Population pharmacokinetics of total and unbound etoposide

A population pharmacokinetics study using the NONMEM program was undertaken to determine the effects of different covariates on the pharmacokinetic parameters of etoposide. A total of 1,044 plasma etoposide concentrations were determined by high-performance liquid chromatography (HPLC) in 100 patients (pts; 75 men and 25 women aged 25–85 years) treated for various tumor types with i.v. (57 pts) or oral (43 pts) etoposide. For 67 pts, etoposide plasma protein binding was determined by equilibrium dialysis; the unbound fraction ranged from 4% to 24%. A linear two-compartment model with first-order absorption (for oral dosing) accurately described the concentration versus time data. The central and peripheral volumes of distribution were significantly correlated with the body surface area [Vc (L) = 5.5 × BSA (m²) and Vp = 4.1 × BSA], but even after BSA had been taken into account, the interindividual variability of the two volumes remained high (34% and 57%, respectively). The clearance (CL) was not correlated with the following covariates: age, BSA, sex, height, and levels of serum bilirubin and liver enzymes. The final regression model for CL was CL (ml/min) = 49.8 × (1 − 0.009 × PRO) × WT/Scr + 33.8 × (1 − 0.29 × META) × (1− (1 − 0.012 × ALB), where ALB , PRO , WT ,and Scr, respectively, were albuminemia, proteinemia (g/l), weight (kg), and serum creatinine (μM ) and META = 1 if the patient had liver metastases (otherwise, META = 0). The interindividual variability in CL (mean value 30 ml/min) decreased only from 32% to 26% when these covariates were taken into account. The mean oral bioavailability was 66%, showing an interindividual variability of 37%. The plasma clearance of the unbound fraction was strongly and negatively correlated with Scr but was not dependent on either PRO or ALB. These data show that modifications in PRO levels do not directly affect plasma exposure to unbound etoposide. This analysis makes possible the rational consideration of modifications of covariates such as Scr in etoposide dosing. This population data base will constitute the prerequisite for adaptative control with feedback dosing for continuous oral administration of etoposide. Received: 12 January 1997 / Accepted: 9 June 1997     

Changes in the clearance of total and unbound etoposide in patients with liver dysfunction

The disposition of total and non-protein-bound etoposide was investigated in 21 cancer patients receiving etoposide and cisplatin combination chemotherapy. Etoposide plasma concentrations were determined using a specific high-performance liquid chromatography (HPLC) method, and etoposide plasma protein binding was determined by equilibrium dialysis. The patients had a wide range of renal function (creatinine clearance, 32 to 159 mL/min/m2) and hepatic function (total bilirubin range, 0.3 to 21.5 mg/dL; aspartate aminotransferase [AST] range, 14 to 415 IU/L; serum albumin range, 2.7 to 4.1 g/dL). The mean etoposide total systemic clearance was not different in 15 patients with total bilirubin less than 1.0 mg/dL versus six patients with total bilirubin 1.1 to 21.5 mg/dL (18.7 +/- 5.9 mL/min/m2 v 26.4 +/- 10.7 mL/min/m2; t-test P = .06), with a trend toward higher total clearance in the patients with abnormal bilirubin values. However, the mean clearance of unbound etoposide was significantly lower in patients with increased total bilirubin (220 +/- 90 mL/min/m2 v 135 +/- 61 mL/min/m2; t-test P = .027). The fraction of etoposide unbound (fu) in plasma was significantly higher in patients with increased bilirubin (9% +/- 3% v 27% +/- 15%; t-test P = .002), explaining the trend toward higher total clearance in these patients. Etoposide clearance (total or unbound) in the 14 patients with measurable hepatic metastases was not different from the clearance in the seven patients without hepatic metastases. This study provides an explanation for why patients with increased bilirubin do not have lower total systemic clearance of etoposide, and indicates that such patients have a higher exposure to unbound etoposide. The results of ongoing pharmacodynamic studies of total and unbound etoposide in patients with increased bilirubin will determine the clinical relevance of altered etoposide protein binding.     

Acute neurologic dysfunction after high-dose etoposide therapy for malignant glioma

Etoposide (VP-16-213) has been used in the treatment of many solid tumors and hematologic malignancies. When used in high doses and in conjunction with autologous bone marrow transplantation, this agent has activity against several treatment-resistant cancers including malignant glioma. In six of eight patients (75%) who we treated for recurrent or resistant glioma, sudden severe neurologic deterioration occurred. This developed a median of 9 days after initiation of high-dose etoposide therapy. Significant clinical manifestations have included confusion, papilledema, somnolence, exacerbation of motor deficits, and sharp increase in seizure activity. These abnormalities resolved rapidly after initiation of high-dose intravenous dexamethasone therapy. In all patients, computerized tomographic (CT) brain scans demonstrated stability in tumor size and peritumor edema when compared with pretransplant scans. This complication appears to represent a significant new toxicity of high-dose etoposide therapy for malignant glioma.     

Clinical trial of high-dose etoposide

In eleven patients with recurrent or refractory malignant lymphomas or lung cancers, a phase I study of high-dose etoposide without autologous bone marrow transplantation was performed. As a starting dose of etoposide 200 mg/m2 was administered for five consecutive days and the daily dose was increased step by step to a dose of 50 mg/m2. The dose of etoposide was escalated in order to define dose-limiting extramedullary toxicity, which was oropharyngeal mucositis and arrhythmias (PVC) at a dose level of 350 mg/m2/day. Bone marrow toxicity was completely reversible, supported by thrombocyte transfusion and antibiotics. Of nine evaluable patients with malignant lymphomas, two complete remissions and one partial remission were obtained. However, some patients unresponsive to standard-dose etoposide did not exhibit any response to the augmented dose of etoposide. Etoposide is thus a suitable drug for high-dose chemotherapy.     

Bioequivalence investigation of high-dose etoposide and etoposide phosphate in lymphoma patients

PURPOSE: To compare etoposide pharmacokinetics following administration of high-dose etoposide and etoposide phosphate, a water-soluble prodrug of etoposide. Bioequivalence was assessed using a two-treatment randomized crossover design. METHODS: Ten patients with high-risk or relapsed lymphoma were treated with a sequential high-dose chemotherapy. They were randomized to receive either 3 x 400 mg/m2 etoposide or an equimolar amount of etoposide phosphate (as 1-h infusions on three consecutive days) in the first course and the alternative drug in the second course. Serial plasma and ultrafiltered plasma samples were collected and analysed for etoposide by a reversed-phase HPLC method with UV and electrochemical detection. Pharmacokinetic parameters were estimated using a two-compartment model. Bioequivalence was assessed calculating the 90% confidence intervals (CI) for the ratios of the geometric means of AUC(0-infinity) and additionally of Cmax of etoposide derived from etoposide phosphate relative to etoposide in plasma and ultrafiltered plasma as point estimates (level of significance alpha < 0.05). RESULTS: Pharmacokinetic parameters of etoposide were comparable in both treatment arms except that terminal half-life was significantly shorter and apparent Vss in ultrafiltered plasma was significantly larger following administration of the prodrug. The point estimates for AUC(0-infinity) of etoposide derived from etoposide phosphate relative to etoposide were 102.9% and 88.4% for plasma and ultrafiltered plasma, respectively. The 90% CIs were in the range from 80% to 125% where bioequivalence can be assumed. The point estimates of Cmax on day 3 of chemotherapy were 96.5% and 81.7% in plasma and ultrafiltrate with the 90% CI in ultrafiltered plasma being out of the range from 80% to 125%. CONCLUSION: With respect to total drug exposure, represented by AUC(0-infinity), high-dose etoposide phosphate is bioequivalent to high-dose etoposide.     

Pharmacokinetics of high-dose etoposide after short-term infusion

Summary The pharmacokinetics of high-dose etoposide (total dose, 2100 mg/m² divided into three doses given as 30-min infusions on 3 consecutive days) were studied in ten patients receiving high-dose combination chemotherapy followed by autologous bone marrow transplantation. In addition to etoposide, all subjects received 2×60 mg/kg cyclophosphamide and either 6×1,000 mg/m² cytosine arabinoside (ara-C), 300 mg/m² carmustine (BCNU), or 1,200 mg/m² carboplatin. Plasma etoposide concentrations were determined by²⁵²Cf plasma desorption mass spectrometry. In all, 27 measurements of kinetics in 10 patients were analyzed. According to graphic analysis, the plasma concentration versus time data for all postinfusion plasma ctoposide values were fitted to a biexponential equation. The mean values for the calculated pharmacokinetic parameters were:t1/2, 256±38 min; mean residence time (MRT), 346±47 min; AUC, 4,972±629g min ml^–1 (normalized to a dose of 100 mg/m²); volume of distribution at steady state (Vd_ss), 6.6±1.2l/m²; and clearance (CL), 20.4±2.4 ml min^–1 m^–2. A comparison of these values with standard-dose etoposide pharmacokinetics revealed that the distribution and elimination processes were not influenced by the dose over the range tested (70–700 mg/m²). Also, the coadministration of carboplatin did not lead to significant pharmacokinetic alterations. Although plasma etoposide concentrations at the time of bone marrow reinfusion (generally at 30 h after the last etoposide infusion) ranged between 0.57 and 2.39 g/ml, all patients exhibited undelayed hematopoietic reconstitution.     

Enhanced cutaneous radiation effects following high-dose busulfan therapy

Summary Fifteen patients received irradiation after combined chemotherapy with high-dose busulfan followed by autologous or allogeneic bone marrow transplantation. Of nine patients irradiated between day 30 and day 70 after their engraftment, seven developed an increased radiation response in the skin: four showed enhanced reactions during irradiation, and three had a total or severe definitive alopecia more than 16 months after CNS irradiation. Six patients were irradiated after day 70; they had either normal reactions or none at all within the cutaneous radiation portals. The possibility that busulfan might be a radiosensitizer is raised.     

Secondary tumours following etoposide containing therapy for germ cell cancer

BACKGROUND: Reports have implied etoposide as the cause of secondary leukaemiain patients treated for germ cell cancer. PATIENTS AND METHODS: Between 1979 and 1992, 679 male patients with germ cell cancerreceived etoposide containing chemotherapy. RESULTS: Six of 679 patients developed acute myeloid leukaemia (relativerisk 150; CI: 55–326). None of these patients had a primarymediastinal germ cell tumour and only 1 patient received previousradiotherapy. The median interval between the onset of cytotoxictreatment and the development of leukaemia was 27 months. TheFAB M4 morphology was seen in 4 of 6 cases. CONCLUSION: The benefit of etoposide containing protocols outweigh the riskof leukaemia in patients with intermediate or high risk disease,however in patients with good risk disease non-etoposide containingprotocols should be explored. etoposide, germ cell tumours, secondary leukaemia     

Extensive-stage small-cell bronchogenic carcinoma: intensive induction chemotherapy with high-dose cyclophosphamide plus high-dose etoposide

Seventeen ambulatory patients with extensive-stage small-cell lung cancer received one or two courses of high-dose induction chemotherapy consisting of cyclophosphamide (100 mg/kg) plus etopside (1,200 mg/m2) followed by four or five cycles of conventional-dose cyclophosphamide (1,000 mg/m2), doxorubicin (40 mg/m2), and vincristine (1.4 mg/m2) (CAV) given every 21 days. No additional chemotherapy was given until relapse or progression was documented. Response was assessed initially after high-dose induction therapy and again after completion of all chemotherapy. After induction therapy, 16/17 (94%) patients had achieved an objective response, including five (29%) complete responses and 11 (65%) partial responses. Two partially responding patients improved to a complete response after CAV, while one partial responder progressed and one patient died of an intercurrent illness while receiving CAV. Thus, the overall response after completing all chemotherapy was 15/16 (94%), including seven (44%) complete responses and eight (50%) partial responses. Median response duration was six months (range, 3 to 11 months), and overall median survival was ten months (range, 2 to 17 months). All 31 courses of induction therapy were associated with leukopenia (less than 1,000/microL), 81% with thrombocytopenia (less than 20,000/microL), and 77% with fever (greater than 38.5 degrees C). Seven episodes of bacteremia and one axillary abscess were documented, and there was one treatment-related death (6%). These toxicities are similar to that produced by high-dose etoposide alone. High-dose cyclophosphamide combined with high-dose etoposide can be administered to ambulatory patients with extensive-stage small-cell lung cancer without requiring bone marrow transplantation to reestablish hematopoiesis. Complete response and median survival rates, however, are similar to those obtained with less intensive therapy.     

Phase I study of high-dose cisplatin,ifosfamide, and etoposide

To test the feasibility of a regimen of high-dose cisplatin, ifosfamide, and etoposide (VP-16; VIPP regimen), we registered 15 patients with advanced non-small-cell lung cancer in a phase I trial of the Northern California Oncology Group. One cycle of treatment consisted of high-dose cisplatin given at 100 mg/m² i.v. on days 1 and 8, VP-16 given at 60–75 mg/m² i.v. on days 1–3, plus ifosfamide given at 1.0–1.2 g/m² i.v. on days 1–3; cycles were repeated every 28 days. There were 13 men and 2 women; the median age was 59 years (range, 47–72 years). The median Karnofsky performance status (KPS) was 90 (range, 70–100). All patients were assessable for toxicity and response. The median number of cycles delivered per patient was two (range, one to four). Hematologic toxicity was dose-limiting and required de-escalation of the ifosfamide and VP-16 doses. Ten patients developed a white blood count of <1000/mm³ and seven patients developed a platelet count of <50,000/mm³. The duration of cytopenia increased progressively with each subsequent cycle of therapy. Two patients required antibiotics for neutropenic fever with documented infections (pneumonia, bacteremia). Seven patients received red blood cell transfusions for a hemoglobin level of <8 gm/dl. Grade III or IV non-hematologic toxicities were uncommon and involved one patient each with grade 3 ototoxicity and grade 3 neurotoxicity. Five patients developed laboratory evidence of renal salt wasting. The overall response rate was 33% (5/15) with a complete response being achieved by two patients (13%) and a partial response being attained by three (20%). The overall median survival was 44 weeks. We conclude that although this regimen demonstrated activity, hematologic toxicity limited its use in the palliative treatment of non-small-cell lung cancer. Using hemopoietic growth-factor support to permit dose escalation, this schedule of VIPP may be of interest in a number of different chemotherapy-sensitive tumor types.     

Efficacy of high-dose methotrexate,ifosfamide, etoposide and dexamethasone salvage therapy for recurrent or refractory childhood malignant lymphoma

BackgroundChildren with recurrent or refractory malignant lymphoma generally have a poor prognosis. There is a need for new active drug combinations for this high-risk group of patients.Patients and methodsThis study evaluated the activity and toxicity of the methotrexate, ifosfamide, etoposide and dexamethasone (MIED) regimen for childhood refractory/recurrent non-Hodgkin’s lymphoma (NHL) or Hodgkin’s lymphoma (HL). From 1991 through 2006, 62 children with refractory/recurrent NHL (n = 24) or HL (n = 38) received one to six cycles of MIED. Based on MIED response, intensification with hematopoietic stem cell transplantation (HSCT) was considered.ResultsThere were 10 complete (CR) and 5 partial responses (PR) among the 24 children with NHL [combined response rate, 63%; 95% confidence interval (CI) 38% to 73%]. There were 13 CR and 18 PR among the 37 assessable children with HL (combined response rate, 84%; 95% CI, 68% to 94%). Although 59% courses were associated with grade IV neutropenia, treatment was well tolerated and without toxic deaths.ConclusionsMIED is an effective regimen for refractory/recurrent childhood malignant lymphoma, permitting a bridge to intensification therapy with HSCT.     

Unresectable non-small cell lung cancer chemotherapy with high-dose cisplatin and etoposide

69 patients with unresectable non-small cell lung cancer, previously untreated, received cisplatin 100 mg/m2 on day 1 and etoposide 120 mg/m2 on days 4, 6, 8 at 4-week intervals. 66 patients were evaluable for tumor response and toxicity. Overall objective response was 25.7% (3 complete responses and 14 partial responses). Response rate in limited disease was 41% and in patients with performance score 0 it was 40%. Squamous cell carcinoma and adenocarcinoma responded in 31 and 24% of evaluable patients. Complete response was associated with a long duration of remission. Median survival time of responding patients was significantly superior to the median of nonresponding patients (p less than 0.001) but compared to stable disease no statistical significance was demonstrable (p greater than 0.05). Hematological and renal toxicity of proposed regimen was generally mild. Nausea and vomiting were the most noxious side effects.     

Prolonged daily administration of oral etoposide in lymphoma following prior therapy with Adriamicin,an ifosfamide-containing salvage combination,and intravenous etoposide

Prolonged daily administration of oral etoposide has been reported to be active in refractory lymphoma. The purpose of this phase II trial was to confirm the activity of this schedule of etoposide in a selected group of heavily pretreated patients with non-Hodgkin's lymphoma (NHL) or Hodgkin's disease (HD). A total of 26 patients (20 with NHL and 6 with HD) were entered in the trial; all had previously been treated with an Adriamycin-based chemotherapy, an ifosfamide-containing salvage combination, and i. v. etoposide. Etoposide was given in a fixed oral daily dose of 100 mg over 3 weeks; the weekly dose (500–700 mg) was selected such that the average daily dose was approximately 50 mg/m². Cycles were repeated on day 29. An objective response was seen in 16 patients (62%; 95% confidence interval, 42%–80%), with a complete response (CR) being observed in 3 cases (12%) and a partial response (PR), in 13 (50%). The median duration of PRs was 3 months. CRs lasted for 15 months in one patient and continue at 12+ and 20+ months in the remaining two patients. The overall actuarial survivial for the entire group was 40% at 2 years; the median survival time was 12 months. The main toxicity was myelosuppression; WHO grade 3 or 4 leukopenia and thrombocytopenia developed in 31% and 12% of the patients, respectively. There was no drug-related death. We conclude that oral etoposide is an effective and tolerable palliative treatment for heavily pretreated lymphoma patients.     

Disposition of high-dose methotrexate in an obese cancer patient.

The disposition of many drugs in obesity is altered, although little is known of the effect of obesity on the pharmacokinetics of anti-cancer drugs. In this report the authors describe the pharmacokinetics of high-dose methotrexate in an obese woman (184% ideal body weight) with osteosarcoma. For this patient, both the volume of distribution at steady-state (0.398 l/kg) and systemic clearance (0.0956 l/h/kg) of methotrexate were increased compared with values observed in adult patients with osteosarcoma. The terminal elimination half-life (9.29 hours) of methotrexate was similar to other reported values in adult patients, thus indicating that increases in methotrexate volume of distribution and clearance may offset each other in obesity. Based on the experience gained from this patient, the authors suggest that renal function and methotrexate serum concentrations should be monitored in obese patients receiving high-dose methotrexate with leucovorin rescue.     

Dose escalation of high-dose cyclophosphamide and etoposide with high-dose doxorubicin (CDE) and filgrastim for poor-risk non-Hodgkin's lymphoma

PURPOSE:: To identify the highest possible dose of cyclophosphamide (C)and etoposide (E) to be given with high-dose doxorubicin (D)and filgrastim (G-CSF) but without stem cell support in high-risknon-Hodgkin's lymphoma. PATIENTS AND METHODS:: High-dose CDE was given to 18 evaluable patients, 5 had previouschemotherapy. All patients received D 90 mg/sqm and G-CSF 20µg/kg/day. The first cohort had C 1800 mg/sqm and E 450mg/sqm. Chemotherapy was given in equally divided doses overthree days. Dose escalation was performed thrice up to C 3900mg/sqm and E 975 mg/sqm. One to four courses were given. RESULTS:: The median number of days (quartile values) with neutrophils<0.5 x 10⁹/l was 9 days (7–10), untransfused platelets<20 x 10⁹/l 6 days (3–7), fever     

Treatment of relapsed and refractory acute leukaemia with high-dose cytosine arabinoside and etoposide

Summary A total of 65 patients under the age of 55 with acute leukaemia received high-dose cytosine arabinoside (Ara-C) in combination with high-dose etoposide without an anthracycline. Complete remission rates for patients with relapsed or refractory acute myelogenous leukaemia (AML) were 15/25 (60%) and 11/16 (69%), respectively. The complete remission rate for patients with refractory or relapsed acute lymphoblastic leukaemia (ALL) was 10/18 (56%). The treatment-related mortality was 17%. Nine patients whose leukaemia relapsed after matched allogeneic, sibling bone-marrow transplantation (BMT) were also treated in this way; the treatment-related mortality in this group was high (7/9) and the duration of remission in the two patients who responded, too short to justify this intensive treatment in such patients. Similarly, patients who underwent BMT after achieving a complete remission with high-dose Ara-C and etoposide did very poorly, only one patient surviving well and disease-free at 8 months. The important finding in this study was the high complete remission rate rapidly obtained in patients with relapsed or refractory AML without using an anthracycline.     

Unaltered pharmacokinetics after the administration of high-dose etoposide without prior dilution

Summary The pharmacokinetics of etoposide following a new method of administration was determined. Undiluted etoposide was given at a dose of 30 mg/kg as part an intensified conditioning regimen prior to bone marrow transplantation. A terminal half-life of 3.4±0.7 h and a volume of distribution of 15.4±9.61 were found (n=8); the AUC was 764±302 g h ml^–1. As compared with those obtained in other pharmacokinetic studies using etoposide diluted in normal saline, our data reflect full systemic bioavailability and unaltered pharmacokinetics. The application of undiluted etoposide makes the therapy easier and less time-consuming and avoids a high fluid volume and a high saline load.     

Phase I trial of high-dose etoposide, high-dose cisplatin, and reinfusion of autologous bone marrow for lung cancer

We undertook a phase I trial using fixed-dose cisplatin, escalating doses of etoposide, and reinfusion of previously obtained autologous bone marrow in 29 relapsed or refractory small cell and non-small-cell lung cancer patients. Median age was 59 years (range of 38-68 years). Three patients had small-cell and 26 patients had non-small-cell lung cancer. Patients received i.v. cisplatin 200 mg/m2 over 5 days and i.v. etoposide 600 mg/m2/day for 3 days (total of 1,800 mg/m2) that was escalated to 800, 1,000, 1,200, 1,400, and 1,600 mg/m2/day for 3 days (total of 2,400-4,800 mg/m2). Cryopreserved autologous bone marrow was thawed and reinfused through a central venous catheter the second day after the completion of chemotherapy. Toxicities included nausea, vomiting, alopecia, high-tone hearing loss, mucositis, diarrhea, renal insufficiency, metabolic acidosis, and severe myelosuppression. The duration of neutropenia (less than 500 neutrophils/microliter) ranged from 5 to 22 days (median of 11 days) and the duration of severe thrombocytopenia (platelets of less than 20,000/microliters untransfused) ranged from 2 to 19 days (median of 9 days). Reversible renal insufficiency (peak serum creatinines of 6.7, 6.6, 4.3, and 3.5 mg/dl) occurred in four patients who completed the therapy. In three patients, death occurred within 4 weeks of chemotherapy and marrow reinfusion. Three complete and 12 partial remissions (range of 1+(-)22+ months, median of 3 months) were observed. No response was noted in eight patients and tumor progression within 1 month of transplant occurred in two patients. The maximally tolerated dose of etoposide was 1,400 mg/m2/day (total of 4,200 mg/m2), since two of three patients developed life-threatening diarrhea at the 1,600 mg/m2/day (total of 4,800 mg/m2) dose. The encouraging antitumor effects of this regimen suggest that this approach may be useful therapy for lung cancer and other tumors sensitive to VP-16 and cisplatin.     

Mitoxantrone and high-dose etoposide for patients with relapsed or refractory acute leukemia.

Among 35 patients with relapsed or refractory acute myelogenous leukemia (AML) who received salvage chemotherapy, 28 were treated with mitoxantrone (7.5 mg/m2/d intravenously [IV] over 1 hour for 5 days) and etoposide (VP-16) (2 g/m2 over 4 days either as a daily infusion or as two daily doses). Seven patients received mitoxantrone (6 mg/m2/d for 5 days) and VP-16 (1500 mg/m2 over 3 days). The median duration of the initial complete remission (CR) was 6 months and 83% of the patients had initial CR that lasted 12 months or less. Forty-six percent of the patients were undergoing a second or subsequent salvage attempt. Eight patients (23%) achieved CR; seven of these CR were obtained after one course of therapy. Twelve patients (33%) died and 15 patients (42%) had disease that was resistant to treatment. Patients undergoing a first salvage attempt had a higher incidence rate of CR than those undergoing a second or subsequent salvage attempt (37% versus 6%; P = 0.03). CR rates were also higher in patients with a favorable (translocation 8;21 or 15;17) or diploid karyotype compared with other patients (32% versus 8%; P = 0.10). The median survival time was 2 months for all patients and 8 months for patients achieving CR. Mucositis occurred in 74% of the patients and was severe in 32%. Diarrhea and rash occurred in less than 33% of the patients. Fever was noticed in all but 1 of the patients and documented infections occurred in 65% of the patients. Six patients had pancytopenia or thrombocytopenia that lasted more than 42 days from the initiation of treatment. Although mitoxantrone and high-dose VP-16 is an effective antileukemic regimen, it is associated with a high incidence of mucositis. Strategies that are used to limit mucosal damage may improve the tolerance of this combination.