Drug interactions and cytotoxic effects of paclitaxel in combination with carboplatin, epirubicin, gemcitabine or vinorelbine in breast cancer cell lines and tumor samples

Paclitaxel and Carboplatin in Combination with Low-intensity Pulsed Ultrasound for Glioblastoma

PURPOSE

We recently reported on clinical trials for patients with recurrent glioblastoma where low-intensity pulsed ultrasound and microbubbles (LIPU/MB) improved paclitaxel or carboplatin delivery into the brain. Here, we report variable local tumor control with paclitaxel at the maximal/target dose in our phase I trial (NCT04528680). To address this, we investigated the combination of paclitaxel with carboplatin in preclinical glioma models.

EXPERIMENTAL DESIGN

We performed MRI-based analysis to evaluate disease control in patients from our trial. We studied the cytotoxicity of paclitaxel and carboplatin against 11 human glioma lines as monotherapy and in combination at concentrations derived from human intraoperative studies. Synergy was assessed with the Loewe model and the survival benefit evaluated in two xenografts. We examined the effects on cell cycle progression, DNA damage, and apoptosis.

RESULTS

Patients treated with paclitaxel and LIPU/MB exhibited variable local tumor control, which correlated with overall survival. We observed limited cross-resistance to paclitaxel and carboplatin in glioma lines, with almost a third of them being exclusively susceptible to one drug. This combination led to susceptibility of 81% of lines and synergy in 55% of them. The combination proved more efficacious in two intracranial xenografts when administered with LIPU/MB, leading to complementary effects on cell cycle arrest.

CONCLUSIONS

Combining paclitaxel and carboplatin in gliomas may be more efficacious than monotherapy, as in other cancers, due to synergy and independent susceptibility to each drug. These results form the basis for an ongoing phase II trial (NCT04528680) where we investigate this combination with LIPU/MB.

Efficacy of Cold Atmospheric Plasma vs. Chemotherapy in Triple-Negative Breast Cancer: A Systematic Review

Breast cancer is a growing disease, with a high worldwide incidence and mortality rate among women. Among the various types, the treatment of triple-negative breast cancer (TNBC) remains a challenge. Considering the recent advances in cold atmospheric plasma (CAP) cancer research, our goal was to evaluate efficacy data from studies based on chemotherapy and CAP in TNBC cell lines and animal models. A search of the literature was carried out in the PubMed, Web of Science, Cochrane Library, and Embase databases. Of the 10,999 studies, there were fifty-four in vitro studies, three in vivo studies, and two in vitro and in vivo studies included. MDA-MB-231 cells were the most used. MTT, MTS, SRB, annexin-V/propidium iodide, trypan blue, and clonogenic assay were performed to assess efficacy in vitro, increasing the reliability and comprehensiveness of the data. There was found to be a decrease in cell proliferation after both chemotherapy and CAP; however, different protocol settings, including an extensive range of drug doses and CAP exposure times, were reported. For both therapies, a considerable reduction in tumor volume was observed in vivo compared with that of the untreated group. The treatment of TNBC cell lines with CAP proved successful, with apoptosis emerging as the predominant type of cellular death. This systematic review presents a comprehensive overview of the treatment landscape in chemotherapy and CAP regarding their efficacy in TNBC cell lines.

Chemosensitivity of three patient-derived primary cultures of canine pericardial mesothelioma by single-agent and combination treatment

Introduction

Canine mesothelioma is a rare malignant tumor that mostly affects body cavities, such as the pericardial and pleural cavities. Chemotherapy plays a crucial role in the treatment of canine mesotheliomas. We aimed to compare the antitumor effects of single-agent and combination chemotherapeutic agents on patient-derived primary cultures of canine pericardial mesothelioma established in this study. We planned to generate xenograft models for future studies.

Material and methods

Effusion samples were collected from three dogs with histologically diagnosed pericardial mesothelioma and used for primary culture. Cultured cells were characterized by immunostaining for pan-cytokeratin AE1/AE3, vimentin, Wilms' tumor suppressor gene 1 (WT1), and cytokeratin 5 (CK5). To assess the tumorigenic properties of cells in the effusion and generate a xenograft model, the cell suspension was injected into a severe combined immunodeficient (SCID) mouse either subcutaneously (SC) or intraperitoneally (IP). Lastly, chemosensitivity of established primary cultures against four drugs, doxorubicin, vinorelbine, carboplatin, and gemcitabine, by single-agent treatment as well as combination treatment of carboplatin at a fixed concentration, either 10 or 100 μM, and gemcitabine at different concentrations ranging from 0-1000 μM was assessed by cell viability assay.

Results

Primary cultures were successfully generated and characterized by dual positivity for AE1/AE3 and vimentin and positive staining for WT-1 and CK5, confirming the mesothelial origin of the cells. In the xenograft models, SC mouse developed a subcutaneous mass, whereas IP mouse developed multiple intraperitoneal nodules. The masses were histopathologically consistent with mesotheliomas. The chemosensitivity assay revealed that carboplatin had the highest anti-tumor effects among the four tested single-agent treatments. Furthermore, carboplatin at 100 μM combined with gemcitabine at clinically relevant doses demonstrated the augmented anti-tumor effects compared to single-agent treatment.

Discussion and conclusion

Primary cultures and xenograft models generated in this study could be useful tools for in vitro and in vivo studies of canine mesothelioma. Carboplatin is a highly effective chemotherapeutic agent against canine mesothelioma when used as a sole agent and in combination with gemcitabine.

Simultaneous chemotherapy/sonodynamic therapy of the melanoma cancer cells using a gold-paclitaxel nanostructure

Nanodrug delivery systems are novel strategies for tumor treatment since delivery of chemotherapy drugs such as paclitaxel (PTX) is associated with substantial challenges due to its poor aqueous solubility. In addition, sonodynamic therapy (SDT) is a promising approach that can increase the uptake, accumulation, and dispersion of desirable amounts of the drugs by activating sonosensitizer and enhancing cell membrane permeability. Herein, gold-paclitaxel nanoparticles (Au-PTX NPs) were synthesized and characterized to evaluate the cytotoxicity toward C540 cancer cells in comparison of free PTX, AuNPs, and AuNPs+free PTX in the absence and presence of ultrasound radiation. Evidence shows that AuNPs have a median diameter size of 95.0 ± 15.4, while the size of Au-PTX NPs is roughly 219.7 ±  40.4 nm. Negative zeta-potential results indicate high stability and good dispersion of nanoparticles. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay results revealed that Au-PTX NPs increased the cytotoxicity compared to other treatment groups that ensure the great potential of AuNPs as a promising nano-carrier for PTX drug delivery. Moreover, the viability of C540 cells treated by Au-PTX NPs under ultrasound radiation was decreased significantly by generating more reactive oxygen species (ROS) upon STD, with representing synergism effects confirming the role of gold nanoparticles as an excellent sonosensitizer and the role of SDT as an adjunctive treatment method with chemotherapy.

Evaluation of Anticancer and Anti-Mitotic Properties of Quinazoline and Quinazolino-Benzothiadiazine Derivatives

BACKGROUND

Cancer is one of the major health and social-economic problems despite considerable progress in its early diagnosis and treatment. Owing to the emergence and increase of multidrug resistance to various conventional drugs, and the continuing importance of health-care expenditure, many researchers have focused on developing novel and effective anticancer compounds.

OBJECTIVE

Chemical repositories provide a good platform to evaluate and exploit known chemical entities for the identification of other biological activities. In the present study, we have selected an in-house library of synthesized compounds based on two different pharmacophoric scaffolds to evaluate their cytotoxic potency on various cancer cell lines and mechanisms of action.

METHODS

A series of in-house synthesized quinazoline and quinazolino-benzothiadiazine derivatives were investigated for their anticancer efficacy against a panel of five cancer (DU145, MCF7, HepG2, SKOV3 and MDA-MB-231) and one normal (MRC5) cell lines. Furthermore, the active compound of the study was investigated to elucidate the mechanism of cytotoxicity by performing series of experiments such as cell cycle analysis, inhibition of tubulin polymerization, alteration of mitochondrial membrane potential, determination of endocytic pathway for drug uptake pathway and combination drug treatment.

RESULTS

Among all the tested compounds, fifteen of them exhibited promising growth-inhibitory effect (0.15- 5.0μM) and induced cell cycle arrest in the G2/M phase. In addition, the selected compounds inhibited the microtubule assembly; altered mitochondrial membrane potential and enhanced the levels of caspase-9 in MCF-7 cells. Furthermore, the active compound with a combination of drugs showed a synergistic effect at lower concentrations, and the drug uptake was mediated through clathrin-mediated endocytic pathway.

CONCLUSION

Our results indicated that quinazoline and quinazolino-benzothiadiazine conjugates could serve as potential leads in the development of new anticancer agents.

Standard-dose epirubicin increases the pathological complete response rate in neoadjuvant chemotherapy for breast cancer: a multicenter retrospective study

Background

Neoadjuvant chemotherapy (NAC) has become the best comprehensive treatment choice for breast cancer. Epirubicin is a crucial drug widely used in breast cancer chemotherapy, but it is often used with a reduced dosage in NAC for Chinese patients for its notable cardiotoxicity and frequent adverse events. This study aimed to investigate the efficacy and safety of standard-dose epirubicin in NAC for Chinese breast cancer patients retrospectively.

Methods

We retrospectively collected clinicopathological parameters of breast cancer patients who underwent epirubicin-based NAC and a later surgery from three separate medical centers. Patients were divided into standard-dose and low-dose groups according to the epirubicin dose. The pathological complete response (pCR) rate, as the main therapeutic outcomes, and the incidence of adverse events were recorded and compared.

Results

The pCR rate of the standard-dose group was 41.2%, while the low-dose group was 10.1% (P<0.001). The univariate analysis showed that ER status (HR, 2.519; 95% CI, 1.057-5.988, P=0.037) and epirubicin dose (HR, 6.200; 95% CI, 2.374-16.193, P<0.001) were associated with pCR rates. The multivariate analysis showed that patients receiving standard-dose epirubicin chemotherapy (HR, 6.925; 95% CI, 2.537-18.902, P<0.001) showed more possibility to achieve pCR after NAC. There was no significant difference in the incidence rates of grade III/IV adverse events between these two different dose groups.

Conclusions

Standard-dose epirubicin increases the pCR rate in breast cancer patients treated with NAC, and no other toxicity is noted.

Synergistic Chemotherapy Drug Response Is a Genetic Trait in Lymphoblastoid Cell Lines

Lymphoblastoid cell lines (LCLs) are a highly successful model for evaluating the genetic etiology of cancer drug response, but applications using this model have typically focused on single drugs. Combination therapy is quite common in modern chemotherapy treatment since drugs often work synergistically, and it is an important progression in the use of the LCL model to expand work for drug combinations. In the present work, we demonstrate that synergy occurs and can be quantified in LCLs across a range of clinically important drug combinations. Lymphoblastoid cell lines have been commonly employed in association mapping in cancer pharmacogenomics, but it is so far untested as to whether synergistic effects have a genetic etiology. Here we use cell lines from extended pedigrees to demonstrate that there is a substantial heritable component to synergistic drug response. Additionally, we perform linkage mapping in these pedigrees to identify putative regions linked to this important phenotype. This demonstration supports the premise of expanding the use of the LCL model to perform association mapping for combination therapies.

Efficacy of nanoparticle albumin-bound paclitaxel regimens for relapsed small cell lung cancer: A retrospective analysis

Although small cell lung cancer (SCLC) is initially sensitive to chemotherapy, it recurs in most cases. Standard regimens for salvage chemotherapy have not been established, and the prognosis of relapsed SCLC remains poor. In the present study, we investigated the clinical efficacy and safety of nanoparticle albumin-bound paclitaxel (nab-paclitaxel) regimens for the treatment of relapsed SCLC.In this retrospective multicenter analysis, 14 patients (3 women and 11 men; median age 71 years) with relapsed SCLC received nab-paclitaxel alone or in combination with carboplatin between February 2013 and July 2014. The safety and efficacy of the regimens were evaluated.The response rates, disease control rates, and median overall survival for the total patient population were 36%, 64%, and 7.8 months, respectively. Response rates, disease control rates, and the median overall survival were 11%, 44%, and 4 months, respectively, in the monotherapy group; and 80%, 100%, and 10.6 months, respectively, in the combination therapy group. The most common adverse events were hematological toxicities such as neutropenia and anemia. Severe neutropenia appeared in some patients, although it was resolved by treatment in all. The most common nonhematological toxicity was anorexia (64%), followed by neurotoxicity and constipation. All nonhematological toxicities were mild and manageable.Our results suggest that chemotherapy with nab-paclitaxel regimens for relapsed SCLC exhibits moderate clinical efficacy and is well-tolerated. Further clinical trials in relapsed SCLC patients are warranted.

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.

Paclitaxel Enhances Carboplatin-DNA Adduct Formation and Cytotoxicity

This rapid report focuses on the pharmacodynamic mechanism of the carboplatin/paclitaxel combination and correlates it with its cytotoxicity. Consistent with the synergistic to additive antitumor activity (the combination index ranging from 0.53 to 0.94), cells exposed to this combination had significantly increased carboplatin-DNA adduct formation when compared to that of carboplatin alone (450 ± 30 versus 320 ± 120 adducts per 10(8) nucleotides at 2 h, p = 0.004). Removal of paclitaxel increased the repair of carboplatin-DNA adducts: 39.4 versus 33.1 adducts per 10(8) nucleotides per hour in carboplatin alone (p = 0.021). This rapid report provides the first pharmacodynamics data to support the use of carboplatin/paclitaxel combination in the clinic.

Prediction of individual response to anticancer therapy: historical and future perspectives

Since the introduction of chemotherapy for cancer treatment in the early 20th century considerable efforts have been made to maximize drug efficiency and at the same time minimize side effects. As there is a great interpatient variability in response to chemotherapy, the development of predictive biomarkers is an ambitious aim for the rapidly growing research area of personalized molecular medicine. The individual prediction of response will improve treatment and thus increase survival and life quality of patients. In the past, cell cultures were used as in vitro models to predict in vivo response to chemotherapy. Several in vitro chemosensitivity assays served as tools to measure miscellaneous endpoints such as DNA damage, apoptosis and cytotoxicity or growth inhibition. Twenty years ago, the development of high-throughput technologies, e.g. cDNA microarrays enabled a more detailed analysis of drug responses. Thousands of genes were screened and expression levels were correlated to drug responses. In addition, mutation analysis became more and more important for the prediction of therapeutic success. Today, as research enters the area of -omics technologies, identification of signaling pathways is a tool to understand molecular mechanism underlying drug resistance. Combining new tissue models, e.g. 3D organoid cultures with modern technologies for biomarker discovery will offer new opportunities to identify new drug targets and in parallel predict individual responses to anticancer therapy. In this review, we present different currently used chemosensitivity assays including 2D and 3D cell culture models and several -omics approaches for the discovery of predictive biomarkers. Furthermore, we discuss the potential of these assays and biomarkers to predict the clinical outcome of individual patients and future perspectives.

The predictive value of epidermal growth factor receptor expression for sensitivity to vinorelbine in breast cancer

Breast cancer patients with positive epidermal growth factor receptor (EGFR) expression have significantly worse post-relapse prognosis than patients with negative EGFR expression. Vinorelbine (NVB) is usually reserved as a salvage therapy after anthracyclines and taxanes in patients with breast cancer. To see whether EGFR expression has a predictive value in NVB-mediated effect on human breast cancer cells, we examined 50 primary breast cancer samples. Of these, 42% were found to be NVB sensitive by ATP-tumour chemosensitivity assay. Sensitivity was correlated with EGFR expression level (p = 0.001). To dynamically examine EGFR's effect on NVB sensitivity in breast cancer cells, we used the real-time cell electronic sensing system with EGFR-positive and EGFR-negative breast cancer cell lines, MCF-7 and MDA-MB-435s, respectively. MCF-7 is NVB sensitive, while MDA-MB-435 is NVB resistant. NVB-induced cytotoxicity to MCF-7 can be partly reversed with inhibitory anti-EGFR antibody. NVB up-regulated EGFR expression in MCF-7 cells, which affects ERK1/2 phosphorylation. This cellular response mechanism may cause greater input to non-lethally damaged cells. These data suggest that EGFR expression can be used as a prognostic factor for breast cancer sensitivity to NVB, which could help identify appropriate treatments for breast cancer.

In vitro chemosensitivity in breast cancer using ATP-tumor chemosensitivity assay

Chemotherapy for breast cancer is given on the basis of empirical information from clinical trials, an approach which falls to take into account the known heterogeneity of chemosensitivity between patients. This study aimed to demonstrate the degree of heterogeneity of chemosensitivity in breast cancers. In this study, we examined the heterogeneity of chemosensitivity in breast cancer specimens (n = 50) using an ex vivo ATP-tumor chemosensitivity assay (ATP-TCA). Assay evaluability was 92% in surgical biopsies or pleural aspirates. A variety of chemosensitivity agents were tested. We found that the most active single agent tested was paclitaxel, to which 65.9% of samples were sensitive. Combinations of agents also showed more strong sensitivity cases. The Adriamycin+5-FU demonstrated a strong sensitivity in 23 of 43 (52.3%) of samples. Adriamycin+paclitaxel was more effective, with strong sensitivity in 37 of 43 cases tested (86.0%). There was a marked heterogeneity of chemosensitivity in breast cancer. Chemosensitivity testing may provide a practical method of testing new regimens before clinical trials in breast cancer patients.

Drug ratio-dependent antagonism: a new category of multidrug resistance and strategies for its circumvention

A newly identified form of multidrug resistance (MDR) in tumor cells is presented, pertaining to the commonly encountered resistance of cancer cells to anticancer drug combinations at discrete drug:drug ratios. In vitro studies have revealed that whether anticancer drug combinations interact synergistically or antagonistically can depend on the ratio of the combined agents. Failure to control drug ratios in vivo due to uncoordinated pharmacokinetics could therefore lead to drug resistance if tumor cells are exposed to antagonistic drug ratios. Consequently, the most efficacious drug combination may not occur at the typically employed maximum tolerated doses of the combined drugs if this leads to antagonistic ratios in vivo after administration and resistance to therapeutic effects of the drug combination. Our approach to systematically screen a wide range of drug ratios and concentrations and encapsulate the drug combination in a liposomal delivery vehicle at identified synergistic ratios represents a means to mitigate this drug ratio-dependent MDR mechanism. The in vivo efficacy of the improved agents (CombiPlex formulations) is demonstrated and contrasted with the decreased efficacy when drug combinations are exposed to tumor cells in vivo at antagonistic ratios.

Docetaxel and carboplatin combination chemotherapy as outpatient palliative therapy in carcinoma of unknown primary: a multicentre Hellenic Cooperative Oncology Group phase II study

INTRODUCTION

Taxane/platinum combinations exhibit synergistic cytotoxicity and activity against a broad range of solid tumours. We sought to optimise the regimen as a suitable outpatient palliative treatment for cancer of unknown primary (CUP).

PATIENTS AND METHODS

Eligible CUP patients with adenocarcinoma or poorly differentiated carcinoma, performance status of 0-2, adequate organ function and assessable disease were treated with docetaxel 75 mg/m(2) and carboplatin at an area under the concentration time-curve (AUC) of 5, both as 30-minute intravenous infusions, every three weeks. Patients with isolated axillary adenopathy, squamous cell cervical or inguinal adenopathy and PSA or germ-cell serum tumour markers were excluded.

RESULTS

Forty-seven patients entered the trial, 24 with predominantly nodal disease or non-mucinous peritoneal carcinomatosis (favourable risk) and 23 with visceral metastases (unfavourable risk). A median of 6 cycles of chemotherapy were administered, with relative dose intensities of both drugs >90%. Response rates were 32% (46% in favourable risk, 17% in unfavourable), comparable to the activity of paclitaxel/platinum regimes, though complete remissions were seen only in favourable risk patients. Granulocyte-colony stimulating factor support was used in a third of treatment cycles. Toxicity was mild and manageable, with grade 3-4 neutropenia in 26% of patients, febrile neutropenia in 7% and severe non-hematologic side-effects in less than 8% of patients. No toxic deaths or severe neurotoxicity were seen. Median time to progression (TTP) and overall survival (OS) were 5.5 and 16.2 months respectively. Survival was driven mainly by favourable-risk patients (22.6 months), as those with visceral metastases had a poor median survival of only 5.3 months. Good performance status and low-volume disease predicted for superior outcome, while docetaxel relative dose-intensity was a positive prognosticator only in favourable-risk patients.

CONCLUSIONS

One-hour docetaxel/carboplatin is a convenient, safe and effective outpatient palliative treatment for CUP patients, providing meaningful survival prolongation only in favourable-risk patients. Insights in the molecular biology of CUP are needed for the development of targeted therapeutic manipulations of malignant resistance and progression.

Phase II trial of gemcitabine/carboplatin (plus trastuzumab in HER2-positive disease) in patients with metastatic breast cancer

BACKGROUND

Gemcitabine and carboplatin have significant preclinical synergy, and both provide synergistic antitumor activity in metastatic breast cancer (MBC) when used in combination with trastuzumab. The gemcitabine/ cisplatin combination is highly active in MBC with response rates (RRs) of approximately 50% in anthracycline- and taxane-pretreated patients and up to 80% in untreated subjects. This phase II trial studied the efficacy and safety of gemcitabine/carboplatin with or without trastuzumab in patients with MBC.

PATIENTS AND METHODS

Patients were stratified into 3 groups: group 1, HER2-positive; group 2, HER2-negative and taxane- naive/remote (no taxanes within past 2 years); and group 3, HER2-negative and previous taxane therapy. Included were women aged > or = 18 years, Eastern Cooperative Oncology Group performance status of 0-2, with Response Evaluation Criteria in Solid Tumors-defined measurable MBC; HER2-negative or HER2 (3+) by immunohistochemistry or fluorescence in situ hybridization positive. All cycles were repeated every 14 days. On day 1, gemcitabine 1500 mg/m2 over 30 minutes was administered followed by carboplatin area under the curve of 2.5. Group 1 also received trastuzumab 8 mg/kg on day 1 of each cycle followed by 4 mg/kg for every 2 weeks thereafter.

RESULTS

One hundred fifty patients were registered (50, 51, and 49 in groups 1, 2, and 3, respectively). The overall RRs were 64%, 27%, and 32%, respectively, with median time to progression of 7.2, 5.5, and 4.4 months, respectively. Overall, grade 3/4 toxicities included neutropenia (45%), leukopenia (17%), and thrombocytopenia (7%). Alopecia was infrequent: grade 1 (34%) and grade 2 (3%), and there was no significant cardiac toxicity.

CONCLUSION

Gemcitabine/carboplatin/trastuzumab is highly active in patients with HER2-positive MBC. Gemcitabine/carboplatin is active in patients with HER2-negative MBC independent of previous taxane therapy. Gemcitabine/carboplatin with or without trastuzumab administered every 2 weeks is associated with a low frequency of serious toxicity.

In vitro studies on gemcitabine combinations with other antiblastics

The use of gemcitabine in combination with chemotherapeutic agents, including cisplatin, pemetrexed and taxanes, is characterized by the enhancement of their anticancer activity. The analysis of the underlying pharmacodynamics has revealed that modulation of nucleotide pools, drug metabolism, and cellular DNA repair capability are the most common factors to explain the additive to synergistic interaction between gemcitabine and anticancer agents in several human cancers in vitro and in vivo.

Methods and goals for the use of in vitro and in vivo chemosensitivity testing

Sensitive, specific, and accurate methods to assay chemosensitivity are needed to (1) screen new therapeutic agents, (2) identify patterns of chemosensitivity for different tumor types, (3) establish patterns of cross-resistance and sensitivity in treatment of naïve and relapsing tumors, (4) identify genomic and proteomic profiles associated with sensitivity, (5) correlate in vitro response with preclinical in vivo effects and clinical outcomes for a particular therapeutic agent, and (6) tailor chemotherapy regimens to individual patients. Various methods are available to achieve these end points, including several in vitro clonogenic and proliferation assays, cell metabolic activity assays, molecular assays to monitor expression of markers for responsiveness, drug resistance, and for induction of apoptosis, in vivo tumor growth and survival assays in metastatic and orthotopic models, and in vivo imaging assays. The advantages and disadvantages of the specific assays are discussed. A summary of research questions related to chemosensitivity testing is also included.

Paclitaxel-carboplatin combination chemotherapy in advanced breast cancer: accumulating evidence for synergy, efficacy, and safety

Patients with metastatic breast cancer receive multiple lines of cytotoxic chemotherapy, with taxane and anthracycline-based regimens being the most active. Anthracyclines carry the risk of significant cardiotoxicity at high cumulative doses and when combined with trastuzumab, an anti-HER2 antibody. Carboplatin has shown promising single-agent activity in advanced breast cancer, is not a P-glycoprotein substrate, and is conveniently administered on an outpatient basis. Preclinical experiments demonstrated schedule-dependent synergistic cytotoxic effects of the paclitaxel first/carboplatin last (PC) combination. Pharmacokinetic parameters of paclitaxel and carboplatin were studied by Hellenic Cooperative Oncology Group (HECOG) and no significant interaction or correlation with clinical parameters were found. We assessed PC both as salvage as well as first-line treatment of advanced breast cancer patients in phase II studies which disclosed 40-60% response rates and median survival times of 12-20 mo with manageable toxicity. These results were confirmed by other groups and prompted us to the first randomized phase III trial comparing PC to the standard of epirubicin/paclitaxel (EP), a trial that showed equivalent efficacy and tolerable toxicity for PC. Registry retrospective analysis identified factors prognostic for improved outcome: good performance status, low tumor burden, lack of anthracycline exposure and of hormonal maintenance therapy. PC combinations with HER1 or HER2 modulators are being evaluated both by HECOG and by international groups. Paclitaxel coupled with carboplatin provides an alternative therapeutic option for anthracycline-exposed patients and warrants further clinical research in the direction of anthracycline-free management of metastatic breast cancer.

Phase II study of prolonged ambulatory infusion carboplatin and oral etoposide for patients progressing through hormonal therapy for prostate cancer

AIM

To develop a well-tolerated outpatient chemotherapy regimen for hormone-insensitive prostate cancer.

METHOD

Forty patients received carboplatin 20 mg/m2 by continuous ambulatory infusion with oral etoposide 50 mg/day for 21 days repeated every 6 weeks.

RESULTS

Four patients had a partial response and 16 patients had stable disease. Two of the partial responders and three additional patients recorded falls in prostate specific antigen of 50% or more. The median freedom from progression was 24 weeks and median survival 32 weeks. Twenty-four of 31 patients had decreasing pain scores and 20 of 34 patients recorded improved quality of life with at least one cycle of treatment. The main toxicity occurred in seven patients with World Health Organization (WHO) grade 4 neutropenia and in four patients with WHO grade 3 neutropenia. Only one patient developed febrile neutropenia. Six patients had grade 3 anaemia and three patients had grade 3 thrombocytopenia. Two patients reported grade 3 lethargy whereas 11 patients had grade 2 lethargy.

CONCLUSION

This was a well-tolerated regimen that improved symptomatic control of hormone-insensitive prostate cancer.

Paclitaxel and epirubicin versus paclitaxel and carboplatin as first-line chemotherapy in patients with advanced breast cancer: a phase III study conducted by the Hellenic Cooperative Oncology Group

BACKGROUND

To compare survival between patients with advanced breast cancer (ABC) treated with epirubicin/paclitaxel (Taxol) or paclitaxel/carboplatin (Cp) chemotherapy.

PATIENTS AND METHODS

From January 1999 to April 2002, 327 eligible patients with ABC were randomized to receive either paclitaxel 175 mg/m(2) in a 3-h infusion followed by epirubicin (EPI) 80 mg/m(2) (group A) or paclitaxel, as in group A, followed by Cp at an AUC of 6 mg x min/ml (group B) every 3 weeks for six cycles.

RESULTS

After a median follow-up of 23.5 months, median survival was not significantly different between the two groups (22.4 months versus 27.8 months, P=0.25), whereas median time to treatment failure was significantly longer in patients treated with paclitaxel/Cp (8.1 months in group A versus 10.8 months in group B, P=0.04). Both regimens were well tolerated. In total, 39 patients (24%) in group A and 46 (29%) in group B suffered at least one severe side-effect. Quality-of-life assessment and cost analysis did not reveal any significant differences between the two groups.

CONCLUSION

Our study suggests that the paclitaxel/Cp combination is an effective therapeutic alternative for patients with ABC in which anthracycline administration has the potential of being harmful.

Results of Two Open-Label, Multicenter Phase II Studies of Docetaxel, Platinum Salts, and Trastuzumab in HER2-Positive Advanced Breast Cancer

BACKGROUND

Preclinical data indicate that docetaxel, platinum salts, and the combination of both drugs are highly synergistic with the anti-HER2 antibody trastuzumab. The University of California at Los Angeles-Oncology Research Network (UCLA-ORN) and the Breast Cancer International Research Group (BCIRG) have conducted two phase II studies to evaluate docetaxel and trastuzumab in combination with either cisplatin or carboplatin for the treatment of women with advanced breast cancer that overexpresses HER2.

METHODS

Each study enrolled 62 patients with HER2-overexpressing tumors. Patients received a median of six cycles of docetaxel at 75 mg/m2 of body surface area and cisplatin (BCIRG 101 study) at 75 mg/m2 or carboplatin (UCLA-ORN study) at AUC = 6 mg/mL. min given on day 1 and then every 21 days. Trastuzumab was given on day 1, cycle 1 (4 mg/kg) and then continued weekly at 2 mg/kg for 1 year or until disease progression. Tumor measurements were obtained at baseline, after three cycles of chemotherapy, and then every 3 months. HER2 gene amplification was determined by fluorescence in situ hybridization.

RESULTS

Patient characteristics were comparable between trials with the exception that 15% of the patients in the UCLA-ORN study had received previous adjuvant taxane therapy. Both regimens were well tolerated, with manageable toxicities. Hematologic toxicities were more frequent in patients in the UCLA-ORN study than in patients in the BCIRG 101 study, whereas the reverse pattern was observed for non-hematologic toxicities. One patient in each study developed reversible congestive heart failure. Responses were observed in 49 of 62 patients in the BCIRG 101 study (overall response rate = 79%, 95% confidence interval [CI] = 66% to 89%) and in 34 of 59 evaluable patients in the UCLA-ORN study (overall response rate = 58%, 95% CI = 44% to 70%). Median times to progression were 9.9 months (95% CI = 8.3 to 13.1 months) and 12.7 months (95% CI = 8.6 to 15.5 months) for patients in the BCIRG 101 and UCLA-ORN studies, respectively. Overall response rates were higher and median time to progression was longer in the subset of patients whose tumors harbored HER2 gene amplification.

CONCLUSION

Combinations of docetaxel, a platinum salt, and trastuzumab are feasible and active in patients with advanced breast cancers that overexpress HER2. The BCIRG is conducting ongoing randomized studies of the three-drug combination in both the metastatic and adjuvant settings.

Phase II trial of paclitaxel, estramustine, etoposide, and carboplatin in the treatment of patients with hormone-refractory prostate carcinoma

BACKGROUND

Preclinical data suggest that the combination of intravenous (i.v.) paclitaxel, carboplatin, oral etoposide, and oral estramustine (TEEC) has significant activity in patients with advanced, hormone-refractory prostate carcinoma. The authors conducted this clinical trial to evaluate the addition of carboplatin to the three-drug combination of paclitaxel, estramustine, and etoposide (TEE).

METHODS

Twenty patients with carcinoma of the prostate that was progressing despite hormone therapy were enrolled on this Phase II trial. Patients were treated with oral estramustine, 280 mg three times daily, and oral etoposide, 50 mg/m2, once daily on Days 1-7, with i.v. paclitaxel, 135 mg/m2, over 1 hour followed by carboplatin (area under the curve, 5) on Day 2 of each 21-day treatment cycle. Patients were evaluated for response after three cycles, and three additional cycles were given to responding or stable patients.

RESULTS

Nineteen patients were evaluable for response, and 12 patients had measurable disease at baseline. The measurable response rate was 58% (7 of 12 patients; 95% confidence interval [95% CI], 28-85%), and all of those were partial responses. Eleven patients had decreases >50% from their baseline prostate specific antigen levels during therapy, for a response rate of 58% (95% CI, 34-80%) by this criterion. The median time to disease progression was 5.5 months, with a median survival of 14.2 months. Major toxicities included Grade (according to version 2 of the National Cancer Institute Common Toxicity Criteria) 4 neutropenia in 4 patients, Grade 4 thrombocytopenia in 4 patients, and anemia > or = Grade 3 in 4 patients. One patient had a deep vein thrombosis.

CONCLUSIONS

The combination of TEEC was active in patients with hormone-refractory prostate carcinoma. The regimen was tolerable, with primarily hematologic toxicity. The addition of carboplatin to TEE did not appear to add to the efficacy of the three-drug combination of antimicrotubule agents.

Growth factor receptors in breast cancer: potential for therapeutic intervention

Increased expression and activation of receptor tyrosine kinases occurs frequently in human breast carcinomas. Several therapies targeting these receptors are currently in clinical trials. Therapeutic strategies include blockade of individual receptors with monoclonal antibodies and inhibition of tyrosine kinase function. Trastuzumab is the first of these biologic therapies to be approved for patients with human epidermal growth factor receptor 2 (HER2)-overexpressing metastatic breast cancer. Novel trastuzumab-based combinations are being investigated in patients with advanced breast cancer. Large clinical trials have also been launched in the adjuvant setting. Small molecules that inhibit specific tyrosine kinases (e.g., epidermal growth factor receptor, HER2) are in phase I and phase II clinical trials. Other growth-factor-targeted drugs that have reached clinical development include STI571 and antibodies directed at the insulin-like growth factor pathway. Biologic therapies directed against these important receptors are promising. In this review we discuss challenges and opportunities for the development of growth-factor-targeted approaches for the treatment of breast cancer.