Effect of human renal and hepatic disease on the pharmacokinetics of anticancer drugs

Effect of modified citrus pectin on galectin-3 inhibition in cisplatin-induced cardiac and renal toxicity

This study evaluated the effect of pharmacological inhibition of galectin 3 (Gal-3) with modified citrus pectin (MCP) on the heart and kidney in a model of cisplatin-induced acute toxicity. Male Wistar rats were divided into four groups (n = 6/group): SHAM, which received sterile saline intraperitoneally (i.p.) for three days; CIS, which received cisplatin i.p. (10 mg/kg/day) for three days; MCP, which received MCP orally (100 mg/kg/day) for seven days, followed by sterile saline i.p. for three days; MCP+CIS, which received MCP orally for seven days followed by cisplatin i.p. for three days. The blood, heart, and kidneys were collected six hours after the last treatment. MCP treatment did not change Gal-3 protein levels in the blood and heart, but it did reduce them in the kidneys of the MCP groups compared to the SHAM group. While no morphological changes were evident in the cardiac tissue, increased malondialdehyde (MDA) levels and deregulation of the mitochondrial oxidative phosphorylation system were observed in the heart homogenates of the MCP+CIS group. Cisplatin administration caused acute tubular degeneration in the kidneys; the MCP+CIS group also showed increased MDA levels. In conclusion, MCP therapy in the acute model of cisplatin-induced toxicity increases oxidative stress in cardiac and renal tissues. Further investigations are needed to determine the beneficial and harmful roles of Gal-3 in the cardiorenal system since it can act differently in acute and chronic diseases/conditions.

Protective effects of annexin A1-derived peptide Ac2-26 on liver and kidney injuries induced by cisplatin in rats

AIMS

In this study we evaluated the effect of pharmacological treatment with annexin A1-derived peptide Ac_2-26 in an experimental model of toxicity induced by cisplatin.

MAIN METHODS

Male rats were divided into Sham (control), Cisplatin (received intraperitoneal injections of 10 mg/kg/day of cisplatin for 3 days) and Ac_2-26 (received intraperitoneal injections of 1 mg/kg/day of peptide, 15 min before cisplatin) groups.

KEY FINDINGS

After 6 h of the last dose of cisplatin, an acute inflammatory response was observed characterized by a marked increase in the number of neutrophils and GM-CSF, IL-1β, IL-6, IL-10 and TNF-α plasma levels. Treatment with Ac_2-26 produced higher levels of GM-CSF, corroborating the high numbers of neutrophils, and the anti-inflammatory cytokine IL-4. Ac_2-26 preserved the morphology of liver structures, preventing the damage caused by cisplatin, but did not reduce plasma levels of the hepatotoxicity biomarkers ARG1, GSTα and SDH. In the kidneys, the peptide maintained the markers of kidney damage CLU and KIM-1 at similar levels to the Sham group but did not avoid morphological changes caused by cisplatin. These effects of Ac_2-26 were associated with the reduction of Fpr1 and Fpr2 levels in the organs studied.

SIGNIFICANCE

Pharmacological treatment with peptide Ac_2-26 partially protects the liver and kidneys against the deleterious effects caused by cisplatin in this experimental model.

Mathematical Modeling of Preclinical Alpha-Emitter Radiopharmaceutical Therapy

Preclinical studies, in vivo, and in vitro studies, in combination with mathematical modeling can help optimize and guide the design of clinical trials. The design and optimization of alpha-particle emitter radiopharmaceutical therapy (αRPT) is especially important as αRPT has the potential for high efficacy but also high toxicity. We have developed a mathematical model that may be used to identify trial design parameters that will have the greatest impact on outcome. The model combines Gompertzian tumor growth with antibody-mediated pharmacokinetics and radiation-induced cell killing. It was validated using preclinical experimental data of antibody-mediated ²¹³Bi and ²²⁵Ac delivery in a metastatic transgenic breast cancer model. In modeling simulations, tumor cell doubling time, administered antibody, antibody specific-activity, and antigen-site density most impacted median survival. The model was also used to investigate treatment fractionation. Depending upon the time-interval between injections, increasing the number of injections increased survival time. For example, two administrations of 200 nCi, ²²⁵Ac-labeled antibody, separated by 30 days, resulted in a simulated 31% increase in median survival over a single 400 nCi administration. If the time interval was 7 days or less, however, there was no improvement in survival; a one-day interval between injections led to a 10% reduction in median survival. Further model development and validation including the incorporation of normal tissue toxicity is necessary to properly balance efficacy with toxicity. The current model is, however, useful in helping understand preclinical results and in guiding preclinical and clinical trial design towards approaches that have the greatest likelihood of success. SIGNIFICANCE: Modeling is used to optimize αRPT.

Optimization of cancer chemotherapy on the basis of pharmacokinetics and pharmacodynamics: from patients enrolled in clinical trials to those in the 'real world'

  Cytotoxic anticancer drugs are the most challenging therapeutic agents among all medicines with relatively narrow efficacy profiles. Therefore, medical oncologists have to practically manage the risk of severe toxic effects to optimize treatment outcomes. Dose and treatment-schedule recommendations for cytotoxic anticancer agents are determined on the basis of clinical trials. Patients enrolled in clinical trials are those likely to receive the drug in clinical practice, excluding those with conditions such as organ dysfunction, obesity, advanced age, or comorbidity. On the other hand, the 'real world' includes large numbers of such patients who do not meet the eligibility criteria of clinical trials. However, there is a paucity of data from sufficiently powered pharmacokinetic and pharmacodynamic studies to support dosage recommendations in such patients. Consequently, dose levels and treatment schedules for chemotherapy in these subjects are somewhat arbitrary and not evidence-based. Pharmacokinetic and pharmacodynamic studies of patients in the 'real world' are needed to address this issue. In this review article, we describe general aspects of clinical pharmacology in cancer patients enrolled in clinical trials and those in the 'real world,' and introduce recent findings regarding the pharmacokinetic and pharmacodynamic properties of irinotecan and S-1 in 'real world' cancer patients.

Dose calculation of anticancer drugs

BACKGROUND

Anticancer drugs are characterized by a narrow therapeutic window and significant inter-patient variability in therapeutic and toxic effects. Current body surface area (BSA)-based dosing fails to standardize systemic anticancer drug exposure and other alternative dosing strategies also have their limitations. Just as important as the initial dose selection is the subsequent dose revision to ensure the dose is correct.

OBJECTIVE

To provide an insight into the different dose individualization and dose adjustment methods, their feasibility and applicability in daily oncology practice and to suggest a practical framework for dose calculation and a basis for future research.

METHODS

Review of relevant literature related to dose calculation of anticancer drugs.

RESULTS

Strategies using clinical parameters, genotype and phenotype markers, and therapeutic drug monitoring all have potential and each has a role for specific drugs. However, no one method is a practical dose calculation strategy for many or all drugs.

CONCLUSION

Given that BSA-dosing leads to significant underdosing it is not reasonable to use this as the sole method of dose calculation. Because of wide disparity in individual patient characteristics and elimination mechanisms, we are unlikely to find the 'Holy Grail' of a single individualized dosing strategy for every patient and anticancer drug in the near future. We propose a pragmatic, although invalidated system for initial dose calculation using dose clusters and structured subsequent dose revision based on treatment-related toxicities and therapeutic drug monitoring. These models need to be tested in clinical trials.

Renal failure does not preclude cure in children receiving chemotherapy for Wilms tumor: a report from the National Wilms Tumor Study Group

BACKGROUND

Children with Wilms tumor can develop renal failure during treatment. Since there are few published data concerning the appropriate chemotherapy for this situation, we reviewed the experience of children who developed renal failure while being treated on National Wilms Tumor Study Group (NWTSG) studies 1-4 (1969-1994).

PATIENTS AND METHODS

Data files in the NWTSG Data Center for all patients with Wilms tumor were screened. Patient demographics and tumor and treatment data were abstracted from those who developed renal failure.

RESULTS

Twenty-eight of 5,910 (0.47%) children with Wilms tumor registered on NWTSG studies I through IV (1971-1994) were treated with chemotherapy after developing renal failure. Among these patients vincristine at full dose (0.05 mg/kg dose) did not increase the risk of severe toxicity. Dactinomycin (full dose: 15 mcg/kg day x 5) increased the risk for severe neutropenia when given at 75-100% of full dose. There was no compelling evidence for increased toxicity of doxorubicin when given at 100% versus 50% dosing (full dose: 20 mg/m(2) day x 3), but the number of patients analyzed was small. The overall survival percentage was 39%, but 64% for those patients who were in their initial treatment phase at the time of renal failure.

CONCLUSION

The data suggest that, in the setting of renal failure, reduction of dosing is not necessary for the three main agents used for treatment of newly diagnosed Wilms tumor, and cure is not precluded. Accurate pharmacologic and pharmacokinetic studies are needed for any patient being treated while in renal failure.

5-Fluorouracil catabolism to 5-fluoro-5,6-dihydrouracil is reduced by acute liver impairment in mice

This study investigated the effect of acute liver damage on the inactivation of 5-fluorouracil (5-FU) to its main catabolite 5-fluoro-5,6-dihydrouracil (5-FUH2) in mice. Plasma pharmacokinetics of 5-FU and 5-FUH2 in mice receiving 5-FU (10, 30, and 90 mg/kg) were compared to those in mice pretreated with carbon tetrachloride and receiving the same 5-FU doses. Carbon tetrachloride-induced hepatic damage was histopathologically examined under light microscopy and serum transaminases and dihydropyrimidine dehydrogenase activities were also measured. Liver histopathology and elevated aminotransferase activity levels confirmed the presence of liver damage. 5-FU C(max) and AUC both increased up to 71% in mice with liver damage. This was reflected by decreased 5-FUH2 production, since 5-FUH2 C(max) and AUC levels decreased up to 47% and 61%, respectively. Metabolic ratios between 5-FUH2 and 5-FU AUCs were considerably decreased as well, further suggesting that liver damage caused a reduction in 5-FU catabolism. DPD activity was not altered in damaged livers. The present results indicate that 5-FU disposition in mice could be profoundly altered in the presence of severe liver impairment, potentially leading to enhanced anabolic activation of 5-FU. This effect seems to be ascribed to a reduction of viable hepatocytes, rather than to an inactivation of DPD activity.

Hepatocellular carcinoma in children and adolescents: results from the Pediatric Oncology Group and the Children's Cancer Group intergroup study

PURPOSE

To determine surgical resectability, event-free survival (EFS), and toxicity in children with hepatocellular carcinoma (HCC) randomized to treatment with either cisplatin (CDDP), vincristine, and fluorouracil (regimen A) or CDDP and continuous-infusion doxorubicin (regimen B).

PATIENTS AND METHODS

Forty-six patients were enrolled onto Pediatric Intergroup Hepatoma Protocol INT-0098 (Pediatric Oncology Group (POG) 8945/Children's Cancer Group (CCG) 8881). After initial surgery or biopsy, children with stage I (n = 8), stage III (n = 25), and stage IV (n = 13) HCC were randomly assigned to receive regimen A (n = 20) or regimen B (n = 26).

RESULTS

For the entire cohort, the 5-year EFS estimate was 19% (SD = 6%). Patients with stage I, III, and IV had 5-year EFS estimates of 88% (SD = 12%), 8% (SD = 5%), and 0%, respectively. Five-year EFS estimates were 20% (SD = 9%) and 19% (SD = 8%) for patients on regimens A and B, respectively (P =.78), with a relative risk of 1.2 (95% confidence interval, 0.60 to 2.3) for regimen B when compared with regimen A. Outcome was similar for either regimen within disease stages. Events occurred before postinduction surgery I in 18 (47%) of 38 patients with stage III or IV disease, and tumor resection was possible in two (10%) of the remaining 20 children with advanced-stage disease after chemotherapy.

CONCLUSION

Children with initially resectable HCC have a good prognosis and may benefit from the use of adjuvant chemotherapy. Outcome was uniformly poor for children with advanced-stage disease treated with either regimen. New therapeutic strategies are needed for the treatment of advanced-stage pediatric HCC.

Pharmacokinetically guided administration of chemotherapeutic agents

The current practice for the dose calculation of most anticancer agents is based on body surface area in m2, although lower interpatient variation in pharmacokinetic parameters has been reported with pharmacokinetically guided administration. As chemotherapeutic agents have a narrow therapeutic window, pharmacokinetically guided administration may lead to less toxicity and higher efficacy than administration on the basis of body surface area. Pharmacokinetically guided administration, using parameters such as area under the plasma concentration-time curve (AUC), steady-state plasma drug concentration and drug exposure time above a certain plasma concentration, has been studied for many antineoplastic agents. Assessment of pharmacokinetic profiles allows the characterisation of relationships between pharmacokinetic parameters and efficacy and toxicity. AUC appears to be more closely correlated with pharmacodynamics than does the dose per unit of body surface area. In particular, the AUC-guided administration of carboplatin has been extensively studied, based on the close relationship between the renal clearance of the drug and glomerular filtration rate. Several formulae and limited sampling models have been derived to predict the AUC of carboplatin. The relationship between AUC and pharmacodynamics has also been studied for other anticancer agents, for example fluorouracil, topotecan, etoposide, cisplatin and busulfan, but all less extensively than for carboplatin. The pharmacokinetically guided administration of these agents needs to be investigated further before the use of alternative administration formulae can become standard clinical practice. Prospective studies of pharmacokinetically guided versus surface area-based administration should be performed to validate pharmacokinetic-pharmacodynamic relationships and to facilitate optimal dosage of anticancer agents in the clinic.

Randomized comparison of cisplatin/vincristine/fluorouracil and cisplatin/continuous infusion doxorubicin for treatment of pediatric hepatoblastoma: A report from the Children's Cancer Group and the Pediatric Oncology Group

PURPOSE

Previous studies demonstrated that chemotherapy with either cisplatin, vincristine, and fluorouracil (regimen A) or cisplatin and continuous infusion doxorubicin (regimen B) improved survival in children with hepatoblastoma. The current trial is a randomized comparison of these two regimens.

PATIENTS AND METHODS

Patients (N = 182) were enrolled onto study between August 1989 and December 1992. After initial surgery, patients with stage I-unfavorable histology (UH; n = 43), stage II (n = 7), stage III (n = 83), and stage IV (n = 40) hepatoblastoma were randomized to receive regimen A (n = 92) or regimen B (n = 81). Patients with stage I-favorable histology (FH; n = 9) were treated with four cycles of doxorubicin alone.

RESULTS

There were no events among patients with stage I-FH disease. Five-year event-free survival (EFS) estimates were 57% (SD = 5%) and 69% (SD = 5%) for patients on regimens A and B, respectively (P =.09) with a relative risk of 1.54 (95% confidence interval, 0.93 to 2.5) for regimen A versus B. Toxicities were more frequent on regimen B. Patients with stage I-UH, stage II, stage III, or stage IV disease had 5-year EFS estimates of 91% (SD = 4%), 100%, 64% (SD = 5%), and 25% (SD = 7%), respectively. Outcome was similar for either regimen within disease stages. At postinduction surgery I, patients with stage III or IV disease who were found to be tumor-free had no events; those who had complete resections achieved a 5-year EFS of 83% (SD = 6%); other patients with stage III or IV disease had worse outcome.

CONCLUSION

Treatment outcome was not significantly different between regimen A and regimen B. Excellent outcome was achieved for patients with stage I-UH and stage II hepatoblastoma and for subsets of patients with stage III disease. New treatment strategies are needed for the majority of patients with advanced-stage hepatoblastoma.

Can pharmacokinetic monitoring improve clinical use of fluorouracil?

Fluorouracil is used clinically against a variety of solid tumors. It is a prodrug that undergoes a series of intracellular conversions to active cytotoxic species. There is wide interindividual variability in fluorouracil metabolism; furthermore, it has nonlinear kinetics that make it relatively more difficult to predict plasma concentrations after brief infusions compared with prolonged infusions. There is an increasing body of evidence that relates plasma fluorouracil concentrations to toxicity and effectiveness, and consequently there may be a definable mathematical relationship that describes a 'therapeutic window'. Dose nomograms and pharmacokinetic models based on limited sampling strategies have been developed, as have empirical dose escalation schedules based on multivariate analysis of the determinants of toxicity, The utility of these approaches should be tested in properly powered, prospective, randomised trials.

Anthracyclines in haematology: pharmacokinetics and clinical studies

The activity of anthracyclines in the treatment of a wide spectrum of haematological malignancies has long been established. Differences in the pharmacokinetic and pharmacodynamic properties of these drugs have resulted in the selection of individual compounds for particular indications while the recent reformulation of anthracyclines in liposomal preparations seems likely to significantly alter their range of activity and toxicity. The problems related to cumulative cardiotoxicity secondary to anthracycline exposure can be ameliorated by the use of dexrazoxane and a number of agents may prove to have a role in altering their cellular resistance to their cytotoxic actions.

Pharmacokinetics of anticancer agents in patients with impaired liver function

This report reviews published information on the clinical pharmacokinetics of antitumour agents in patients with liver dysfunction, associated with primary liver disease or liver metastases. Information was available for anthracyclines and their related compounds, antimetabolites, cyclophosphamide, vinca alkaloids, taxanes and epipodophyllotoxins. Changes in the pharmacokinetic profile or metabolism in patients with mild or severe hepatobiliary dysfunction are described and the relationships between serum levels, parameters employed for measuring hepatic function and toxic or therapeutic effects are examined. Current knowledge of the pharmacokinetics of antineoplastic agents in liver disease is far from complete, mostly obtained in small numbers of non-homogeneous patients often presenting only moderate liver dysfunction, and empirical guidelines for dose assessment are still largely applied in clinical practice. Because of the complex pathophysiological mechanisms of liver insufficiency in cancer patients, there is still doubt whether endogenous markers are useful. Although caution in treating cancer patients with liver insufficiency is compulsory, for most compounds there seems no need to recommend dose reductions for moderate impairment. However, for the tubulin acting agents, vincristine, vinblastine and possibly for paclitaxel and docetaxel, there is strong evidence that dose adjustment is mandatory in order to avoid excessive neutropenia and neurotoxicity.

Individual dose adaptation of anticancer drugs

The dose of anticancer drugs is currently adjusted to the patient body surface area, although patients have different abilities to clear anticancer drugs. The dose adjustment to physiological functions permits major toxic accidents to be avoided. The adjustment to tumour drug content is considered, but for ethical or technical reasons, it cannot be used routinely The best criterion for the dose adjustment seems to be drug plasma concentration. The relationship between plasma concentration and efficacy may not be excellent, since it depends on the presence of resistant cells and on the blood flow through the tumour. A relationship between plasma concentration and/or the area under the curve (AUC) with toxicity has been reported with all major anticancer drugs. Different methods of dose adjustment to the drug plasma concentration are reported. In conclusion, dose adjustment to the drug plasma concentration or to the AUC can improve the chemotherapy efficacy, while reducing toxicity.

Late seroconversion and high chronicity rate of hepatitis C virus infection in patients with hematologic disorders

BACKGROUND

Patients with hematologic disorders requiring repeated blood and platelet transfusions are at high risk for development of post-transfusion non-A, non-B hepatitis.

PATIENTS AND METHODS

Fifty-five patients with hematologic diseases and post-transfusion non-A, non-B hepatitis were studied. Sera were assayed for hepatitis C virus (HCV) antibodies with a second-generation enzyme-linked immunoassay. Sera from 40 patients were examined for the presence of HCV RNA with a nested PCR method.

RESULTS

The clinical picture of acute non-A, non-B hepatitis did not differ from that described in other patient groups: however, progression to chronic hepatitis was very common (95%). Thirty-eight (95%) of 40 patients, whose sera were analysed both serologically and for the presence of HCV RNA had verified HCV infections. In some patients time to seroconversion was prolonged, up to more than 14 months. Seventeen patients with resistant or relapsed acute leukemia were treated with combination chemotherapy during the acute or chronic phase of hepatitis. Suppression of the inflammatory activity as reflected by a decrease of serum aminotransferase levels was recorded during the subsequent pancytopenic period.

CONCLUSIONS

Hepatitis C has a high chronicity rate in patients with hematologic disorders which parallels the situation of hepatitis B in the immunocompromised host. Furthermore, like the situation in hepatitis B, the hosts' immune response to infection seems to be involved in the pathogenesis of liver injury. Time to seroconversion may be prolonged and detection of HCV RNA is therefore important for diagnosis.

Carboplatin and etoposide pharmacokinetics in patients with testicular teratoma

The pharmacokinetics of carboplatin and etoposide were studied in four testicular teratoma patients receiving four courses each of combination chemotherapy consisting of etoposide (120 mg/m2 daily x 3); bleomycin (30 mg weekly) and carboplatin. The carboplatin dose was calculated so as to achieve a constant area under the plasma concentration vs time curve (AUC) of 4.5 mg carboplatin/ml x min by using the formula: dose = 4.5 x (GFR + 25), where GFR is the absolute glomerular filtration rate measured by 51Cr-EDTA clearance. Carboplatin was given on either day 1 or day 2 of each course and pharmacokinetic studies were carried out in each patient on two courses. Etoposide pharmacokinetics were also studied on two separate courses in each patient on the day on which carboplatin was given and on a day when etoposide was given alone. The pharmacokinetics of carboplatin were the same on both the first and second courses, on which studies were carried out with overall mean +/- SD values (n = 8) of 4.8 +/- 0.6 mg/ml x min, 94 +/- 21 min, 129 +/- 21 min, 20.1 +/- 5.41, 155 +/- 33 ml/min and 102 +/- 24 ml/min for the AUC, beta-phase half-life (t 1/2 beta), mean residence time (MRT), volume of distribution (Vd) and total body (TCLR) and renal clearances (RCLR), respectively. The renal clearance of carboplatin was not significantly different from the GFR (132 +/- 32 ml/min). Etoposide pharmacokinetics were also the same on the two courses studied, with overall mean values +/- SD (n = 8) of: AUC = 5.1 +/- 0.9 mg/ml x min, t 1/2 alpha = 40 +/- 9 min, t 1/2 beta = 257 +/- 21 min, MRT = 292 +/- 25 min, Vd = 13.3 +/- 1.31, TCLR = 46 +/- 9 ml/min and RCLR = 17.6 +/- 6.3 ml/min when the drug was given alone and AUC = 5.3 +/- 0.6 mg/ml x min, t 1/2 alpha = 34 +/- 6 min, t 1/2 beta = 242 +/- 25 min, MRT = 292 +/- 25 min, Vd = 12.5 +/- 1.81, TCLR = 43 +/- 6 ml/min and RCLR = 13.4 +/- 3.5 ml/min when it was given in combination with carboplatin. Thus, the equation used to determine the carboplatin accurately predicted the AUC observed and the pharmacokinetics of etoposide were not altered by concurrent carboplatin administration. The therapeutic efficacy and toxicity of the carboplatin-etoposide-bleomycin combination will be compared to those of cisplatin, etoposide and bleomycin in a randomised trial.

Clinical pharmacology of 5-fluorouracil

5-Fluorouracil, first introduced as a rationally synthesized anticancer agent 30 years ago, continues to be widely used in the management of several common malignancies including cancer of the colon, breast and skin. This drug, an analogue of the naturally occurring pyrimidine uracil, is metabolised via the same metabolic pathways as uracil. Although several potential sites of antitumour activity have been identified, the precise mechanism of action and the extent to which each of these sites contributes to tumour or host cell toxicity remains unclear. Several assay methods are available to quantify 5-fluorouracil in serum, plasma and other biological fluids. Unfortunately, there is no evidence that plasma drug concentrations can predict antitumour effect or host cell toxicity. The recent development of clinically useful pharmacodynamic assays provides an attractive alternative to plasma drug concentrations, since these assays allow the detection of active metabolites of 5-fluorouracil in biopsied tumour or normal tissue. 5-Fluorouracil is poorly absorbed after oral administration, with erratic bioavailability. The parenteral preparation is the major dosage form, used intravenously (bolus or continuous infusion). Recently, studies have demonstrated the pharmacokinetic rationale and clinical feasibility of hepatic arterial infusion and intraperitoneal administration of 5-fluorouracil. In addition, 5-fluorouracil continues to be used in topical preparations for the treatment of malignant skin cancers. Following parenteral administration of 5-fluorouracil, there is rapid distribution of the drug and rapid elimination with an apparent terminal half-life of approximately 8 to 20 minutes. The rapid elimination is primarily due to swift catabolism of the liver. As with all drugs, caution should be used in administering 5-fluorouracil in various pathophysiological states. In general, however, there are no set recommendations for dose adjustment in the presence of renal or hepatic dysfunction. Drug interactions continue to be described with other antineoplastic drugs, as well as with other classes of agents.

Pharmacologic considerations in the treatment of acute lymphoblastic leukemia

Great strides have been made in the chemotherapy of childhood ALL over the past three decades. Principles and concepts learned from early successes in treating this disease subsequently have been applied to the treatment of other pediatric cancers and adult malignancies. Because of the prominent role of chemotherapy in the treatment of ALL, a clear understanding of the clinical pharmacology of the antileukemic drugs is essential. This article reviews issues relating to the clinical pharmacology of the anticancer drugs that are commonly used in the treatment of acute lymphoblastic leukemia.

Systemic treatment of cancer in the elderly

The goal of this review is to provide a readable and exhaustive reference in three major areas of geriatric oncology: complications of chemotherapy and radiotherapy, responsiveness of cancer to systemic treatment, social issues in the care of elderly patients with terminal illnesses. The conclusions of this study are: 1. Progressive deterioration of renal function is the most consistent change of aging. Adjustment of doses of renally excreted drugs to individual creatinine clearance may prevent life-threatening myelotoxicity in the elderly. 2. Intensive chemotherapy regimens (acute leukemia, non Hodgkin's lymphoma) cause more serious and prolonged myelotoxicity in the elderly. Elderly are more susceptible than younger patients to cardiotoxicity and central and peripheral neurotoxicity. Age is a poor predictor of complications in other organs or systems. 3. The prognosis of patients with Hodgkin's disease worsens with aging, possibly due to increased prevalence of mixed cellularity histology. It is controversial whether the prognosis of other neoplasias is poorer. Prognosis is not age-related in multiple myeloma. In general, elderly in good performance status may benefit from systemic cancer treatment to the same extent as younger patients, except for Hodgkin's disease. 4. The Informal Support Network, epitomized by the family, appears the most suitable environment to care for the elderly with cancer.

Therapeutic drug monitoring in oncology. Problems and potential in antineoplastic therapy

Therapeutic drug monitoring is now widely used in many areas of medicine. With its proliferation has come an understanding of the clinical situations in which it is likely to be of value. Factors that can limit the usefulness of therapeutic drug monitoring and situations where it is less likely to be of benefit have also been identified. At present, the routine use of therapeutic drug monitoring in antineoplastic therapy is limited to measurement of plasma methotrexate concentrations after high-dose methotrexate therapy. The lack of a more widespread application of therapeutic drug monitoring in oncology has been due to deficiencies in knowledge about the clinical pharmacology of antineoplastic agents and to factors specific to the chemotherapy of neoplasms. These factors include the broad heterogeneity of malignant neoplasms, the complexities of the drug-tumour interaction, difficulties in assessment of this interaction and the use of combinations of antineoplastic agents with cumulative efficacies and toxicities. Despite these problems, there are many areas in antineoplastic therapy where the use of therapeutic drug monitoring could prove of benefit. The prevention of the chronic pulmonary toxicity of bleomycin, the assessment of the bioavailability of oral chemotherapy, and monitoring drug disposition in the presence of hepatic or renal dysfunction are just some of the potential applications. If recent emphasis on dose as a critical factor in the success of cancer chemotherapy is substantiated, then the need to apply therapeutic drug monitoring within oncology will become more pressing.

Pharmacokinetic studies in lung cancer patients

Pharmacokinetic measurements to monitor and design cytotoxic treatments in cancer patients are being used more and more in order to optimize dosage and administration schedules. Ideally, information on drug concentrations over time should help reveal dose-response correlations. The cytotoxic drugs carmustine, etoposide, cyclophosphamide, iphosphamide, cis-diammineplatinum, Adriamycin (doxorubicin), and 4'-epi-Adriamycin have been monitored on different treatment programs of patients with advanced lung cancers. The collected experience emphasizes the many individual variables encountered in clinical practice complicating the effort of correlating pharmacokinetic data with clinical results. The examples, presented on the basis of the authors' experiences, pertain to drug instability, gastrointestinal absorption, enzymatic induction in the liver, drug interaction, and drug tissue concentrations.