). The management of cyclophosphamide-induced water toxicity and hepatotoxicity is centered around the discontinuation of medication, the correction of electrolyte abnormalities, and supportive treatment.

Association between CYP2B6 genetic variability and cyclophosphamide therapy in pediatric patients with neuroblastoma

Cyclophosphamide, an oxazaphosphorine prodrug is frequently used in treatment of neuroblastoma, which is one of the most prevalent solid organ malignancies in infants and young children. Cytochrome P450 2B6 (CYP2B6) is the major catalyst and CYP2C19 is the minor enzyme in bioactivation and inactivation pathways of cyclophosphamide. CYP-mediated metabolism may contribute to the variable pharmacokinetics of cyclophosphamide and its toxic byproducts leading to insufficient response to the therapy and development of clinically significant side effects. The aim of the study was to reveal the contribution of pharmacogenetic variability in CYP2B6 and CYP2C19 to the treatment efficacy and cyclophosphamide-induced side effects in pediatric neuroblastoma patients under cyclophosphamide therapy (N = 50). Cyclophosphamide-induced hematologic toxicities were pivotal in all patients, whereas only moderate hepatorenal toxicity was developed. The patients' CYP2B6 metabolizer phenotypes were associated with the occurrence of lymphopenia, thrombocytopenia, and monocytopenia as well as of liver injury, but not with kidney or urinary bladder (hemorrhagic cystitis) toxicities. Furthermore, the patients' age (< 1.5 years, P = 0.03) and female gender (P ≤ 0.02), but not CYP2B6 or CYP2C19 metabolizer phenotypes appeared as significant prognostic factors in treatment outcomes. Our results may contribute to a better understanding of the impact of CYP2B6 variability on cyclophosphamide-induced side effects.

Precision Oncology by Point-of-Care Therapeutic Drug Monitoring and Dosage Adjustment of Conventional Cytotoxic Chemotherapies: A Perspective

Therapeutic drug monitoring (TDM) of conventional cytotoxic chemotherapies is strongly supported yet poorly implemented in daily practice in hospitals. Analytical methods for the quantification of cytotoxic drugs are instead widely presented in the scientific literature, while the use of these therapeutics is expected to keep going for longer. There are two main issues hindering the implementation of TDM: turnaround time, which is incompatible with the dosage profiles of these drugs, and exposure surrogate marker, namely total area under the curve (AUC). Therefore, this perspective article aims to define the adjustment needed from current to efficient TDM practice for cytotoxics, namely point-of-care (POC) TDM. For real-time dose adjustment, which is required for chemotherapies, such POC TDM is only achievable with analytical methods that match the sensitivity and selectivity of current methods, such as chromatography, as well as model-informed precision dosing platforms to assist the oncologist with dose fine-tuning based on quantification results and targeted intervals.

Upregulation of Nrf2/HO-1 Signaling and Attenuation of Oxidative Stress, Inflammation, and Cell Death Mediate the Protective Effect of Apigenin against Cyclophosphamide Hepatotoxicity

Liver injury is among the adverse effects of the chemotherapeutic agent cyclophosphamide (CP). This study investigated the protective role of the flavone apigenin (API) against CP-induced liver damage, pointing to the involvement of Nrf2/HO-1 signaling. Rats were treated with API (20 and 40 mg/kg) for 15 days and received CP (150 mg/kg) on day 16. CP caused liver damage manifested by an elevation of transaminases, alkaline phosphatase (ALP), and lactate dehydrogenase (LDH), and histological alterations, including granular vacuolation, mononuclear cell infiltration, and hydropic changes. Hepatic reactive oxygen species (ROS), malondialdehyde (MDA), and nitric oxide (NO) were increased and glutathione (GSH) and antioxidant enzymes were decreased in CP-administered rats. CP upregulated the inflammatory markers NF-κB p65, TNF-α, IL-6, and iNOS, along with the pro-apoptotic Bax and caspase-3. Pre-treatment with API ameliorated circulating transaminases, ALP, and LDH, and prevented histopathological changes in CP-intoxicated rats. API suppressed ROS, MDA, NO, NF-κB p65, iNOS, inflammatory cytokines, oxidative DNA damage, Bax, and caspase-3 in CP-intoxicated rats. In addition, API enhanced hepatic antioxidants and Bcl-2 and boosted the Nrf2 and HO-1 mRNA abundance and protein. In conclusion, API is effective in preventing CP hepatotoxicity by attenuating oxidative stress, the inflammatory response, and apoptosis. The hepatoprotective efficacy of API was associated with the upregulation of Nrf2/HO-1 signaling.

Constructing vascularized hepatic tissue by cell-assembled viscous tissue sedimentation method and its application for vascular toxicity assessment

In vitro Construction of the liver sinusoidal structure using artificial tissue is an important but worthwhile challenge, particularly for assessing the risk of diseases such as sinusoidal obstruction syndrome (SOS). Current models are unsuitable for evaluating the toxicity because of lacking sinusoidal capillary. In this study, we developed a vascularized hepatic tissue (VHT) using a unique tissue engineering technique, the cell assembled viscous tissue by sedimentation (CAViTs) method. The "viscous bodies" created using the CAViTs method exhibited significant self-assembly within 6 h after seeding, promoting cell-cell interaction. The level of albumin secreted by the VHT was four times higher than that of 2D-coculture and maintained for 1 month. The gene expression pattern of the VHT was closer to that of total human liver, compared with the 2D system. Quantitative evaluations of the vascular structure of VHT treated with two typical SOS-inducing compounds, monocrotaline and retrorsine, revealed higher sensitivity (IC₅₀ = 40.35 µM), 19.92 times higher than the cell-viability assay. Thus, VHT represents an innovative in vitro model that mimics the vessel network structure and could become a useful tool for the early screening of compounds associated with a risk of vascular toxicity. STATEMENT OF SIGNIFICANCE: Mimicking sinusoidal structures in in vitro liver model is important to consider from the perspective of predicting hepatotoxicity such like sinusoidal obstruction syndrome (SOS). However, it was difficult to reconstruct the vascular structure within the hepatocyte-rich environment. In this study, we constructed a vascularized hepatic tissue in a high-throughput manner by a unique method using collagen and heparin, and evaluated its applicability to toxicity assessment. Vessel morphology analysis of the model treated by monocrotaline, which is a well-known SOS-inducing compound, could predict the toxicity with higher sensitivity. To the best of our knowledge, this is the first report to provide vascularized hepatic tissues using sinusoidal endothelial cells at least for demonstrating applicability to the evaluation of SOS induction risk.

Myeloablative Busulfan/Melphalan Consolidation following Induction Chemotherapy for Patients with Newly Diagnosed High-Risk Neuroblastoma: Children's Oncology Group Trial ANBL12P1

Consolidation using high-dose chemotherapy with autologous stem cell transplantation (ASCT) is an important component of frontline therapy for children with high-risk neuroblastoma. The optimal preparative regimen is uncertain, although recent data support a role for busulfan/melphalan (BuMel). The Children's Oncology Group (COG) conducted a trial (ANBL12P1) to assess the tolerability and feasibility of BuMel ASCT following a COG induction. Patients with newly diagnosed high-risk neuroblastoma who did not progress during induction therapy and met organ function requirements received i.v. busulfan (every 24 hours for 4 doses based on age and weight) and melphalan (140 mg/m² for 1 dose), followed by ASCT. Busulfan doses were adjusted to achieve to an average daily area under the curve (AUC) <5500 µM × minute. The primary endpoint was the occurrence of severe sinusoidal obstruction syndrome (SOS) or grade ≥4 pulmonary complications within the first 28 days after completion of consolidation therapy. A total of 146 eligible patients were enrolled, of whom 101 underwent BuMel ASCT. The overall incidence of protocol-defined unacceptable toxicity during consolidation was 6.9% (7 of 101). Six patients (5.9%) developed SOS, with 4 (4%) meeting the criteria for severe SOS. An additional 3 patients (3%) experienced grade ≥4 pulmonary complications during consolidation. The median busulfan AUC was 4558 µM × min (range, 3462 to 5189 µM × minute) for patients with SOS and 3512 µM × min (2360 to 5455 µM × minute) (P = .0142). No patients died during consolidation. From the time of study enrollment, the mean 3-year event-free survival for all 146 eligible patients was 55.6 ± 4.2%, and the mean 3-year overall survival was 74.5 ± 3.7%. The BuMel myeloablative regimen following COG induction was well tolerated, with acceptable pulmonary and hepatic toxicity.

Liver Inflammatory Injury Initiated by DAMPs-TLR4-MyD88/TRIF-NFκB Signaling Pathway Is Involved in Monocrotaline-Induced HSOS

Hepatic sinusoidal obstruction syndrome (HSOS) causes considerable morbidity and mortality in clinic. Up to now, the molecular mechanisms involved in the development of HSOS still remain unclear. Here, we report that hepatic inflammation initiated by damage-associated molecular patterns (DAMPs) plays a critical role in the development of HSOS. Monocrotaline (MCT) belongs to pyrrolizidine alkaloids. Monocrotaline-induced HSOS in mice and rats was evidenced by the increased serum alanine/aspartate aminotransferase (ALT/AST) activities, the elevated hepatic metalloproteinase 9 (MMP9) expression, and results from liver histological evaluation and scanning electron microscope observation. However, MCT-induced HSOS was markedly attenuated in myeloid differentiation primary response gene 88 (MyD88), TIR-domain-containing adapter-inducing interferon-β (TRIF) and toll like receptor 4 (TLR4) knock-out mice. Monocrotaline increased liver myeloperoxidase activity, serum contents of proinflammatory cytokines, hepatic aggregation of immune cells, and nuclear accumulation of nuclear factor κB (NFκB). However, these inflammatory responses induced by MCT were all diminished in MyD88, TRIF, and TLR4 knock-out mice. Monocrotaline elevated serum contents of DAMPs including high mobility group box 1 (HMGB1) and heat shock protein 60 (HSP60) both in mice and in rats. HSOS was markedly exacerbated and serum contents of HMGB1 and HSP60 were elevated in nuclear factor erythroid 2-related factor 2 (Nrf2) knock-out mice treated with MCT. Our findings indicate that hepatic inflammatory injury mediated by DAMPs-initiated TLR4-MyD88/TRIF-NFκB inflammatory signal pathway plays an important role in HSOS development.

Alogliptin: a novel approach against cyclophosphamide-induced hepatic injury via modulating SIRT1/FoxO1 pathway

Cyclophosphamide (CP) is one of the most potent alkylating agents and is widely used in the treatment of numerous neoplastic conditions, autoimmune diseases and following organ transplantation. Due to its ability to induce oxidative stress and subsequent apoptosis, CP is affiliated with many adverse effects with special emphasis on the highly prevalent hepatotoxicity. Dipeptidyl peptidase 4 (DDP-IV) inhibitors are being rediscovered for new biological effects due to their ability to target multiple pathways, among which is the phosphoinositide 3-kinase (PI3K) and protein kinase B (Akt) axis. This could offer protection to multiple organs against reactive oxygen species (ROS) through modulating sirtuin 1 (SIRT1) expression and, in turn, inactivation of forkhead box transcription factor of the O class 1 (FoxO1), thus inhibiting apoptosis. Accordingly, the current study aimed to investigate the potential therapeutic benefit of alogliptin (Alo), a DPP-IV inhibitor, against CP-induced hepatotoxicity through enhancing PI3K/Akt/SIRT1 pathway. Forty male Wistar rats were randomly divided into four groups. The CP-treated group received a single dose of CP (200 mg/kg; i.p.). The Alo-treated group received Alo (20 mg/kg; p.o.) for 7 days with single CP injection on Day 2. Alo successfully reduced hepatic injury as witnessed through decreased liver function enzymes, increased phospho (p)-PI3K, p-Akt, superoxide dismutase (SOD) levels, SIRT1 expression, p-FoxO1 and anti-apoptotic B-cell lymphoma 2 (Bcl-2). This resulted in decreased apoptosis, as witnessed through decreased caspase-3 levels and improved histopathological picture. In conclusion, the current study succeeded to elaborate, for the first time, the promising impact of Alo in ameliorating chemotherapy-induced liver injury.

Population Pharmacokinetic, Pharmacogenetic, and Pharmacodynamic Analysis of Cyclophosphamide in Ethiopian Breast Cancer Patients

Cyclophosphamide (CPA) containing chemotherapy regimen is the standard of care for breast cancer treatment in sub-Saharan Africa. Wide inter-individual variations in pharmacokinetics (PK) of cyclophosphamide (CPA) influence the efficacy and toxicity of CPA containing chemotherapy. Data on the pharmacokinetics (PK) profile of CPA and its covariates among black African patients is lacking. We investigated population pharmacokinetic/pharmacogenetic/pharmacodynamic (PK-PG-PD) of CPA in Ethiopian breast cancer patients. During the first cycle of CPA-based chemotherapy, the population PK parameters for CPA were determined in 267 breast cancer patients. Absolute neutrophil count was recorded at baseline and day 20 post-CPA administration. A population PK and covariate model analysis was performed using non-linear mixed effects modeling. Semi-mechanistic and empiric drug response models were explored to describe the relationship between the area under concentration-time curve (AUC), and neutrophil toxicity. One compartment model better described CPA PK with population clearance and apparent volume of distribution (V_D) of 5.41 L/h and 46.5 L, respectively. Inter-patient variability in CPA clearance was 54.5%. Patients carrying CYP3A5*3 or *6 alleles had lower elimination rate constant and longer half-life compared to wild type carriers. CYP2C9 *2 or *3 carriers were associated with increased clearance of CPA. Patients who received 500 mg/m² based CPA regimen were associated with a 32.3% lower than average clearance and 37.1% lower than average V_D compared to patients who received 600 mg/m². A 0.1 m² unit increase in body surface area (BSA) was associated with a 5.6% increment in V_D. The mean V_D (33.5 L) in underweight group (BMI < 18.5 kg/m²) was significantly lower compared to those of overweight (48.1 L) or obese patients (51.9 L) (p < 0.001). AUC of CPA was positively correlated with neutropenic toxicity. In conclusion, we report large between-patient variability in clearance of CPA. CYP3A5 and CYP2C9 genotypes, BSA, BMI, and CPA dosage regimen influence PK of CPA. Plasma CPA exposure positively predicts chemotherapy-associated neutropenic toxicity.

Oxidative degradation of cyclophosphamide using thermal plasma activation and UV/H2O2 treatment in tap water

There is a growing concern about pharmaceuticals entering the aquatic environment. Many of these compounds cannot be removed completely in sewage treatment plants. To remove these unwanted medicines from water, oxidative degradation techniques may complement the current purification steps. In this paper we studied the effect of advanced oxidation on the cytostatic drug cyclophosphamide (CP) by comparing thermal plasma activation with UV/H₂O₂ treatment. Plasma activated water (PAW) contains highly reactive oxygen and nitrogen species (RONS) as a result of electric gas discharges in air over water. CP solutions in tap water were oxidized over a period of 120 min and subsequently analyzed by LC-MS/MS to measure the compound degradation. Plasma activation was applied at 50, 100, or 150 W electric power input and UV/H₂O₂ treatment was carried out by the addition of H₂O₂ and placing an UV-C source above the test solution for immediate irradiation. The oxidative degradation of CP in PAW resulted in a complete degradation within 80 min at 150 W. CP was also completely degraded within 60 min applying UV/H₂O₂ oxidation. Both treatment techniques do induce different structural changes, demonstrating that CP is completely degraded in tap water.

Severe and prolonged cyclophosphamide-induced hepatotoxicity in a breast cancer patient carrying a CYP2B6*7 variant

As a widely used alkylating agent, cyclophosphamide often leads to various toxicities. Severe hepatotoxicity has been rarely reported in breast cancer patients receiving chemotherapy containing cyclophosphamide. Differences in cyclophosphamide metabolism may contribute to variability in adverse events of patients. Here, we report on a case of a 68-year-old Chinese female with breast cancer who experienced severe and prolonged hepatotoxicity induced by cyclophosphamide. Pharmacogenetic tests showed that she was a carrier of CYP2B6*7 allele and this is the first case of a CYP2B6*7 variant in the Han Chinese population so far reported. In addition, the patient was also a carrier of an ALDH3A1*2 variant potentially contributing to the occurrence of hepatotoxicity. CYP2B6 and ALDH3A1 genotyping may play a role in guiding cyclophosphamide therapy.

Hepatic Sinusoidal Obstruction Syndrome in a Patient With Multiple Myeloma Treated With CyBorD

Hepatic sinusoidal obstruction syndrome (SOS) is a life-threatening state generally occurring as a complication of conditioning regimens used for hematopoietic stem cell transplant. Hepatic SOS after a standard dose of chemotherapy in malignancies is rare, and there are only a few cases in pediatric literature. We report a 56-year-old man with multiple myeloma who experienced SOS after being initiated on chemotherapy including cyclophosphamide, dexamethasone, and bortezomib and who experienced a delay in treatment with defibrotide, because it is currently approved by the Food and Drug Administration for only patients who develop SOS after hematopoietic stem cell transplant.

Genistein Ameliorates Cyclophosphamide - Induced Hepatotoxicity by Modulation of Oxidative Stress and Inflammatory Mediators

AIM:

The present study investigated the protective effect of the phytoestrogen, genistein (GEN), against (CP)-induced acute hepatotoxicity in rats.

MATERIAL AND METHODS:

Male adult rats were randomly assigned into five groups. Normal control group received the vehicles; CP group received a single dose of CP (200 mg/kg, i.p). The other three groups received subcutaneous GEN at doses of 0.5, 1 and 2 mg/kg/day, respectively, for 15 consecutive days prior CP injection. Sera and liver tissues were collected forty-eight hours after CP injection for assessment of liver function enzymes (ALT and AST) in rat sera, the hepatic oxidative/nitrosative biomarkers (GSH, MDA and NOx), hepatic interleukin-1β, and myeloperoxidase activity. Immunohistochemistry of cyclooxygenase-2 and histopathological examination of liver tissues were also conducted.

RESULTS:

The CP-induced acute liver damage was evidenced by elevated serum ALT and AST accompanied by increased hepatic oxidative stress and inflammatory biomarkers. Immunohistochemical outcomes revealed hepatic cyclooxygenase-2 expression in CP group with distortion of liver architecture. GEN-pretreatment significantly ameliorated the deterioration of liver function and exerted significant anti-oxidant and anti-inflammatory activity with a marked decline in hepatic cyclooxygenase-2 expression in a dose dependent-manner.

CONCLUSION:

The present study demonstrated that the antioxidant and anti-inflammatory activities of GEN might contribute to its protective effects against CP-induced liver damage.

Immunoassay approach for diagnosis of exposure to pyrrolizidine alkaloids

Numerous pyrrolizidine alkaloid (PA) poisoning cases have been documented worldwide. Protein covalent binding with reactive metabolites generated from metabolic activation of PAs to form pyrrole-protein adducts is suggested to be a primary mechanism of PA-induced toxicities. The present study aimed to develop antibodies for diagnosis of PA exposure. Polyclonal antibodies were raised in rabbits and proven to specifically recognize pyrrole-protein adducts regardless of amino acid residues modified by the reactive metabolites of PAs. The developed antibodies were successfully applied to detect pyrrole-protein adducts in blood samples obtained from PA-treated rats and exhibited a potential for the clinical diagnosis of PA exposure.

Enantioselectivity in the Metabolism of Cyclophosphamide in Patients With Multiple or Systemic Sclerosis

The aim of this study was to evaluate the enantioselective pharmacokinetics of cyclophosphamide and its metabolites 4-hydroxycyclophosphamide and carboxyethylphosphoramide mustard in patients with systemic or multiple sclerosis. Patients with systemic sclerosis (n = 10) or multiple sclerosis (n = 10), genotyped for the allelic variants of CYP2C9*2 and CYP2C9*3 and of the CYP2B6 G516T polymorphism, were treated with 50 mg cyclophosphamide/kg daily for 4 days. Serial blood samples were collected up to 24 hours after administration of the last cyclophosphamide dose. Cyclophosphamide, 4-hydroxycyclophosphamide, and carboxyethylphosphoramide enantiomers were analyzed in plasma samples using liquid chromatography-tandem mass spectrometry coupled to chiral column Chiralcel OD-R or Chiralpak AD-RH. Cytokines IL-2, IL-4, IL-6, IL-8, IL-10, IL- 12p70, IL-17, TNF-α, and INT-δ in the plasma samples collected before cyclophosphamide infusion were analyzed by Milliplex MAP human cytokine/chemokine. Pharmacokinetic parameters showed higher plasma concentrations of (S)-(-)-cyclophosphamide (AUC 215.0 vs 186.2 μg·h/mL for multiple sclerosis patients and 219.1 vs 179.2 μg·h/mL for systemic sclerosis patients) and (R)-4-hydroxycyclophosphamide (AUC 5.6 vs 3.7 μg·h/mL for multiple sclerosis patients and 6.3 vs 5.6 μg·h/mL for systemic sclerosis patients) when compared to their enantiomers in both groups of patients, whereas the pharmacokinetics of the carboxyethylphosphoramide metabolite was not enantioselective. Cytokines' plasma concentrations were similar between multiple and systemic sclerosis groups. The pharmacokinetics of cyclophosphamide is enantioselective in patients with systemic sclerosis and multiple sclerosis, with higher plasma concentrations of the (S)-(-)-cyclophosphamide enantiomer due to the preferential formation of the (R)-4-hydroxycyclophosphamide metabolite.

Gamma-Glutamylcysteine Ethyl Ester Protects against Cyclophosphamide-Induced Liver Injury and Hematologic Alterations via Upregulation of PPARγ and Attenuation of Oxidative Stress, Inflammation, and Apoptosis

Gamma-glutamylcysteine ethyl ester (GCEE) is a precursor of glutathione (GSH) with promising hepatoprotective effects. This investigation aimed to evaluate the hepatoprotective effects of GCEE against cyclophosphamide- (CP-) induced toxicity, pointing to the possible role of peroxisome proliferator activated receptor gamma (PPARγ). Wistar rats were given GCEE two weeks prior to CP. Five days after CP administration, animals were sacrificed and samples were collected. Pretreatment with GCEE significantly alleviated CP-induced liver injury by reducing serum aminotransferases, increasing albumin, and preventing histopathological and hematological alterations. GCEE suppressed lipid peroxidation and nitric oxide production and restored GSH and enzymatic antioxidants in the liver, which were associated with downregulation of COX-2, iNOS, and NF-κB. In addition, CP administration significantly increased serum proinflammatory cytokines and the expression of liver caspase-3 and BAX, an effect that was reversed by GCEE. CP-induced rats showed significant downregulation of PPARγ which was markedly upregulated by GCEE treatment. These data demonstrated that pretreatment with GCEE protected against CP-induced hepatotoxicity, possibly by activating PPARγ, preventing GSH depletion, and attenuating oxidative stress, inflammation, and apoptosis. Our findings point to the role of PPARγ and suggest that GCEE might be a promising agent for the prevention of CP-induced liver injury.

Cyclophosphamide pharmacokinetics and pharmacogenetics in children with B-cell non-Hodgkin's lymphoma

Introduction

Variation in cyclophosphamide pharmacokinetics and metabolism has been highlighted as a factor that may impact on clinical outcome in various tumour types. The current study in children with B-cell non-Hodgkin's lymphoma (NHL) was designed to corroborate previous findings in a large prospective study incorporating genotype for common polymorphisms known to influence cyclophosphamide pharmacology.

Methods

A total of 644 plasma samples collected over a 5 year period, from 49 B-cell NHL patients ≤18 years receiving cyclophosphamide (250 mg/m²), were used to characterise a population pharmacokinetic model. Polymorphisms in genes including CYP2B6 and CYP2C19 were analysed.

Results

A two-compartment model provided the best fit of the population analysis. The mean cyclophosphamide clearance value following dose 1 was significantly lower than following dose 5 (1.83 ± 1.07 versus 3.68 ± 1.43 L/h/m², respectively; mean ± standard deviation from empirical Bayes estimates; P < 0.001). The presence of at least one CYP2B6*6 variant allele was associated with a lower cyclophosphamide clearance following both dose 1 (1.54 ± 0.11 L/h/m² versus 2.20 ± 0.31 L/h/m², P = 0.033) and dose 5 (3.12 ± 0.17 L/h/m² versus 4.35 ± 0.37 L/h/m², P = 0.0028), as compared to homozygous wild-type patients. No pharmacokinetic parameters investigated were shown to have a significant influence on progression free survival.

Conclusion

The results do not support previous findings of a link between cyclophosphamide pharmacokinetics or metabolism and disease recurrence in childhood B-cell NHL. While CYP2B6 genotype was shown to influence pharmacokinetics, there was no clear impact on clinical outcome.

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The influence of cyclophosphamide clinical pharmacology on childhood cancer outcome has been investigated

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The presence of at least one CYP2B6*6 variant allele was associated with a lower rate of cyclophosphamide clearance

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Pharmacokinetic parameters investigated were not shown to have a marked influence on clinical outcome

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Findings do not support a link between cyclophosphamide metabolism and disease recurrence in B-cell non-Hodgkin's lymphoma

Ginseng alleviates cyclophosphamide-induced hepatotoxicity via reversing disordered homeostasis of glutathione and bile acid

Cyclophosphamide (CP), a chemotherapeutic agent, is restricted due to its side effects, especially hepatotoxicity. Ginseng has often been clinically used with CP in China, but whether and how ginseng reduces the hepatotoxicity is unknown. In this study, the hepatoprotective effects and mechanisms under the combined usage were investigated. It was found that ginseng could ameliorate CP-induced elevations of ALP, ALT, ALS, MDA and hepatic deterioration, enhance antioxidant enzymes’ activities and GSH’s level. Metabolomics study revealed that 33 endogenous metabolites were changed by CP, 19 of which were reversed when ginseng was co-administrated via two main pathways, i.e., GSH metabolism and primary bile acids synthesis. Furthermore, ginseng could induce expression of GCLC, GCLM, GS and GST, which associate with the disposition of GSH, and expression of FXR, CYP7A1, NTCP and MRP 3, which play important roles in the synthesis and transport of bile acids. In addition, NRF 2, one of regulatory elements on the expression of GCLC, GCLM, GS, GST, NTCP and MRP3, was up-regulated when ginseng was co-administrated. In conclusion, ginseng could alleviate CP-induced hepatotoxicity via modulating the disordered homeostasis of GSH and bile acid, which might be mediated by inducing the expression of NRF 2 in liver.

18β-Glycyrrhetinic acid exerts protective effects against cyclophosphamide-induced hepatotoxicity: potential role of PPARγ and Nrf2 upregulation

18β-Glycyrrhetinic acid (18β-GA) has been proposed as a promising hepatoprotective agent. The current study aimed to investigate the protective action and the possible mechanisms of 18β-GA against cyclophosphamide (CP)-induced liver injury in rats, focusing on the role of peroxisome proliferator-activated receptor gamma (PPARγ) and NF-E2-related factor-2 (Nrf2). Rats were administered 18β-GA at doses 25 and 50 mg/kg 2 weeks prior to CP injection. Five days after CP administration, animals were sacrificed and samples were collected. CP induced hepatic damage evidenced by the histopathological changes and significant increase in serum pro-inflammatory cytokines, liver marker enzymes, and liver lipid peroxidation and nitric oxide (NO) levels. 18β-GA counteracted CP-induced oxidative stress and inflammation as assessed by restoration of the antioxidant defenses and diminishing of pro-inflammatory cytokines, lipid peroxidation, and NO production. These hepatoprotective effects appear to depend on activation of Nrf2 and PPARγ, and subsequent suppression of nuclear factor-kappa B. In conclusion, the present study provides evidence that 18β-GA exerts hepatoprotective effects against CP through induction of antioxidant defenses and suppression of inflammatory response. This report also confers new information that 18β-GA protects liver against the toxic effect of chemotherapeutic alkylating agents via activation of Nrf2 and PPARγ.

Protective effect of astragalus polysaccharides on liver injury induced by several different chemotherapeutics in mice

Side effects are an unavoidable consequence of chemotherapy drugs, during which liver injury often takes place. The current study was designed to investigate the protective effect of Astragalus polysaccharides (APS) against the hepatotoxicity induced by frequently-used chemical therapy agents, cyclophosphamide (CTX), docetaxel (DTX) and epirubicin (EPI)) in mice. Mice were divided into five groups, controls, low or high dose groups (DTXL, CTXL, EPIL or DTXH, CTXH, EPIH), and low or high dose chemotherapeutics+APS groups (DTXL+APS, CTXL+APS, EPIL+APS or DTXH+APS, CTXH+APS, EPIH+APS). Controls were treated with equivalent normal saline for 28 days every other day; low or high dose group were intraperitoneal (i.p) injected with low or high doses of CTX, DTX and EPI for 28 days every other day; low or high dose chemotherapeutics+APS group were separately intraperitoneal (i.p) injected with chemotherapeutics for 28 days every other day and i.p with APS (100 mg/kg) for 7 days continually from the 22th to the 28th days. The body weight, serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), histopathological features, and ultrastructure morphological change of liver tissues, protein expression level of caspase-3 were estimated at different time points. With high dose treatment of DTX, CTX and EPI, weight gain was inhibited and serum levels of ALT and AST were significantly increased. Sections of liver tissue showed massive hepatotoxicity in CTXH group compared to the control group, including hepatic lobule disorder, granular and vacuolar degeneration and necrosis in hepatic cells. These changes were confirmed at ultrastructural level, including obvious pyknosis, heterochromatin aggregation, nuclear membrane resolution, and chondrosome crystal decrease. Western blotting revealed that the protein levels of caspase-3 increased in CTXH group. The low dose groups exhibited trivial hepatotoxicity. More interestingly, after 100 mg/kg APS, liver injury was redecued not only regarding serum transaminase activities (low or high dose chemotherapeutics+APS group), but also from pathological and ultrastructural changes and the protein levels of caspase-3 (CTXH+APS group). In conclusion, DTX, CTX and EPI induce liver damage in a dose dependent manner, whereas APS exerted protective effects.

The Hepatoprotective Effect of Haoqin Qingdan Decoction against Liver Injury Induced by a Chemotherapeutic Drug Cyclophosphamide

Haoqin Qingdan decoction (HQQD), a modern Chinese formula, has been widely used in Eastern Asia. Our study focuses on the hepatoprotective effect of HQQD against cyclophosphamide-induced hepatotoxicity. S180, a kind of ascites tumor cells, was used to establish S180-bearing mice, followed by the injection of cyclophosphamide (CP, 80 mg/kg) every other day for 5 times. HQQD was used intragastrically at the dose of 80 g/kg, 40 g/kg, and 20 g/kg twice a day for 12 days. HL-7702 hepatic cell line was incubated with HQQD-medicated serum. Then we detected the effects of HQQD on (i) tumor suppression; (ii) morphological examination; (iii) SOD, MDA, GSH, ALT, and AST; (iv) cleaved caspase-3 expression and (v) cellular viability. CP caused dramatic elevations of AST, ALT, and MDA, while HQQD notably attenuated these elevations. SOD and GSH were notably increased, which were efficiently attenuated by HQQD. CP injection significantly increased apoptosis by increasing cleaved caspase-3 expression, which was obviously inhibited by HQQD, accompanied by the improvement of cells viability. Histopathological examinations supported the above findings. Therefore, HQQD may protect liver tissue through attenuating oxidative stress and the caspase-3-dependent intrinsic apoptosis induced by CP, which suggests the potentially therapeutic effect of HQQD in the use of alkylating agent for cancer chemotherapy.

Pyrrolizidine Alkaloids: Potential Role in the Etiology of Cancers, Pulmonary Hypertension, Congenital Anomalies, and Liver Disease

Large outbreaks of acute food-related poisoning, characterized by hepatic sinusoidal obstruction syndrome, hemorrhagic necrosis, and rapid liver failure, occur on a regular basis in some countries. They are caused by 1,2-dehydropyrrolizidine alkaloids contaminating locally grown grain. Similar acute poisoning can also result from deliberate or accidental consumption of 1,2-dehydropyrrolizidine alkaloid-containing herbal medicines, teas, and spices. In recent years, it has been confirmed that there is also significant, low-level dietary exposure to 1,2-dehydropyrrolizidine alkaloids in many countries due to consumption of common foods such as honey, milk, eggs, salads, and meat. The level of 1,2-dehydropyrrolizidine alkaloids in these foods is generally too low and too intermittent to cause acute toxicity. However, these alkaloids are genotoxic and can cause slowly developing chronic diseases such as pulmonary arterial hypertension, cancers, cirrhosis, and congenital anomalies, conditions unlikely to be easily linked with dietary exposure to 1,2-dehydropyrrolizidine alkaloids, especially if clinicians are unaware that such dietary exposure is occurring. This Perspective provides a comprehensive review of the acute and chronic toxicity of 1,2-dehydropyrrolizidine alkaloids and their potential to initiate certain chronic diseases, and suggests some associative considerations or indicators to assist in recognizing specific cases of diseases that may have resulted from dietary exposure to these hazardous natural substances. If it can be established that low-level dietary exposure to 1,2-dehydropyrrolizidine alkaloids is a significant cause of some of these costly and debilitating diseases, then this should lead to initiatives to reduce the level of these alkaloids in the food chain.

Hesperidin protects against cyclophosphamide-induced hepatotoxicity by upregulation of PPARγ and abrogation of oxidative stress and inflammation

The most important reason for the non-approval and withdrawal of drugs by the Food and Drug Administration is hepatotoxicity. Therefore, this study was undertaken to evaluate the protective effects of hesperidin against cyclophosphamide (CYP)-induced hepatotoxicity in Wistar rats. The rats received a single intraperitoneal dose of CYP of 200 mg/kg body mass, followed by treatment with hesperidin, orally, at doses of 25 and 50 mg/kg for 11 consecutive days. CYP induced hepatic damage, as evidenced by the significantly elevated levels of serum pro-inflammatory cytokines, serum transaminases, liver lipid peroxidation, and nitric oxide. As a consequence, there was reduced glutathione content, and the activities of the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase, were markedly reduced. In addition, CYP administration induced a considerable downregulation of peroxisome proliferator activated receptor gamma (PPARγ) and upregulation of nuclear factor-kappa B (NF-κB) and inducible nitric oxide synthase (iNOS) mRNA expression. Hesperidin, in a dose-dependent manner, rejuvenated the altered markers to an almost normal state. In conclusion, hesperidin showed a potent protective effect against CYP-induced oxidative stress and inflammation leading to hepatotoxicity. The study suggests that hesperidin exerts its protective effect against CYP-induced hepatotoxicity through upregulation of hepatic PPARγ expression and abrogation of inflammation and oxidative stress.

Peroxisome Proliferator Activator Receptor (PPAR)- γ Ligand, but Not PPAR- α , Ameliorates Cyclophosphamide-Induced Oxidative Stress and Inflammation in Rat Liver

Hepatoprotective potential of peroxisome proliferator activator receptor (PPAR)-α and -γ agonists, fenofibrate (FEN), and pioglitazone (PIO), respectively, against cyclophosphamide (CP)-induced toxicity has been investigated in rat. FEN and PIO (150 and 10 mg/kg/day, resp.) were given orally for 4 weeks. In separate groups, CP (150 mg/kg, i.p.) was injected as a single dose 5 days before the end of experiment, with or without either PPAR agonist. CP induced hepatotoxicity, as it caused histopathological alterations, with increased serum alanine and aspartate transaminases, total bilirubin, albumin, alkaline phosphatase and lactate dehydrogenase. CP caused hepatic oxidative stress, indicated by decrease in tissue reduced glutathione, with increase in malondialdehyde and nitric oxide levels. CP also caused decrease in hepatic antioxidant enzyme levels, including catalase, superoxide dismutase, glutathione peroxidase, and glutathione S-transferase. Furthermore, CP increased serum and hepatic levels of the inflammatory marker tumor necrosis factor (TNF)-α, evaluated using ELISA. Preadministration of PIO, but not FEN, prior to CP challenge improved hepatic function and histology, and significantly reversed oxidative and inflammatory parameters. In conclusion, activation of PPAR-γ, but not PPAR-α, conferred protection against CP-induced hepatotoxicity, via activation of antioxidant and anti-inflammatory mechanisms, and may serve as supplement during CP chemotherapy.

Low-dose cyclophosphamide-induced acute hepatotoxicity

Patient: Male, 48

Final Diagnosis: Low dose cyclophosphamide-induced acute hepatotoxicity

Symptoms: Epigastric pain

Medication: Withdrawal of cyclophosphamide

Clinical Procedure: —

Specialty: Nephrology • Hepatology • Gastroenterology • Toxicology

Two difficulty diagnosis cases of severe veno-occlusive disease

Backgroud

The occurrence of Hepatic veno-occlusive disease (VOD) is rale liver disease. However, severe VOD is often lethal and one of the most common causes of death following stem cell transplantation (SCT).

Case Reports:

Case 1 was a 30-year-old woman who was diagnosed as Budd-Chiari syndrome with liver failure. She was admitted to our department to undergo liver transplantation. Four days after admission, she underwent liver transplantation. Her liver explant showed VOD. Case 2 was a 74-year-old woman who was admitted to a community hospital for further examination. Her condition continued to deteriorate with liver failure, and she died 39 days after admission. Liver autopsy also showed VOD. Either of the patients had difficulty in diagnose as VOD. Neither of the patients had a history of SCT.

Conclusions:

VOD should be considered as a cause of acute hepatic failure, even if the patient has no history of SCT.

A phase I/II study of CY and topotecan in patients with high-risk malignancies undergoing autologous hematopoietic cell transplantation: the St Jude long-term follow-up

Fifty-eight consecutive children with high-risk malignancies were treated with CY, and targeted topotecan followed by autologous hematopoietic cell transplantation (AHCT) in a phase I/II Institutional Review Board-approved study. Twelve participants enrolled in phase I; 5 received dose level 1 of topotecan 3 mg/m(2) per day, with subsequent doses targeted to total systemic exposure of 100±20 ng h/mL and CY 750 mg/m(2) per day. Seven participants received dose level 2. CY dose escalation to 1 g/m(2) per day was considered excessively toxic; one died from irreversible veno-occlusive disease and two experienced reversible hepatotoxicity. These adverse events halted further dose escalation. A total of 46 participants were enrolled in phase II; results are on the 51 participants who received therapy at dose level 1, the maximum tolerated dose. Diagnoses included neuroblastoma (26), sarcoma (9), lymphoma (8), brain tumors (5), Wilms (2) and retinoblastoma (1). Twenty participants (39.3%) were in CR1 at enrollment; median age was 5.1 years. Most common non-hematological grade III-IV toxicity was gastrointestinal (n=37). Neutrophil and platelet engraftment occurred at a median of 15 and 24 days, respectively. Twenty-six (51%) participants remain alive at a median of 6.4 years after AHCT. CY 3.75 g/m(2), and targeted topotecan followed by AHCT are feasible and produce acceptable toxicity in children with high-risk malignancies.

Pyrrolizidine alkaloids in food: a spectrum of potential health consequences

Contamination of grain with 1,2-dehydropyrrolizidine ester alkaloids (dehydroPAs) and their N-oxides is responsible for large incidents of acute and subacute food poisoning, with high morbidity and mortality, in Africa and in central and south Asia. Herbal medicines and teas containing dehydroPAs have also caused fatalities in both developed and developing countries. There is now increasing recognition that some staple and widely consumed foods are sometimes contaminated by dehydroPAs and their N-oxides at levels that, while insufficient to cause acute poisoning, greatly exceed maximum tolerable daily intakes and/or maximum levels determined by a number of independent risk assessment authorities. This suggests that there may have been cases of disease in the past not recognised as resulting from dietary exposure to dehydroPAs. A review of the literature shows that there are a number of reports of liver disease where either exposure to dehydroPAs was suspected but no source was identified or a dehydroPA-aetiology was not considered but the symptoms and pathology suggests their involvement. DehydroPAs also cause progressive, chronic diseases such as cancer and pulmonary arterial hypertension but proof of their involvement in human cases of these chronic diseases, including sources of exposure to dehydroPAs, has generally been lacking. Growing recognition of hazardous levels of dehydroPAs in a range of common foods suggests that physicians and clinicians need to be alert to the possibility that these contaminants may, in some cases, be a possible cause of chronic diseases such as cirrhosis, pulmonary hypertension and cancer in humans.

Management of uncommon chemotherapy-induced emergencies

Chemotherapy can induce various clinical emergencies. Prompt recognition and management of these adverse events are important for avoiding further morbidity and mortality. Some events such as hypersensitivity and extravasation are quite common, whereas emergencies such as neutropenic typhlitis, pancreatitis, and acute haemolysis are very rare. Little information exists on the management of rare chemotherapy-induced emergencies that affect fewer than 1% of patients. We review these uncommon chemotherapy-induced life-threatening emergencies, their pathogenesis and management, and recommendations for rechallenge with the offending chemotherapy.

Personalized dosing of cyclophosphamide in the total body irradiation-cyclophosphamide conditioning regimen: a phase II trial in patients with hematologic malignancy

This study investigates the efficacy and safety of personalized cyclophosphamide (CY) dosing in 50 patients receiving CY along with total body irradiation (TBI). Participants received CY 45 mg/kg with subsequent therapeutic drug monitoring using Bayesian parameter estimation to personalize the second CY dose to a target area under the curve (AUC) for carboxyethylphosphoramide mustard (CEPM) (a reporter molecule for CY-derived toxins) and for hydroxycyclophosphamide (to ensure engraftment). The mean second CY dose was 66 mg/kg; the total dose ranged from 45 to 145 mg/kg. After completion of this phase II study, we compared participants' clinical outcomes with those of concurrent controls (n = 100) who received TBI along with standard CY doses of 120 mg/kg. Patients receiving personalized CY dosing had significantly lower postconditioning peak total serum bilirubin (P = 0.03); a 38% reduction in the hazard of acute kidney injury (AKI) (P = 0.03); and nonrelapse and overall survival rates similar to those in the controls (P = 0.70 and 0.63, respectively) despite the lower doses of CY administered to most of the patients in the personalized dosage group.

Relations between polymorphisms in drug-metabolising enzymes and toxicity of chemotherapy with cyclophosphamide, thiotepa and carboplatin

PURPOSE

High-dose chemotherapy with cyclophosphamide, thiotepa and carboplatin (CTC) has been developed as a possible curative treatment modality in several solid tumours. However, a large interindividual variability in toxicity is encountered in high-dose chemotherapy. A priori identification of patients at risk for toxicity could be an attractive prospect. Genotyping of genes encoding drug-metabolising enzymes might provide such a tool.

EXPERIMENTAL DESIGN

We assessed 16 selected polymorphisms in nine genes (CYP2B6, CYP2C9, CYP2C19, CYP3A4, CYP3A5, GSTA1, GSTP1, ALDH1A1 and ALDH3A1) of putative relevance in CTC metabolism using polymerase chain reaction and DNA sequencing in 113 patients who were treated with high-dose chemotherapy regimens based on CTC.

RESULTS

Patients heterozygous for the ALDH3A1*2 allele (allelic frequency 21.2%) had an increased risk of haemorrhagic cystitis when compared with patients with wild-type alleles [5/38 vs. 1/70; odds ratio (OR): 11.95, 95% confidence interval (CI): 1.18-120.56; P=0.04]. Furthermore, patients heterozygous for the ALDH1A1*2 allele (allelic frequency 5.8%) had an increased risk of liver toxicity when compared with patients with wild-type alleles (6/13 vs. 19/99; OR: 5.13, 95% CI: 1.30-20.30; P=0.02). No other relations reached significance.

CONCLUSION

Patients heterozygous for the ALDH3A1*2 and ALDH1A1*2 allele have an increased risk of haemorrhagic cystitis and liver toxicity, respectively, compared with patients with wild-type alleles when treated with a high-dose chemotherapy combination of CTC. Pharmacogenetic approaches can identify patients who are at risk of experiencing toxic side effects in high-dose chemotherapy.

Sirolimus is associated with veno-occlusive disease of the liver after myeloablative allogeneic stem cell transplantation

Sirolimus is an effective agent used in graft-versus-host disease (GVHD) prophylaxis after allogeneic transplantation. It also has antiproliferative effects on vascular endothelium when used to coat coronary artery stents. We noted an excess of veno-occlusive disease (VOD) in a clinical trial, and retrospectively reviewed the records of 488 patients to determine the association between sirolimus and VOD. When used with cyclophosphamide/total body irradiation (Cy/TBI) conditioning, sirolimus is associated with an increased incidence of VOD (OR 2.35, P = .005). The concomitant use of methotrexate further increased this rate (OR 3.23, P < .001), while sirolimus without methotrexate was not associated with an increased risk of VOD (OR 1.55, P = .33). Mortality after VOD diagnosis was unaffected, and overall treatment-related mortality was lowest when sirolimus was used without methotrexate. Similar findings were noted in matched, related, and unrelated as well as mismatched donor subgroups. When used with busulfan-based conditioning, sirolimus use was associated with an even higher rate of VOD (OR 8.8, P = .008). Our findings suggest that sirolimus use is associated with VOD after TBI-based transplantation when used with methotrexate after transplantation. Sirolimus-based GVHD prophylaxis without methotrexate is associated with the greatest overall survival. Myeloablative doses of busulfan should not be used with sirolimus-based immunosuppression.

Population pharmacokinetics of cyclophosphamide and metabolites in children with neuroblastoma: a report from the Children's Oncology Group

Cyclophosphamide-based regimens are front-line treatment for numerous pediatric malignancies; however, current dosing methods result in considerable interpatient variability in tumor response and toxicity. In this pediatric population, the authors' objectives were (1) to quantify and explain the pharmacokinetic variability of cyclophosphamide and 2 of its metabolites, hydroxycyclophosphamide (HCY) and carboxyethylphosphoramide mustard (CEPM), and (2) to apply a population pharmacokinetic model to describe the disposition of cyclophosphamide and these metabolites. A total of 196 blood samples were obtained from 22 children with neuroblastoma receiving intravenous cyclophosphamide (400 mg/m2/d) and topotecan. Blood samples were quantitated for concentrations of cyclophosphamide, HCY, and CEPM using liquid chromatography-mass spectrometry and analyzed using nonlinear mixed-effects modeling with the NONMEM software system. After model building was complete, the area under the concentration-time curve (AUC) was computed using NONMEM. Cyclophosphamide elimination was described by noninducible and inducible routes, with the latter producing HCY. Glomerular filtration rate was a covariate for the fractional elimination of HCY and its conversion to CEPM. Considerable interpatient variability was observed in the AUC of cyclophosphamide, HCY, and CEPM. These results represent a critical first step in developing pharmacokinetic-linked pharmacodynamic studies in children receiving cyclophosphamide to determine the clinical relevance of the pharmacokinetic variability in cyclophosphamide and its metabolites.

Population pharmacokinetics and pharmacodynamics of doxorubicin and cyclophosphamide in breast cancer patients: a study by the EORTC-PAMM-NDDG

AIMS

To investigate the population pharmacokinetics and pharmacodynamics of doxorubicin and cyclophosphamide in breast cancer patients.

PATIENTS AND METHODS

Sixty-five female patients with early or advanced breast cancer received doxorubicin 60 mg/m(2) over 15 minutes followed by cyclophosphamide 600 mg/m(2) over 15 minutes. The plasma concentration-time data of both drugs were measured, and the relationship between drug pharmacokinetics and neutrophil counts was evaluated using nonlinear mixed-effect modelling. Relationships were explored between drug exposure (the area under the plasma concentration-time curve [AUC]), toxicity and tumour response.

RESULTS

Fifty-nine patients had complete pharmacokinetic and toxicity data. In 50 patients with measurable disease, the objective response rate was 60%, with complete responses in 6% of patients. Both doxorubicin and cyclophosphamide pharmacokinetics were associated with neutrophil toxicity. Cyclophosphamide exposure (the AUC) was significantly higher in patients with at least stable disease (n = 44) than in patients with progressive disease (n = 6; 945 micromol . h/L [95% CI 889, 1001] vs 602 micromol . h/L [95% CI 379, 825], p = 0.0002). No such correlation was found for doxorubicin. Body surface area was positively correlated with doxorubicin clearance; AST and patient age were negatively correlated with doxorubicin clearance; creatinine clearance was positively correlated with doxorubicinol clearance; and occasional concurrent use of carbamazepine was positively correlated with cyclophosphamide clearance.

CONCLUSIONS

The proposed inhibitory population pharmacokinetic-pharmacodynamic model adequately described individual neutrophil counts after administration of doxorubicin and cyclophosphamide. In this patient population, exposure to cyclophosphamide, as assessed by the AUC, might have been a predictor of the treatment response, whereas exposure to doxorubicin was not. A prospective study should validate cyclophosphamide exposure as a predictive marker for the treatment response and clinical outcome in this patient group.

Hepatic veno-occlusive disease after hematopoietic stem cell transplantation: update on defibrotide and other current investigational therapies

Hepatic veno-occlusive disease (VOD), also known as sinusoidal obstruction syndrome (SOS), remains one of the most serious and common complications after myeloablative hematopoietic stem cell transplantation (HSCT). Clinical diagnosis of hepatic VOD is based on the clinical triad of (1) painful hepatomegaly, (2) hyperbilirubinemia and (3) unexplained fluid retention. While milder cases usually resolve spontaneously, severe VOD is associated with a grim prognosis. Defibrotide (DF), a polydisperse mixture of single-stranded oligonucleotide with antithrombotic and fibrinolytic effects on microvascular endothelium, has emerged as an effective and safe therapy for patients with severe VOD. Multiple studies, including a recent large international multicenter phase II clinical trial, have demonstrated 30-60% complete remission rates with DF, even among patients with severe VOD and multiorgan failure. This article will review our current understanding of hepatic VOD, and update the clinical trial experience with DF and other potential therapies for this feared transplant complication.

Cancer chemotherapy II: atypical hepatic injuries

Although chemotherapy generally is accompanied by regular testing for liver enzyme abnormalities, atypical reactions may occur that escape ordinary detection, because hepatocyte injury is not the primary event. The presence of fatty liver, mitochondrial changes, and even biliary abnormalities can be associated with normal or nearly normal liver enzyme levels. This article discusses unique aspects of liver damage associated with cancer chemotherapy. These unique reactions merit special attention and a special vigilance from clinicians.

Fluconazole coadministration concurrent with cyclophosphamide conditioning may reduce regimen-related toxicity postmyeloablative hematopoietic cell transplantation

In a previous study comparing fluconazole and itraconazole administered as antifungal prophylaxis in hematopoietic cell transplant (HCT) recipients, we found that fluconazole administration concurrent with cyclophosphamide (CY)-based conditioning was associated with fewer early toxicities compared to itraconazole. Fluconazole inhibits cytochrome P450 2C9, which is involved with the activation of CY, and so might provide protection from CY-related toxicities. To investigate this further, we compared CY and CY-metabolite data from patients who received fluconazole (n = 56) concurrent with CY-containing conditioning and in patients who did not (n = 17). The fluconazole group had greater exposure to CY, and lower peak serum concentration of CY-metabolite 4-hydroxycyclophosphamide. In a separate cohort, we examined outcomes in patients randomized to receive either fluconazole (n = 152) or placebo (n = 147) concurrent with CY-containing conditioning in a prior randomized trial. Patients who received fluconazole experienced less hepatic and renal toxicity, and had lower mortality. No difference in relapsed malignancy was apparent. These data support the hypothesis that fluconazole, when coadministered with CY, decreases CY-related toxicities by inhibiting cytochrome P450 2C9 metabolism.