A multi-center prospective phase II study of high-dose chemotherapy in germ-cell cancer patients relapsing from complete remission

High dose chemotherapy followed by autologous hematopoietic stem cell transplantation for advanced germ cell tumors: State of the art and a single-center experience

BACKGROUND

Evidence for the choice of second line, standard vs high dose chemotherapy, (SDCT, HDCT) for patients with relapsed germ cell tumors (GCTs) comes mainly from retrospective studies.

MATERIAL AND METHODS

relevant literature was reviewed, considering as endpoints both survival and long term quality of life (QoL). Patients with metastatic GCT progressing after first-line treatment at our Institution were retrospectively evaluated.

RESULTS

HDCT seems to achieve a higher rate of long-term remissions. QoL data for this group of patients are lacking. Our experience on 29 patients was in line with these results. Two-year OS for the 18 patients treated with one or two HDCT/PBSCT procedures was 47.5 %, while 2-year PFS was 44 %. For the 11 receiving SDCT 2-year OS was 36.4 %, and 2-year PFS was 32.7 %.

CONCLUSIONS

HDCT/PBSCT confirmed to be effective in treating patients with relapsed GCT, but prospective studies are needed.

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.

Multicentric phase II trial of TI-CE high-dose chemotherapy with therapeutic drug monitoring of carboplatin in patients with relapsed advanced germ cell tumors

Background

High‐dose chemotherapy (HDCT) with TI‐CE regimen is a valid option for the treatment of relapsed advanced germ cell tumors (GCT). We report a phase II trial with therapeutic drug monitoring of carboplatin for optimizing area under the curve (AUC) of this drug.

Methods

Patients with unfavorable relapsed GCT were treated according to TI‐CE regimen: two cycles combining paclitaxel and ifosfamide followed by three cycles of HD carboplatin plus etoposide administered on 3 days. Carboplatin dose was adapted on day 3 based on carboplatin clearance (CL) at day 1 in order to reach a target AUC of 24 mg.min/mL per cycle. The primary endpoint was the complete response (CR) rate.

Results

Eighty‐nine patients who received HDCT were included in the modified intent‐to‐treat (mITT) analysis. Measured mean AUC was 24.4 mg.min/mL per cycle (22.4 and 26.8 mg.min/mL for 10th and 90th percentiles). Thirty‐five (44.3%) patients achieved a CR with or without surgery of residual masses and 20 patients achieved a partial response with negative tumor markers. With a median follow‐up of 44 months (m), median PFS was 12.3 m (95% CI: 7.5–25.9) and OS was 46.3 m (95% CI: 18.6–not reached). For high‐ and very high‐risk patients, according to the International Prognostic Score at first relapse or treated after at least one salvage treatment (n = 51), 2‐year PFS rate was 41.1%.

Conclusion

The rates of complete and favorable responses were clinically relevant in this very poor risk population. Individual monitoring of carboplatin plasma concentration permitted to control more accurately the target AUC and avoided both underexposure and overexposure to the drug.

Role of one, two and three doses of high-dose chemotherapy with autologous transplantation in the treatment of high-risk or relapsed testicular cancer: a systematic review

Approximately 20-30% of patients with metastatic germ cell cancers (GCCs) can develop relapsed or refractory (RR) disease, about 40-50% of patients who relapse after salvage chemotherapy may reach long-term remission. The goal of this review was to identify patients who appear to benefit from high-dose chemotherapy (HDCT) and autologous stem cell transplant (ASCT). To access this, we performed a systematic medical literature review to evaluate the effectiveness of HDCT in the frontline setting, as well as in patients with RR testicular cancer. We searched databases for interventional clinical studies and identified 5883 studies. We selected 49 studies for inclusion, which included a total of 5985 patients. Seventeen studies reported results of newly diagnosed poor-risk GCC patients and 32 studies reported results of RR patients. For newly diagnosed patients with poor prognostic predictors, a risk adjusted strategy using unfavorable tumor marker decline with initial standard chemotherapy regimen and upfront HDCT demonstrated improved outcomes. Our data suggest a minimum of two HDCT cycles with ASCT should be standard of care for patients with RR GCC. Failure of HDCT results in a poor prognosis with only 10% of patients achieving lasting remission with salvage therapy.

High-dose chemotherapy for germ cell tumors: do we have a model?

INTRODUCTION

Since the late nineties, the intensification of chemotherapy doses with hematopoietic stem cell rescue held promise for patients with advanced and poor prognosis germ cell tumors (GCTs). High-dose chemotherapy (HDCT) has, nowadays, a recognized indication in the salvage setting of advanced GCTs and is steadily utilized worldwide.

AREAS COVERED

We evaluated the available data with the use of HDCT in these patients. In addition, we provided an original perspective on several issues as experts on behalf of the European Society for Blood and Marrow Transplantation and IGG, including peripheral blood stem cells mobilization and the use of HDCT in special subpopulations of GCT, with the aim to help clarify critical issues in the absence of available clear-cut information.

EXPERT OPINION

Despite HDCT being currently considered a therapeutic option in the salvage setting, critical questions regarding patient selection are still unanswered. Eligibility of patients with a chemoresistant disease, the use of available prognostic factors as well as tumor marker decline in clinical practice are pending issues. Moving forward, these are critical arguments in favor of further clinical research in the field of advanced GCTs.

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.

Salvage chemotherapy after failure of first-line chemotherapy in patients with metastatic testicular cancer

PURPOSE OF REVIEW

Because of the small number of relapsed patients, their prognostic variability and the complexity of second-line therapy, randomized studies are largely lacking and treatment recommendations for patients with relapse after first-line chemotherapy are derived from retrospective series or phase II studies. This review summarizes the existing evidence including several recently published larger studies on the use of high-dose chemotherapy in these patients.

RECENT FINDINGS

Patients with unfavorable features such as incomplete response to first-line therapy, cisplatin refractoriness, multiple relapses or advanced stage at initial diagnosis have been shown to benefit from salvage high-dose chemotherapy with autologous stem cell support. Long-term survival rates of up to 60% have been reported after salvage high-dose chemotherapy for these patients. The treatment for patients relapsing after complete remission to first-line therapy, cisplatin-sensitive disease and gonadal primary remains controversial. Excellent long-term event-free survival rates of up to 80% have been reported after both conventional and high-dose chemotherapy. Surgery remains an important part of any salvage strategy.

SUMMARY

The prognosis of patients relapsing after first-line cisplatin-based chemotherapy has improved with multimodality therapy including conventional and high-dose chemotherapy, surgery and radiation. The treatment of these patients requires a close cooperation of experienced medical oncologists, urologists and radiation oncologists.

High-dose chemotherapy and stem-cell rescue for metastatic germ-cell tumors

BACKGROUND

Metastatic testicular tumors that have not been successfully treated by means of initial chemotherapy are potentially curable with salvage chemotherapy.

METHODS

We conducted a retrospective review of 184 consecutive patients with metastatic testicular cancer that had progressed after they received cisplatin-containing combination chemotherapy. We gave 173 patients two consecutive courses of high-dose chemotherapy consisting of 700 mg of carboplatin per square meter of body-surface area and 750 mg of etoposide per square meter, each for 3 consecutive days, and each followed by an infusion of autologous peripheral-blood hematopoietic stem cells; the other 11 patients received a single course of this treatment. In 110 patients, cytoreduction with one or two courses of vinblastine plus ifosfamide plus cisplatin preceded the high-dose chemotherapy.

RESULTS

Of the 184 patients, 116 had complete remission of disease without relapse during a median follow-up of 48 months (range, 14 to 118). Of the 135 patients who received the treatment as second-line therapy, 94 were disease-free during follow-up; 22 of 49 patients who received treatment as third-line or later therapy were disease-free. Of 40 patients with cancer that was refractory to standard-dose platinum, 18 were disease-free. A total of 98 of 144 patients who had platinum-sensitive disease were disease-free, and 26 of 35 patients with seminoma and 90 of 149 patients with nonseminomatous germ-cell tumors were disease-free. Among the 184 patients, there were three drug-related deaths during therapy. Acute leukemia developed in three additional patients after therapy.

CONCLUSIONS

Testicular tumors are potentially curable by means of high-dose chemotherapy plus hematopoietic stem-cell rescue, even when this regimen is used as third-line or later therapy or in patients with platinum-refractory disease.

A phase II study using a topoisomerase I-based approach in patients with multiply relapsed germ-cell tumours

BACKGROUND

The outcome of patients with germ-cell tumours (GCTs), who relapse more than once or relapse with a mediastinal primary is poor. We have shown that topoisomerase 1 may be an attractive target in relapsed GCT. We investigated the role of irinotecan, paclitaxel and oxaliplatin (IPO) followed by topotecan-based high-dose therapy in responding patients, in this patient population.

PATIENTS AND METHODS

Twenty-eight patients with multiply relapsed gonadal and mediastinal GCT were recruited to this phase 2 study. All patients received IPO chemotherapy and 12 (43%) went on to receive high-dose therapy. The outcome of these patients was assessed using the Kaplan-Meier method with a median progression-free follow-up of 1 year.

RESULTS

Twenty patients (71%) responded to the therapy including five complete remissions (18%), 13 (46%) marker-negative partial responses and two (7%) marker-positive partial responses. Nine (32%) patients continue to be progression free, and the median survival for the whole group currently measures 17 months. Out of 12 individuals who received subsequent high-dose therapy consolidation, seven (58%) remain progression free. The commonest grade III/IV toxicity was infection (68%) and there were no IPO-related toxic deaths; there was one death from high-dose therapy.

CONCLUSION

Topoisomerase I-based IPO chemotherapy that lacks etoposide is very active in multiply relapsed GCT. This data merit further investigation.

Chemotherapy for advanced germ cell tumors

PURPOSE

Germ cell tumors constitute the most curable of all cancers. Standard treatment of previously untreated and treated patients has evolved on the basis of prospective clinical trials and prognostic factors. This review summarizes the prognostic criteria on which treatment decisions may be based, and outlines the current treatment approaches.

PATIENTS AND METHODS

Randomized and nonrandomized trials of first-line, salvage, and palliative therapy and the role of surgery after chemotherapy were reviewed. In the treatment of previously untreated patients, emphasis was placed on interpretation of data of trials according to the International Germ Cell Cancer Collaborative Group model, which has evolved into a universally accepted classification algorithm for determining appropriate risk-directed chemotherapy. This system permits treatment choices based on the balance between benefit and toxicity and allows comparison of results across multiple clinical trials.

RESULTS

Standard therapy for good-risk patients is four cycles of etoposide plus cisplatin or three cycles of cisplatin, etoposide plus bleomycin (BEP x 3); both approaches cure approximately 90% of patients. After chemotherapy and normalization of markers, patients should generally undergo resection of residual masses. Approximately 75% of intermediate-risk and 45% of poor-risk patients group achieve a durable complete response with BEP x 4. Potentially curative options in the salvage setting include ifosfamide plus cisplatin-containing standard dose therapy and high-dose carboplatin plus stem-cell rescue. Surgery remains an essential component of care.

CONCLUSION

Curative therapy exists even in patients with resistant disease, and treatment choices can be based on established clinical criteria. Serum tumor markers and surgery after chemotherapy have essential roles in patient management

Management of Recurrent Testicular Germ Cell Tumors

Although front-line chemotherapy cures most men with testicular germ cell tumors, salvage therapy is still important in a small but significant minority. Second-line conventional-dose or high-dose chemotherapy with stem cell rescue may cure 25%-50% of patients. New chemotherapeutic agents, including the taxanes gemcitabine and oxaliplatin, have added to the therapeutic armamentarium. Salvage surgical resection has an important role in selected patients. Cisplatin-refractory patients have a poor prognosis with current therapy, and novel chemotherapeutic and biologic agents need to be discovered for such patients.

High-dose chemotherapy for male germ cell tumor

Today, 20-30% of male patients with advanced germ cell tumor (GCT) do not have durable, complete remission in spite of cis-platinum (CDDP)-based chemotherapy. High-dose chemotherapy (HDCT) has been tried in CDDP refractory GCT patients. Initially HDCT was performed with autologous bone marrow transplantation in heavily treated patients. However, the clinical outcome was not good and the treatment-related death rate was not ignorable. Therefore, earlier introduction of HDCT with peripheral blood stem cell transplantation was preferable as it renders HDCT more effective and less toxic, and multicycle HDCT is feasible. The durable free rate of recent HDCT for refractory GCT patients is 32-65%. HDCT is also performed as first line chemotherapy for poor prognosis GCT patients. Induction chemotherapy followed by multicycles of HDCT was tried. The durable free rate of recent HDCT as first line chemotherapy is 43-73%. Although previous reports suggest the superiority of HDCT, one recent randomized controlled trial (RCT) failed to show an improvement with one cycle of HDCT followed by three cycles of standard-dose chemotherapy (SDCT) compared with four cycles of SDCT. Ongoing RCT comparing multicycles of HDCT with SDCT for poor prognostic GCT patients will clarify the role of HDCT. Recently, new regimens of HDCT containing paclitaxel have been devised. In this review, the history, current status and future of HDCT for advanced or refractory GCT will be discussed.

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.

Intensive Chemotherapy with Autologous Peripheral Blood Stem Cell Transplantation During a 10-Year Period in 64 Patients with Germ Cell Tumor

Despite gratifying cure rates in germ cell tumors, conventional-dose chemotherapy achieves long-term remissions in less than 50% of patients at high risk. High-dose chemotherapy followed by autologous (auto) peripheral blood stem cell transplantation (PBSCT) has shown impressive remission rates in high-risk and relapsed germ cell tumors. We report on 64 consecutive patients with high- (n=39), intermediate- (n=18), and refractory or relapsed low- (n=7) risk germ cell tumors who underwent auto-PBSCT between January 1993 and February 2003. PBSCTs were performed as a single (n=40) or repeated (n=24) transplantation using either etoposide, ifosfamide, and carboplatin (n=80) or related protocols (paclitaxel, ifosfamide, carboplatin, etoposide [n=7]; carboplatin, etoposide, thiotepa [n=4]). With a median follow-up of 6 years, estimated 2- and 5-year overall survivals were 77.2% (95% confidence interval [CI] 66.7-87.7) and 73.1% (95% CI 61.7-84.5), respectively. We observed unfavorable results in those patients showing refractoriness to cisplatin (hazard ratio 20.36; 95% CI 6.64-62.47) or no response to induction chemotherapy (hazard ratio 10.67; 95% CI 1.37-83.37). Auto-PBSCT was well tolerated, showed objective antitumor activity, and achieved long-term survival in patients at high risk and with relapse. Our data suggest that auto-PBSCT can increase response rates and may improve the outcome in these patients.

Leptomeningeal carcinomatosis in relapsed non-seminoma testis: a 1-year complete remission with high-dose chemotherapy

A 1-year complete remission could be achieved with high-dose systemic chemotherapy in a 33-year-old patient with relapsed germ cell tumor presenting with leptomeningeal carcinomatosis (LC). Although LC in general has a very poor prognosis for patients with chemosensitive malignancies, systemic chemotherapy should be considered.

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.

Relevance of high-dose chemotherapy in solid tumours

Drug resistance is a major problem in the treatment of solid tumours. Based on a steep dose-response relationship for especially alkylating agents on tumour cell survival, high-dose chemotherapy was considered of interest for the treatment of solid tumours. Results of phase 1 and 2 studies with high-dose chemotherapy in a variety of tumour types showed good response rates. Nowadays, several phase 3 studies are available especially in metastatic and high-risk breast cancer patients. The high expectations of high-dose chemotherapy did not come true. This review analyses results of randomised studies and comments on the discrepancy between findings in patients versus those in tissue culture. Potential factors involved are the presence of tumour stem cells with different characteristics from more mature tumour cells, limitations in drug escalation in the clinic, transplant mortality, trial design and tumour cell contamination of the haematopoietic stem cell transplant. Maturation of the results from recent studies indicating a more modest benefit in, e.g., adjuvant breast cancer balanced versus long-term side effects will ultimately determine the role of high-dose chemotherapy in certain solid tumours. In case of well-defined indications for high-dose chemotherapy, further selection of patients based on patient and tumour characteristics as well as the introduction of new agents will most likely play a role.

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.

Current aspects of high-dose chemotherapy in germ-cell tumors

The optimal treatment in patients with 'poor prognosis' germ-cell tumors (GCT) according to the 'International Germ Cell Cancer Collaborative Group' (IGCCCG)--classification and in patients with refractory or relapsed disease after cisplatin-based chemotherapy remains controversial. It is well known that the majority of these patients will suffer systemic relapses after primary or salvage treatment and most of them will ultimately die of their disease. Therefore, the optimizing of the standard treatment is clearly desirable. The question of using conventional-dose or high-dose chemotherapy (HDCT) in this high-risk patients is under discussion. However, HDCT as primary treatment in 'poor prognosis' patients and as first- or subsequent salvage therapy in patients with relapsed or refractory GCT remains to be a relevant curative option. Prognostic factors have recently been recognized to aid in this decision.

Individualised dosing strategy for high-dose carboplatin in patients with germ cell cancer

In contrast to conventional chemotherapy, carboplatin is still dosed per unit of body surface area (BSA) in high-dose chemotherapy protocols in clinical practice. To individualise dosing, a population pharmacokinetic model for poor-risk germ cell tumour patients receiving 1500 mg m(-2) carboplatin was developed. The typical central volume of distribution (19.9 l) and typical clearance (110 ml min(-1)) corresponded approximately to the extracellular fluid space or glomerular filtration rate, respectively. The covariate analysis identified several patient-specific factors. Carboplatin clearance was significantly related to creatinine clearance and body height, explaining 73% of the interindividual variability. Thus, an equation to predict individual clearance prior to treatment was developed (CL=0.41 x creatinine clearance+1.05 x body height-124.4). The relative frequency of developing toxicity increased significantly with higher AUC values for different types of toxicity. In addition, overall nonhaematological toxicity correlated significantly with exposure of carboplatin, leading to the assessment of a target AUC. Based on the prediction of individual clearance and the definition of a target AUC associated with moderate toxicity, an individualised dosing equation is proposed. Retrospectively, the individualised dosing strategy would have led to a higher dose on average and a broader range to be administered, compared to empirical dosing per unit BSA in the high-dose setting.

Stage I seminoma of the testis: a bi-institutional retrospective analysis of patients treated with radiation therapy only

OBJECTIVE

To analyse relapse patterns, toxicity and second malignancy in patients with stage I pure germ cell testicular tumours, treated in 1970-1999.

PATIENTS AND METHODS

In all, 487 patients received irradiation after surgery to the infra- (407, 83.5%) or infra- and supra-diaphragmatic volumes (80, 16.5%). Treatment-related toxicity was classified according to previous criteria and fertility investigated in 246 men. Second malignancies were identified by retrospective analysis of clinical records or telephone interviews in men who no longer needed a long-term follow-up.

RESULTS

The 10-year overall survival was 97% (98% and 96%, respectively, for the aortic nodes only, or aortic and iliac nodes, i.e. the 'dog leg' field) and disease-free survival was 94%. Twenty-one patients relapsed (five with a true 'in-field' recurrence, nine progressed to the mediastinum, and seven had disseminated disease). Acute toxicity was mainly gastrointestinal, with 7.6% classified as grade II. In all, 73 men achieved paternity after irradiation; nine did not but had normal sperm. Second malignancies were diagnosed in 16 (3.3%) men.

CONCLUSION

Para-aortic irradiation may be used safely in patients with stage I seminoma and undisturbed testicular drainage, with equivalent results to the 'dog-leg' group; these unrandomized data confirm the lower toxicity and equivalent survival rates of this treatment.

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.

High-dose chemotherapy in adult patients with germ cell tumors

BACKGROUND

Approximately 80% of patients with advanced germ cell tumors (GCTs) can be cured with cisplatin-based chemotherapy. Patients with poor-prognosis disease have a cure rate of only 50%, whereas patients with first relapse have only a 25% chance of prolonged survival and potential cure following standard therapy. High-dose chemotherapy (HDC) is being investigated in patients with GCTs to improve the results of salvage treatment and in first-line setting for poor prognosis disease.

METHODS

The authors review the results of the clinical trials that have evaluated the role of HDC in GCT patients. Data were obtained using a computer-assisted MEDLINE search, and meeting abstracts with clinical relevance in this field were hand-searched. Open randomized phase III studies are described and examined.

RESULTS

Several phase II studies have shown a possible benefit for patients with recurrent disease, but the preliminary results of a phase III randomized trial did not demonstrate a survival advantage for HDC after three courses of standard-dose chemotherapy in the salvage therapy of patients in whom first-line treatment has failed. Three prospective, randomized trials are evaluating the role of HDC in a first-line setting.

CONCLUSIONS

New HDC strategies are emerging, involving new drugs (eg, paclitaxel), intensive induction regimens, and upfront and/or multiple courses of HDC. The evaluation of mature data of randomized trials will better define the role of HDC in this disease.

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.

Salvage high-dose chemotherapy in patients with germ cell tumors: an Italian experience with 84 patients

BACKGROUND

High-dose chemotherapy (HDCT) followed by hematopoietic stem cell support (HSCS) potentially may be curative in patients with germ cell tumor (GCT) who develop recurrent tumors or who have an inadequate response after receiving standard-dose chemotherapy. The authors report their experience with HDCT as salvage therapy for patients with GCT.

METHODS

Between 1986 and 2000, 84 patients with GCT, with a median age 29 years (range, 15-50 years), were treated with 105 courses of HDCT with HSCS. Patients were stratified into good, intermediate, and poor risk categories according to a validated prognostic index.

RESULTS

Overall, 28 patients (33%) have been continuously disease free. In the good risk group, 24 patients (69%) have been continuously disease free compared with 4 patients (13%) in the intermediate risk group (P < 0.001) and 0 patients in the poor risk group (P < 0.001). Treatment-related mortality occurred only among patients in the poor risk (n = 6 patients) and the intermediate risk groups (n = 4 patients).

CONCLUSIONS

In the authors' experience, HDCT induced impressive long-term remissions as salvage treatment among patients in the good risk group. Moreover, the use of validated prognostic classifications may contribute to a better definition of the role of HDCT other than improving the outcome of patients with GCT. The definitive statement on the possible role of HDCT in patients with GCT will derive from the ongoing Phase III randomized studies.

Toxicity of high-dose carboplatin: ultrafiltered and not total plasma pharmacokinetics is of clinical relevance

Combination chemotherapy containing high-dose carboplatin is a therapeutic option for patients with poor-risk germ cell tumors. Since such treatment is relatively toxic, pharmacokinetic characteristics of total and ultrafiltered platinum, representing different species of platinum complexes formed, were investigated in 29 patients in relation to toxicity. The goodness-of-fit parameters revealed that a two-compartment model with weighting (1/C2i) resulted in the best fit. The terminal half-life of total platinum > 5 days was fourfold longer than that of ultrafiltered platinum, indicating long-term retention. At stem cell rescue, an ultrafiltered concentration of < or = 0.223 microg/ml did not impair hematological recovery. Ultrafiltered but not total platinum concentrations or AUC values were significantly correlated to an increase in creatinine concentration and different types of toxicity associated with high-dose treatment. Since the fraction unbound is time dependent and highly variable among patients, measuring ultrafiltered concentrations is highly recommended as they represent the clinically relevant platinum complexes in high-dose treatment.

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.

Evaluation of long-term toxicity in patients after cisplatin-based chemotherapy for non-seminomatous testicular cancer

BACKGROUND

Because of the increasing number of long-term survivors of metastatic testicular germ-cell cancer, a general concern has been secondary morbidities, especially cardiovascular risk factors.

PATIENTS AND METHODS

Thirty-two patients treated with cisplatin- and doxorubicin-containing chemotherapy > or = 13 years before the time of analyses were evaluated for neuro-, oto-, pulmonary-, vascular- and gonadal toxicity including evaluation of myocardial damage and cardiovascular risk factors and analysis of microcirculation.

RESULTS

Thirty percent of the patients showed abnormal left ventricle function. Elevated follicle stimulating hormone (FSH) and luteinising hormone (LH) levels in 75% of patients were often associated with low testosterone levels. Elevated total cholesterol levels were found in 82% and higher triglyceride levels in 44% of patients, most of them were overweight. About 25% of the patients developed diastolic arterial hypertension after chemotherapy. Reduced hearing was confirmed in 23% of patients, especially at frequencies higher than 3000 Hz. Moreover, 53% of patients presented transient evoked otoacoustic emissions. In 38% of patients non-symptomatic neuropathy was detected, in 28% symptomatic neuropathy, and in 6% disabling polyneuropathy. In 80% of patients with neuropathic symptoms additional morphological and functional abnormalities were found by nailfold capillary videomicroscopy, compared to only 57% of the patients without neuropathic symptoms.

CONCLUSIONS

Patients cured by cisplatin-based chemotherapy for metastatic testicular cancer have to be cognizant of their unfavorable cardiovascular risk profile, that might be a greater risk than developing a relapse or second malignancy.

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.

Chemotherapy in patients with metastatic or relapsed germ-cell tumours

The optimal treatment in patients with poor prognosis germ-cell tumours (GCT), according to the International Germ Cell Cancer Collaborative Group (IGCCCG) classification, and in patients with refractory or relapsed disease after cisplatin-based chemotherapy is controversial. As the majority of patients will suffer systemic relapses, chemotherapy is the mainstay of treatment. However, the question of whether or not to use conventional-dose or high-dose chemotherapy (HDCT) in these patients arises. Prognostic factors have recently been recognised to aid in this decision. However, reliable data on chemotherapy as primary treatment in poor prognosis patients and as the first-salvage attempt in patients with relapsed or refractory GCT are lacking. This report reviews the recent developments in first-line and salvage HDCT strategies and discusses the role of predictive factors for treatment outcome.

Long-term haematological recovery following high-dose chemotherapy with autologous bone marrow transplantation or peripheral stem cell transplantation in patients with solid tumours

long-term peripheral blood counts and factors influencing long-term trilineage haematological recovery of consecutive patients in a single institution treated with high-dose chemotherapy (hdc) and abmt or psct for solid tumours were examined. patients with a relapse-free survival of >1 year were included in the analysis (n = 131). Peripheral blood counts were examined 6 months and yearly following transplantation. Median follow-up was 4.1 years (range 1-10+ years). Three years after transplantation 91% of patients had normal white blood counts (WBC), 94% normal haemoglobin (Hb) and 75% normal platelets. Trilineage recovery was complete in 70% (n = 83) at 3 years and 85% (n = 50) at 5 years. Recovery of Hb occurred before WBC and platelet recovery. Approximately 25% of patients displayed an elevated MCV throughout the follow-up period. These long-term results were independent of age, high-dose regimen, number of reinfused stem cells and stem cell source. Double (n = 12) vs single (n = 119) transplantations showed significantly slower trilineage recovery and higher MCV. No secondary graft failure, myelodysplasia or leukaemia was encountered. In conclusion, complete trilineage recovery after HDC followed by ABMT or PSCT occurs slowly. PSCT and ABMT are capable of maintaining long-term haematopoiesis. Slower recovery is seen after double transplantations. The results suggest lasting implications for bone marrow function after autologous transplantation.