Sequence-dependent alteration of doxorubicin pharmacokinetics by paclitaxel in a phase I study of paclitaxel and doxorubicin in patients with metastatic breast cancer

Metronomic doses and drug schematic combination response tested within chambered coverslips for the treatment of breast cancer cells (JIMT-1)

Low-dose metronomic (LDM) chemotherapy is an alternative to conventional chemotherapy and is the most frequently used approach in low dose chemotherapy regimens. The selection of patients, drug dosages, and dosing intervals in LDM is empirical. In this study, we systematically examined the schedule-dependent interaction of drugs on a breast cancer cell line (BCC) cultured in chambered coverslips. The LDM studies were combined with cell staining in order to better characterize different cell states and cell death modes, including caspase-dependent apoptosis, caspase-independent cell death and autophagy-dependent cell death. Microscope images were examined using the Fiji Trainable Weka Segmentation plugin to analyse cell area in 7500 images showing different modes of cell death. Paclitaxel combined with LDM chemotherapy demonstrated a reduction in the area covered by live cells. In contrast, there was an induction of high levels of cell death due to caspase-dependent apoptosis.

Dual drug delivery and sequential release by amphiphilic Janus nanoparticles for liver cancer theranostics

Co-delivery of two drugs with diverse physicochemical properties and specific administration order for cancer theranostics are vitally important for drug resistance conquering and side effects reducing. Consequently, we explored a unique amphiphilic PCL-AuNC/Fe(OH)₃-PAA Janus nanoparticle (JNP) to simultaneously preserve the hydrophilic drug (doxorubicin) and hydrophobic drug (docetaxel) in their distinct domains. Owing to their extraordinary heterostructure and independent pH and NIR sensitive properties, the optional sequential drug release by a single inorganic JNP was realized for the first time, and the results presented the synchronous release of two drugs had 5% better therapeutic effect. In addition, the excellent computed X-ray tomography/magnetic resonance (CT/MR) imaging capabilities from AuNC and Fe(OH)₃ suggested our JNPs could effectively guide the cancer therapy. Furthermore, the mice treated with dual drug loaded PCL-AuNC/Fe(OH)₃-PAA JNPs under near infrared (NIR) laser irradiation showed better tumor inhibition than solo drug, cocktail and dual drug treated groups, indicating the effectivity and significance of combined cancer therapy.

Paclitaxel and Doxorubicin Combination in the First-line Treatment of Metastatic Breast Cancer

Anthracyclines and taxanes are currently the most effective drugs in the treatment of metastatic breast carcinoma. The aim of this study was to determine the efficacy and toxicity of paclitaxel and doxorubicin combination in the first-line treatment of metastatic breast cancer. Forty-five women with metastatic breast cancer were recruited in the study. Median age was 49 years (range, 33-70). Treatment protocol: doxorubicin (50 mg/m2/day, 30-min infusion) followed by paclitaxel (200 mg/m2/day, 3-hr infusion) every 3 weeks. Response rates included complete response in 13 (28.9%) patients and partial response in 19 (42.2%) patients, with an overall response rate of 71%. Five (11%) patients had stable disease and 8 (18%) patients had progressive disease. At a median follow-up of 19.7 months, median time to progression for all patients was 19.9 months (95% confidence interval, 12.8 to 27 months). Median overall survival time was 28.4 months. Grade 3-4 nausea/vomiting and hematological toxicities were observed in 12 (26%) and 6 (13.3%) patients, respectively. Cardiac toxicity was observed in 2 (4.4%) patients. In this trial, paclitaxel and doxorubicin combination was demonstrated to be a favorable and active regimen in the first-line treatment of metastatic breast cancer.

Precision cardio-oncology: understanding the cardiotoxicity of cancer therapy

Current oncologic treatments have brought a strong reduction in mortality in cancer patients. However, the cancer therapy-related cardiovascular complications, in particular chemo-therapy and radiation therapy-induced cardiotoxicities are a major cause of morbidity and mortality in people living with or surviving cancer. The simple fact is that all antineoplastic agents and radiation therapy target tumor cells but also result in collateral damage to other tissues including the cardiovascular system. The commonly used anthracycline chemotherapy agents can induce cardiomyopathy and congestive heart failure. Targeted therapies with human epidermal growth factor antibodies, tyrosine kinase inhibitors or vascular endothelial growth factor antibodies, and the antimetabolites also have shown to induce cardiomyopathy and myocardial ischemia. Cardiac arrhythmias and hypertension have been well described with the use of tyrosine kinase inhibitors and antimicrotubule agents. Pericarditis can happen with the use of cyclophosphamide or cytarabine. Mediastinal radiation can cause constrictive pericarditis, myocardial fibrosis, valvular lesions, and coronary artery disease. Despite significant progresses in the understanding of the molecular and pathophysiologic mechanisms behind the cardiovascular toxicity of cancer therapy, there is still lack of evidence-based approach for the monitoring and management of patients. This review will focus mainly on the recent advances in the molecular mechanisms of cardiotoxicity related to common cancer therapies while introducing the concept of cardio-oncology service. Applying the general principles of multi-disciplinary approaches toward the diagnosis, prevention, monitoring, and treatment of cancer therapy-induced cardiomyopathy and heart failure will also be discussed.

Introduction to taxane pharmacokinetics and pharmacodynamics

Objective. To compare the pharmacokinetics and pharmacodynamics of the taxanes, paclitaxel and docetaxel.

Data sources. A MEDLINE search was conducted using docetaxel, dose, drug interactions, liver dysfunction, liver impairment, mechanism of action, paclitaxel, pharmacodynamics, pharmacokinetics, and schedule as search terms. Reference lists, bibliographies of pertinent articles, and abstracts from the American Society of Clinical Oncology and the American Association for Cancer Research annual meetings were also identified and reviewed. Both preclinical and clinical literature were reviewed and analyzed.

Data synthesis. The taxanes, paclitaxel and docetaxel, are a novel class of antineoplastic drugs that provide notable activity, and produce high response rates but minimal side effects. These agents share a similar mechanism of action, but several important pharmacokinetic and pharmacodynamic differences exist. The higher tubulin affinity, slower efflux from cells, triphasic elimination, and prolonged drug exposure of docetaxel confer pharmacokinetic and pharmacodynamic advantages over paclitaxel. The nonlinear pharmacokinetics of paclitaxel may result in disproportionate increases in plasma concentrations and AUCs; however, several safe and effective paclitaxel regimens are currently used. Because the taxanes are metabolized extensively in the liver by cytochrome P-450 enzymes, patients with hepatic impairment have reduced total body clearance that may result in increased toxicity. Additionally, drugs that induce, inhibit, or compete with microsomal enzymes known to metabolize the taxanes, can result in clinically significant drug interactions. These pharmacokinetic differences should be carefully considered when dosing and scheduling paclitaxel or docetaxel in clinical practice.

The role of docetaxel in the treatment of non-small cell lung cancer lung cancer: an update

INTRODUCTION

Non-small cell lung cancer lung cancer (NSCLC) is a devastating disease, with poor prognosis for patients with metastatic disease. The management of these patients has evolved during the past decade, challenging the role of cytotoxic chemotherapy as the only available treatment option. Nevertheless, chemotherapy still retains a dominant position for the majority of both treatment naïve and pretreated patients. Among the chemotherapeutic agents, docetaxel is one of the most commonly used in 1st and subsequent treatment lines, even in the current era of precision medicine. Areas covered: We searched Medline, Embase, Scopus and Cochrane Library for randomized phase III trials that evaluated docetaxel in various clinical settings of NSCLC and for meta-analyses of such trials and we present all relevant data regarding the pharmacology and clinical use of docetaxel in NSCLC. Expert commentary: Despite its diminishing role, docetaxel in combination with novel targeted agents remains an important option of the therapeutic armamentarium in advanced NSCLC.

A guide to clinically relevant drug interactions in oncology

This paper presents an overview of new information on clinically relevant drug-drug interactions, particular focuses on negative drug interactions in oncology. We have generated a concise table of drug-drug interactions that provides a synopsis of the clinical outcome of the interaction along with a recommendation for management. We have also generated other tables that describe specific interactions with methotrexate and dosing guidelines for cytotoxic drugs in the presence of renal or hepatic dysfunction. Since warfarin is one of the non-anticancer drugs that is commonly used in cancer patients for the treatment and prevention of venous thromboembolism, its interactions with other anticancer drugs that have been reported in literatures were also reviewed in this paper. In general, drug interactions observed in cancer patients may be categorized into pharmacokinetic, pharmacodynamic and pharmaceutic interactions. Pharmacokinetic interactions involve one drug altering the absorption, distribution, metabolism, or excretion of another drug. Interpatient variability in the pharmacokinetic profile of many anticancer agents often complicates the predictability of the antitumor response and toxicities. Among four pharmacokinetic characteristics, drug interactions involving hepatic metabolism is probably the most common and important mechanism responsible for oncologic drug interactions. For example, several anticancer drugs including taxanes, vinca alkaloids, and irinotecan are known to be metabolized by cytochrome CYP3A4. Enzyme-inducing anticonvulsants have been shown to significantly decrease the plasma levels of these anticancer drugs, thereby compromising the anti-tumor effects. N ephrotoxicity or changes in hepatic function caused by some anticancer drugs (e.g., cisplatin, asparaginase) may also have an impact on the pharmacokinetics of the interacting agents. Pharmacodynamic interactions may occur when two or more drugs acting at a common receptor-binding site impact on the pharmacologic action of the object drug, without influencing the pharmacokinetics of each interacting agent. In clinical setting, a decrease of antitumor efficacy was observed in breast cell lines when gemcitabine or vinorelbine were used in combination with paclitaxel. On the other hand, a decreased incidence of thrombocytopenia was seen in patients receiving combination of carboplatin and palcitaxel compared to those receiving carboplatin alone. The third type of drug-drug interaction is known as pharmaceutic interaction. When one drug may alter the physical or chemical compatibility of another drug that utlimately leads to a change in appearance of the solution or a decrease of effectiveness of the drug due to drug inactivation or degradation.

Review : Pharmacokinetics and pharmacodynamics of the taxanes

Objectives. To review the pharmacokinetics and pharmacodynamics of docetaxel and paclitaxel.

Data Sources. We reviewed the literature through a MEDLINE search from 1982 to 1996. The terms docetaxel, paclitaxel, taxanes, and taxoids were used in the search. Relevant articles cited in literature obtained by MEDLINE searching, as well as new articles published in early 1997 in specific oncology journals, were also considered.

Data Extraction. We have reviewed the current literature with regard to the chemistry, mechanisms of action and pharmacology, pharmacokinetics, clini cal use, adverse effects, drug interactions, formula tion, dosage, administration, and pharmaceutical is sues of the taxanes.

Conclusion. Both docetaxel and paclitaxel are novel antineoplastic agents with significant activity in many types of cancer. The pharmacokinetics of both agents are best characterized by a three-compartment disposition profile. However, the pharmacokinetics of paclitaxel, not docetaxel, are non-linear and can be described by a saturation process in distribution and elimination. The nonlinearity appears to be associated more frequently with shorter infusions and/or higher doses. There is evidence suggesting that the time duration of paclitaxel concentrations maintained above 0.1 μM/L (T>0.1 μM ) is associated with improved survival and development of toxicity. On the other hand, currently there is no information relating opti mal systemic exposure of docetaxel to efficacy and toxicity. In addition, these pharmacokinetic-pharma codynamic relationship may change with therapy with antineoplastic agents and other agents adminis tered concurrently, and necessitates additional phar macokinetic-pharmacodynamic investigations.

Coenzyme complex decreased cardiotoxicity when combined with chemotherapy in treating elderly patients with gastrointestinal cancer

OBJECTIVE

To investigate the effect of coenzyme complex on decreasing cardiotoxicity in elderly patients with gastrointestinal cancer who were treated by chemotherapy.

METHODS

From September 2011 to February 2015, we recruited 54 elderly (with more than 70 years of age) patients with gastrointestinal cancer, with advanced disease. Then treated with chemotherapy combined with or without coenzyme complex. After two cycles of treatment, the effect of coenzyme complex on decreasing cardiotoxicity were evaluated.

RESULTS

Chemotherapy was combined with coenzyme complex in 32 patients (22man, 10 woman; median age: 74 years, range: 70-87 years) without coenzyme complex in 22 patients (15man, 7 woman; median age: 73 years, range: 70-80 years) with gastrointestinal cancer. Cardiac event was significantly lower in patients treated with chemotherapy combined with coenzyme complex (p<0.01).

CONCLUSIONS

Coenzyme Complex decreased cardiotoxicity when combined with chemotherapy in treating elderly patients with gastrointestinal cancer.

Generation and functional assessment of 3D multicellular spheroids in droplet based microfluidics platform

Here we describe a robust, microfluidic technique to generate and analyze 3D tumor spheroids, which resembles tumor microenvironment and can be used as a more effective preclinical drug testing and screening model. Monodisperse cell-laden alginate droplets were generated in polydimethylsiloxane (PDMS) microfluidic devices that combine T-junction droplet generation and external gelation for spheroid formation. The proposed approach has the capability to incorporate multiple cell types. For the purposes of our study, we generated spheroids with breast cancer cell lines (MCF-7 drug sensitive and resistant) and co-culture spheroids of MCF-7 together with a fibroblast cell line (HS-5). The device has the capability to house 1000 spheroids on chip for drug screening and other functional analysis. Cellular viability of spheroids in the array part of the device was maintained for two weeks by continuous perfusion of complete media into the device. The functional performance of our 3D tumor models and a dose dependent response of standard chemotherapeutic drug, doxorubicin (Dox) and standard drug combination Dox and paclitaxel (PCT) was analyzed on our chip-based platform. Altogether, our work provides a simple and novel, in vitro platform to generate, image and analyze uniform, 3D monodisperse alginate hydrogel tumors for various omic studies and therapeutic efficiency screening, an important translational step before in vivo studies.

Pharmacokinetic interactions of breast cancer chemotherapeutics with human doxorubicin reductases

Paclitaxel (PTX), docetaxel (DTX), 5-fluorouracil (5-FU), cyclophosphamide (CYC) or tamoxifen (TMX) are combined with doxorubicin (DOX) in first-line chemotherapy regimens that are indicated for breast cancer patients. Although the efficacies of these drugs in combination treatments have been demonstrated in clinical practice, their possible interference with DOX metabolism has not been described in detail to date. In the present study, we investigated the possible interactions of human carbonyl reducing enzymes with 5-FU, PTX, DTX, CYC and TMX. First, the reducing activities of carbonyl reducing enzymes toward DOX were tested using incubations with purified recombinant enzymes. In the subsequent studies, we investigated the possible effects of the tested anticancer agents on the DOX-reducing activities of the most potent enzymes (AKR1C3, CBR1 and AKR1A1) and on the DOX metabolism driven by MCF7, HepG2 and human liver cytosols. In both of these assays, we observed that CYC and its active metabolites inhibited DOX metabolism. In the final study, we tracked the changes in AKR1C3, CBR1 and AKR1A1 expression levels following exposure to the tested cytostatics in MCF7 and HepG2 cells. Consequently, no significant changes in the expression levels of tested enzymes were detected in either cell line. Based on these findings, it is feasible to presume that inhibition rather than induction plays a role in the interactions of the tested anticancer agents with DOX-reducing enzymes. In conclusion, our results describe important molecular events that occur during combination breast cancer therapies and might modulate pharmacokinetic DOX resistance and/or behaviour.

Cardiotoxicity and oncological treatments

BACKGROUND

Cardiotoxic and other side effects limit the usefulness of treatments for cancer.

METHOD

This article is based on pertinent articles that were retrieved by a selective search in PubMed and other databases, and on the guidelines of the European Society of Cardiology, the Association of Scientific Medical Societies in Germany, and the European Society of Medical Oncology.

RESULTS

Prospective studies have shown that some treatments for cancer are cardiotoxic. The heart damage that they cause can manifest itself as arrhythmia, arterial hypertension, thromboembolism, angina pectoris, myocardial infarction, or heart failure. It has been observed that potentially lethal complications can arise as late as 40 years after treatment of the original cancer. The anthracycline drug doxorubicin, given in a dose of 500 mg/m2 of body surface area, has been found to cause cardiac complications in 4-36% of the patients treated with it. Trastuzumab and epirubicin cause dose-limiting cardiac events in 1.7-5% of patients, depending on the dosage. Paclitaxel causes bradycardia, intracardiac conduction block, or arrhythmia in 0.5% of patients. 18% of patients treated with sunitimib or sorafenib have clinical manifestations relating to the heart (angina pectoris, dyspnea). 5-fluorouracil can cause angina pectoris at the beginning of treatment and rarely causes myocardial infarction. Cardiac radiation therapy, a form of treatment practiced in earlier decades, can cause cardiac complications 20 years after the event. The opportunity to prevent cardiac complications of anthracycline drugs with dexrazoxane is decidedly limited, but initial studies have shown that treatment with beta-blockers and ACE inhibitors lessens the likelihood of cardiotoxic side effects. When cardiac complications arise, the generally applicable rules for the treatment of each type of cardiac problem should be followed. The oncological treatment protocol should be adjusted or switched to one that is less damaging to the heart.

CONCLUSION

Treating physicians need to be thoroughly acquainted with the cardiotoxic effects of anti-cancer drugs so that they can diagnose them early on and avoid jeopardizing the overall success of treatment.

A multicenter phase I-II study of docetaxel plus epirubicin plus bevacizumab as first-line treatment in women with HER2-negative metastatic breast cancer

PURPOSE

To assess the efficacy and toxicity of docetaxel (D) plus epirubicin (E) in combination with bevacizumab (B) [DEB regimen] as front-line treatment in patients with metastatic breast cancer (MBC).

PATIENTS AND METHODS

Women with previously untreated HER2-negative MBC received B (15 mg/kg), E (75 mg/m2) and D (75 mg/m2) with prophylactic G-CSF support every 3 weeks (q3w) for up to 9 cycles followed by B (15 mg/kg q3w) until disease progression. Primary endpoint was the overall response rate (ORR). Circulating tumor cells (CTCs) were evaluated using the CellSearch system at different time points during therapy.

RESULTS

Eighty-three women were enrolled with median age 62 years, performance status 0-1 in 93%, triple negative disease in 12% and liver metastases in 47%. In an intention to treat analysis, complete response was achieved in 13 (15.7%) and partial response in 42 (50.6%) (overall response rate 66.3%; 95% CI 56.09-76.44%). The median time to progression was 20.1 months and the 1-year overall survival rate 82.3%. Grade 3-4 neutropenia occurred in 37%, febrile neutropenia in 10%, anemia in 4%, thrombocytopenia in 2% and diarrhea in 2% of patients. There were two deaths possibly related to study treatment (sigmoid perforation n = 1; sudden death n = 1). Moreover, one patient developed pulmonary embolism and another one myocardial infarction while on treatment. Although DEB administration significantly reduced the proportion of patients presenting CTCs, the detection of ≥5 or ≥1 CTCs before treatment initiation was significantly associated with worse progression-free survival (p = 0.001 and p = 0.004) and overall survival (p = 0.001 and p = 0.027), respectively.

CONCLUSIONS

The DEB regimen is a very active but also potentially toxic combination in MBC. Detection of CTCs before treatment is associated with worse outcome.

CLINICALTRIALSGOV

NCT00705315.

The p53 breast cancer tissue biomarker in Indian women

BACKGROUND

Combination chemotherapy is highly effective in locally advanced breast cancer. A negative expression of biomarker p53 indicates a higher chance of responding to this regimen. Patients' p53 status may be used as a biological cancer marker to identify those who would benefit from more aggressive treatments.

AIMS

The role of p53 in modulating apoptosis has suggested that it may affect the efficacy of anticancer agents. p53 alterations in 80 patients with locally advanced breast cancer IIIB undergoing neoadjuvant chemotherapy were prospectively evaluated.

MATERIALS AND METHODS

Patients received three cycles of paclitaxel (175 mg/m(2)) and doxorubicin (60 mg/m(2)) every 21 days. Tumor sections were analyzed before treatment for altered patterns of p53 expression, using immunohistochemistry and DNA sequencing.

RESULTS

An overall response rate of 83.5% was obtained, including 15.1% complete pathological responses. The regimen was well tolerated with 17.7% grade 2/3 nausea and 12.8% grade 3/4 leukopenia. There was a statistically significant correlation between response and expression of p53. Of 25 patients who obtained a complete clinical response, only two were classified as p53-positive (P = 0.004, χ(2)). Of 11 patients who obtained a complete pathological remission, one was positive (P = 0.099, χ(2)).

CONCLUSION

Immunohistochemical (IHC) analysis has been shown to be a prognostic factor for patients with breast cancer in India. Paclitaxel is one of the most promising anticancer agents for the therapy of breast cancer, where it has also shown activity in tumors resistant to doxorubicin.

Long-term cardiac and pulmonary complications of cancer therapy

Cardiac complications resulting from chemotherapy and radiation pose a significant risk for morbidity and mortality to the cancer survivor. Cardiac side effects may progress over time and are a concern for patients treated during childhood. Long-term pulmonary complications are relatively infrequent, and acute respiratory effects of drugs (mostly bleomycin) or radiation normally resolve early after therapy. Although most cardiovascular risk statistics and clinical experience are derived from patients treated before 1985, the modern radiation approach that limits the exposure of the heart and reduces the total dose seems to attenuate the previously observed cardiovascular risk. Potential preventive measures for high-risk patients are of increasing interest but remain experimental.

Clinical trials and progress with paclitaxel in ovarian cancer

Paclitaxel is a front-line agent for ovarian cancer chemotherapy, along with the platinum agents. Derived from the Pacific yew tree, Taxus brevifolia, paclitaxel has covered significant ground from the initial discovery of its antineoplastic properties to clinical applications in many forms of human cancers, including ovarian cancer. Although much has been published about the unique mechanism of action of this agent, several issues remain to be resolved. Finding the appropriate dosage schedule for paclitaxel in chemo-naïve and recurrent ovarian cancer, defining the role of paclitaxel in maintenance chemotherapy, and elucidating the mechanisms of taxane resistance are areas of intense research. Newer forms of taxanes are being manufactured to avoid troublesome adverse effects and to improve clinical efficacy. These issues are reviewed in detail in this paper with an emphasis on clinically relevant evidence-based information.

A randomized, double-blind, placebo-controlled, dose ranging study to assess the efficacy and safety of eltrombopag in patients receiving carboplatin/paclitaxel for advanced solid tumors

OBJECTIVES

Eltrombopag, an oral, nonpeptide thrombopoietin receptor agonist, has been shown to increase platelet counts in adults with chronic immune thrombocytopenia and chronic hepatitis C. This multicenter phase 2 study assessed the efficacy and safety of eltrombopag in patients receiving first-line carboplatin/paclitaxel for the treatment of advanced solid tumors.

RESEARCH DESIGN AND METHODS

Patients (N = 183) were randomized to placebo or eltrombopag 50 mg, 75 mg, or 100 mg given orally following chemotherapy on days 2 through 11 of each 21-day cycle, for at least two cycles. The primary endpoint was the difference in platelet count from day 1 in cycle 2 to the platelet nadir in cycle 2.

CLINICAL TRIAL REGISTRY NUMBER

NCT00102726.

RESULTS

Although the primary endpoint was not met, postnadir platelet counts increased during cycles 1 and 2 in all eltrombopag treatment groups compared with placebo. The most commonly reported adverse events across all study arms (including placebo) were nausea and alopecia and eltrombopag was generally well tolerated.

CONCLUSIONS

This study provides preliminary information that eltrombopag does increase platelets in patients receiving chemotherapy for advanced solid tumors. Further investigation is needed to identify the optimal dose(s) and schedule of eltrombopag in patients receiving myelosuppressive chemotherapy.

Amrubicin for the treatment of advanced lung cancer

Although the advancement of the chemotherapy of non-small cell lung cancer and small cell lung cancer is remarkable in recent years, it is still unsatisfactory. Therefore, some new agents or a new treatment strategy for lung cancer is required. Amrubicin is a totally synthetic anthracycline anticancer drug that acts as a potent topoisomerase II inhibitor. Recently, amrubicin has been approved in Japan for the treatment of small- and non-small cell lung cancers and some clinical trials about amrubicin were conducted in Japan, and promising results have been reported for the treatment of small cell lung cancer in particular. The preclinical, pharmacology and clinical data of amrubicin for the treatment of advanced lung cancer are reviewed.

Phase I/II study of G3139 (Bcl-2 antisense oligonucleotide) in combination with doxorubicin and docetaxel in breast cancer

PURPOSE

Preclinical data showed enhancement of breast cancer cell death when G3139 was combined with anthracyclines and taxanes. We evaluated the efficacy and safety of a Bcl-2 antisense oligonucleotide, G3139, in combination with doxorubicin (A) and docetaxel (T) in patients with locally advanced breast cancer (LABC).

EXPERIMENTAL DESIGN

Following a brief phase I to determine the phase II dose, patients with locally advanced breast cancer received G3139 administered by continuous i.v. infusion for 5 to 7 days with bolus A (50 mg/m2) and T (75 mg/m2) administered on either day 3 or 6 of therapy with G3139. Cycles were repeated every 21 days x 6 in the neoadjuvant setting. Serial plasma samples were obtained for pharmacokinetic analysis. Tissue samples were obtained before and after therapy for pharmacodynamic analysis of Bcl-2 expression.

RESULTS

Thirty patients (median age, 49 years; range, 24-71 years) received 160 cycles. During the phase I portion of the trial, the dose of G3139 was escalated from 3 to 7 mg/kg/d (i.v. for 5 days) in combination with AT. During the phase II portion of the trial, several doses and schedules of G3139 were evaluated. There were no pathologic complete responses. Pharmacodynamic studies showed limited Bcl-2 down-regulation in the primary tumors.

CONCLUSIONS

G3139 in combination with doxorubicin and docetaxel is well tolerated. No pathologic complete response was seen and pharmacodynamic studies showed very little down-regulation of Bcl-2 in primary tumors, perhaps related to issues with insufficient drug delivery to the intact tumor.

Expert opinion on the use of anthracyclines in patients with advanced breast cancer at cardiac risk

Anthracyclines are considered to be among the most active agents for the treatment of breast cancer. However, their use is limited by cumulative, dose-related cardiotoxicity. Such cardiotoxicity results in a permanent loss of cardiac myocytes and a progressive reduction in cardiac function following each subsequent dose of anthracycline. Initially, damage to the heart is subclinical; however, increasingly impaired cardiac function can result in cardiovascular symptoms, with serious cardiac injury resulting in chronic heart failure. Since the early detection and treatment of cardiotoxicity can reduce its clinical effects, it is important that oncologists are aware of these adverse effects and manage them appropriately. This review examines the risk factors for anthracycline-associated cardiotoxicity and offers recommendations on strategies to reduce the cardiotoxicity of anthracyclines in the management of patients with advanced breast cancer.

Protein nanoparticles as drug carriers in clinical medicine

Solvent-based delivery vehicles for chemotherapy agents have been instrumental in providing a means for hydrophobic agents to be administered intravenously. These solvents, however, have been associated with serious and dose-limiting toxicities. Solvent-based formulations of taxanes, a highly active class of cytotoxic agents, are associated with hypersensitivity reactions, neutropenia, and neuropathy. Nanoparticle technology utilizing the human protein albumin exploits natural pathways to selectively deliver larger amounts of drug to tumors while avoiding some of the toxicities of solvent-based formulations. 130 nM albumin-bound (nab) paclitaxel (nab-paclitaxel; Abraxane) was recently approved for use in patients with metastatic breast cancer who have failed combination therapy. In a randomized, phase III study in metastatic breast cancer, nab-paclitaxel was found to have improved efficacy and safety compared with conventional, solvent-based paclitaxel. Preliminary data also suggest roles for nab-paclitaxel as a single agent and in combination therapy for first-line treatment of metastatic breast cancer as well as in other solid tumors, including non-small-cell lung cancer, ovarian cancer, and malignant melanoma. The nab technology promises to have broad utility in cancer therapy, and clinical trials are underway using nab formulations of other water-insoluble anticancer agents such as docetaxel and rapamycin.

Albumin-bound paclitaxel: a next-generation taxane

Taxanes are standard treatment for metastatic breast cancer; however, the solvents used as vehicles in these formulations cause severe toxicities. The FDA recently approved a solvent-free formulation of paclitaxel for the treatment of metastatic breast cancer that utilises 130-nanometer albumin-bound (nab) technology (Abraxane; nab-paclitaxel) to circumvent the requirement for solvents. nab-Paclitaxel utilises the natural properties of albumin to reversibly bind paclitaxel, transport it across the endothelial cell and concentrate it in areas of tumour. The proposed mechanism of drug delivery involves, in part, glycoprotein 60-mediated endothelial cell transcytosis of paclitaxel-bound albumin and accumulation in the area of tumour by albumin binding to SPARC (secreted protein, acidic and rich in cysteine). Clinical studies have shown that nab-paclitaxel is significantly more effective than paclitaxel formulated as Cremophor EL (CrEL, Taxol, CrEL-paclitaxel), with almost double the response rate, increased time to disease progression and increased survival in second-line patients. The absence of CrEL from the formulation is associated with decreased neutropenia and rapid improvement of peripheral neuropathy with nab-paclitaxel, compared with CrEL-paclitaxel. For these reasons, nab-paclitaxel can be administered using higher doses of paclitaxel than that achievable with CrEL-paclitaxel, with shorter infusion duration and without the requirement for corticosteroid and antihistamine premedication to reduce the risk of solvent-mediated hypersensitivity reactions. Taken together, these studies have demonstrated that nab technology has increased the therapeutic index of paclitaxel compared with the conventional, solvent-based formulation.

Inflammatory Breast Cancer as a Model Disease to Study Tumor Angiogenesis: Results of a Phase IB Trial of Combination SU5416 and Doxorubicin

PURPOSE

We used inflammatory breast cancer (IBC) as a model disease to investigate biological changes associated with an antiangiogenesis agent, SU5416, combined with doxorubicin.

EXPERIMENTAL DESIGN

Patients with stage IIIB or IV IBC were treated neoadjuvantly with the combination of SU5416 and doxorubicin for induction therapy. The dose of SU5416 (administered on days 1 and 4, every 3 weeks) and doxorubicin (administered on day 1 every 3 weeks) were escalated in cohorts of three patients starting at 110 and 60 mg/m2, respectively, for a total of five cycles leading up to mastectomy. Patients underwent serial assessment (pharmacokinetic sampling, biopsy of breast, tumor blood flow dynamic contrast-enhanced magnetic resonance imaging, plasma angiogenesis, and endothelial cell damage markers) prior to treatment, at the end of cycles no. 2 and no. 5, and after mastectomy.

RESULTS

Eighteen patients were enrolled; neutropenia was dose-limiting, and overall median survival was not reached (50 months of study follow-up). Four patients (22%) experienced congestive heart failure, which resolved and were likely attributable to a smaller volume of distribution and higher Cmax of doxorubicin in combination with SU5416. We did observe a significant decline in tumor blood flow using Kep calculated by Brix (pretreatment versus post-cycle no. 5; P = 0.033), trend for a decline in tumor microvessel density after treatment, and low baseline levels of soluble intracellular adhesion molecule were associated with improved event-free survival.

CONCLUSIONS

This study showed evidence of an unfavorable cardiac interaction between SU5416 and doxorubicin, which prohibits further investigation of this combination. However, this study supports the importance of using IBC as a model for investigating angiogenesis inhibitors.

Amrubicin for non-small-cell lung cancer and small-cell lung cancer

Amrubicin is a totally synthetic anthracycline anticancer drug and a potent topoisomerase II inhibitor. Recently, amrubicin was approved in Japan for the treatment of small- and non-small-cell lung cancers (SCLC and NSCLC). Here, we review the efficacy and toxicities of amrubicin monotherapy and amrubicin in combination with cisplatin for extensive-disease SCLC (ED-SCLC), and of amrubicin monotherapy for advanced NSCLC, as observed in the clinical trials. Recommended dosage for previously untreated advanced NCSLC was 45 mg/m2/day by intravenous administration for 3 days. Dose-limiting toxicities were leucopenia, thrombocytopenia, and gastrointestinal disturbance. Response rate was 27.9% for advanced NSCLC, and 75.8% for ED-SCLC with a median survival time (MST) of 11.7 months. Recommended dosage of amrubicin was 40 mg/m2/day in combination with cisplatin at 60 mg/m2/day, with MST of 13.6 months and 1-year survival rate of 56.1%. In sensitive or refractory relapsed SCLC, response rate was 52 and 50%, progression-free survival was 4.2 and 2.6 months, overall survival was 11.6 and 10.3 months, and 1-year survival rate was 46 and 40%, respectively. These results are promising for the treatment of both NSCLC and SCLC. Further clinical trials will clarify the status of amrubicin in the treatment of lung cancer.

A dose escalation and pharmacokinetic study of biweekly pegylated liposomal doxorubicin, paclitaxel and gemcitabine in patients with advanced solid tumours

To determine the maximum tolerated doses (MTDs) and dose-limiting toxicities (DLTs) of pegylated liposomal doxorubicin (PLD), paclitaxel (PCX) and gemcitabine (GEM) combination administered biweekly in patients with advanced solid tumours. Twenty-two patients with advanced-stage solid tumours were treated with escalated doses of PLD on day 1 and PCX plus GEM on day 2 (starting doses: 10, 100 and 800 mg m⁻², respectively) every 2 weeks. DLTs and pharmacokinetic (PK) parameters of all drugs were determined during the first cycle of treatment. All but six (73%) patients had previously received at least one chemotherapy regimen. The DLT dose level was reached at PLD 12 mg m⁻², PCX 110 mg m⁻² and GEM 1000 mg m⁻² with neutropaenia being the dose-limiting event. Of the 86 chemotherapy cycles delivered, grade 3 and 4 neutropaenia occurred in 20% with no cases of febrile neutropaenia. Non-haematological toxicities were mild. The recommended MTDs are PLD 12 mg m⁻², PCX 100 mg m⁻² and GEM 1000 mg m⁻² administered every 2 weeks. The PK data revealed no obvious drug interactions. Biweekly administration of PLD, PCX and GEM is a well-tolerated chemotherapy regimen, which merits further evaluation in various types of solid tumours.

Weekly paclitaxel and high-dose 5-fluorouracil plus leucovorin in hormone-refractory prostate cancer: In vitro combined effects and a Phase II trial

PURPOSE

Paclitaxel and 5-fluorouracil have been used to treat hormone-refractory prostate cancer with some success. In vitro data suggest that the combined cytotoxicity may be sequence dependent. Thus, we explored the combined effects of the 2 agents, both in vitro and in vivo.

PATIENTS AND METHODS

The combined cytotoxicity of paclitaxel and 5-fluorouracil, and the possible schedule dependence were studied in vitro using PC-3 and DU145 cells and the microculture tetrazolium assay. There were 23 patients with hormone-refractory prostate cancer treated with the regimen T-HDFL: paclitaxel 90 mg/m2 intravenously 1 hour on days 1 and 8; 5-fluorouracil 2000 mg/m2; and leucovorin 300 mg/m2 intravenous 24-hour infusion on days 2 and 9, which repeated every 21 days. The allowed percentage of bone marrow irradiation was 50%.

RESULTS

Significant synergistic cytotoxicity was seen only when paclitaxel was given 24 hours before 5-fluorouracil. With the T-HDFL regimen, 11 (52%) of the 21 evaluable patients had > or = 50% reduction of prostate-specific antigen, lasting for 6 weeks. Of the 7 patients with measurable disease, 2 had a partial response. Median overall survival was 14.1 months. Grade III/IV leukopenia occurred in 2 patients. There was no treatment-related death. Toxicities were well tolerated.

CONCLUSIONS

The combined cytotoxicity of paclitaxel and 5-fluorouracil is schedule dependent. It is feasible to administer weekly paclitaxel and high-dose 5-fluorouracil infusions in patients with hormone-refractory prostate cancer. Our findings may serve as an important rationale for future trial design.

Targeted anti-mitotic therapies: can we improve on tubulin agents?

The advent of molecularly targeted drug discovery has facilitated the identification of a new generation of anti-mitotic therapies that target proteins with specific functions in mitosis. The exquisite selectivity for mitosis and the distinct ways in which these new agents interfere with mitosis provides the potential to not only overcome certain limitations of current tubulin-targeted anti-mitotic drugs, but to expand the scope of clinical efficacy that those drugs have established. The development of these new anti-mitotic drugs as targeted therapies faces significant challenges; nevertheless, these potential therapies also serve as unique tools to dissect the molecular mechanisms of the mitotic-checkpoint response.

Using nanotechnology to improve the characteristics of antineoplastic drugs: Improved characteristics of nab-paclitaxel compared with solvent-based paclitaxel

Nanotechnology refers to the use of very small pieces of matter, typically < or =200 nm in diameter. Nanoparticle albumin-bound (nab) paclitaxel, a soluble form of the cytotoxin paclitaxel that has demonstrated utility in the setting of cancer chemotherapy, is produced by nab technology using the protein albumin. nab-Paclitaxel targets tumors, enhances tumor penetration by the novel mechanism of albumin receptor-mediated (gp60) endothelial transcytosis, and avoids the use of surfactants and solvents such as Cremophor and Tween. nab-Paclitaxel minimizes the toxicities associated with Cremophor and eliminates the need for premedication for hypersensitivity reactions caused by Cremophor. The albumin coating that surrounds the active drug assists in the transport of the nanoparticles to the interior of the tumor cell that preferentially takes in albumin as a nutrient through the gp60 pathway. In nonclinical studies, nab-paclitaxel achieved higher intratumoral concentrations compared with solvent-based paclitaxel and increased the bioavailability of paclitaxel by eliminating the entrapment of paclitaxel in the plasma. Compared with solvent-based paclitaxel, at equitoxic doses, the nab-paclitaxel produced more complete regressions, longer time to recurrence, longer doubling times, and prolonged survival. nab-Paclitaxel has been shown to have superior efficacy compared with solvent-based paclitaxel without the need for premedication in clinical trials of patients with advanced solid tumors. nab-Paclitaxel has been effective in patients for whom previous chemotherapy has not been helpful. nab Technology has the potential to be applied to other insoluble drugs.

Paclitaxel, carboplatin and pegylated liposomal doxorubicin in ovarian and peritoneal carcinoma: a phase I study of the Gynecologic Oncology Group

PURPOSE

Based on the activity and tolerability of liposomal doxorubicin in platinum- and paclitaxel-resistant ovarian carcinoma, we conducted a phase I trial of pegylated liposomal doxorubicin with paclitaxel and carboplatin to determine the maximum tolerated dose (MTD) in chemotherapy naive ovarian, peritoneal and tubal carcinoma patients.

METHODS

Three schedules were studied: paclitaxel, carboplatin and pegylated liposomal doxorubicin every 28 days; paclitaxel and carboplatin every 21 days with liposomal doxorubicin every 42 days; and weekly paclitaxel, carboplatin (AUC=5) every 21 days and liposomal doxorubicin every 42 days. The paclitaxel dose was 175 mg/m(2) over 3 h on an every 3-4 week schedule and 60 mg/m(2) when administered weekly. Based on the frequency of neutropenic sepsis, grade 4 thrombocytopenia and > or =grade 3 non-hematologic toxicity, the starting dose of liposomal doxorubicin of 20 mg/m(2) was escalated to determine the MTD.

RESULTS

A total of 210 (21-day) cycles were administered to 37 patients. Dose-limiting toxicity (DLT) occurred when liposomal doxorubicin was administered at 40 mg/m(2). Because of treatment-related delays resulting in decreased paclitaxel/carboplatin dose intensity, administration was modified to be given every 21 days, with liposomal doxorubicin given every 42 days. Since neutropenia was the DLT of this schedule, the schema was further modified to administer paclitaxel weekly; however, weekly administration was inconsistent because of toxicity.

CONCLUSION

Paclitaxel 175 mg/m(2), carboplatin (AUC=5) and pegylated liposomal doxorubicin 30 mg/m(2) are tolerable without supportive therapy. The usual dose intensity of paclitaxel/carboplatin was maintained by administering liposomal doxorubicin every other cycle.

Drug interactions in cancer therapy

Drug interactions in oncology are of particular importance owing to the narrow therapeutic index and the inherent toxicity of anticancer agents. Interactions with other medications can cause small changes in the pharmacokinetics or pharmacodynamics of a chemotherapy agent that could significantly alter its efficacy or toxicity. Improvements in in vitro methods and early clinical testing have made the prediction of potentially clinically significant drug interactions possible. We outline the types of drug interaction that occur in oncology, the mechanisms that underlie these interactions and describe select examples.

The role of taxanes in the treatment of breast cancer

Among the novel chemotherapeutic agents introduced in the last decade, the taxanes have emerged as the most powerful group of compounds, and results available so far confirm that they will be remembered in the future as the breast cancer chemotherapy of the 1990s. Two taxanes are available (paclitaxel and docetaxel) and they share some characteristics, although they do have some significant differences both in terms of their preclinical profile and, most importantly, their clinical characteristics. There are three main clinical differences: different efficacy-toxicity ratio in relation to dose and schedule; different integrability in anthracycline- and taxane-containing regimens, secondary to differences in pharmacokinetic interactions with anthracyclines; and different level of synergism between each taxane and trastuzumab. In clinical practice, the taxanes are now standard therapy in metastatic breast cancer. Their role as monochemotherapy or in combination with anthracyclines in advanced breast cancer has suggested their potential therapeutic impact in the treatment of patients with early breast cancer. Recent results in the adjuvant setting show that taxanes, used either in combination or in sequential therapy, possess the capability to induce significant improvements, in particular in terms of survival; thus confirming the positive impact of taxanes on the natural history of breast cancer. However, further results of all completed or ongoing Phase III trials in the early setting will help define the optimal use of taxanes and maximise the induced benefits for breast cancer patients.

Anticancer agents and cardiotoxicity

Although rare, cardiotoxicity is a significant complication of cancer treatment. The incidence and severity of cardiotoxicity are dependent on the type of drugs used, dose and schedule employed, and age of patients, as well as the presence of coexisting cardiac diseases and previous mediastinal irradiation. Anthracyclines are among one of the most active agents in oncology, but their use is often hampered by their cumulative dose-limiting cardiotoxicity. Combination therapy with new drugs in the last decade, such as taxanes and trastuzumab, in the treatment of metastatic breast cancer has yielded impressive results but also unexpected cardiotoxicity. Existing methods of minimizing cardiotoxicity include the use of protective agents such as dexrazoxane, different preparations of anthracyclines such as liposomal formulations, and alternative scheduling techniques. Assessment of left ventricular ejection fraction (LVEF) with two-dimensional (2D)-echocardiography or radionuclide ventriculography (RNVG) remains the most pragmatic means of monitoring for cardiotoxicity. The increasing number of long-term survivors of pediatric cancers, as well as the use of trastuzumab, taxanes, and anthracyclines in adjuvant treatment of breast cancer, means that more than ever, cardiotoxicity will remain an important issue for clinicians.

Effects of naringin on the pharmacokinetics of intravenous paclitaxel in rats

It was reported that paclitaxel is an inhibitor of hepatic P-glycoprotein (P-gp) and hepatic microsomal cytochrome P450 (CYP) 3A1/2, and that naringin is an inhibitor of biliary P-gp and CYP3A1/2 in rats. The purpose of this study was to report the effects of oral naringin on the pharmacokinetics of intravenous paclitaxel in rats. Oral naringin (3.3 and 10 mg/kg) was pretreated 30 min before intravenous (3 mg/kg) administration of paclitaxel. After intravenous administration of paclitaxel, the AUC was significantly greater (40.8% and 49.1% for naringin doses of 3.3 and 10 mg/kg, respectively), and Cl was significantly slower (29.0% and 33.0% decrease, respectively) than controls. The significantly greater AUC could be due mainly to an inhibition of metabolism of paclitaxel via CYP3A1/2 by oral naringin. The inhibition of hepatic P-gp by oral naringin could also contribute to the significantly greater AUC of intravenous paclitaxel by oral naringin.

Survival outcome of inoperable non-small cell lung cancer patients receiving conventional dose epirubicin and Paclitaxel as first-line treatment

OBJECTIVE

High-dose epirubicin was shown to be effective in the treatment of inoperable non-small cell lung cancer (NSCLC). Paclitaxel is synergistic to a conventional dose of anthracyclines in the treatment of advanced cancer. A phase II study was designed to test the effectiveness of combining paclitaxel with a conventional dose of epirubicin in inoperable NSCLC patients.

METHODS

Eligibility criteria included inoperable stage IIIB or IV NSCLC patients, Eastern Cooperative Oncology Group performance status of 0-2, measurable or evaluable disease and adequate organ function. Epirubicin 70 mg/m2 intravenous infusion for 15 min was given on day 1. Paclitaxel 175 mg/m2 intravenous infusion for 3 h was given on day 2. Cycles were repeated every 21 days. Tumor response was evaluated every two cycles. Patients received treatment until disease progression, unacceptable toxicity or stable disease after cycle 6.

RESULTS

Thirty-eight patients received a total of 185 cycles (median 6 cycles). Seventeen patients responded to treatment (response rate 44.7%). Twenty-six (68%) patients received second-line chemotherapy. All patients were followed until their death. Median survival was 11.9 months (95% confidence interval 9.0-14.9 months). Median time-to-treatment-failure was 4.6 months.

CONCLUSION

Conventional dose epirubicin plus paclitaxel is effective as a first-line treatment for inoperable NSCLC patients.

Addition of 5-fluorouracil to doxorubicin-paclitaxel sequence increases caspase-dependent apoptosis in breast cancer cell lines

Introduction

The aim of the study was to evaluate the activity of a combination of doxorubicin (Dox), paclitaxel (Pacl) and 5-fluorouracil (5-FU), to define the most effective schedule, and to investigate the mechanisms of action in human breast cancer cells.

Methods

The study was performed on MCF-7 and BRC-230 cell lines. The cytotoxic activity was evaluated by sulphorhodamine B assay and the type of drug interaction was assessed by the median effect principle. Cell cycle perturbation and apoptosis were evaluated by flow cytometry, and apoptosis-related marker (p53, bcl-2, bax, p21), caspase and thymidylate synthase (TS) expression were assessed by western blot.

Results

5-FU, used as a single agent, exerted a low cytotoxic activity in both cell lines. The Dox→Pacl sequence produced a synergistic cytocidal effect and enhanced the efficacy of subsequent exposure to 5-FU in both cell lines. Specifically, the Dox→Pacl sequence blocked cells in the G2-M phase, and the addition of 5-FU forced the cells to progress through the cell cycle or killed them. Furthermore, Dox→Pacl pretreatment produced a significant reduction in basal TS expression in both cell lines, probably favoring the increase in 5-FU activity. The sequence Dox→Pacl→48-h washout→5-FU produced a synergistic and highly schedule-dependent interaction (combination index < 1), resulting in an induction of apoptosis in both experimental models regardless of hormonal, p53, bcl-2 or bax status. Apoptosis in MCF-7 cells was induced through caspase-9 activation and anti-apoptosis-inducing factor hyperexpression. In the BRC-230 cell line, the apoptotic process was triggered only by a caspase-dependent mechanism. In particular, at the end of the three-drug treatment, caspase-8 activation triggered downstream executioner caspase-3 and, to a lesser degree, caspase-7.

Conclusion

In our experimental models, characterized by different biomolecular profiles representing the different biology of human breast cancers, the schedule Dox→Pacl→48-h washout→5-FU was highly active and schedule-dependent and has recently been used to plan a phase I/II clinical protocol.

Paclitaxel chemotherapy: from empiricism to a mechanism-based formulation strategy

Paclitaxel is an anticancer agent effective for the treatment of breast, ovarian, lung, and head and neck cancer. Because of water insolubility, paclitaxel is formulated with the micelle-forming vehicle Cremophor EL to enhance drug solubility. However, the addition of Cremophor EL results in hypersensitivity reactions, neurotoxicity, and altered pharmacokinetics of paclitaxel. To circumvent these unfavorable effects resulting from the addition of Cremophor EL, efforts have been made to develop new delivery systems for paclitaxel administration. For example, ABI-007 is a Cremophor-free, albumin-stabilized, nanoparticle paclitaxel formulation that was found to have significantly less toxicity than Cremophor-containing paclitaxel in mice. Pharmacokinetic studies indicate that in contrast to Cremophor-containing paclitaxel, ABI-007 displays linear pharmacokinetics over the clinically relevant dose range of 135-300 mg/m(2). In a phase III study conducted in patients with metastatic breast cancer, patients treated with ABI-007 achieved a significantly higher objective response rate and time to progression than those treated with Cremophor-containing paclitaxel. Together these findings suggest that nanoparticle albumin-bound paclitaxel may enable clinicians to administer paclitaxel at higher doses with less toxicity than is seen with Cremophor-containing paclitaxel. The role of this novel paclitaxel formulation in combination therapy with other antineoplastic agents needs to be determined.

Pharmacokinetics of combined doxorubicin and paclitaxel in mice

Doxorubicin (DOX) has excellent antitumor activity when combined with paclitaxel (PTX) and this combination is used as first-line treatment for metastatic breast cancer. Results from clinical studies on pharmacokinetic interaction of these agents are not conclusive and pre-clinical studies are still needed. Pharmacokinetic studies were carried out in female Balb/c mice with combined DOX (6 mg/kg) and PTX (10 mg/kg) treatment. Combined treatment with PTX and DOX leads to alterations in the pharmacokinetics of both agents, with the predominant effect being elevated drug levels in liver and gut tissues. DOX levels in kidney and heart tissues were unaffected by concurrent PTX treatment. Further, plasma levels of DOX are not changed by concurrent PTX treatment suggesting that monitoring of plasma levels of DOX, when used in combination with another drug that is a P-glycoprotein (PGP) substrate, will not reflect actual pharmacokinetic changes occurring in other tissues.

Pegylated liposomal doxorubicin hydrochloride (PLD) and paclitaxel in recurrent or metastatic head and neck carcinoma: a phase I/II study conducted by the Hellenic Cooperative Oncology Group (HeCOG)

A phase I pharmacokinetics and dose-finding study and a phase II study of the combination of pegylated liposomal doxorubicin HCl (PLD) and paclitaxel were conducted in patients with recurrent or metastatic head and neck cancer (HNC). Sixty patients with recurrent or metastatic disease were enrolled in the study: 11 patients in the phase I study and 49 patients in the phase II study. In the phase I study, the initial dose level of PLD was 35 mg/m as a 1-h infusion with escalating increments of 5 mg/m until the maximum tolerated dose (MTD) was reached. A fixed dose of paclitaxel (175 mg/m) was administered as a 3-h infusion. The combination was administered every 28 days. Pharmacokinetic studies performed on 10 patients indicated that the sequence of drug administration did not cause clinically significant modifications in the pharmacokinetics of either drug. The MTD for PLD was 45 mg/m (dose level 3) and the dose-limiting toxicity was febrile neutropenia, occurring in three of five patients. The phase II dose of PLD was 40 mg/m (dose level 2) and a total of 214 cycles were delivered. Grade 3 or 4 neutropenia was observed in 26% patients and febrile neutropenia occurred in 16% of patients. Grade 3 palmar-plantar erythrodysesthesia (PPE) was recorded in only one patient. The overall response rate was 28% for patients with non-nasopharyngeal tumors [95% confidence interval (CI) 15-45%] and 28.6% for the study population (95% CI 17-43%). The median survival for the study population was 9.7 months; 1-year survival was 38%. We conclude that the recommended dose for the combination of PLD and paclitaxel is 40 and 175 mg/m every 28 days, without granulocyte colony stimulating factor support. The combination of paclitaxel with PLD demonstrated activity in recurrent or metastatic HNC, a favorable toxicity profile and relative ease of administration.

Phase IB and pharmacological study of the novel taxane BMS-184476 in combination with doxorubicin

The aim of this study was to define the maximum tolerated dose (MTD) and the pharmacological profile of the paclitaxel analogue BMS-184476 given once every 3 weeks, or on days 1 and 8 every 3 weeks (d1&8), in combination with a fixed dose of 50 mg/m(2) of Doxorubicin (Doxo) administered on day 1 of a 21-day cycle. Adult patients with advanced solid malignancies received escalating doses of BMS-184476 infused over 1 h after bolus Doxo. Pharmacokinetics (PK) of BMS-184476, Doxo and metabolites were investigated. The effect of BMS-184476 on doxorubicinol formation was studied in the cytosol from human myocardium. The MTD of 3-weekly BMS-184476 was 30 mg/m(2). The MTD/recommended Phase II dose was 35 mg/m(2)/week (70 mg/m(2) per cycle) in the d1&8 schedule. The dose-limiting toxicity was neutropenia for both schedules. Other toxicities were loss of appetite, asthenia, and mild, cumulative peripheral neuropathy. The objective response rate in 17 previously untreated or minimally pretreated patients with breast cancer treated at 35 mg/m(2)/week of BMS-184476 was 59% (95% Confidence Interval (CI): 33-82%). Two of the 7 patients not responding to the study regimen later responded to Doxo and paclitaxel. Plasma disposition of BMS-184476 at 30, 35 and 40 mg/m(2) was linear without evidence of a PK interaction with Doxo. In studies with cytosol from human myocardium, the formation of cardiotoxic doxorubicinol was not enhanced by BMS-184476. Dosing of BMS-184476 for 2 consecutive weeks allowed the administration of larger doses of the taxane with a promising antitumour activity in patients with untreated or minimally pretreated breast cancer. The higher than expected myelotoxicity of the 3-weekly schedule is unexplained by the investigated interactions. Lack of enhanced doxorubicinol formation in human myocardium is consistent with the cardiac safety of the regimen.

Pharmacological effects of formulation vehicles : implications for cancer chemotherapy

The non-ionic surfactants Cremophor EL (CrEL; polyoxyethyleneglycerol triricinoleate 35) and polysorbate 80 (Tween) 80; polyoxyethylene-sorbitan-20-monooleate) are widely used as drug formulation vehicles, including for the taxane anticancer agents paclitaxel and docetaxel. A wealth of recent experimental data has indicated that both solubilisers are biologically and pharmacologically active compounds, and their use as drug formulation vehicles has been implicated in clinically important adverse effects, including acute hypersensitivity reactions and peripheral neuropathy.CrEL and Tween 80 have also been demonstrated to influence the disposition of solubilised drugs that are administered intravenously. The overall resulting effect is a highly increased systemic drug exposure and a simultaneously decreased clearance, leading to alteration in the pharmacodynamic characteristics of the solubilised drug. Kinetic experiments revealed that this effect is primarily caused by reduced cellular uptake of the drug from large spherical micellar-like structures with a highly hydrophobic interior, which act as the principal carrier of circulating drug. Within the central blood compartment, this results in a profound alteration of drug accumulation in erythrocytes, thereby reducing the free drug fraction available for cellular partitioning and influencing drug distribution as well as elimination routes. The existence of CrEL and Tween 80 in blood as large polar micelles has also raised additional complexities in the case of combination chemotherapy regimens with taxanes, such that the disposition of several coadministered drugs, including anthracyclines and epipodophyllotoxins, is significantly altered. In contrast to the enhancing effects of Tween 80, addition of CrEL to the formulation of oral drug preparations seems to result in significantly diminished drug uptake and reduced circulating concentrations. The drawbacks presented by the presence of CrEL or Tween 80 in drug formulations have instigated extensive research to develop alternative delivery forms. Currently, several strategies are in progress to develop Tween 80- and CrEL-free formulations of docetaxel and paclitaxel, which are based on pharmaceutical (e.g. albumin nanoparticles, emulsions and liposomes), chemical (e.g. polyglutamates, analogues and prodrugs), or biological (e.g. oral drug administration) strategies. These continued investigations should eventually lead to more rational and selective chemotherapeutic treatment.

Influence of trastuzumab on epirubicin pharmacokinetics in metastatic breast cancer patients

BACKGROUND

Anthracycline cardiotoxicity is increased by the contemporaneous administration of trastuzumab. The mechanism by which it occurs is as yet unknown. The aim of this study was to evaluate whether trastuzumab modifies the pharmacokinetics of epirubicin and its metabolites.

PATIENTS AND METHODS

Women with HER2-positive metastatic breast cancer were treated with epirubicin 75 mg/m(2) i.v. bolus followed by docetaxel 75 mg/m(2) in a 1-h infusion, every 3 weeks for six cycles, and trastuzumab (once at 4 mg/m(2), then 2 mg/m(2) weekly thereafter) in a 30-min infusion. Epirubicin pharmacokinetic data of seven patients were evaluated at the first cycle of therapy (baseline, with trastuzumab administered 24 h after epirubicin), and at the sixth cycle (i.e. 15 weeks after baseline, with trastuzumab administered immediately before epirubicin).

RESULTS

No pharmacokinetic change in the parent compound epirubicin was detected. The area under the plasma concentration-time curve (AUC(0-24 h)) was 1230 +/- 318 [mean +/- standard deviation (SD)] at the first cycle and 1287 +/- 385 h. micro g/l at the sixth. The mean (+/-SD) maximum plasma concentration (C(max)) and the terminal elimination half-life at the first cycle (1303 +/- 490 micro g/l and 12.5 +/- 3.1 h, respectively) were similar to those obtained at the sixth cycle (1229 +/- 580 micro g/l and 11.5 +/- 2.9 h, respectively). Pharmacokinetic data of epirubicin metabolites evaluated at the first and sixth cycle of chemotherapy were superimposable without any statistical difference.

CONCLUSION

Enhanced anthracycline cardiotoxicity related to trastuzumab administration was not linked to pharmacokinetic interferences with epirubicin and its metabolites.

Drug interactions of paclitaxel metabolism in human liver microsomes

The human liver metabolism of paclitaxel (Taxol), an anticancer drug, leads to three metabolites: 6alpha-hydroxypaclitaxel, 3'-p-hydroxypaclitaxel and 6alpha,3'-p-dihydroxypaclitaxel. The inter-individual variability of paclitaxel metabolism was investigated first in vitro using 22 human liver microsomes. Three metabolites have been detected by HPLC. This preliminary work revealed marked inter-individual differences in paclitaxel metabolism. The amount of major metabolite 6alpha-hydroxypaclitaxel formed varied 16-fold (0.7 to 11.5 nmol/mg/h). We next studied the effect of 29 compounds (antineoplastics, antiemetics, histamine-2 receptor antagonist, antalgics, antifungals, antivirals, psychotropics, antibiotic, corticoid, antiarrhythmic, calcium channel blocker) on paclitaxel metabolism in human liver microsomes. Among the compounds studied, quercetin, antifungal drugs such as ketoconazole and miconazole, and the antineoplastic drug doxorubicin inhibited formation of 6alpha-hydroxypaclitaxel. Dixon plots indicated that quercetin and doxorubicin inhibited 6alpha-hydroxypaclitaxel formation through a competitive mechanism with a Ki of 10.1 microM and 64.8 microM, respectively. The inhibition of this metabolite by ketoconazole was through a noncompetitive mechanism with a Ki of 11.8 microM. Our data thus suggest that special attention should be paid when these drugs are combined in clinical practice.

Correlation of p53 status with outcome of neoadjuvant chemotherapy using paclitaxel and doxorubicin in stage IIIB breast cancer

BACKGROUND

The role of p53 in modulating apoptosis has suggested that it may affect efficacy of anticancer agents. We prospectively evaluated p53 alterations in 73 patients with locally advanced breast cancer (IIIB) submitted to neoadjuvant chemotherapy.

PATIENTS AND METHODS

Patients received three cycles of paclitaxel (175 mg/m2) and doxorubicin (60 mg/m2) every 21 days. Tumor sections were analyzed before treatment for altered patterns of p53 expression using immunohistochemistry and DNA sequencing.

RESULTS

An overall response rate of 83.5% was obtained, including 15.1% complete pathological responses. The regimen was well tolerated with 17.7% grade 2/3 nausea and 12.8% grade 3/4 leukopenia. There was a statistically significant correlation between response and expression of p53. Of the 25 patients who obtained a complete clinical response, two were classified as positive (P = 0.004, chi-square). Of 11 patients who obtained a complete pathological remission, one was positive (P = 0.099, chi-square). Discussion The combination is highly effective in locally advanced breast cancer. A negative expression of p53 indicates a higher chance of responding to this regimen. The p53 status may be used as a biological marker to identify those patients who would benefit from more aggressive treatments.

Cardiotoxic effects of anthracycline-taxane combinations

The association of doxorubicin (DOX) and paclitaxel (PTX) is very active in breast cancer. Unfortunately, PTX may potentiate the cardiotoxic effects of anthracyclines: it causes nonlinear disposition of DOX and its metabolites, leading to persistant of elevated plasma concentrations of the anthracyclines. However, this pharmacokinetic interference is not sufficient to explain the enhanced cardiotoxicity of the combination. Recent data suggest that PTX stimulates the conversion of DOX to cardiotoxic metabolites (namely doxorubicinol) inside cardiomyocytes. Docetaxel (DTX) does not have a major influence on DOX plasma concentration because it does not interfere with its elimination. Clinical data suggest that DTX may not enhance anthracycline cardiotoxicity, but patients seldom received a total anthracycline dose compatible with increased risk. Furthermore, there are experimental data indicating that DTX can also stimulate the metabolism of DOX to toxic species in human heart.

Doxorubicin-docetaxel sequential schedule: results of front-line treatment in advanced breast cancer

OBJECTIVE

We conducted a multi-institutional phase II study to evaluate the tolerability and activity of a sequential schedule of treatment with doxorubicin and docetaxel in chemotherapy-naive women with advanced breast cancer.

METHODS

A total of 73 patients with PS (ECOG) 0-2, aged <70 years and adequate bone marrow, renal, liver and cardiac functions were included in the study (13 stage III B and 60 stage IV). The schedule of administration was doxorubicin 50 mg/m2 by intravenous (i.v.) 30 min injection on day 1 followed the day after by docetaxel 75 mg/m2, by i.v. 60 min infusion. Cycles were repeated every 28 days.

RESULTS

Overall, the median number of administered cycles was 6 (range 1-14). The most common toxicity was hematological, with 56.2% of the patients who experienced grade 3-4 neutropenia. However, febrile neutropenia occurred only in 2.8% of the cases. The median cumulative dose of doxorubicin was 350 mg/m2 (range 50-700 mg/m2). Eleven patients (15.4%) were documented to have >10% but <20% decrease in the left ventricular ejection fraction. No case of congestive heart failure was recorded. No patient experienced treatment-related death. Among the 68 evaluable patients, the overall objective response rate was 73.5% (95% confidence limits: 63-84%): 10 patients (14.7%) obtained a complete remission and 40 (58.8%) had a partial response. Only 10 patients (14.7%) experienced progressive disease. The median duration of response was 10 months (2-54+).

CONCLUSION

This sequential treatment with doxorubicin and docetaxel is an effective, feasible and a well-tolerated regimen. The main toxicity was neutropenia. The lack of cardiotoxicity is an important advantage of such a doxorubicin-docetaxel combination and it justifies phase III comparative studies with other anthracyclines/taxanes containing schedules in both advanced and early-stage breast cancer.