Ifosfamide: should the honeymoon be over?

Pharmacotherapy in Children and Adolescents: Oncology

Pharmacotherapy in paediatric oncology is a difficult task. It is challenging to determine the optimal dose in children of different age groups. In addition, anticancer drugs display severe side effects reducing the quality of life. Late effects like secondary tumours and cardiotoxicity can be apparent years after treatment and must be taken into account when planning treatment schedules. Classical cytoreducing agents are still of great importance in treating children with leukaemia and solid tumours. In addition, drugs developed by rational drug design (targeted drugs) are a very important part of many treatment protocols, and newer drugs are emerging in several types of cancer. Unfortunately, there is only limited experience with newer drugs in children, because new drugs are mostly developed for adults. Complicated therapy regimens require a solid knowledge of the pharmacology of the drugs applied. This chapter attempts to introduce some pharmacological knowledge for the most important anticancer drugs in children with a focus on side effects and age-specific considerations.

Ifosfamide-induced nephrotoxicity in 593 sarcoma patients: a report from the Late Effects Surveillance System

BACKGROUND

Ifosfamide is widely used in paediatric oncology, but its use is limited by nephrotoxic side effects. The aim of this study was to evaluate the incidence and risk factors of tubulopathy, with special emphasis on the influence of age, where different findings have been published so far.

PROCEDURE

Five hundred ninety three children and adolescents treated for Ewing, osteo- or soft-tissue sarcoma (median age at diagnosis: 11.7 years) were prospectively investigated for nephrotoxicity in the Late Effects Surveillance System (LESS) study. Tubulopathy was diagnosed in case of continuing hypophosphatemia and proteinuria.

RESULTS

After a median follow up of 19 months, 27 patients (4.6%; 95% CI: 3.0-6.6%) had newly developed tubulopathy. This incidence was 0.4% (95% CI: 0-2.4%) in patients treated with a cumulative ifosfamide dose of < or =24 g/m2, 6.5% (95% CI: 3.6-10.7%) after 24-60 g/m2, and 8.0% (95% CI: 4.2-13.6%) after > or = 60 g/m2. In multivariate analysis, children younger than 4 years at time of diagnosis had an 8.7-fold (95% CI: 3.5-21.8) higher risk for tubulopathy than older patients. Neither carboplatin treatment nor abdominal irradiation showed any significant influence.

CONCLUSION

Ifosfamide-induced nephrotoxicity was found in 4.6% of patients. Risk factors were the cumulative ifosfamide dose and young age at treatment.

Ifosfamide: pharmacokinetic properties for central nervous system metastasis prevention

The incidence of central nervous system (CNS) recurrence in patients with lymphoma is about 5%. Nevertheless, this complication is very serious because it is almost always fatal. Its incidence is not sufficiently high to warrant the use of CNS prophylaxis in all patients. The identification of subgroups for whom CNS prophylaxis may be of benefit is therefore important and the age-adjusted international prognostic index (aa-IPI) may be useful in this respect. Ifosfamide (IFO) is a widely used antitumor agent, requiring activation to isophosphoramide mustard (IPM) for DNA alkylation. IFO anabolism occurs through the hepatic microsomal cytochrome P450 system. As with the majority of antineoplastic agents, IFO has toxic side-effects. These include neurotoxicity due to the chloroacetaldehyde (CAA) catabolite. However, the incidence of neurotoxicity is low when IFO is administered as a continuous intravenous infusion. Both inactive IFO and active IPM cross the blood-brain barrier, making IFO treatment effective in the prevention of CNS metastasis in lymphoma patients at high risk of recurrence. The benefit/risk ratio for such patients should evaluated.

Metabolism and transport of oxazaphosphorines and the clinical implications

The oxazaphosphorines including cyclophosphamide (CPA), ifosfamide (IFO), and trofosfamide represent an important group of therapeutic agents due to their substantial antitumor and immuno-modulating activity. CPA is widely used as an anticancer drug, an immunosuppressant, and for the mobilization of hematopoetic progenitor cells from the bone marrow into peripheral blood prior to bone marrow transplantation for aplastic anemia, leukemia, and other malignancies. New oxazaphosphorines derivatives have been developed in an attempt to improve selectivity and response with reduced toxicity. These derivatives include mafosfamide (NSC 345842), glufosfamide (D19575, beta-D-glucosylisophosphoramide mustard), NSC 612567 (aldophosphamide perhydrothiazine), and NSC 613060 (aldophosphamide thiazolidine). This review highlights the metabolism and transport of these oxazaphosphorines (mainly CPA and IFO, as these two oxazaphosphorine drugs are the most widely used alkylating agents) and the clinical implications. Both CPA and IFO are prodrugs that require activation by hepatic cytochrome P450 (CYP)-catalyzed 4-hydroxylation, yielding cytotoxic nitrogen mustards capable of reacting with DNA molecules to form crosslinks and lead to cell apoptosis and/or necrosis. Such prodrug activation can be enhanced within tumor cells by the CYP-based gene directed-enzyme prodrug therapy (GDEPT) approach. However, those newly synthesized oxazaphosphorine derivatives such as glufosfamide, NSC 612567 and NSC 613060, do not need hepatic activation. They are activated through other enzymatic and/or non-enzymatic pathways. For example, both NSC 612567 and NSC 613060 can be activated by plain phosphodiesterase (PDEs) in plasma and other tissues or by the high-affinity nuclear 3'-5' exonucleases associated with DNA polymerases, such as DNA polymerases and epsilon. The alternative CYP-catalyzed inactivation pathway by N-dechloroethylation generates the neurotoxic and nephrotoxic byproduct chloroacetaldehyde (CAA). Various aldehyde dehydrogenases (ALDHs) and glutathione S-transferases (GSTs) are involved in the detoxification of oxazaphosphorine metabolites. The metabolism of oxazaphosphorines is auto-inducible, with the activation of the orphan nuclear receptor pregnane X receptor (PXR) being the major mechanism. Oxazaphosphorine metabolism is affected by a number of factors associated with the drugs (e.g., dosage, route of administration, chirality, and drug combination) and patients (e.g., age, gender, renal and hepatic function). Several drug transporters, such as breast cancer resistance protein (BCRP), multidrug resistance associated proteins (MRP1, MRP2, and MRP4) are involved in the active uptake and efflux of parental oxazaphosphorines, their cytotoxic mustards and conjugates in hepatocytes and tumor cells. Oxazaphosphorine metabolism and transport have a major impact on pharmacokinetic variability, pharmacokinetic-pharmacodynamic relationship, toxicity, resistance, and drug interactions since the drug-metabolizing enzymes and drug transporters involved are key determinants of the pharmacokinetics and pharmacodynamics of oxazaphosphorines. A better understanding of the factors that affect the metabolism and transport of oxazaphosphorines is important for their optional use in cancer chemotherapy.

Pharmacokinetics and metabolism of ifosfamide in relation to DNA damage assessed by the COMET assay in children with cancer

The degree of damage to DNA following ifosfamide (IFO) treatment may be linked to the therapeutic efficacy. The pharmacokinetics and metabolism of IFO were studied in 19 paediatric patients, mostly with rhabdomyosarcoma or Ewings sarcoma. Ifosfamide was dosed either as a continuous infusion or as fractionated doses over 2 or 3 days. Samples of peripheral blood lymphocytes were obtained during and up to 96 h after treatment, and again prior to the next cycle of chemotherapy. DNA damage was measured using the alkaline COMET assay, and quantified as the percentage of highly damaged cells per sample. Samples were also taken for the determination of IFO and metabolites. Pharmacokinetics and metabolism of IFO were comparable with previous studies. Elevations in DNA damage could be determined in all patients after IFO administration. The degree of damage increased to a peak at 72 h, but had returned to pretreatment values prior to the next dose of chemotherapy. There was a good correlation between area under the curve of IFO and the cumulative percentage of cells with DNA damage (r²=0.554, P=0.004), but only in those patients receiving fractionated dosing. The latter patients had more DNA damage (mean±s.d., 2736±597) than those patients in whom IFO was administered by continuous infusion (1453±730). The COMET assay can be used to quantify DNA damage following IFO therapy. Fractionated dosing causes a greater degree of DNA damage, which may suggest a greater degree of efficacy, with a good correlation between pharmacokinetic and pharmacodynamic data.

The development of VAC chemotherapy in rhabdomyosarcoma: what does one do for an encore?

The establishment of the Intergroup Rhabdomyosarcoma Study (IRS) Committee in 1972 by three extant American pediatric cooperative groups initiated five generations of studies in the multidisciplinary treatment of soft-tissue sarcomas. Taking the lead from the use of vincristine, actinomycin-D, and cyclophosphamide (VAC) by Dr. Ruth Heyn, Dr. Harold Mauer and colleagues developed a more robust VAC as well as three similar drug regimens with hematopoietic growth factor support, which, in the context of surgery with or without radiotherapy, achieved a 3-year failure-free survival rate of 83% (IRS-IV) in nonmetastatic embryonal rhabdomyosarcoma. This review documents the development of VAC and some of the new directions currently being pursued by the Children's Oncology Group Soft Tissue Committee.

Addition of ifosfamide and etoposide to standard chemotherapy for Ewing's sarcoma and primitive neuroectodermal tumor of bone

BACKGROUND

Ewing's sarcoma and primitive neuroectodermal tumor of bone are closely related, highly malignant tumors of children, adolescents, and young adults. A new drug combination, ifosfamide and etoposide, was highly effective in patients with Ewing's sarcoma or primitive neuroectodermal tumor of bone who had a relapse after standard therapy. We designed a study to test whether the addition of these drugs to a standard regimen would improve the survival of patients with newly diagnosed disease.

METHODS

Patients 30 years old or younger with Ewing's sarcoma, primitive neuroectodermal tumor of bone, or primitive sarcoma of bone were eligible. The patients were randomly assigned to receive 49 weeks of standard chemotherapy with doxorubicin, vincristine, cyclophosphamide, and dactinomycin or experimental therapy with these four drugs alternating with courses of ifosfamide and etoposide.

RESULTS

A total of 518 patients met the eligibility requirements. Of 120 patients with metastatic disease, 62 were randomly assigned to the standard-therapy group and 58 to the experimental-therapy group. There was no significant difference in five-year event-free survival between the treatment groups (P=0.81). Among the 398 patients with nonmetastatic disease, the mean (+/-SE) five-year event-free survival among the 198 patients in the experimental-therapy group was 69+/-3 percent, as compared with 54+/-4 percent among the 200 patients in the standard-therapy group (P=0.005). Overall survival was also significantly better among patients in the experimental-therapy group (72+/-3.4 percent vs. 61+/-3.6 percent in the standard-therapy group, P=0.01).

CONCLUSIONS

The addition of ifosfamide and etoposide to a standard regimen does not affect the outcome for patients with metastatic disease, but it significantly improves the outcome for patients with nonmetastatic Ewing's sarcoma, primitive neuroectodermal tumor of bone, or primitive sarcoma of bone.

Stem cell toxicity of oxazaphosphorine metabolites in comparison to their antileukemic activity

The oxazaphosphorine agent cyclophosphamide (CP) is an alkylating agent with a relative low stem cell toxicity. The aim of this study was to further evaluate the stem cell toxicity of the active metabolites of CP and its structural analogue ifosfamide (IFO) in comparison to their antileukemic efficacy. Cells of different malignant hematologic disorders (HL-60, HS-Sultan and THP-1) and CD34+ stem cells were treated with cytotoxic CP-metabolite mafosfamide (MAFO) and IFO-metabolites 4-hydroxy-IFO (4-OH-IFO) and chloroacetaldehyde. The clonogenity of the cells was investigated by using a colony-forming assay. All metabolites reduced the formation of both tumor-derived colonies and stem cell-derived CFU-GMs in a concentration-dependent manner. Our data showed a relative tumor-specific, stem cell protecting action of the substances tested with a higher toxicity against tumor cells (IC(50) against HS-Sultan: MAFO 1.1 microM; 4-OH-IFO 1.3 microM; CAA 3 microM) than against stem cells (IC(50) MAFO 14.8 microM; 4-OH-IFO 16.9 microM; CAA 14 microM). However, while the cytotoxic action of 4-OH-IFO corresponded to MAFOs activity, CAAs cytotoxic effect against the hematologic tumor cells was lower. In conclusion, the results confirm the observed cytotoxicity of CAA against solid tumors for cells of malignant hematologic disorders. Although the relative cytotoxic specificity of CAA is lower than for 4-OH-IFO and MAFO, also CAA, like 4-OH-IFO and MAFO, was found to be in part a tumoricidal, stem cell protecting substance.

Intergroup rhabdomyosarcoma study-IV: results for patients with nonmetastatic disease

PURPOSE

The study goal was to improve outcome in children with rhabdomyosarcoma by comparing risk-based regimens of surgery, radiotherapy (RT) and chemotherapy.

PATIENTS AND METHODS

Eight hundred eighty-three previously untreated eligible patients with nonmetastatic rhabdomyosarcoma entered the Intergroup Rhabdomyosarcoma Study-IV (IRS-IV) (1991 to 1997) after surgery and were randomized treatment by primary tumor site, group (1 to 3), and stage (I to III). Failure-free survival (FFS) rates and survival were the end points used in comparisons between randomized groups and between patient subgroups treated on IRS-III and IRS-IV. Most patients were randomized to receive vincristine and dactinomycin (VA) and cyclophosphamide (VAC, n = 235), or VA and ifosfamide (VAI, n = 222), or vincristine, ifosfamide, and etoposide (VIE, n = 236). Patients with group 3 tumors were randomized to receive conventional RT (C-RT) versus hyperfractionated RT (HF-RT).

RESULTS

Overall 3-year FFS and survival were 77% and 86%, respectively. Three-year FFS rates with VAC, VAI, and VIE were 75%, 77%, and 77%, respectively (P =.42). No significant difference in outcome was noted with HF-RT versus C-RT (P =.85 and P =.90, respectively). Overall, patients with embryonal tumors benefited from intensive three-drug chemotherapy in IRS-IV (3-year FFS, 83%). The improvement was seen for patients with stage I or stage II/III, group 1/2 disease, many of whom received VA chemotherapy on IRS-III. Patients with stage 2/3, group 3 disease had similar outcomes on IRS-III and IRS-IV. Three-year FFS for the nonrandomized patient subsets was 75% with renal abnormalities; 81% for paratesticular, group 1 cases; and 91% for group 1/2 orbit or eyelid tumors. Patients with paratesticular primaries had poorer outcomes if they were more than 10 years old (3-year FFS, 63% v 90%). Myelosuppression occurred in most patients, but toxic deaths occurred in less than 1%.

CONCLUSION

VAC and VAI or VIE with surgery (with or without RT), are equally effective for patients with local or regional rhabdomyosarcoma and are more effective for embryonal tumors than therapies used previously. Younger patients with group 1 paratesticular embryonal tumors and all patients with group 1/2 orbit or eyelid tumors can usually be cured with VA chemotherapy along with postoperative RT for group 2 disease.

High risk of infertility and long term gonadal damage in males treated with high dose cyclophosphamide for sarcoma during childhood

BACKGROUND

Therapy with alkylating agents, such as cyclophosphamide, can be associated with irreversible gonadal toxicity in male survivors of adult cancer. To the authors's knowledge the effect of high dose therapy with cyclophosphamide during childhood on adult testicular reproductive and endocrine function has not been established.

METHODS

Gonadal function was studied in 17 adult male survivors of childhood sarcomas treated with high dose pulse cyclophosphamide therapy as part of a VAC (vincristine, actinomycin, and cyclophosphamide) or Adria-VAC (doxorubicin, vincristine, actinomycin, and cyclophosphamide) chemotherapy regimen. Patients answered a questionnaire concerning sexual functioning and underwent a comprehensive physical examination, semen analysis, and hormonal evaluation.

RESULTS

Of the 17 males who underwent semen analysis, 10 (58.8%) had azoospermia, 5 (29.4%) had oligospermia, and only 2 (11.8%) were found to have a normal sperm count. All patients treated prior to the onset of puberty had an abnormal semen analysis. The 2 patients with normal sperm counts received the lowest doses of cyclophosphamide (< 7.5 g/m(2)). The baseline follicle-stimulating hormone level was elevated in only 10 of 14 patients with abnormal sperm counts (71.4%). Testosterone levels were normal in 15 of 16 patients (93.8%); however, the baseline luteinizing hormone (LH) level was elevated in 6 of 15 patients with normal testosterone levels (40%). Gonadotropin-releasing hormone-stimulated LH levels were > 3 times that of baseline in 13 of /14 patients (92.9%), suggesting some degree of Leydig cell insufficiency.

CONCLUSIONS

The results of the current study show a high risk of gonadal dysfunction in men exposed to cyclophosphamide during childhood as part of a VAC/Adria-VAC chemotherapy regimen. Exposure prior to puberty was not found to be protective, and the risk of infertility appeared to increase with higher doses of therapy. To the authors' knowledge the clinical significance of impaired Leydig cell function beginning at a young age is unknown and merits further study.

Clinical pharmacokinetics and pharmacodynamics of ifosfamide and its metabolites

This review discusses several issues in the clinical pharmacology of the antitumour agent ifosfamide and its metabolites. Ifosfamide is effective in a large number of malignant diseases. Its use, however, can be accompanied by haematological toxicity, neurotoxicity and nephrotoxicity. Since its development in the middle of the 1960s, most of the extensive metabolism of ifosfamide has been elucidated. Identification of specific isoenzymes responsible for ifosfamide metabolism may lead to an improved efficacy/toxicity ratio by modulation of the metabolic pathways. Whether ifosfamide is specifically transported by erythrocytes and which activated ifosfamide metabolites play a key role in this transport is currently being debated. In most clinical pharmacokinetic studies, the phenomenon of autoinduction has been observed, but the mechanism is not completely understood. Assessment of the pharmacokinetics of ifosfamide and metabolites has long been impaired by the lack of reliable bioanalytical assays. The recent development of improved bioanalytical assays has changed this dramatically, allowing extensive pharmacokinetic assessment, identifying key issues such as population differences in pharmacokinetic parameters, differences in elimination dependent upon route and schedule of administration, implications of the chirality of the drug and interpatient pharmacokinetic variability. The mechanisms of action of cytotoxicity, neurotoxicity, urotoxicity and nephrotoxicity have been pivotal issues in the assessment of the pharmacodynamics of ifosfamide. Correlations between the new insights into ifosfamide metabolism, pharmacokinetics and pharmacodynamics will rationalise the further development of therapeutic drug monitoring and dose individualisation of ifosfamide treatment.

Fractionated cyclophosphamide and etoposide for children with advanced or refractory solid tumors: a phase II window study

PURPOSE

Cyclophosphamide (CPA) has a broad spectrum of activity against solid tumors. Hepatic self-induction of the active metabolite 4-hydroxycyclophosphamide occurs after repeated administration. We evaluated the clinical efficacy of a window regimen that administers fractionated CPA in conjunction with etoposide (VP16) in children with advanced or refractory solid tumors.

PATIENTS AND METHODS

Seventeen children with advanced (n = 12) or refractory (n = 5) solid tumors were entered onto this phase II window study. The treatment regimen consisted of intravenous (IV) CPA 500 mg/m(2)/d and IV VP16 100 mg/m(2)/d. Both drugs were administered daily by short infusions for 5 consecutive days.

RESULTS

A total of 34 courses were administered, with a median of two courses per patient. The median interval between chemotherapy courses was 21 days (range, 17 to 35 days). Thirty-three courses were assessable for toxicity, and all patients were assessable for response. No life-threatening toxicities were observed. The incidence of grade 3 or 4 neutropenia was 94% and of fever and neutropenia 38%. Fever and neutropenia occurred after 12 of 26 courses without recombinant human granulocyte colony-stimulating factor (rhG-CSF) and after one of eight courses with rhG-CSF (P =. 09). Grade 3 or 4 thrombocytopenia occurred after 10 courses (29%). There were no positive blood cultures. One heavily pretreated patient developed a localized perirectal abscess that required drainage. There were 10 patients (59%) with partial responses, four (23.5%) with stable disease, and three with progressive disease.

CONCLUSION

Fractionated IV CPA and VP16 over 5 days can be safely administered in children with advanced or refractory solid tumors and has notable antineoplastic activity.

Modulation of P450-dependent ifosfamide pharmacokinetics: a better understanding of drug activation in vivo

The anti-cancer prodrug ifosfamide (IF) is metabolized by liver P450 enzymes by two alternative pathways. IF is activated to 4-hydroxy IF (4-OH-IF), which ultimately yields the alkylating mustard isophosphoramide, whereas IF N-dechlororethylation inactivates the drug and produces the neurotoxic metabolite chloroacetaldehyde (CA). Both reactions are catalysed by multiple liver P450 enzymes in vitro in isolated rat liver microsomes. The present pharmacokinetic study investigates the potential for modulation of these alternative pathways of IF metabolism in vivo using the adult male Fischer 344 rat model. Rats were treated with IF alone or in conjunction with various P450 inducers and inhibitors in an effort to improve the balance between drug activation and drug inactivation. Plasma concentrations, areas under the curve (AUC) and half-lives were calculated for 4-OH-IF and CA, allowing estimations of the extent of IF activation and deactivation/toxification. Induction of liver P450 2B enzymes by 4-day high-dose phenobarbital (PB) pretreatment significantly decreased the fraction of IF undergoing 4-hydroxylation (AUC(4-OH-IF)/AUC(4-OH-IF)+AUC(CA)), from 37% to 22% of total metabolism (P < 0.05), consistent with in vitro findings that the PB-inducible P450 enzyme 2B1 plays a major role in IF N-dechloroethylation. Pretreatment with the P450 3A inducer dexamethasone proportionally decreased the AUC for both IF metabolites, without any net impact on the fraction of IF undergoing metabolic activation. By contrast, the P450 2B1 inhibitor metyrapone preferentially increased the AUC for the 4-hydroxylation pathway in 3-day low-dose PB-induced rats, thereby increasing the total fraction of IF metabolized via the activation pathway from 36% to 54% (P < 0.05), whereas the P450 inhibitors orphenadrine and troleandomycin had no significant affect on AUC values. These findings demonstrate specific roles for P450 2B and 3A enzymes in catalysing these pathways of IF metabolism in vivo, and demonstrate the potential for modulation of IF's alternative metabolic pathways in a therapeutically useful manner. These studies also highlight several clinically relevant drug interactions that may occur during concomitant administration of IF with drugs and other compounds that modulate hepatic P450 enzyme levels.

A dose-intensive, cyclophosphamide-based regimen for the treatment of recurrent/progressive or advanced solid tumors of childhood: a report from the Australia and New Zealand Children's Cancer Study Group

BACKGROUND

Children with solid tumors that progress or recur after conventional multimodality therapies have a very poor prognosis. In a pilot study, vincristine, etoposide, and dose-escalated cyclophosphamide (VETOPEC) was shown to be a promising salvage regimen. Continued accrual of patients and increased duration of follow-up has resulted in substantial experience with VETOPEC.

METHODS

Between May 1991 and March 1994, 56 pediatric patients from 6 centers were enrolled in this study; 44 had recurrent or progressive tumors (Group A) and 12 had newly diagnosed, advanced tumors with a very poor prognosis (Group B). The VETOPEC regimen was comprised of vincristine, 0.05 mg/kg, on Days 1 and 14; etoposide, 2.5 mg/kg, on Days 1, 2, and 3; and fractionated, dose-escalated cyclophosphamide on Days 1, 2, and 3. The initial cyclophosphamide dose was 90 mg/kg (2.7 g/m2)/cycle with an escalation of 15 mg/kg/cycle in each subsequent cycle, to a maximum (over 6 cycles) of 165 mg/kg (5.0 g/m2)/cycle. Tumor response was evaluated every two to three cycles and included central review of imaging.

RESULTS

The combined and partial response rates for Groups A and B were 66% (25 of 38 patients) and 91% (10 of 11 patients), respectively. In Group A, best evaluable responses and event free (EF) survivors were observed with: brain tumors (7 of 9 patients; 2 EF at 39 and 45 months [mos], respectively), Wilms' tumor (6 of 7 patients; 3 EF at 37-49 mos), and lymphoma (4 of 4 patients; 2 EF at 52 and 59 mos, respectively); in Group B best evaluable responses and EF were observed with: neuroblastoma (5 of 6 patients; 1 disease free at 57 mos) and rhabdomyosarcoma (4 of 4 patients; no survivors). Hematologic toxicity was limiting despite support with myeloid growth factors in 33 patients. Four deaths in Group A and one in Group B were directly associated with this toxicity. Specifically, no cases of drug-related myocardial toxicity or pneumonitis were observed.

CONCLUSIONS

This chemotherapy regimen with its intense scheduling produced a high response rate and appreciable survival in patients with a variety of recurrent, progressive, or advanced solid tumors of childhood.

6-Day continuous infusion of high-dose ifosfamide with bone marrow growth factors in advanced refractory malignancies

Ifosfamide is an analogue of cyclophosphamide active in the treatment of numerous tumours. Although its use by continuous infusion seems to be responsible for less toxicity, differences of efficacy and toxicity, observed according to its doses and schedules of administration, still remain debated. The objective of this study was to assess the toxicity of high-dose ifosfamide given by continuous infusion over 6 days and its therapeutic activity in various advanced tumours. Twenty-six patients were treated with 14 g/m2 ifosfamide, an equal dose of MESNA, and routine granulocyte- or granulocyte/macrophage-colony-stimulating factor during the intercycle. Courses were repeated every 3 weeks until disease progression or unacceptable toxicity occurred; 75 cycles were administered. The mean number of cycles per patient was 3 (range 1-11). Extrahaematological toxicity was manageable in most patients, WHO grade II or more neurological (5 patients) and renal (5 patients) toxicities occurring in those heavily pretreated with platinum compounds and presenting peritoneal disease. WHO grade III or more neutropenia occurred in 60% of cycles, while grade III-IV thrombocytopenia and anaemia were observed in 19% of them. Three partial responses (germ-cell tumour, chondrosarcoma, soft-tissue sarcoma) and one complete response (metastatic osteosarcoma) were assessed, all in patients with tumours refractory or resistant to standard-dose ifosfamide, which underlines the possibility of circumventing the resistance to ifosfamide given in conventional schedules. The present results confirm previous reports of changes in the therapeutic index of ifosfamide according to its dose and administration schedule.

Treatment of advanced seminoma with cyclophosphamide, vincristine and carboplatin on an outpatient basis

This study describes the efficacy and toxicity of a combination regimen consisting of cyclophosphamide, vincristine (oncovin) and carboplatin (COC) for advanced seminoma on an outpatient basis. Twenty-seven patients (mean age 43 years, range 28-63 years) were classified as stage IIC (n = 5), stage IID (n = 12), stage III (n = 9) or stage IV (n = 1). Six had been treated with prior radiotherapy; elevated beta-HCG and elevated LDH serum levels were observed in 15 and 25 patients respectively. Patients were treated with four cycles of 750 mg m-2 cyclophosphamide intravenously (i.v.), 1.4 mg m-2 vincristine i.v. (maximum 2 mg) and carboplatin adjusted to creatinine clearance. Cycles were given at 3 week intervals. The median dose of carboplatin administered was 400 mg m-2 (range 300-450 mg m-2). Six patients [22%; 95% confidence interval (CI), 6-38%] achieved a complete response (CR), 19 (70%; 95% CI, 51-88%) a partial response and two (8%; 95% CI, 0 18%) showed only a response in tumour markers but not a reduction of retroperitoneal mass (NR). Post-chemotherapeutic masses were not removed surgically or irradiated. After a median follow-up of 26 months (range 5-69 months), two patients have died, one from cardiac arrest 2 years after achieving CR, the other with relapsed seminoma 5 months after therapy. None of the other patients relapsed. Main toxicity was haematological, with 22 patients (81%) experiencing thrombocytopenia WHO grade III/IV and 27 (100%) leucocytopenia WHO grade III/IV, requiring dose reduction in five patients. Seven patients experienced granulocytopenic fever. Non-haematological toxicity was rare. Peripheral neuropathy grade I was observed in four patients and grade III in one. Haemorrhagic cystitis occurred once. In conclusion, despite considerable haematological toxicity, COC is feasible on an outpatient basis, even after prior radiotherapy, and is an effective regimen for advanced seminoma with only 1/27 treatment failures after a median follow-up of 26 months.