Feasibility of multiple courses of high-dose cyclophosphamide, thiotepa, and carboplatin for breast cancer or germ cell cancer

Measurement of ThioTEPA and Its Metabolite TEPA in Plasma and Cerebrospinal Fluid by Turbulent Flow Chromatography-Tandem Mass Spectrometry

N,N',N''-Triethylenethiophosphoramide (thioTEPA) is a polyfunctional, organophosphorus alkylating agent that has been a primary treatment of multiple solid malignancies for many years and more recently as part of conditioning regimens prior to hematopoietic stem cell transplantation for a variety of hematologic malignancies. In vivo, thioTEPA is quickly metabolized to N,N',N″-triethylenephosphoramide (TEPA). ThioTEPA and TEPA have similar alkylating activity and both exhibit outstanding central nervous system penetration. Therefore, it is possible and desirable to monitor both compounds in plasma and cerebrospinal fluid (CSF).This chapter describes a method to measure both compounds simultaneously. ThioTEPA and TEPA are extracted with solvent from plasma and CSF by the addition of deuterated internal standards prepared in methanol. Chromatographic separation is attained using a C18 column and mass spectrometry which is performed in the positive ion mode. Herein, we describe a fast, accurate, and sensitive assay to quantify both compounds in plasma and CSF by turbulent flow LC-MS/MS which allows for fast and accurate therapeutic drug monitoring and timely dose modifications.

Hematopoietic stem cell mobilization strategies to support high-dose chemotherapy: A focus on relapsed/refractory germ cell tumors

High-dose chemotherapy (HDCT) with autologous hematopoietic stem cell transplantation has been explored and has played an important role in the management of patients with high-risk germ cell tumors (GCTs) who failed to be cured by conventional chemotherapy. Hematopoietic stem cells (HSCs) collected from the peripheral blood, after appropriate pharmacologic mobilization, have largely replaced bone marrow as the principal source of HSCs in transplants. As it is currently common practice to perform tandem or multiple sequential cycles of HDCT, it is anticipated that collection of large numbers of HSCs from the peripheral blood is a prerequisite for the success of the procedure. Moreover, the CD34+ cell dose/kg of body weight infused after HDCT has proven to be a major determinant of hematopoietic engraftment, with patients who receive > 2 × 10⁶ CD34+ cells/kg having consistent, rapid, and sustained hematopoietic recovery. However, many patients with relapsed/refractory GCTs have been exposed to multiple cycles of myelosuppressive chemotherapy, which compromises the efficacy of HSC mobilization with granulocyte colony-stimulating factor with or without chemotherapy. Therefore, alternative strategies that use novel agents in combination with traditional mobilizing regimens are required. Herein, after an overview of the mechanisms of HSCs mobilization, we review the existing literature regarding studies reporting various HSC mobilization approaches in patients with relapsed/refractory GCTs, and finally report newer experimental mobilization strategies employing novel agents that have been applied in other hematologic or solid malignancies.

Thrombotic microangiopathy, cancer, and cancer drugs

Thrombotic microangiopathy (TMA) is a complication that can develop directly from certain malignancies, but more often results from anticancer therapy. Currently, the incidence of cancer drug-induced TMA during the last few decades is >15%, primarily due to the introduction of anti-vascular endothelial growth factor (VEGF) agents. It is important for clinicians to understand the potential causes of cancer drug-induced TMA to facilitate successful diagnosis and treatment. In general, cancer drug-induced TMA can be classified into 2 types. Type I cancer drug-induced TMA includes chemotherapy regimens (ie, mitomycin C) that can potentially promote long-term kidney injury, as well as increased morbidity and mortality. Type II cancer drug-induced TMA includes anti-VEGF agents that are not typically associated with cumulative dose-dependent cell damage. In addition, functional recovery of kidney function often occurs after drug interruption, assuming a type I agent was not given prior to or during therapy. There are no randomized controlled trials to provide physician guidance in the management of TMA. However, previously accumulated information and research suggest that endothelial cell damage has an underlying immunologic basis. Based on this, the emerging trend includes the use of immunosuppressive agents if a refractory or relapsing clinical course that does not respond to plasmapheresis and steroids is observed.

Probing the binding of thioTEPA to human serum albumin using spectroscopic and molecular simulation approaches

The present work is devoted to probing the molecular interaction of N,N′,N″-triethylenethiophosphoramide (thioTEPA) with human serum albumin (HSA) using UV-visible and fluorescence spectroscopies. Further, molecular dynamics and molecular docking simulations were used to investigate the binding site of thioTEPA. The outcomes of the spectroscopic observations and also the Stern−Volmer and van’t Hoff equations were employed to determine the binding thermodynamic parameters. It was found out that the interaction of thioTEPA with HSA is enthalpy driven through a quenching mechanism that is both static and dynamic at domain I of HSA. No significant changes in the local and overall secondary structure, polarity, and hydrophobicity of HSA were observed. The low values of binding free energies and binding constants are evidence for necessary high dosage of thioTEPA in chemotherapies. These results may be attributed to the spherical geometry and steric hindrance of the free vibrating aziridinyl groups of thioTEPA.

A phase II trial of high-dose chemotherapy (HDCT) supported by hematopoietic stem-cell transplantation (HSCT) in germ-cell tumors (GCTs) patients failing cisplatin-based chemotherapy: the Multicentric TAXIF II study

BACKGROUND

High-dose chemotherapy (HDCT) is an effective salvage treatment of germ-cell tumors (GCTs) patients. In the first salvage setting, 30%-70% of patients may achieve durable remissions. Even when HDCT is administered as subsequent salvage treatment, up to 20% of patients may still be definitively cured. However, patients with refractory/relapsed disease still have a very poor long-term prognosis, requiring earlier intervention of HDCT.

PATIENTS AND METHODS

This phase II trial was addressed to nonrefractory patients failing Cisplatin-based chemotherapy. Inclusion criteria included seminomatous GCT in relapse after two lines of chemotherapy, nonseminomatous GCT in relapse after first or second lines, partial remission after first line, primary mediastinal GCT in first relapse. Patients received two cycles combining Epirubicin and Paclitaxel (Epi-Tax), followed by three consecutive HDCT, one using a Paclitaxel/Thiotepa (Thio-Tax) association and two using the 5-day Ifosfamide-Carboplatin-Etoposide regimen. The main objective was to determine the complete response rate.

RESULTS

Forty-five patients were included between September 2004 and December 2007: 44 received the first HDCT cycle, 39 two HDCT cycles, 29 could receive the whole protocol. Sixteen patients did not receive the entire protocol, including eight (17.7%) for toxic side-effects. Two patients (4.4%) died of toxicities, and 17 (37.7%) of disease progression. With a median follow-up time of 26 months (range, 4-51), the final overall response rate was 48.8% (including a complete response rate of 15.5% and a partial response/negative serum markers rate of 26.6%) in an intent-to-treat analysis. The median progression-free survival (PFS) and overall survival (OS) times were 22 months [95% confidence interval (CI) 2-not reached] and 32 months (95% CI 4-49), respectively. The 2-year PFS was a plateau setup at 50% (95% CI 32-67) and the 2-year OS was 66% (95% CI 44-81).

CONCLUSION

The TAXIF II protocol was effective in nonrefractory GCT patients failing Cisplatin-based chemotherapy. The toxic death rate remained acceptable in the field of HDCT regimens.

TRIAL REGISTRATION NUMBER

NCT00231582.

High Dose Thiotepa in Patients with Relapsed or Refractory Osteosarcomas: Experience of the SFCE Group

Introduction. Osteosarcoma relapse has a poor prognosis, with less than 25% survival at 5 years. We describe the experience of the French Society of Paediatric Oncology (SFCE) with high dose (HD) thiotepa and autologous stem cell transplantation (ASCT) in 45 children with relapsed osteosarcoma. Patients and Methods. Between 1992 and 2004, 53 patients received HD thiotepa (900 mg/m²) followed by ASCT in 6 centres. Eight patients were excluded from analysis, and we retrospectively reviewed the clinical radiological and anatomopathological patterns of the 45 remaining patients. Results. Sixteen girls and 29 boys (median age, 15.9 years) received HD thiotepa after initial progression of metastatic disease (2), first relapse (26), and second or third relapse (17). We report 12 radiological partial responses and 9 of 31 histological complete responses. Thirty-two patients experienced further relapses, and 13 continued in complete remission after surgical resection of the residual disease. Three-year overall survival was 40%, and 3-year progression-free survival was 24%. Delay of relapse (+/− 2 years from diagnosis) was a prognostic factor (P = 0.011). No acute toxic serious adverse event occurred. Conclusion. The use of HD thiotepa and ASCT is feasible in patients with relapsed osteosarcoma. A randomized study for recurrent osteosarcoma between standard salvage chemotherapy and high dose thiotepa with stem cell rescue is ongoing.

Intensified chemotherapy with stem-cell rescue in germ-cell tumors

BACKGROUND

Based on the high chemosensitivity of germ-cell tumors (GCTs), the concept of high-dose chemotherapy (HDCT) has been developed worldwide and investigated through many clinical trials. It has been carried out in different clinical settings, ranging from resistant or absolute refractory disease to chemosensitive relapse. HDCT with stem-cell support has been also explored as a part of first-line strategy for poor-prognosis patients.

PATIENTS AND METHODS

Our review summarized results from clinical trials evaluating the role of HDCT in patients with advanced GCTs. So far available data were obtained through a Medline search of English-language literature.

RESULTS

Several phase II trials and retrospective series have shown a possible benefit for GCT patients with recurrent disease as well as in first-line setting. Despite these results, data derived from randomized phase III studies failed to demonstrate any survival advantage for HDCT over conventional chemotherapy.

CONCLUSIONS

The role of HDCT in GCTs remains controversial. We need new prospective studies based on prognostic factors with multiple transplants of carboplatin and etoposide as the preferred high dose regimen. At present, based mainly on retrospective and phase II studies, HDCT may represent a therapeutic option for patients with primary refractory disease or for those with a second or further relapse.

An aCGH classifier derived from BRCA1-mutated breast cancer and benefit of high-dose platinum-based chemotherapy in HER2-negative breast cancer patients

BACKGROUND

Breast cancer cells deficient for BRCA1 are hypersensitive to agents inducing DNA double-strand breaks (DSB), such as bifunctional alkylators and platinum agents. Earlier, we had developed a comparative genomic hybridisation (CGH) classifier based on BRCA1-mutated breast cancers. We hypothesised that this BRCA1-like(CGH) classifier could also detect loss of function of BRCA1 due to other causes besides mutations and, consequently, might predict sensitivity to DSB-inducing agents.

PATIENTS AND METHODS

We evaluated this classifier in stage III breast cancer patients, who had been randomly assigned between adjuvant high-dose platinum-based (HD-PB) chemotherapy, a DSB-inducing regimen, and conventional anthracycline-based chemotherapy. Additionally, we assessed BRCA1 loss through mutation or promoter methylation and immunohistochemical basal-like status in the triple-negative subgroup (TN subgroup).

RESULTS

We observed greater benefit from HD-PB chemotherapy versus conventional chemotherapy among patients with BRCA1-like(CGH) tumours [41/230 = 18%, multivariate hazard ratio (HR) = 0.12, 95% confidence interval (CI) 0.04-0.43] compared with patients with non-BRCA1-like(CGH) tumours (189/230 = 82%, HR = 0.78, 95% CI 0.50-1.20), with a significant difference (test for interaction P = 0.006). Similar results were obtained for overall survival (P interaction = 0.04) and when analyses were restricted to the TN subgroup. Sixty-three percent (20/32) of assessable BRCA1-like(CGH) tumours harboured either a BRCA1 mutation (n = 8) or BRCA1 methylation (n = 12).

CONCLUSION

BRCA1 loss as assessed by CGH analysis can identify patients with substantially improved outcome after adjuvant DSB-inducing chemotherapy when compared with standard anthracycline-based chemotherapy in our series.

Rapid and complete resolution of chemotherapy-induced thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS) with rituximab

PURPOSE

Gemcitabine-induced thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS) is a well described, albeit rare, complication, which is associated with a high morbidity and mortality. Treatment with standard TTP/HUS therapies such as plasma exchange, and cessation of gemcitabine is often unsuccessful. The purpose of this report is to describe the successful treatment of gemcitabine-induced TTP/HUS with rituximab, a CD20 monoclonal antibody that has been used for the treatment of refractory idiopathic TTP/HUS.

METHODS

We describe the clinical course and follow-up of a patient who developed gemcitabine-induced TTP/HUS, did not respond to cessation of gemcitabine, administration of plasma exchanges, and intravenous glucocorticoids, but responded to rituximab.

RESULTS

TTP/HUS responded rapidly and resolved completely with two courses (8 doses) of intravenous rituximab. In three of four reported cases (including the current report), rituximab was rapidly effective in resolving chemotherapy-induced TTP/HUS that was refractory to plasma exchanges and glucocorticoids.

CONCLUSIONS

Rituximab may be indicated for early treatment of chemotherapy-induced TTP/HUS, particularly when plasma exchange is not rapidly effective.

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.

Polymorphisms of drug-metabolizing enzymes (GST, CYP2B6 and CYP3A) affect the pharmacokinetics of thiotepa and tepa

AIMS

Thiotepa is widely used in high-dose chemotherapy. Previous studies have shown relations between exposure and severe organ toxicity. Thiotepa is metabolized by cytochrome P450 and glutathione S-transferase enzymes. Polymorphisms of these enzymes may affect elimination of thiotepa and tepa, its main metabolite. The purpose of this study was to evaluate effects of known allelic variants in CYP2B6, CYP3A4, CYP3A5, GSTA1 and GSTP1 genes on pharmacokinetics of thiotepa and tepa.

METHODS

White patients (n = 124) received a high-dose regimen consisting of cyclophosphamide, thiotepa and carboplatin as intravenous infusions. Genomic DNA was analysed using polymerase chain reaction and sequencing. Plasma concentrations of thiotepa and tepa were determined using validated GC and LC-MS/MS methods. Relations between allelic variants and elimination pharmacokinetic parameters were evaluated using nonlinear mixed effects modelling (nonmem).

RESULTS

The polymorphisms CYP2B6 C1459T, CYP3A4*1B, CYP3A5*3, GSTA1 (C-69T, G-52A) and GSTP1 C341T had a significant effect on clearance of thiotepa or tepa. Although significant, most effects were generally not large. Clearance of thiotepa and tepa was predominantly affected by GSTP1 C341T polymorphism, which had a frequency of 9.3%. This polymorphism increased non-inducible thiotepa clearance by 52% [95% confidence interval (CI) 41, 64, P < 0.001] and decreased tepa clearance by 32% (95% CI 29, 35, P < 0.001) in heterozygous patients, which resulted in an increase in combined exposure to thiotepa and tepa of 45% in homozygous patients.

CONCLUSIONS

This study indicates that the presently evaluated variant alleles explain only a small part of the substantial interindividual variability in thiotepa and tepa pharmacokinetics. Patients homozygous for the GSTP1 C341T allele may have enhanced exposure to thiotepa and tepa.

Influence of polymorphisms of drug metabolizing enzymes (CYP2B6, CYP2C9, CYP2C19, CYP3A4, CYP3A5, GSTA1, GSTP1, ALDH1A1 and ALDH3A1) on the pharmacokinetics of cyclophosphamide and 4-hydroxycyclophosphamide

PURPOSE

The anticancer agent, cyclophosphamide, is metabolized by cytochrome P450 (CYP), glutathione S-transferase (GST) and aldehyde dehydrogenase (ALDH) enzymes. Polymorphisms of these enzymes may affect the pharmacokinetics of cyclophosphamide and thereby its toxicity and efficacy. The purpose of this study was to evaluate the effects of known allelic variants in the CYP2B6, CYP2C9, CYP2C19, CYP3A4, CYP3A5, GSTA1, GSTP1, ALDH1A1 and ALDH3A1 genes on the pharmacokinetics of the anticancer agent, cyclophosphamide, and its active metabolite 4-hydroxycyclophosphamide.

EXPERIMENTAL DESIGN

A cohort of 124 Caucasian patients received a high-dose chemotherapy combination consisting of cyclophosphamide (4-6 g/m2), thiotepa (320-480 mg/m2) and carboplatin (area under the curve 13-20 mg x min/ml) as intravenous infusions over 4 consecutive days. Genomic DNA was analysed using PCR and sequencing. Liquid chromatography-tandem mass spectrometry was used to measure plasma concentrations of cyclophosphamide and 4-hydroxycyclophosphamide. The relationship between allelic variants and the elimination pharmacokinetic parameters noninducible cyclophosphamide clearance (CL(nonind)), inducible cyclophosphamide clearance (CL(ind)) and elimination rate constant of 4-hydroxycyclophosphamide (k(4OHCP)) were evaluated using nonlinear mixed effects modelling.

RESULTS

The interindividual variability in the noninducible cyclophosphamide clearance, inducible cyclophosphamide clearance and 4-hydroxycyclophosphamide clearance was 23, 27 and 31%, respectively. No effect of the allelic variants investigated on the clearance of cyclophosphamide or 4-hydroxycyclophosphamide could be demonstrated.

CONCLUSION

This study indicates that the presently evaluated variant alleles in the CYP2B6, CYP2C9, CYP2C19, CYP3A4, CYP3A5, GSTA1, GSTP1, ALDH1A1 and ALDH3A1 genes do not explain the interindividual variability in cyclophosphamide and 4-hydroxycyclophosphamide pharmacokinetics and are, probably, not the cause of the observed variability in toxicity.

Carbamazepine induces bioactivation of cyclophosphamide and thiotepa

PURPOSE

We report a patient with metastatic breast cancer who received three cycles of high-dose chemotherapy with cyclophosphamide [1,000 mg/(m(2) day)], thiotepa (80 mg/(m(2) day) and carboplatin (dose calculated based on modified Calvert formula with 3.25 mg min/ml as daily target AUC) over 4 days, followed by peripheral blood progenitor cell support. During the first two cycles the patient concomitantly used carbamazepine for the treatment of epilepsy. Due to severe nausea and vomiting the patient was unable to ingest carbamazepine; therefore, this was discontinued after the second cycle.

METHODS

Blood samples were drawn on 2 days (day 1 and 2, 3 or 4) of each cycle and plasma levels of cyclophosphamide, its active metabolite 4-hydroxycyclophosphamide, thiotepa, its main, active metabolite tepa and carboplatin were determined.

RESULTS

Exposure to 4-hydroxycyclophosphamide and tepa on day 1 was increased in the presence of carbamazepine (58 and 75%, respectively), while exposure to cyclophosphamide and thiotepa was reduced (40 and 43%, respectively).

CONCLUSION

Since increased exposure to the active metabolites is associated with an increased risk of toxicity, it is important to be aware of this drug-drug interaction.

Evaluation of the COM.TEC cell separator in predicting the yield of harvested CD34+ cells

BACKGROUND

This multicenter study was performed with the intention to evaluate the exactness of the predicted CD34+ cell yield calculated by two leukapheresis programs of the cell separator COM.TEC upon the number of donor's circulating CD34+ cells and the blood volume processed.

STUDY DESIGN AND METHODS

Patients and healthy donors (n = 166) received mobilization by chemotherapy and/or granulocyte colony-stimulating factor and underwent CD34+ cell harvest by the leukapheresis programs MNC or RV-PBSC (n = 203).

RESULTS

CD34+ cells were collected by 112 harvests on MNC and by 91 collections on RV-PBSC. The median collection efficiency of CD34+ cells was significantly better for the program MNC than for RV-PBSC (p < 0.001): 67% (31-109) vs. 42% (19-100). The collected CD34+ cell yield was in median more exactly by MNC than by RV-PBSC (p < 0.001): 85% (31-176) vs. 59% (22-110) of the predicted value. Concentrates obtained by RV-PBSC showed in median significantly higher percentages of mononuclear cells (p < 0.001) and CD34+ cells (p < 0.001), 86% (43-99) vs. 56% (25-95) and 1.2% (0.2-14.3) vs. 0.4% (0.1-6.0), and had lower contaminations by erythrocytes (p < 0.001) and platelets (p < 0.001), 13 mL (4-48) vs. 25 mL (5-60) and 1.9 x 1011 vs. 3.1 x 1011, than those harvested by MNC.

CONCLUSION

The significantly better collection efficiency of CD34+ cells and the more exact prediction of the harvested CD34+ cell yield make the leukapheresis program MNC a safe and efficient procedure. However, concentrates collected by RV-PBSC are of a better cellular quality with a significantly higher percentage of mononuclear and CD34+ cells and a lower contamination by erythrocytes and platelets.

Population pharmacokinetics of cyclophosphamide and its metabolites 4-hydroxycyclophosphamide, 2-dechloroethylcyclophosphamide, and phosphoramide mustard in a high-dose combination with Thiotepa and Carboplatin

The anticancer prodrug cyclophosphamide (CP) is activated by the formation of 4-hydroxycyclophosphamide (4OHCP), which decomposes into phosphoramide mustard (PM). This activation pathway is inhibited by thiotepa. CP is inactivated by formation of 2-dechloroethylcyclophosphamide (2DCECP). The aim of this study was to develop a population pharmacokinetic model describing the complex pharmacokinetics of CP, 4OHCP, 2DCECP, and PM when CP is administered in a high-dose combination with thiotepa and carboplatin. Patients received a combination of CP (1000-1500 mg/m/d), carboplatin (265-400 mg/m/d), and thiotepa (80-120 mg/m/d) administered in short infusions over 4 days. Twenty blood samples were collected per patient per course. Concentrations of CP, 4OHCP, 2DCECP, PM, thiotepa, and tepa were determined in plasma. Using NONMEM, an integrated population pharmacokinetic model was used to describe the pharmacokinetics of CP, 4OHCP, 2DCECP, and PM, including the already described processes of autoinduction of CP and the interaction with thiotepa. Data were available on 35 patients (70 courses). The pharmacokinetics of CP were described with a 2-compartment model, and those of 4OHCP, 2DCECP, and PM with 1-compartment models. Before onset of autoinduction, it was assumed that CP is eliminated through a noninducible pathway accounting for 20% of total CP clearance, whereas 2 inducible pathways resulted in formation of 4OHCP (75%) and 2DCECP (5%). It was assumed that 4OHCP was fully converted to PM. Induction of CP metabolism was mediated by 2 hypothetical amounts of enzyme whose quantities increased in time in the presence of CP (kenz=0.0223 and 0.0198 hours). Induction resulted in an increased formation of 4OHCP (approximately 50%), PM (approximately 50%), and 2DCECP (approximately 35%) during the 4-day course, and concomitant decreased exposure to CP (approximately 50%). The formation of 2DCECP was not inhibited by thiotepa. Apparent volumes of distribution of CP, PM, and 2DCECP could be estimated being 43.7, 55.5, and 18.5 L, respectively. Exposure to metabolites varied up to 9-fold. The complex population pharmacokinetics of CP, 4OHCP, 2DCECP, and PM in combination with thiotepa and carboplatin has been established and may form the basis for further treatment optimization with this combination.

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

We investigated whether the occurrence of veno-occlusive disease of the liver (VOD) may be associated with individual variations in the pharmacokinetics of high-dose cyclophosphamide. Patients received single or multiple courses of cyclophosphamide (1000 or 1500 mg m-2 day-1), thiotepa (80 or 120 mg m-2 day-1) and carboplatin (265-400 mg m-2 day-1) (CTC) for 4 consecutive days. The area under the plasma concentration-time curves (AUCs) were calculated for cyclophosphamide and its activated metabolites 4-hydroxycyclophosphamide and phosphoramide mustard based on multiple blood samples. Possible relationships between the AUCs and the occurrence of VOD were studied. A total of 59 patients (115 courses) were included. Four patients experienced VOD after a second CTC course. The first-course AUC of 4-hydroxycyclophosphamide (P=0.003) but not of phosphoramide mustard (P=0.101) appeared to be predictive of the occurrence of VOD after multiple courses. High exposures to bioactivated cyclophosphamide may lead to increased organ toxicity.

High dose chemotherapy with autologous hematopoietic stem cell support for solid tumors other than breast cancer in adults

Since the early 1980s high dose chemotherapy with autologous hematopoietic stem cell support was adopted by many oncologists as a potentially curative option for solid tumors, supported by a strong rationale from laboratory studies and apparently convincing results of early phase II studies. As a result, the number and size of randomized trials comparing this approach with conventional chemotherapy initiated (and often abandoned before completion) to prove or disprove its value was largely insufficient. In fact, with the possible exception of breast carcinoma, the benefit of a greater escalation of dose of chemotherapy with stem cell support in solid tumors is still unsettled and many oncologists believe that this approach should cease. In this article, we critically review and comment on the data from studies of high dose chemotherapy so far reported in adult patients with small cell lung cancer, ovarian cancer, germ cell tumors and sarcomas.

Sparse Sampling Design for Therapeutic Drug Monitoring of Sequentially Administered Cyclophosphamide, Thiotepa, and Carboplatin (CTC)

The alkylating agents cyclophosphamide, thiotepa, and carboplatin (CTC) are administered simultaneously in high-dose chemotherapy regimens. This regimen is sometimes complicated by severe organ toxicities, which may be caused by interindividual variability in the pharmacokinetics of the agents. Monitoring plasma levels and adapting doses may reduce variability in exposure to the compounds and their metabolites. The aim of this study was to develop and validate a sparse sampling design for routine dose individualization of cyclophosphamide, thiotepa, and carboplatin both during and between courses in the CTC regimen. Models describing the population pharmacokinetics of the prodrug cyclophosphamide (4000 or 6000 mg/m) and its activated metabolite 4-hydroxycylophosphamide, thiotepa (320 or 480 mg/m), and its equipotent metabolite tepa, and carboplatin (1067 or 1600 mg/m) in the 4-day CTC regimen have been developed previously using the program NONMEM. Based on these models, plasma concentrations were calculated in 20 groups of 50 simulated patients in each group during multiple courses of therapy, and the exposure, expressed as area under the plasma concentration-versus-time curve (AUC), was calculated. Subsequently, individual model-predicted AUCs were calculated for all courses, based on selected simulated plasma concentrations during the first course of therapy. Strategies were compared by assessment of their predictive performance of the AUC and their applicability in clinical practice. Withdrawal of 3 samples on the first day of the course at 190, 290, and 400 minutes after start of cyclophosphamide infusion resulted in unbiased and precise first course AUC predictions of 4-hydroxycylophosphamide, thiotepa and tepa, and carboplatin (precision [root mean squared relative prediction error, %RMSE] 20%, 16%, 8.8%, respectively). Applying this same strategy at day 3 (or 4) of the course, with an additional sample at 600 minutes on both days, resulted in unbiased and precise predictions of the AUC of a following course (%RMSE 21%, 18%, 17%, respectively). Prospective validation of the strategies in 23 additional patients yielded comparable results. It can be concluded that a good and useful sparse sampling design was developed for precise and accurate estimation of the AUCs of 4-hydroxycyclophosphamide, thiotepa and tepa, and carboplatin in the CTC regimen. This method is valuable in pharmacokinetically guided dose adaptation both during and between CTC courses.

Aprepitant inhibits cyclophosphamide bioactivation and thiotepa metabolism

BACKGROUND

Patients receiving the highly emetogenic high-dose chemotherapy regimen with cyclophosphamide, thiotepa and carboplatin (CTC) may benefit from the neurokin-1 receptor antagonist aprepitant in addition to standard anti-emetic therapy. As aprepitant has been shown to be a moderate inhibitor of the cytochrome P450 (CYP) 3A4 isoenzyme, its effect on the pharmacokinetics and metabolism of cyclophosphamide and thiotepa was evaluated. Moreover, preliminary results on the clinical efficacy of aprepitant in the CTC regimen are reported.

PATIENTS AND METHODS

Six patients were enrolled in a protocol that employed a 4-day course of CTC high-dose chemotherapy with cyclophosphamide (1,500 mg/m2/day), thiotepa (120 mg/m2/day) and carboplatin (AUC 5 mg min/ml/day). Two patients received the tCTC protocol, which comprises two-third of the dose of CTC. In addition to standard anti-emetic therapy, the patients received aprepitant from one day before the start of their course until 3 days after chemotherapy. Blood samples were collected on days one and three of the course and analyzed for cyclophosphamide and its activated metabolite 4-hydroxycyclophosphamide, thiotepa and its main active metabolite tepa. The influence of aprepitant on the pharmacokinetics of cyclophosphamide and thiotepa was analyzed using a population pharmacokinetic analysis including a reference population of 49 patients receiving the same chemotherapy regimen without aprepitant and sampled under the same conditions. The frequency of nausea and vomiting in the six patients receiving CTC was compared with those of the last 22 consecutive patients receiving CTC chemotherapy without aprepitant. Inhibitory activity of aprepitant on cyclophosphamide and thiotepa metabolism was also tested in human liver microsomes.

RESULTS

In our patient population, the rate of autoinduction of cyclophosphamide (P=0.040) and the formation clearance of tepa (P<0.001) were reduced with 23% and 33% when aprepitant was co-administered, respectively. Exposures to the active metabolite 4-hydroxycyclophosphamide and tepa were therefore reduced (5% and 20%, respectively) in the presence of aprepitant. In human liver microsomes, the 50% inhibitory concentrations (IC50) of aprepitant for inhibition of cyclophosphamide (IC50=1.3 microg/ml) and thiotepa (IC50=0.27 microg/ml) metabolism were within the therapeutic range. Patients receiving aprepitant experienced less frequently CINV both during and after the CTC course compared with the reference population (nausea 3.7 days vs. 5.8 days, P=0.052; vomiting 0.5 days vs. 4.8 days, P<0.001).

CONCLUSION

Aprepitant inhibited both cyclophosphamide and thiotepa metabolism, most probably due to inhibition of the CYP 3A4 and/or 2B6 isoenzymes. The effects of this interaction are, however, small compared to the total variability. Addition of aprepitant may provide superior protection against vomiting in patients receiving the highly emetogenic high-dose CTC chemotherapy.

Significant induction of cyclophosphamide and thiotepa metabolism by phenytoin

PATIENT AND METHOD

A 42-year-old male patient with relapsing germ-cell cancer was enrolled in a salvage protocol that employed two 4-day courses of CTC high-dose chemotherapy with cyclophosphamide (1,500 mg m(-2) day(-1)), thiotepa (120 mg m(-2) day(-1)), and carboplatin, followed by peripheral blood progenitor cell support. From five days before the start of the second CTC course the patient received phenytoin for generalized epileptic seizures. Blood samples were collected on day 1 of both CTC courses and analyzed for cyclophosphamide and its activated metabolite 4-hydroxycyclophosphamide, and for thiotepa and its main active metabolite tepa.

RESULTS

Exposure (expressed as area under the plasma concentration vs time curve) to 4-hydroxycyclophosphamide and tepa in the second CTC course was increased by 51% and 115%, respectively, compared with the first CTC course, whereas exposure to cyclophosphamide and thiotepa was significantly reduced (67% and 29%, respectively). Because high exposure to 4-hydroxycyclophosphamide and tepa correlates with increased toxicity, the treatment risk of this patient was significantly increased. Therefore doses were reduced on the third day of the second course.

CONCLUSION

It was concluded that phenytoin significantly induces both cyclophosphamide and thiotepa metabolism, most probably by induction of the cytochrome p450 enzyme system. This potential clinical significant interaction should be taken into account when phenytoin is administered in combination with cyclophosphamide and thiotepa in clinical practice.

Sequential high-dose chemotherapy protocol for relapsed poor prognosis germ cell tumors combining two mobilization and cytoreductive treatments followed by three high-dose chemotherapy regimens supported by autologous stem cell transplantation. Results of the phase II multicentric TAXIF trial

BACKGROUND

High-dose chemotherapy (HD-CT) is able to circumvent platinum resistance of resistant/refractory germ-cell tumors (GCTs), but expectancy of cure remains low. New strategies are needed with new drugs and a sequential approach.

MATERIALS AND METHODS

Patients with relapsed poor-prognosis GCTs were scheduled to receive two cycles combining epirubicin and paclitaxel (Taxol) followed by three consecutive HD-CT supported by stem cell transplantation [one course combining cyclophosphamide, 3 g/m(2) + thiotepa, 400 mg/m(2), followed by two ICE regimens (ifosfamide, 10 g/m(2), carboplatin, AUC 20, etoposide, 1500 mg/m(2))].

RESULTS

From March 1998 to September 2001 (median follow-up, 31.8 months), 45 patients (median age, 28 years) were enrolled in this phase II study. Twenty-two patients received the complete course. Twenty-five patients died from progression and five from toxicity. The overall response rate was 37.7%, including an 8.9% complete response rate. The median overall survival was 11.8 months. The 3-year survival and progression-free survival rate was 23.5%. The 'Beyer' prognostic score predicted the outcome after HD-CT.

CONCLUSION

Although our results warrant further studies on HD-CT in relapsed poor prognosis GCTs, patients with a Beyer score >2 did not benefit from this approach and should not be enrolled in HD-CT trials. Better selection criteria have to be fulfilled in forthcoming studies.

Integrated Population Pharmacokinetic Model of both cyclophosphamide and thiotepa suggesting a mutual drug-drug interaction

PURPOSE/AIMS

Cyclophosphamide (CP) and thiotepa (TT) are frequently administered simultaneously in high-dose chemotherapy regimens. The prodrug CP shows strong autoinduction resulting in increased formation of its activated metabolite 4-hydroxycyclophosphamide (4OHCP). TT inhibits this bioactivation of CP. Previously, we successfully modelled CP bioactivation and the effect of TT on the autoinduction. Recently we suggested that CP may also induce the conversion of TT in to its metabolite tepa (T). The aim of the current study was to investigate whether the influence of CP on TT metabolism can be described with a population pharmacokinetic model and whether this interaction can be incorporated in an integrated model describing both CP and TT pharmacokinetics.

METHODS

Plasma samples were collected from 49 patients receiving 86 courses of a combination of high-dose CP (4000 or 6000 mg/m2), TT (320 or 480 mg/m2) and carboplatin (1067 or 1600 mg/m2) given in short infusions during four consecutive days. For each patient, approximately 20 plasma samples were available per course. Concentrations of CP, 4OHCP, TT and T were determined using GC and HPLC. Kinetic data were processed using NONMEM.

RESULTS

The pharmacokinetics of TT and T were described with a two-compartment model. TT was eliminated through a non-inducible and an inducible pathway, the latter resulting information of T (ClindTT = 12.4 l/hr, ClnonindTT = 17.0 l/hr). Induction of TT metabolism was mediated by a hypothetical amount of enzyme, different from that involved in CP induction, whose amount increased with time in the presence of CP. The amount of enzyme followed a zero-order formation and a decrease with a first-order elimination rate constant of 0.0343 hr(-1) (t1/2 = 20 hr). This model was significantly better than a model lacking the induction by CP. The model was successfully incorporated into the previously published pharmacokinetic model for CP, and resulted in comparable parameter estimates for this compound and its metabolite 4OHCP.

CONCLUSION

The pharmacokinetics of TT, when administered in combination with CP, were successfully described. The model confirms induction of TT metabolism with time and it appears likely that CP is responsible for this phenomenon. The existence of a mutual pharmacokinetic interaction between CP and TT, as described in our integrated model, may be relevant in clinical practice.

Accuracy, Feasibility, and Clinical Impact of Prospective Bayesian Pharmacokinetically Guided Dosing of Cyclophosphamide, Thiotepa, and Carboplatin in High-Dose Chemotherapy

Purpose: Relationships between toxicity and pharmacokinetics have been shown for cyclophosphamide, thiotepa, and carboplatin (CTC) in high-dose chemotherapy. We prospectively evaluated whether variability in exposure to CTC and their activated metabolites can be decreased with pharmacokinetically guided dose administration and evaluated its clinical effect.

Experimental Design: Patients received multiple 4-day courses of cyclophosphamide (1,000–1,500 mg/m2/d), thiotepa (80–120 mg/m2/d), and carbop latin (area under the plasma concentration-time curve 3.3–5 mg × min/mL/d). Doses were adapted on day 3 based on pharmacokinetic analyses of cyclophosphamide, 4-hydroxycyclophosphamide, thiotepa, tepa, and carboplatin done on day 1 using a Bayesian algorithm. Doses were also adjusted before and during second and third courses. Observed toxicity was compared with that in patients receiving standard dose CTC (n = 43).

Results: A total of 46 patients (108 courses) were included. For cyclophosphamide, thiotepa, and carboplatin, a total of 39, 58, and 65 dose adaptations were done within courses and 17, 40, and 43 before courses. The precision within which the target exposure was reached improved compared with no adaptation, especially after within-course adaptations (precision for cyclophosphamide, thiotepa, and carboplatin is 19%, 16%, and 13%, respectively); &gt;85% led to an exposure within ±25% of the target compared with 60% without dose adjustments. Toxicity was similar to that in a reference population, although the incidence of veno-occlusive disease was reduced.

Conclusions: Bayesian pharmacokinetically guided dosing for CTC was feasible and led to a marked reduction in variability of exposure.

High-dose chemotherapy with haematopoietic stem cell transplantation for metastatic breast cancer patients: final results of the French multicentric randomised CMA/PEGASE 04 protocol

The aim of our study was to evaluate the impact on time to progression (TTP) and overall survival (OS) of high-dose chemotherapy (HD-CT) over conventional CT in metastatic breast cancer patients. Between 09/92 and 12/96, 61 patients with chemosensitive metastatic breast cancer were randomised between HD-CT using the CMA regimen (Mitoxantrone, Cyclophosphamide, Melphalan) applied as consolidation (32 patients) or maintenance CT (29 patients). At randomisation, 13 patients were in complete response, 47 in partial response and one had stable disease. The median TTPs from randomisation were 6 and 12 months in the standard and intensive groups, respectively (P < 0.0056), with a relapse rate of 86.2% vs. 62.5% at 2 years, and 100% vs. 81.3% at 5 years. The median OS times were 19.3 and 44.1 months, with an OS rate of 13.8% vs. 36.8% at 5 years (P < 0.0294). The CMA regimen could prolong the TTP of patients with chemosensitive metastatic breast cancer. Further studies are needed to determine if this translates into an effect on OS.

Stem-cell transplantation for the treatment of advanced solid tumors

Over the past two decades, high-dose chemotherapy (HDC) with autologous stem-cell transplantation (ASCT) has been explored for a variety of solid tumors in adults, particularly breast cancer, ovarian cancer and non-seminomatous germ-cell tumors. The results of prospective phase II studies seemed superior in many cases to the outcome expected with standard-dose chemotherapy (SDC). The value of HDC for adult solid tumors remains, in most instances, a controversial issue, currently under the scrutiny of randomized phase III trial evaluation. ASCT pursuing an immune graft-versus-tumor effect has been evaluated in recent years for patients with advanced and refractory solid malignancies. This article reviews the results of the main phase II and III studies of HDC with ASCT, as well as the preliminary experience using allogeneic transplantation for solid tumors.

Toxicity of the high-dose chemotherapy CTC regimen (cyclophosphamide, thiotepa, carboplatin): the Netherlands Cancer Institute experience

High-dose chemotherapy (HD-CT) has a role in the potentially curative treatment of several tumours. The relative efficacies of the different regimens have not been studied in comparative trials, but it is clear that toxicities differ significantly between them. We analysed the immediate and long-term toxicity in the first 100 consecutive patients treated with the CTC regimen (cyclophosphamide 6000 mg m(-2), carboplatin 1600 mg m(-2) (or 20 mg ml(-1) min under the curve (AUC)) both as daily 1 h infusion, thiotepa 480 mg m(-2) as twice daily 30 min infusion, all divided over 4 consecutive days) followed by peripheral blood progenitor cell reinfusion (PBPC-Tx). Most patients had high-risk (n=86) or metastatic (n=4) breast cancer, or a germ cell tumour (n=8). Two patients (with a medulloblastoma and an aesthesioneuroblastoma, respectively) received CTC as off-protocol salvage regimen. The main toxicity was bone marrow suppression. Most patients had PBPC-Tx with granulocyte colony-stimulating factor (G-CSF), and the median time to neutrophil count 500 x 10(6) l(-1) and platelet count >20 x 10(9) l(-1) without transfusion independence was 10 (range 8-25) and 13 (8-60) days, respectively. The toxic death rate was 1%. Other frequent toxicities were neutropenic fever requiring antibiotics (n=65), central catheter-related infection (n=12) or a bleeding episode (n=48), mostly epistaxis (n=26). Reversible cardiac toxicity was seen in six patients and pulmonary events occurred in seven patients (infection (n=6), embolism (n=1)). Grade 3-4 gastrointestinal toxicity was frequent: nausea and vomiting 55%, diarrhoea 28% and mild liver toxicity (transaminase elevations) 9%. One patient pretreated with cisplatin had a kidney transplantation 8 years after HD-CT. Late complications included reversible radiation pneumonitis (n=12) and chronic heart failure (n=2). We found five second solid malignancies and two myelodysplasias. In conclusion, the CTC regimen is associated with a moderate, mainly reversible, toxicity. Future studies need to compare the efficacy and toxicity of the different HD-CT regimens.

Leukapheresis after high-dose chemotherapy and autologous peripheral blood progenitor cell transplantation: a novel approach to harvest a second autograft

BACKGROUND

Autologous peripheral blood progenitor cells (PBPCs) are usually collected after the administration of conventional-dose chemotherapy (CDCT) and growth factors. However, there are no data available concerning the collection of PBPCs after high-dose chemotherapy (HDCT) and autologous hematopoietic transplantation in a larger series.

STUDY DESIGN AND METHODS

Patients (n = 30) underwent leukapheresis for PBPC harvest after CDCT. After HDCT and autografting, the collection of a second PBPC autograft was attempted.

RESULTS

Leukapheresis was performed after CDCT in all cases at a median of 118 CD34+ cells per microL (range, 18-589) and resulted in 6.4 x 10(6) CD34+ cells per kg (range, 1.7-29.0). After HDCT and autografting, 24 patients (80%) underwent secondary leukapheresis, although they had a significantly lower median of peripheral blood (PB) CD34+ cells (30/microL; range, 10-171; p < 0.001). In these patients a median of 3.6 x 10(6) CD34+ cells per kg (range, 1.6-10.1) was collected in the post-transplantation course. In the remaining six patients (20%) with PB CD34+ cells < 10 per microL, no PBPC harvesting was performed. These so-called poor mobilizers had received significantly less CD34+ cells for autologous transplantation than patients with successful post-HDCT mobilization (median, 2.5 x 10(6)/kg [range, 1.7-3.0] vs. 6.5 x 10(6)/kg [range, 3.2-19.6]; p < 0.001).

CONCLUSION

Collection of PBPCs is possible in most patients during the recovery phase of hematopoiesis after HDCT plus autografting, and the number of circulating PBPCs may be related to the CD34+ cell dose transfused by the preceding autograft.

A phase I/II study of 4 monthly courses of high-dose cyclophosphamide and thiotepa for metastatic breast cancer patients

This pilot phase I/II study intended to determine the maximum tolerated dose of cyclophosphamide and thiotepa administered on four consecutive courses with peripheral blood progenitor cell and granulocyte-colony stimulating factor support, as first-line therapy for hormone-refractory metastatic breast cancer patients. Twenty-eight patients were entered in the study. After two courses of epirubicin (120 mg m(-2)) and cyclophosphamide (2 g m(-2)) followed by granulocyte-colony stimulating factor injection and leukaphereses, patients received four cycles of cyclophosphamide and thiotepa. Each cycle was followed by peripheral blood progenitor cell and granulocyte-colony stimulating factor supports, then repeated every 28 to 35 days. Six escalating dose levels of cyclophosphamide and thiotepa were planned, beginning at cyclophosphamide 1.5 g m(-2) and thiotepa 200 mg m(-2). At least three patients were enrolled for each dose level. Eighteen patients completed the study. The maximum tolerated dose was 3000 mg m(-2) cyclophosphamide and 400 mg m(-2) thiotepa per course. Haematological toxicity was manageable on an outpatient basis and did not increase significantly with dose escalation. Dose-limiting toxicity was chemotherapy-induced immunosuppression, which resulted in one toxic death and two life-threatening infections. Median times to treatment failure and survival were 11 and 26 months, respectively. Three patients were alive, free of disease 30 months after completion of the study. Such therapy allows for high-dose intensity and high cumulative doses on a short period of time with manageable toxicity.

Relationship between irreversible alopecia and exposure to cyclophosphamide, thiotepa and carboplatin (CTC) in high-dose chemotherapy

Reversible alopecia is a commonly observed, important and distressing complication of chemotherapy. Permanent alopecia, however, is rare after standard-dose therapy, but has occasionally been observed after high-dose chemotherapy with cyclophosphamide, thiotepa and carboplatin (CTC). We evaluated the relationships between total exposure to these three compounds and their different metabolites in the high-dose CTC regimen, and the subsequent development of irreversible alopecia. Twenty-four patients received two or three courses of high-dose CTC, each followed by peripheral blood progenitor cell transplantation. Plasma levels of cyclophosphamide, its active metabolite 4-hydroxycyclophosphamide, thiotepa, its active metabolite tepa, and carboplatin were determined, and the area-under-the-plasma concentration-versus-time curves (AUC) of the compounds were calculated. Eight of the 24 patients included in the study developed permanent alopecia, while seven had normal hair regrowth and nine patients developed incomplete and/or thin hair regrowth. The carboplatin AUC and the summed AUC of thiotepa and tepa were both significantly associated with increasing irreversibility of hair loss. These results suggest that high exposure to carboplatin and the sum of the thiotepa and tepa exposure may lead to the development of permanent alopecia. This knowledge could guide therapeutic drug monitoring in order to prevent the occurrence of permanent alopecia and thereby improve the patients' quality of life.

Relationship between exposure and toxicity in high-dose chemotherapy with cyclophosphamide, thiotepa and carboplatin

BACKGROUND

High-dose chemotherapy in combination with peripheral blood progenitor cell transplantation is widely used in the treatment of several malignancies. The use of high-dose chemotherapy can be complicated by the occurrence of severe and sometimes life threatening toxicity. A wide interpatient variability in toxicity is encountered, which may be caused by variability in the pharmacokinetics of the agents. The aim of this study was to establish the pharmacokinetics of cyclophosphamide, thiotepa, carboplatin and all relevant metabolites in a widely used high-dose combination and to study possible relationships between the pharmacokinetics and toxicity.

PATIENTS AND METHODS

Blood samples were collected from patients treated with modifications of the CTCb regimen consisting of cyclophosphamide (1000-1500 mg/m2/day), carboplatin (265-400 mg/m2/day) and thiotepa (80-120 mg/m2/day) as short infusions for four consecutive days. Thiotepa and its main metabolite tepa, ultrafilterable carboplatin, cyclophosphamide and its activated metabolites 4-hydroxycyclophosphamide and phosphoramide mustard were determined. Pharmacokinetics were assessed with the use of population pharmacokinetic analyses. Relationship between the area under the concentration-time curves (AUCs) of these compounds and toxicity were tested.

RESULTS

A total of 46 patients (83 courses of chemotherapy) was included. Relationships were identified between elevation of transaminases and the thiotepa and tepa AUC, mucositis and the tepa AUC and ototoxicity and the carboplatin AUC. A strong trend between the 4-hydroxycyclophosphamide AUC and veno-occlusive disease was found.

CONCLUSIONS

The complex pharmacokinetics of the different agents and their metabolites have been established and several relationships between the pharmacokinetics and toxicity were identified. These findings may form the basis for further treatment optimisation and dose-individualisation in this high-dose chemotherapy combination.

Reinfusion of autologous lymphocytes with granulocyte-macrophage colony-stimulating factor induces rapid recovery of CD4+ and CD8+ T cells after high-dose chemotherapy for metastatic breast cancer

PURPOSE

Repeated high-dose chemotherapy (HDCT) followed by peripheral-blood progenitor cell (PBPC) transplantation can induce a complete remission in patients with metastatic breast cancer sensitive to standard chemotherapy (CT), but the majority of patients relapse within 1 to 2 years. The immune system is seriously compromised after HDCT, which precludes the development of effective immunotherapy. We investigated whether autologous lymphocytes, reinfused after HDCT, could induce a rapid recovery of T cells.

PATIENTS AND METHODS

Three patients were monitored for immune recovery without reinfusion of lymphocytes. In the next 11 patients, stem cells were harvested after CT + granulocyte colony-stimulating factor (G-CSF) and lymphocytes were harvested after CT + granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-2. These patients received stem cells and G-CSF after the first HDCT; stem cells, G-CSF, and lymphocytes after the second; and stem cells, GM-CSF, and lymphocytes after the third HDCT.

RESULTS

Patients not receiving lymphocyte reinfusion had a very slow recovery of lymphocytes. In particular, CD4 counts remained low (< 200/microL for 9 months). Lymphocyte reinfusion had a significant effect on the recovery of lymphocytes, T cells, and CD8+ T cells (normalized on day 25). Recovery of CD4+ T cells was significantly accelerated by lymphocyte reinfusion and GM-CSF, leading to counts of 500/microL at 25 days.

CONCLUSION

Lymphocyte reinfusion with G-CSF had a significant effect on the recovery of CD8+ T cells, whereas rapid recovery of CD4+ T cells required lymphocyte reinfusion and GM-CSF, which possibly acts as a survival factor through activation of antigen presenting cells. Whether the rapid recovery of CD4+ and CD8+ T cells prevents or delays relapse of the disease should be further investigated.

Validation of a therapeutic drug monitoring strategy for thiotepa in a high-dose chemotherapy regimen

Thiotepa is an alkylating agent widely used in high-dose chemotherapy. The pharmacokinetics of thiotepa and its main metabolite tepa show a wide interpatient variability, which may be responsible for the interpatient variability in toxicity. The aim of this study was to develop and validate a pharmacokinetically guided dosing strategy with the sum of the thiotepa and tepa area under the concentration-time curve (AUC) as the target parameter. A total of 46 patients received 77 courses of chemotherapy with thiotepa (80-120 mg/m(2) per day) divided into two daily 30-minute infusions in combination with cyclophosphamide and carboplatin. Patients received up to three courses of chemotherapy. The interpatient, course-to-course, day-to-day, and residual variability in the pharmacokinetics of thiotepa and tepa were estimated with a population analysis with the software program NONMEM. The planned strategy consisted of the collection of blood samples on day 1 and either day 3 or day 4 of each 4-day course. The thiotepa dose was planned to be adjusted on day 3 of each course and before the start of a new course on the basis of Bayesian predictions of the pharmacokinetics with data of day 1 and/or the possible previous course. The prediction procedure was validated by dividing the dataset into an index and validation set. The Bayesian predictions of the validation set were compared with true AUC values generated with individual fits of each course. The performance of the complete strategy was tested with a simulation procedure in 1,000 patients. Interpatient variability and course-to-course variability were in the same order (+/-20%); day-to-day variability was less (+/-15%). The sampling strategy resulted in predictions of the AUC without bias with acceptable precision (+/-20%). The simulation showed that variability in exposure was effectively decreased by the dosing strategy. This strategy resulted in a reduction in the variability of the exposure to thiotepa and tepa and can be implemented in a clinical study.

High-dose sequential epirubicin and cyclophosphamide with peripheral blood stem cell support for advanced breast cancer: results of a phase II study

The aim of this study was to evaluate the feasibility of a high-dose intensity and high-dose density multicycle epirubicin and cyclophosphamide regimen with peripheral blood stem cells (PBSC) and haematopoietic growth factor (G-CSF) support in advanced breast cancer patients. From August 1994 to September 1999, 56 breast cancer patients (8 stage IIIB and 48 stage IV) received 205 courses of cyclophosphamide 3 g x m(-2) and epirubicin 100 mg x m(-2) every 14 days. G-CSF 5 microg x kg(-1) x day(-1) was administered from day 3 to neutrophil recovery. 4 courses were planned. PBSC were collected after course 1, and reinfused after courses 3 and 4, with > or = 2 x 10(6) CD34+ PBSC x kg(-1) required for each reinfusion. 48 patients (86%) received all 4 planned courses. Early withdrawal was consecutive to infectious complications (n = 4), severe asthenia (n = 3), haemorrhagic cystitis (n = 1). A median number of 10.8 x 10(6) CD34+ PBSC x kg(-1) (range, 3-80) was harvested with 1 or 2 apheresis in 48 patients (94%). Median relative dose intensity was 91.3% (range, 72-102%). Grade 4 neutrophil toxicity was observed in 100% of patients. Febrile neutropenia was observed in 40% of courses (median duration 2 days). Red blood cells and platelets had to be transfused in 54% and 27% of courses, respectively. There were no toxic deaths. Objective response rate was 69% in stage IV patients (31/45 evaluable pts), with a 16% complete response rate. Their median progression-free and overall survivals were 22.5 and 37 months, respectively. This epirubicine-containing high-dose regimen appeared feasible, albeit with high toxicity. Time-related progression parameters exceed commonly reported ones. Controlled studies of upfront sequential high-dose chemotherapy are still needed to evaluate its real benefit.

Urinary excretion of thioTEPA and its metabolites in patients treated with high-dose cyclophosphamide, thioTEPA and carboplatin

The urinary excretion of N,N',N"-triethylenethiophosphoramide (thioTEPA), and its metabolites N,N',N"-triethylenephosphoramide (TEPA), N,N'-diethylene,N"-2-chloroethylphosphoramide (monochloroTEPA) and thioTEPA--mercapturate was determined in patients receiving thioTEPA as part of a high-dose combination chemotherapy regimen with cyclophosphamide and carboplatin. The thioTEPA dose was 40 or 60 mg/m(2) in short infusions, twice daily, during 4 days. Urine samples were collected after each voiding on each day of drug administration until 24--48 h after the last thioTEPA infusion. ThioTEPA, TEPA and monochloroTEPA concentrations were determined with gas chromatography and thioTEPA--mercapturate with liquid chromatography--mass spectrometry with direct sample injection. ThioTEPA was present in urine 30 min after infusion and was still excreted 18 h after the last infusion. All metabolites were detected in urine 1 h after infusion. Patients with a creatinine clearance above 140 ml/minl showed higher excretion of TEPA than patients with a creatinine clearance below 140 ml/min (12.8 versus 4.9%, p=0.01). The excretion of monochloroTEPA relative to the excreted amount of TEPA increased at lower pH values of the urine. The excretion of thioTEPA--mercapturate relative to the dose was higher in patients treated with 60 mg/m(2). Excretion of thioTEPA and monochloroTEPA both accounted for only 0.5% of the dose, while TEPA and thioTEPA--mercapturate both accounted for 11.1%.

Phase II study of a multi-course high-dose chemotherapy regimen incorporating cyclophosphamide, thiotepa, and carboplatin in stage IV breast cancer

The purpose of this study was to determine the feasibility and efficacy of multiple courses of high-dose cyclophosphamide, carboplatin and thiotepa with peripheral blood progenitor cell (PBPC) transplantation in women with advanced breast cancer. Forty-one patients with advanced hormone-refractory breast cancer were enrolled in the study. The treatment started with two courses of 5-fluorouracil 500 mg/m(2), epirubicin 120 mg/m(2) and cyclophosphamide 500 mg/m(2) (FE(120)C) followed by PBPC harvesting. The high-dose regimen consisted of three subsequent courses of 'tiny' CTC, cyclophosphamide 4000 mg/m(2), thiotepa 320 mg/m(2) and carboplatin 1060 mg/m(2) (target AUC 13.3 mg/ml/min) (tCTC) divided over 4 consecutive days. The second and third courses were scheduled to begin on day 28 after the previous transplantation. A total of 86 tCTC courses was given to 33 of the 41 enrolled patients. Major toxicities consisted of hemorrhagic cystitis (six patients), prolonged gastro-intestinal toxicity (three patients) and veno-occlusive disease (two patients). There was one therapy-related death (unknown cause). Twenty patients (49%) achieved a complete response, nine (22%) a partial response and three patients stable disease after treatment. The median follow-up of the surviving patients was 43 months (range 25-61). Six patients remain in complete remission beyond 3 years. At 4 years, the progression-free survival (PFS) and overall survival (OS) for the whole patient group were 23 and 30% with a median duration of 12 and 27 months, respectively and for FE(120)C-responsive patients 32 and 36%, respectively with a median duration of 15 and 33 months. In the patient group with a PFS > or = 18 months all patients had limited disease (metastatic disease in only one or two sites) and fewer patients had bone or liver metastases compared to the overall patient group (33% vs 51%). This report shows that three closely spaced courses of tCTC are feasible, with acceptable toxicity. Triple tCTC can achieve complete or partial remission in most patients and long-term PFS in a selected subgroup of patients who have limited metastatic disease and are responsive to conventional-dose chemotherapy.

Sensitive gas chromatographic determination of the cyclophosphamide metabolite 2-dechloroethylcyclophosphamide in human plasma

Cyclophosphamide (CP) is one of the most frequently used anticancer agents. It is a prodrug requiring activation before exerting cytotoxicity. CP is deactivated to 2-dechloroethylcyclophosphamide (2-DCECP) with formation of an equimolar amount of chloroacetaldehyde. The aim of this study was to develop and validate a sensitive and simple assay for 2-DCECP in plasma of patients treated with CP. Sample pre-treatment consisted of solid-phase extraction of 500 microl of plasma over OASIS HLB (1 ml) cartridges with trofosfamide as internal standard. Separation and detection of underivatized 2-DCECP was performed with capillary gas chromatography with nitrogen/phosphorous selective detection. Extraction recovery of 2-DCECP exceeded 87%. No interference from endogenous compounds, other metabolites of CP and frequently coadministered drugs was detected. The assay was linear in the range of 5-5000 ng/ml in plasma. Accuracy, within-day and between-day precision were less than 11% for the complete concentration range. In plasma, 2-DCECP was stable for at least 1 month when kept at -70 degrees C. Analysis of samples from patients treated with CP demonstrated the applicability of the assay. In conclusion, a sensitive and simple assay for 2-DCECP in plasma, which meets the current requirements for bioanalytical assays, was developed.

A mechanism-based pharmacokinetic model for the cytochrome P450 drug-drug interaction between cyclophosphamide and thioTEPA and the autoinduction of cyclophosphamide

Cyclophosphamide (CP) is widely used in high-dose chemotherapy regimens in combination with thioTEPA. CP is a prodrug and is activated by cytochrome P450 to 4-hydroxycyclophosphamide (HCP) which yields the final cytotoxic metabolite phosphoramide mustard (PM). The metabolism of CP into HCP exhibits autoinduction but is inhibited by thioTEPA. The aim of this study was to develop a population pharmacokinetic model for the bioactivation route of CP incorporating the phenomena of both autoinduction and the drug-drug interaction between CP and thioTEPA. Plasma samples were collected from 34 patients who received high-dose CP, thioTEPA and carboplatin in short infusions during 4 consecutive days. Elimination of CP was described by a noninducible route and an inducible route leading to HCP. The latter route was mediated by a hypothetical amount of enzyme. Autoinduction leads to a zero-order increase in amount of this enzyme during treatment. Inhibition by thioTEPA was modeled as a reversible, competitive, concentration-dependent inhibition. PM pharmacokinetics were described by first-order formation from HCP and first-order elimination. The final models for CP, HCP, and PM provided an adequate fit of the experimental data. The volume of distribution, noninducible and initial inducible clearances of CP were 31.0 L, 1.58 L/hr and 4.76 L/hr, respectively. The enzyme amount increased with a zero-order rate constant of 0.041 amount * hr-1. After each thioTEPA infusion, however, approximately 80% of the enzyme was inhibited. This inhibition was reversible with a half-life of 6.5 hr. The formation and elimination rate constants of PM were 1.58 and 0.338 hr-1, respectively. The developed model enabled the assessment of the complex pharmacokinetics of CP in combination with thio TEPA. This model provided an adequate description of enzyme induction and inhibition and can be used for treatment optimization in this combination.

Thrombotic microangiopathy: a new dose-limiting toxicity of high-dose sequential chemotherapy

Ten patients with refractory (n = 8) or early relapsing (n = 2) aggressive non-Hodgkin's lymphoma were enrolled in a pilot study evaluating a high-dose sequential chemotherapy regimen with peripheral blood stem cell (PBSC) support. Five treatment phases were scheduled: phase I (cyclophosphamide + etoposide followed by lenograstim (G-CSF), and a PBSC harvest); phase II (cisplatinum + cytarabine + etoposide followed by lenograstim); phases III and IV (cyclophosphamide + cytarabine + etoposide followed by autologous PBSC infusion and lenograstim); and phase V (carmustine + cytarabine + etoposide + melphalan followed by autologous PBSC infusion and lenograstim). Ten, nine, eight, six and four of the 10 patients received one, two, three, four and five of the five scheduled phases of treatment, respectively. Four patients were withdrawn from the study due to progressive disease and two due to thrombotic microangiopathy (TM). Moreover, in the four patients who completed all treatment phases, an additional case of TM was seen. In all three patients with TM, laboratory studies showed evidence of Coombs negative hemolytic anemia, thrombocytopenia, renal dysfunction and in addition cardiac failure in two patients. TM may be a new dose-limiting toxicity of high-dose sequential chemotherapy followed by repeated PBSC transplantation.

The status of high-dose chemotherapy in breast cancer

High-dose chemotherapy in breast cancer is a subject of considerable controversy. Preliminary results from several randomized trials have shown that it is certainly not the breakthrough hoped for in the early 1990s. The available data are, however, compatible with a modest but potentially important effect on relapse-free survival in the adjuvant treatment of high-risk breast cancer. To prove such an effect, several more years of maturation are required for a number of randomized studies. At this point in time, there is no justification for the use of high-dose chemotherapy in breast cancer outside clinical studies.

Population pharmacokinetics of thioTEPA and its active metabolite TEPA in patients undergoing high-dose chemotherapy

AIMS

To study the population pharmacokinetics of thioTEPA and its main metabolite TEPA in patients receiving high-dose chemotherapy consisting of thioTEPA (80-120 mg x m(-2) x day(-1)), cyclophosphamide (1000-1500 mg x m(-2) x day(-1)) and carboplatin (265-400 mg x m(-2) x day(-1)) for 4 days.

METHODS

ThioTEPA and TEPA kinetic data were processed with a two-compartment model using the nonlinear mixed effect modelling program NONMEM. Interindividual variability (IIV), interoccasion variability (IOV) and residual variability in the pharmacokinetics were estimated. The influence of patient characteristics on the pharmacokinetics was also determined.

RESULTS

A total number of 40 patients receiving 65 courses of chemotherapy was included. Clearance of thioTEPA (CL) was 34 l x h(-1) with an IIV and IOV of 18 and 11%, respectively. The volume of distribution of thioTEPA was 47 l (IIV = 7.5%; IOV = 19%). The fraction of thioTEPA converted to TEPA divided by the volume of distribution of TEPA was 0.030 l-1 (IIV = 39%; IOV = 32%) and the elimination rate constant of TEPA was 0.64 h(-1) (IIV = 27%; IOV = 32%). CL of thioTEPA was correlated with alkaline phosphatase and serum albumin. The volume of distribution of thioTEPA and the elimination rate constant of TEPA were correlated with total protein levels and body weight, respectively.

CONCLUSIONS

A model for the description of the pharmacokinetics of thioTEPA and TEPA was developed. Factors involved in the interpatient variability of thioTEPA and TEPA pharmacokinetics were identified. Since, IOV of both thioTEPA and TEPA was equal to or smaller than IIV, therapeutic drug monitoring based on data of previous courses may be meaningful using this population model.

Salvage treatment with paclitaxel, ifosfamide, and cisplatin plus high-dose carboplatin, etoposide, and thiotepa followed by autologous stem-cell rescue in patients with relapsed or refractory germ cell cancer

PURPOSE

To study feasibility and efficacy of a new salvage regimen in patients with relapsed and/or refractory germ cell tumors.

PATIENTS AND METHODS

Between May 1995 and February 1997, 80 patients were entered onto a phase II study. Conventional-dose salvage treatment with three cycles of paclitaxel 175 mg/m(2), ifosfamide 5 x 1.2 g/m(2), and cisplatin 5 x 20 mg/m(2) (TIP) was followed by one cycle of high-dose chemotherapy (HDCT) with carboplatin 500 mg/m(2) x 3, etoposide 600 mg/m(2) x 4, and thiotepa 150 to 250 mg/m(2) x 3 (CET). In 23 patients, one additional cycle of paclitaxel 175 mg/m(2) and ifosfamide 5 g/m(2) (TI) was given immediately before TIP to improve stem-cell mobilization.

RESULTS

Fifty-five (69%) of 80 patients responded to TIP, 24 (30%) of 80 patients had stable disease (n = 5) or tumor progression (n = 19), and one patient died. Only 62 (78%) of 80 patients received subsequent HDCT. Among those, 41 (66%) of 62 patients responded and 20 (32%) of 62 patients had stable disease (n = 3) or tumor progression (n = 17). One patient died after HDCT from multiorgan failure. Survival probabilities at 3 years were 30% for overall and 25% for event-free survival. Peripheral neurotoxicity with sensorimotor impairment grade 2 through 4 in 29%, paresthesias grade 2 through 4 in 24%, and skin toxicity grade 2 through 3 in 15% of patients were the most relevant side effects.

CONCLUSION

Treatment with TIP followed by high-dose CET is feasible and can induce long-term remissions in 25% of patients with relapsed or refractory germ cell tumors. Peripheral nervous toxicity in approximately one third of patients is a disadvantage of this salvage strategy.

Repetitive high-dose therapy with cyclophosphamide, thiotepa and docetaxel with peripheral blood progenitor cell and filgrastim support for metastatic and locally advanced breast cancer: results of a phase I study

This phase I study was designed to determine the optimal dosages of a novel repetitive high-dose therapy regimen for patients with metastatic breast cancer (MBC). The planned treatment was three cycles of high-dose cyclophosphamide, thiotepa and docetaxel delivered every 35 days with progressive dose-escalation in successive cohorts. Each cycle was supported by peripheral blood progenitor cells (PBPC) and filgrastim. Eighteen patients were entered into this trial. Of the planned 54 treatment cycles, 44 were delivered and 11 patients completed all three cycles. The dose-limiting toxicities were interstitial pneumonitis and mucositis with moderately severe diarrhea (n = 3) and rash (n = 3). There were no treatment-related deaths. Of the 17 patients with evaluable disease, 16 patients responded with six patients achieving a complete remission and an additional four patients achieving no detectable disease (negative restaging including PET scan) but a persistently abnormal bone scan. At a median follow-up of 12 months, median progression-free survival was 11 months with the median overall survival not reached. The recommended doses for phase II/III studies are cyclophosphamide (4 g/m2), thiotepa (300 mg/m2) and docetaxel (100 mg/m2).

Simultaneous determination of thioTEPA, TEPA and a novel, recently identified thioTEPA metabolite, monochloroTEPA, in urine using capillary gas chromatography

An assay for the simultaneous quantitative determination of thioTEPA, TEPA and the recently identified metabolite N,N'-diethylene-N"-2-chloroethylphosphoramide (monochloroTEPA) in human urine has been developed. MonochloroTEPA was synthesized by incubation of TEPA with sodium chloride at pH 8. Thus, with this assay monochloroTEPA is quantified as TEPA equivalents. Analysis of the three analytes in urine was performed using gas chromatography with selective nitrogen-phosphorous detection after extraction with a mixture of 1-propanol and chloroform from urine samples. Diphenylamine was used as internal standard. Recoveries ranged between 70 and 100% and both accuracy and precision were less than 15%. Linearity was accomplished in the range of 25-2500 ng/ml for monochloroTEPA and 25-5000 ng/ml for thioTEPA and TEPA. MonochloroTEPA proved to be stable in urine for at least 4 weeks at -80 degrees C. ThioTEPA, TEPA and monochloroTEPA cummulative urinary excretion from two patients treated with thioTEPA are presented demonstrating the applicability of the assay for clinical samples and that the excreted amount of monochloroTEPA exceeded that of thioTEPA on day 2 to 5 of urine collection.

Stability of thioTEPA and its metabolites, TEPA, monochloroTEPA and thioTEPA-mercapturate, in plasma and urine

The degradation of N,N',N"-triethylenethiophosphoramide (thioTEPA) and its metabolites N,N',N"-triethylenephosphoramide (TEPA), N, N'-diethylene,N"-2-chloroethylphosphoramide (monochloroTEPA) and thioTEPA-mercapturate in plasma and urine has been investigated. ThioTEPA, TEPA and monochloroTEPA were analyzed using a gas chromatographic (GC) system with selective nitrogen/phosphorous detection; thioTEPA-mercapturate was analyzed on a liquid chromatography-mass spectrometric (LC-MS) system. The influences of pH and temperature on the stability of thioTEPA and its metabolites were studied. An increase in degradation rate was observed with decreasing pH as measured for all studied metabolites. In urine the rate of degradation at 37 degrees C was approximately 2.5+/-1 times higher than at 22 degrees C. At 37 degrees C thioTEPA and TEPA were more stable in plasma than in urine, with half lives ranging from 9-20 h for urine and 13-34 h for plasma at pH 6. Mono- and dichloro derivatives of thioTEPA were formed in urine and the monochloro derivative was found in plasma. Degradation of TEPA in plasma and urine resulted in the formation of monochloroTEPA. During the degradation of TEPA in plasma also the methoxy derivative of TEPA was formed as a consequence of the applied procedure. The monochloro derivative of thioTEPA-mercapturate was formed in urine, whereas for monochloroTEPA no degradation products could be detected.

Multiple courses of high-dose ifosfamide, carboplatin, and etoposide with peripheral-blood progenitor cells and filgrastim for small-cell lung cancer: A feasibility study by the European Group for Blood and Marrow Transplantation

PURPOSE

To determine the feasibility and safety of multiple sequential courses of high-dose chemotherapy and peripheral-blood progenitor cells (PBPCs) administered in a multicenter setting to patients with small-cell lung cancer.

PATIENTS AND METHODS

Sixty-nine patients (limited disease, n = 30; extensive disease, n = 39) treated at 15 European centers were scheduled to receive three courses of high-dose chemotherapy with ifosfamide 10 g/m(2), carboplatin 1200 mg/m(2), and etoposide 1200 mg/m(2) (ICE) divided over 4 days at 28-day intervals. PBPCs were harvested before treatment and mobilized with epirubicin 150 mg/m(2) administered via an intravenous bolus divided over 2 days and filgrastim 5 microg/kg/d administered subcutaneously.

RESULTS

The performed leukaphereses (one to five per patient) yielded a median of 16.6 x 10(6)/kg (range, 1.0 to 96.6 x 10(6)/kg) CD34(+) cells, which was sufficient for three reinfusions. Fifty patients (72%) completed the treatment according to schedule. Nine patients completed two courses, and six patients completed one course of treatment. The increase in dose-intensity was 290% that of a standard ICE regimen. The median duration of myelosuppression was similar between courses, namely 4 days (range, 1 to 12 days) for leukocytes less than 0.5 x 10(9)/L and 4 days (range, 0 to 22 days) for thrombocytes less than 20 x 10(9)/L. Febrile neutropenia developed in 66% of courses, severe diarrhea in 14%, mucositis in 10%, and nausea and vomiting in 21% of courses. There were six cases of toxic death (9%), most of which occurred in the first year of accrual and thus were attributable to the learning curve. The antitumor effect of the regimen was reflected in an 86% remission rate (95% confidence interval [CI], 74% to 93%), with 51% of patients achieving a complete response (95% CI, 38% to 63%). Median overall survival was 18 months for patients with limited disease and 11 months for patients with extensive disease.

CONCLUSION

This multiple sequential high-dose ICE regimen could be safely administered on a multicenter basis to patients with small-cell lung cancer. The dose-intensity could be increased to 290% that of standard ICE regimen. The benefit of this approach is currently being tested in a randomized trial that aims to double the long-term rate of survival for patients with small-cell lung cancer.