Epirubicin in hepatocellular carcinoma: pharmacokinetics and clinical activity

Improved survival for hepatocellular carcinoma with portal vein tumor thrombosis treated by intra-arterial chemotherapy combining etoposide, carboplatin, epirubicin and pharmacokinetic modulating chemotherapy by 5-FU and enteric-coated tegafur/uracil: A pilot study

AIM: To investigate the poor prognosis of HCC with PVTT, we evaluated the efficacy by a new combination chemotherapy for advanced hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT).

METHODS: From 2002 to 2007, a total of 10 consecutive patients with Stage IVA HCC accompanied by PVTT were studied prospectively to examine the efficacy of treatment by intra-arterial infusion of a chemotherapeutic agents consisting of etoposide, carboplatin, epirubicin and pharmacokinetic modulating chemotherapy by 5-FU and enteric-coated tegafur/uracil.

RESULTS: The mean course of chemotherapy was 14.4 (range, 9-21) mo. One patient showed complete response (CR) with disappearance of HCC and PVTT after treatment, and the two patients showed partial response (PR), response rate (CR + PR/All cases 30%). The median survival time after the therapy was 457.2 d. The one-year survival rate was 70%. Adverse reactions were tolerable.

CONCLUSION: Although the prognosis of most patients with Stage IVA HCC by PVTT is poor, our combination chemotherapy may induces long-term survival and is an effective treatment and produced anti-tumor activity with tolerable adverse effects in patients for advanced Stage IVA HCC accompanied by PVTT.

A phase I/II trial of chemoembolization for hepatocellular carcinoma using a novel intra-arterial drug-eluting bead

BACKGROUND & AIMS

To assess the safety and efficacy of transarterial chemoembolization (TACE) using doxorubicin-eluting beads (DEB) for hepatocellular carcinoma (HCC).

METHODS

Patients with incurable HCC and Child-Pugh class A cirrhosis were considered eligible for this phase I/II trial. Two courses of TACE using DEB were given at an interval of 2 months, and tumor response was assessed by computerized tomography scan. The phase I trial was a dose-escalating study starting from 25 mg to 150 mg doxorubicin in cohorts of 3 patients. The 150-mg doxorubicin dose was used for the phase II study. Primary end points were treatment-related complications and deaths. Secondary end points included tumor response and pharmacokinetics of doxorubicin.

RESULTS

In the phase I study involving 15 patients, no dose-limiting toxicity was observed for up to 150 mg doxorubicin, which was used for 20 patients in the phase II study. The pharmacokinetic study showed a low peak plasma doxorubicin concentration (49.4 +/- 23.7 ng/mL), and no systemic toxicity was observed. The treatment-related complication rate was 11.4%. There was no treatment-related death. Among 30 patients who completed 2 courses of TACE, the partial response rate and the complete response rates were 50% and 0%, respectively, by response evaluation criteria in solid tumors (RECIST) criteria at computerized tomography scan 1 month after the second TACE. By modified RECIST criteria, taking into account the extent of tumor necrosis, 19 (63.3%) patients had a partial response and 2 (6.7%) had a complete response.

CONCLUSIONS

This study shows that TACE using DEB is a safe and effective treatment for HCC, supporting a phase III randomized trial to compare this novel treatment with conventional TACE using doxorubicin-Lipiodol emulsion.

Dose adaptation of antineoplastic drugs in patients with liver disease

Dose adaptation for liver disease is important in patients treated with antineoplastic drugs because of the high prevalence of impaired liver function in this population and the dose-dependent, frequently serious adverse effects of these drugs. We classified the antineoplastic drugs marketed in Switzerland at the end of 2004 according to their bioavailability and/or hepatic extraction to predict their kinetic behaviour in patients with decreased liver function. This prediction was compared with kinetic studies carried out with these drugs in patients with liver disease. The studies were identified by a structured, computer-based literature search. Of the 69 drugs identified, 52 had a predominant extrarenal (in most cases hepatic) metabolism and/or excretion. For 49 drugs, hepatic extraction could be calculated and/or bioavailability data were available, allowing classification according to hepatic extraction. For 18 drugs, kinetic studies have been reported in patients with impaired liver function, with the findings generally resulting in quantitative recommendations for adaptation of the dosage. In particular, recommendations are precise for 16 drugs excreted by the bile (e.g. doxorubicin and derivatives and vinca alkaloids). Validation studies comparing such recommendations with kinetics and/or dynamics of antineoplastic drugs in patients with decreased liver function have not been published. We conclude that there are currently not enough data for safe use of cyctostatics in patients with liver disease. Pharmaceutical companies should be urged to provide kinetic data (especially hepatic extraction data) for the classification of such drugs and to conduct kinetic studies for drugs with primarily hepatic metabolism in patients with impaired liver function to allow quantitative advice to be given for dose adaptation.

Systemic Therapy of Advanced Hepatocellular Carcinoma: How Hopeful Should We Be?

Worldwide, hepatocellular carcinoma (HCC) is the fifth most common cancer and the third most common cause of cancer-related death. In the U.S., 18,510 new cancers of the liver and intrahepatic bile duct are expected in 2006, with an estimated 16,200 deaths. The incidence rates for HCC in the U.S. continued to rise steadily through 1998 and doubled during the period 1975-1995. Unresectable or metastatic HCC carries a poor prognosis, and systemic therapy with cytotoxic agents provides marginal benefit. A majority of HCC patients (>80%) presents with advanced or unresectable disease. Even for those with resected disease, the recurrence rate can be as high as 50% at 2 years. Because of the poor track record of systemic therapy in HCC, there has been a sense of nihilism for this disease in the oncology community for decades. However, with the arrival of newly developed molecularly targeted agents and the success of some of these agents in other traditionally challenging cancers, like renal cell carcinoma, there has recently been renewed interest in developing systemic therapy for HCC. This review attempts to concisely summarize the historical perspective and the current status of systemic therapy development in HCC.

Combined effect of epirubicin and lymphokine-activated killer cells on the resistant human breast cancer cells

Accumulating evidence suggests the concept that epirubicin and lymphokine-activated killer (LAK) cells cytotoxicity may be mediated by free radicals generation and P-glycoprotein-positive (Pg-p+) cancer cells are more sensitive for LAK cells than their drug-sensitive parental lines. We tested this hypothesis further by exposing drug-sensitive (WT) and epirubicin-resistant MCF-7 human breast tumor cells to epirubicin and LAK cells. Subsequently, we monitored cell proliferation as a measure of cytotoxicity. The cytotoxicity of epirubicin, LAK, and LAK + epirubicin (1/10 of IC50) was evaluated in 400-fold epirubicin resistant MCF-7 EPI(R) (P-glycoprotein overexpressing) and drug-sensitive MCF-7 WT cells. IC50 values were measured using the MTT cytotoxicity test. The MCF-7 EPI(R) cells exhibited an increased susceptibility to LAK cells than did the MCF-7 WT cells. P-gp+ MCF-7 EPI(R) cells were lysed by human LAK cells to a greater extend than were their drug-sensitive counterparts. LAK + epirubicin combined treatment increased susceptibility of MCF-7 WT and MCF-7 EPI(R) cells to LAK cells cytotoxicity. For both cell lines, cytotoxicity was dependent upon the concentration of the epirubicin and effector cell/target cell (E/T) ratio. The resistance of MCF-7 EPI(R) cells to epirubicin appears to be associated with a developed tolerance to superoxide, most likely because of a tree-fold increase in superoxide dismutase (SOD) activity and 13-fold augmented selenium dependent glutathione peroxidase (GSH-Px) activity. Acting in concert, these two enzymes would decrease the formation of hydroxyl radical from reduced molecular oxygen intermediates. The addition of SOD decreased cytotoxicity of epirubicin and LAK cells. Taken together, these observations support the role of oxygen radicals in the cytotoxicity mechanism of epirubicin and suggest further that the development of resistance to this drug by the MCF-7 EPI(R) tumor cells may have a component linked to oxygen free radicals. It is proposed that production of reactive oxygen species by the treatment of epirubicin and LAK cells can cause cytotoxicity of MCF-7 WT and MCF-7 EPI(R) cells. SOD, catalase, GSH-Px, GST (glutathione S-transferase), and GSH (reduced glutathione) must be considered as part of the intracellular antioxidant defense mechanism of MCF-7 WT and MCF-7 EPI(R) cells against reactive oxygen species.

A Phase II Study of Epirubicin and Thalidomide in Unresectable or Metastatic Hepatocellular Carcinoma

BACKGROUND

The median survival time for patients with unresectable hepatocellular carcinoma (HCC) is <6 months, and no effective standard systemic chemotherapy is available. Both epirubicin (Ellence); Pfizer Pharmaceuticals, New York, NY, http://www.pfizer.com) and thalidomide (Thalomid); Celgene Corporation, Warren, NJ, http://www.celgene.com) have reported activity for HCC as single agents, and they have different mechanisms of action and nonoverlapping toxicities. Therefore, we performed a phase II study using the combination of epirubicin and thalidomide in patients with unresectable and metastatic HCC.

METHODS

Nineteen patients with measurable, unresectable, or metastatic HCC were enrolled. All patients were required to have adequate major organ function and performance status. The treatment consisted of weekly epirubicin at a dose of 20 mg/m(2) administered i.v. and daily thalidomide at a dose of 200 mg orally given as a 3-weeks-on/1-week-off schedule. Intrapatient dose escalation of thalidomide was allowed every 2 weeks up to 800 mg daily as long as tolerated. Physical examinations, toxicity assessments, and serum chemistry analyses were performed weekly, and tumor measurements were conducted every 8 weeks.

RESULTS

All 19 patients enrolled into the study were evaluable for toxicity assessment and 17 patients were evaluable for response assessment. A total of 71 cycles of chemotherapy was administered, with a median of two cycles administered to each patient (range 1-14). No complete or partial responses were observed. Seven patients (41%) had stable disease, with a median duration of 6 months (range 5-14). The median survival time for all 19 patients was 196 days (95% confidence interval 93-302). The treatment was generally well tolerated. Treatment-related toxicities included constipation (grade 3, 5%; grade 2, 37%; grade 1, 21%), fatigue (grade 3, 5%; grade 2, 42%), and sensory neuropathy (grade 2, 5%; grade 1, 32%). Four patients required dose reductions of thalidomide due to treatment-related toxicities, and the median tolerated dose of thalidomide was 200 mg daily.

CONCLUSIONS

The combination of epirubicin and thalidomide was well tolerated when administered in the schedule used in this study. This regimen has limited activity in HCC, with some patients achieving stable disease and clinical benefit. There is a need for defining more effective systemic therapies for HCC.

Maximum a posteriori Bayesian estimation of epirubicin clearance by limited sampling

AIMS

To develop a limited sampling strategy for estimation of epirubicin clearance.

METHODS

The data set comprised 1051 concentrations measured in 105 patients with advanced or metastatic breast cancer treated with epirubicin alone. Ten limited sampling designs comprising two or three blood samples were proposed, taken at times identified by D-optimality from population pharmacokinetic parameter estimates. The data set was then truncated to include the sampling times for each of the designs. MAP Bayesian estimates of clearance were generated for each design and compared with clearance estimates obtained using all the data. The limited sampling designs were also validated using a separate data set obtained from 18 patients with either breast cancer or hepatocellular carcinoma. The sensitivity of the best limited sampling designs to sample time recording errors of 0-10% or 10-20% was then assessed using a simulated data set including 200 patients.

RESULTS

The optimum sampling times were: end of the injection and 18 min, 40 min, 3 h, 10 h and 48 h after the start of the injection. The best three-sample design included samples at 40 min, 3 h and 48 h and gave unbiased estimates of clearance with an imprecision of 9.1% (95% CI 7.3, 10.5). The best two sample design included samples at 3 and 48 h and gave unbiased estimates of clearance with an imprecision of 12.4% (95% CI 9.6, 14.6). Using the validation data set, these two and three sample designs gave unbiased estimates of clearance with an imprecision of 5.6% (95% CI 3.7, 7.0) and 4.2% (95% CI 2.6, 5.3), respectively. Simulations that included 0-10% or 10-20% errors in the recording of the blood sampling times had negligible effects on the bias and imprecision of clearance estimates.

CONCLUSIONS

Limited sampling designs have been identified and validated that estimate epirubicin clearance with adequate precision and without bias from two or three blood samples. These designs also allow flexibility in blood sample collection and are robust with regard to sample time recording errors.

Uptake of lipiodol-cytotoxics conjugates by hepatocellular carcinoma cells

PURPOSE

The aim of this study was to quantify the uptake of anthracyclic cytotoxic drugs by hepatocellular carcinoma cells and the effect of Lipiodol, an iodinated poppy seed oil, on the uptake of anthracyclic cytotoxic conjugates by hepatocellular carcinoma (HCC) cells.

METHODS

Monolayers of hepatocellular carcinoma cell line (HepG2) and a normal human hepatocyte cell line were exposed to 10 microg/mL doxorubicin or epirubicin with or without 2% lipiodol for 1 to 72 hours. The fluorescence intensity in the cytospin and fixed cell were measured using confocal laser scanning microscope.

RESULTS

The uptake of both doxorubicin and epirubicin by the HCC cells was mainly cytoplasmic. The mean fluorescence intensity at 24 hours of lipiodol-doxorubicin-treated cells was increased to 80.7 pixel units, whereas doxorubicin-treated cells intensity was 47.9 pixel units (P <.05). Lipiodol did not have any effect on the uptake of epirubicin. Clonogenic assay confirmed a significant sensitivity difference between doxorubicin and epirubicin-treated hepatocellular carcinoma cell lines.

CONCLUSIONS

Lipiodol has a selective effect on the uptake of certain cytotoxic agents. Lipiodol-doxorubicin-targeted treatment of hepatocellular carcinoma may improve the intracellular uptake and hence cytotoxicity of doxorubicin in vivo.

Phase II study of sequential treatment of advanced non-small-cell lung cancer: three cycles of high-dose epirubicin plus cisplatin followed by weekly vinorelbine

Previous phase I, II, and III studies on high-dose epirubicin (HDEPI), alone or in combination with cisplatin (CP), indicate an interesting activity of this drug in the treatment of non-small-cell lung cancer (NSCLC). However, the toxicological profile of HDEPI limits its prolonged use. In our experience, vinorelbine (VNR) seems to be a suitable drug for long-term monotherapy for advanced NSCLC. On these grounds, advanced NSCLC patients were treated with the following strategy: 3 consecutive cycles of CP 60 mg/m2 and HDEPI 120 mg/m2 on day 1, every 3 weeks; then, irrespective of response, weekly VNR at a dose of 25 mg/m2 was administered at home. From December 1996 to March 1998, 25 patients entered the study. After receiving 3 cycles of CP/HDEPI, 8 patients (32%) had a partial response and 3 (12%) had a minor response. Nine patients had stable disease (36%) and 4 (16%) had progressive disease. Twenty-three patients received weekly VNR, and the median number of administrations was 10 (range, 1-38). After VNR treatment, we observed a partial response in 2 patients who previously had stable disease. Therefore, the overall response rate to sequential treatment was 40%; median time to progression was 7 months (range, 2-26 months). The major toxicities due to the CP/HDEPI regimen were neutropenia (72%) and alopecia (80%). During the VNR treatment, grade 3/4 neutropenia was seen in 36% of patients. The doses and the timing of VNR administrations were modified according to toxicity. Symptoms such as cough, dyspnea, and pain, present in 21 patients before the treatment, improved in 11 cases (52%). Median overall survival is 9 months (range, 3-40+ months); one patient is still alive after 40 months. One- and 2-year survival rates are, respectively, 44% and 16%. This study confirms the activity of CP/HDEPI in NSCLC and indicates that the sequential treatment of CP/HDEPI for 3 cycles followed by weekly VNR could be considered an effective strategy for locally advanced or metastatic NSCLC.

Hepatocellular carcinoma: are we making progress?

Hepatocellular carcinoma is a very prevalent malignancy worldwide, with increasing incidence in the United States. Despite many available treatment options, the prognosis remains poor. Surgical resection or liver transplantation still represents the only potentially curative treatments for HCC. Until more effective systemic therapies are available, different localized treatment approaches will continue to be applied in the management of this disease. Although systemic chemotherapy has been disappointing, increased understanding of the tumor biology in HCC coupled with new drug development may lead to newer agents with novel mechanisms of action that are more efficacious. The poor treatment outcome and dismal prognosis make prevention of HCC an important strategy in controlling this aggressive type of malignancy. Vaccine programs for HBV are ongoing. Efforts are underway to develop a vaccine for HCV. Interferon therapy appears to decrease the risk of developing HCC in patients with hepatitis, especially those with HCV. A number of other approaches for decreasing risk in these patients as well as in those with alcoholic-related cirrhosis are currently being evaluated.

Epirubicin in patients with liver dysfunction: development and evaluation of a novel dose modification scheme

This study aimed to develop an epirubicin dose modification scheme in women with breast cancer and liver dysfunction. We first identified target areas under the concentration-time curve (AUCs) of 2400 and 1600 ng/ml.h from pharmacokinetic studies in 15 women with normal liver tests. In a second group of 16 women with abnormal liver biochemistry, the relationship between raised asparate aminotransferase (AST) and epirubicin clearance was: dose=AUC (97.5-34.2xlog AST). Adaptive dosing was evaluated prospectively in a third group of 41 women with serum AST > or =2xnormal+/-raised bilirubin. The median AUCs were 2444 and 1608 ng/ml.h, close to the high and low target AUCs, respectively. Variability in AUC was lower with adaptive dosing than in a fourth group given an unadjusted dose of epirubicin (coefficient of variation=25.8, 30.0 and 46.5%, respectively; P=0.06). Epirubicin dosing based on AST is safe and may reduce pharmacokinetic variability.

Uptake of Lipiodol--cytotoxic conjugates by hepatoblastoma cells

BACKGROUND

Improvements in the management of children with hepatoblastoma have followed advances made in cytotoxic agents and treatment regimens. The aim of this study was to quantify the effect of Lipiodol, an iodinated poppy-seed oil, on the uptake of anthracyclic cytotoxic conjugates by hepatoblastoma cells in culture.

METHODS

Monolayer cultures of (1) a hepatoblastoma cell line generated from freshly explanted tumour tissue, (2) an immortal hepatoblastoma cell line (C3a) and (3) a human hepatocyte cell line were exposed to doxorubicin 10 microg/ml with or without 2 per cent Lipiodol for 1-72 h. The fluorescence intensity in the treated cells, which correlates with intracellular doxorubicin concentration, was measured by confocal laser scanning microscopy. Cytotoxicity was assessed by trypan blue exclusion and electron microscopy.

RESULTS

Doxorubicin accumulated in the nucleus and cytoplasm of all the cell lines. With Lipiodol, the mean fluorescence intensity of intracellular doxorubicin was increased for up to 48 h in both hepatoblastoma lines, but not in the hepatocyte cell line. Lipiodol increased the uptake and intracellular concentration of doxorubicin in the hepatoblastoma cells in culture. Lipiodol also enhanced the cytotoxicity of doxorubicin on the cultured hepatoblastoma cells.

CONCLUSION

Lipiodol significantly enhanced the uptake of doxorubicin by hepatoblastoma cells in culture. Lipiodol-doxorubicin targeted treatment of hepatoblastoma may improve the intracellular uptake and hence cytotoxicity of doxorubicin in vivo, enabling a reduction in the total dose administered and side-effects.

The MEGX test: a tool for the real-time assessment of hepatic function

The dynamic liver function test based on the hepatic conversion of lidocaine to monoethylglycinexylidide (MEGX) can complement established static liver function tests if prognostic information is of particular interest. Because of its ease of use and rapid turnaround, the MEGX test has found widespread application for realtime assessment of hepatic function in transplantation, critical care medicine, and various experimental models. Lidocaine is metabolized primarily by the liver cytochrome P450 system through sequential oxidative N-dealkylation, the major initial metabolite in humans being MEGX. Because of the relatively high extraction ratio of lidocaine, this liver function test depends not only on hepatic metabolic capacity but also on hepatic blood flow. For the determination of MEGX in serum, an immunoassay based on the fluorescence polarization immunoassay technique high-performance liquid chromatography and gas liquid chromatography methods have been described. Whereas high-performance liquid chromatography and gas liquid chromatography are specific for MEGX, the fluorescence polarization immunoassay also cross-reacts with 3-OH-MEGX. Although this is not a problem in humans, some species, such as the rat, produce significant amounts of this metabolite. The findings of most studies published so far suggest that the MEGX test is a useful tool that can improve our decision-making process with respect to the selection of transplant candidates. Patients with a MEGX 15- or 30-minute test value <10 microg/L have a particularly poor 1-year survival rate. Serial monitoring of liver graft recipients early after transplantation with the MEGX test may initially alert the clinician to a major change in liver function; if used with other tests, such as serum hyaluronic acid concentrations, it may become more discriminatory. In critically ill patients, several studies have shown that an initially rapid decrease in MEGX test values is associated with an enhanced risk for the development of multiple organ dysfunction syndrome and a poor outcome. Further, this decrease appears to be associated with an enhanced systemic inflammatory response. The MEGX test has potential for investigating the pathogenesis of multiple organ dysfunction syndrome with regard to early hepatic functional impairment in critically ill patients after polytrauma or sepsis.

Multicenter randomized clinical trial on high-dose epirubicin plus cis-platinum versus vinorelbine plus cis-platinum in advanced non small cell lung cancer

BACKGROUND

High dose Epirubicin (HD-EPI) (>90 mg/m2) and Vinorelbine (VNR) demonstrated antitumor activity as single agent (about 20%) in the treatment of advanced NSCLC. This trial compares these two agents combined with cisplatin (CP).

PATIENTS AND METHODS

From August 1992 to February 1996, 228 patients with locally advanced or metastatic NSCLC were randomized to receive either EPI 120 mg/m2 as i.v. bolus plus Cisplatin (CP) 60 mg/m2 on day 1 (regimen A) or VNR 25 mg/m2 as i.v. bolus on day 1 and 8 plus CP 60 mg/m2 on day 1 (regimen B). Both treatments were recycled every 21 days up to a maximum cumulative dose of EPI of 840 mg/m2 or 12 cycles. Eligible patients were 212 and 198 patients were evaluable for objective response (95 in arm A and 103 in arm B). The main characteristics of eligible patients were: male/female 179/33; median age 61 (42-72); median Karnofsky PS 80 (70-100); stage IIIA 12%, stage IIIB 40%, stage IV 41%, recurrence 7%; histotype: epidermoid 48%, adenoca 36%, others 16%.

RESULTS

The following response rates were observed in regimens A and B, respectively; CR, 1 and 2%, PR, 32 and 25% (P = 0.4567). Median CR + PR duration was 9 and 8 months, respectively. Median survival was 10.5 and 9.6 months, respectively. Grade III-IV leucopenia occurred in 38 and 21% in arm A and arm B, respectively(P = 0.01), thrombocytopenia in 6 and 0% (P = 0.02), anemia in 8 and 7% (n.s.). Non-hematological toxicity was moderate and the only difference between the treatments was alopecia (88 vs. 33% in arm A and B, respectively). Supraventricular arrhythmia occurred in three patients on regimen A; a >15% LVEF absolute decrease was observed in 9 (22.5%) and three (14%) patients on arm A and arm B, respectively (n.s.). No congestive heart failure was observed.

CONCLUSION

HD-EPI+CP and VNR+CP are both active combinations in advanced NSCLC with a similar response rate, response duration and survival but regimen A was significantly more toxic (myelosuppression and alopecia).

Disposition of epirubicin after intraarterial administration in Lipiodol to patients with hepatocellular carcinoma

Delivering emulsions of anthracycline drugs in Lipiodol, an iodinated poppy-seed oil, via the hepatic artery for the treatment of hepatocellular carcinoma (HCC) has become increasingly popular. However, investigations to determine the extent to which the Lipiodol sequesters the anthracycline in the liver have been limited. Concern has been expressed that such emulsions are not stable and that the anthracycline is, therefore, released rapidly into the circulation. We studied the pharmacokinetics of epirubicin (50 mg m-2) in five patients with nonresectable primary hepatocellular carcinoma after infusion of an epirubicin/Lipiodol emulsion via the hepatic artery. We used a reliable and specific high-performance liquid chromatography assay that allows quantitation of plasma concentrations of epirubicin, epirubicinol, epirubicin glucuronide, and epirubicin aglycone. Although a large interpatient variability in pharmacokinetics was observed, our results were similar to historical data after epirubicin intravenous therapy. Only the results from one patient provided evidence of significant retention of the drug in the liver. It would appear that more stable formulations of epirubicin/Lipiodol are required to increase the efficacy of this form of treatment. We suggest that pharmacokinetic studies should accompany clinical evaluation of emulsions of epirubicin/Lipiodol for the treatment of HCC.

Gender affects doxorubicin pharmacokinetics in patients with normal liver biochemistry

We studied the variability in doxorubicin pharmacokinetics in 27 patients, all of whom had normal liver biochemistry tests. Blood samples were collected after the first cycle of single-agent doxorubicin given as an i.v. bolus and plasma levels were measured by high-performance liquid chromatography (HPLC). The relationship of doxorubicin clearance (dose/AUC) with biochemical tests (AST, bilirubin, alkaline phosphatase, albumin, creatinine) and physical characteristics (age, gender, height, weight, tumour type) was investigated. The 6 men had a significantly higher doxorubicin clearance than did the 21 women (median values, 59 and 27 lh-1 m-2, respectively; P = 0.002). Doxorubicin clearance was significantly lower in patients with breast cancer than in those with other tumours (median values, 26 and 53 lh-1 m-2, respectively; P = 0.0008). The other biochemical and physical parameters did not correlate with doxorubicin clearance. However, in multivariate analysis, gender was the only factor predicting doxorubicin clearance (r2 = 40%). The ratio of the AUCs for doxorubicinol and doxorubicin (R) was higher in the men than in the women (median values, 0.62 and 0.36, respectively; P = 0.03). We conclude that gender may be an important determinant of doxorubicin clearance in patients with normal liver biochemistry.