Pharmacokinetic optimisation of treatment schedules for anthracyclines and paclitaxel in patients with cancer

Will nanomedicine become a good solution for the cardiotoxicity of chemotherapy drugs?

Cancer is one of the leading causes of death worldwide, and with the continuous development of life sciences and pharmaceutical technology, more and more antitumor drugs are being used in clinics to benefit cancer patients. However, the incidence of chemotherapy-induced cardiotoxicity has been continuously increasing, threatening patients' long-term survival. Cardio-oncology has become a research hot spot, and the combination of nanotechnology and biomedicine has brought about an unprecedented technological revolution. Nanomaterials have the potential to maximize the efficacy and reduce the side effects of chemotherapeutic drugs when used as their carriers, and several nano-formulations of frequently used chemotherapeutic drugs have already been approved for marketing. In this review, we summarize chemotherapeutic drugs that are highly associated with cardiotoxicity and evaluate the role of nano-delivery systems in reducing cardiotoxicity based on studies of their marketed or R&D nano-formulations. Some of the marketed chemotherapy drugs are combined with nano-delivery systems that can effectively deliver chemotherapy drugs to tumors and cannot easily penetrate the endothelial barrier of the heart, thus decreasing their distribution in the heart and reducing the cardiotoxicity to some extent. However, many chemotherapy nanomedicines that are marketed or in R&D have not received enough attention in determining their cardiotoxicity. In general, nanomedicine is an effective method to reduce the cardiotoxicity of traditional chemotherapy drugs. However, cardiovascular complications in cancer treatment are very complex diseases, requiring the application of multiple measures to achieve effective management and prevention.

Validated HPLC-UV Method for Simultaneous Estimation of Paclitaxel and Doxorubicin Employing Ion Pair Chromatography: Application in Formulation Development and Pharmacokinetic Studies

Though paclitaxel (PTX) and doxorubicin (DOX) are amongst the most widely used and investigated drug pair for combination chemotherapy but surprisingly, not a single validated HPLC-UV method is available to analyze PTX and DOX simultaneously. So, herein a HPLC-UV method is developed and validated for the same, filling an indispensable gap in the literature. As these two moieties have characteristically different polarities, resolving them under the common chromatographic conditions is a challenging task. Herein, the principle of ion pair chromatography is utilized to resolve these two moieties on a C18 column employing an isocratic mobile phase comprised of acetonitrile and octane sulfonic acid buffer (67 : 37) and detected simultaneously at 231 nm using a UV detector only. The retention time is 4.4 and 7.2 min for PTX and DOX, respectively, with a total analysis time of less than 10 minutes, suitable for the formulation development and research, while LOQ is less than 0.066 μg/ml for both the drugs, suitable for the therapeutic drug monitoring at preclinical and clinical research setup. To substantiate the applicability of the developed method, a nanoformulation coloaded with PTX and DOX was designed and analyzed using the developed protocol. The method is also applied successfully to study the plasma kinetic profile of both the moieties simultaneously in Balb/c mice. Further, the method is validated as per the ICH guidelines fulfilling the unmet need of a validated analytical tool to simultaneously estimate PTX and DOX. Moreover, the results suggest that the principal of common ion chromatography demonstrated here can also be applied further for the simultaneous chromatographic separation of other polar and nonpolar moieties too. Consequently, the reported method surely will advance the toolset required for the precision-based combination chemotherapy.

Comparison of Autologous Breast Reconstruction Complications by Type of Neoadjuvant Chemotherapy Regimen

BACKGROUND

Neoadjuvant chemotherapy before mastectomy helps reduce tumor burden and pathologic response in breast cancer. Limited evidence exists regarding how neoadjuvant chemotherapy impacts outcomes following microvascular breast reconstruction. This study examines the effects of neoadjuvant chemotherapy regimens and schedules on microvascular breast reconstruction complication rates and also assesses the effects of neoadjuvant chemotherapy on circulating immune cells related to wound healing.

METHODS

Patients who underwent neoadjuvant chemotherapy and microvascular breast reconstruction at Yale New Haven Hospital between 2013 and 2018 were identified. Demographic variables, oncologic history, chemotherapy regimens, and complication profiles were collected. Chemotherapy regimens were stratified by inclusion of anthracycline and order of taxane administration. Chi-square, Fisher's exact, and t tests were used for univariate analysis. Multivariate binary logistic regression was used to control for covariates.

RESULTS

One hundred patients met inclusion criteria. On multivariate analysis, the administration of taxane first in an anthracycline-containing chemotherapy sequence was associated with increased complications (OR, 3.521; p = 0.012), particularly fat necrosis (OR, 2.481; p = 0.040). In the logistic regression model evaluating the effect of the taxane-first regimen on complication rates, the area under the curve was estimated to be 0.760 (p < 0.0001), particularly fat necrosis 0.635 (p < 0.05). The dosage of chemotherapy, number of days between neoadjuvant chemotherapy completion and surgery, and number of circulating immune cells did not significantly differ among patients who experienced complications.

CONCLUSIONS

Taxane-first, anthracycline-containing neoadjuvant chemotherapy regimens were associated with increased complications, particularly fat necrosis. The increased postreconstruction complication risk must be weighed against the benefits of taxane-first regimens in improving tumor outcome.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

A Dose-Escalating Pilot Study (NCT03017404) of Pegylated Liposomal Doxorubicin and Cyclophosphamide, Followed by Docetaxel Administration as a Neoadjuvant Chemotherapy Regimen in Patients with Locally Advanced Breast Cancer

BACKGROUND

Pegylated liposomal doxorubicin (PEG-LD) has a comparable efficacy but a distinct toxicological profile compared with free doxorubicin. The use of PEG-LD and cyclophosphamide followed by docetaxel regimen as neoadjuvant chemotherapy has not been well established.

OBJECTIVES

We aimed to assess the maximum tolerated dose (MTD) and toxicity of this regimen in patients with locally advanced breast cancer.

METHODS

A total of 19 patients were enrolled in this trial. In the initial treatment plan, patients were given PEG-LD at 35, 40, 45, or 50 mg/m2 on day 1 during the first four cycles, and cyclophosphamide was administered at a dose of 600 mg/m2. During the last four cycles, docetaxel was administered at 75 mg/m2 on day 1 of a 21-day scheme.

RESULTS

The MTD was 40 mg/m2 PEG-LD and 600 mg/m2 cyclophosphamide administered on day 1 of a 21-day cycle. Dose-limiting toxicity, grade 3 hand-foot syndrome, was observed in one patient during level 2 and three patients during level 3. Other side effects included neutropenia, anemia, stomatitis, rash, nausea/vomiting, alopecia, transaminase elevation, and cardiotoxicity. The pathological complete response rate was 21.1%.

CONCLUSIONS

Our study demonstrated that combination of 40 mg/m2 PEG-LD and 600 mg/m2 cyclophosphamide, followed by 75 mg/m2 docetaxel on day 1 of a 21-day scheme, was an efficacious and well-tolerated neoadjuvant regimen for patients with locally advanced breast cancer.

The role of quercetin and vitamin C in Nrf2-dependent oxidative stress production in breast cancer cells

The balance between the production and elimination of reactive oxygen species (ROS) is essential in determining whether cells survive or undergo apoptosis. Nuclear factor erythroid 2-related factor 2 (Nrf2) may act as a sensor for electrophilic stress, thus regulating the intracellular antioxidant response. The present study investigated the role of vitamin C (VC) and quercetin (Q) in the induction of Nrf2-mediated oxidative stress in cancer cells. An MTT assay was conducted to examine the anti-proliferative effects of VC and Q. Reverse transcription-quantitative polymerase chain reaction and western blot analysis were performed to determine the messenger RNA (mRNA) and protein expression of Nrf2, respectively. The activity of nicotinamide adenine dinucleotide phosphate dehydrogenase quinone 1, heme oxygenase 1, glutathione peroxidase, glutathione reductase and reduced glutathione were measured by spectrophotometric analysis. Intracellular generation of ROS was determined using 2'-7'-dichlorodihydrofluorescein diacetate fluorescent probes. The results demonstrated that the cytotoxicity (50% inhibitory concentration) of VC and Q were 271.6-480.1 and 155.1-232.9 µM, respectively. Additionally, there was a significant decrease in the expression of Nrf2 mRNA and protein levels following the treatment of breast cancer cells with VC and Q (P=0.024). Following treatment with VC and Q, the nuclear/cytosolic Nrf2 ratio was reduced by 1.7-fold in MDA-MB 231 cells, 2-fold in MDA-MB 468 cells, 1.4-fold in MCF-7 cells and 1.2 fold in A549 cells. Sequential treatment with VC and Q decreased endogenous production of ROS in a dose-dependent manner (P=0.027). The results of the current study suggest that VC and Q treatment may be developed as an adjuvant for patients with cancer and overexpression of Nrf2.

A Phase II Trial of Neoadjuvant Chemotherapy with Genexol® (Paclitaxel) and Epirubicin for Locally Advanced Breast Cancer

PURPOSE

Neoadjuvant chemotherapy (NC) is yet to be established as the definitive treatment regimen for locally advanced breast cancer (LABC). The aim of this study was to determine the efficacy and toxicity of NC with epirubicin and paclitaxel.

METHODS

Between March 2007 and January 2009, 50 patients with LABC were enrolled in an open-label, phase II, multicenter study carried out at five distinct institutions. All patients were scheduled to receive four cycles of 60 mg/m(2) epirubicin and 175 mg/m(2) paclitaxel every 3 weeks, preoperatively, unless they developed profound side effects or disease progression. After curative surgery, two additional cycles of chemotherapy were administered to patients who had shown a positive response to NC.

RESULTS

In all, 196 cycles of chemotherapy were administered preoperatively; 47 of the 50 patients (94%) underwent all four cycles of designated treatment. Complete disappearance of invasive foci of the primary tumor, and negative axillary lymph nodes were confirmed in eight patients (16.0%), post operation. The cumulative 5-year disease-free survival rate was 70.0% for patients with complete remission (CR) and partial remission (PR), and 33.3% for patients with stable disease (SD) and progressive disease (PD) (p=0.018). The cumulative 5-year overall survival was 90.0% for patients who achieved CR and PR and 55.6% for patients who had SD and PD (p=0.001). Neutropenia (42.0%) was the most common grade 3/4 toxicity. However, none of the toxicities resulted in cessation of the treatment.

CONCLUSION

The encouraging pathologic response observed in the patients treated with epirubicin plus paclitaxel NC in this study suggests that epirubicin could be a substitute for doxorubicin, which is the most cardiotoxic agent.

Sensitization of ABCB1 overexpressing cells to chemotherapeutic agents by FG020326 via binding to ABCB1 and inhibiting its function

The effectiveness of chemotherapeutic treatment is usually limited by the overexpression of adenosine triphosphate binding cassette (ABC) transporters, which mediate multidrug resistance (MDR) by acting as efflux pumps to remove chemotherapeutic agents from MDR cancer cells. Thus, the inhibition of ABC transporters may represent a promising strategy to reverse MDR. This study was to characterize the actions of FG020326, a newly synthesized triaryl-substituted imidazole derivative, to reverse MDR in vitro and in vivo. FG020326 significantly potentiated the cytotoxicity of paclitaxel, doxorubicin, and vincristine in the ABCB1 (P-glycoprotein, P-gp) overexpressing cells KBv200 and MCF-7/adr, but not in the ABCB1 negative parental cell lines KB and MCF-7. However, FG020326 did not alter the cytotoxicity of the aforementioned drugs in ABCC1 (MRP1), ABCC4 (MRP4), ABCG2 (BCRP) and LRP overexpressing cell lines, KB-CV60, NIH3T3/MRP4-2, S1-M1-80 and SW1573/2R120, respectively. FG020326, following p.o. administration, was present in concentrations sufficient for reversal of MDR in mice. The co-administration of FG020326 with paclitaxel or vincristine significantly enhanced the antitumor activity of these drugs without significantly increasing toxicity in the mice bearing the KBv200 cell xenografts. In addition, FG020326, at concentrations that reversed MDR, did not significantly affect the activity of CYP3A4 or alter the pharmacokinetic profile of paclitaxel after co-administration with paclitaxel. FG020326 produced a significant concentration-dependent displacement of [3H]azidopine and inhibition of efflux of drug from cells. Furthermore, FG020326 was co-localized with ABCB1 in cell membranes. Hence, FG020326 is characterized as a third generation MDR modulator that holds great promise for the treatment of cancer patients with ABCB1-mediated MDR.

Assessment of the validity of a population pharmacokinetic model for epirubicin

AIMS

The aim of this study was to evaluate a population model for epirubicin clearance using internal and external validation techniques.

METHODS

Jackknife samples were used to identify outliers in the population dataset and individuals influencing covariate selection. Sensitivity analyses were performed in which serum aspartate transaminase (AST) values (a covariate in the population model) or epirubicin concentrations were randomly changed by +/-10%. Cross-validation was performed five times, on each occasion using 80% of the data for model development and 20% to assess the performance of the model. External validation was conducted by assessing the ability of the population model to predict concentrations and clearances in a separate group of 79 patients.

RESULTS

Structural parameter estimates from all jackknife samples were within 7.5% of the final population estimates and examination of log likelihood values indicated that the selection of AST in the final model was not due to the presence of outliers. Alteration of AST or epirubicin concentrations by +/-10% had a negligible effect on population parameter estimates and their precision. In the cross-validation analysis, the precision of clearance estimates was better in patients with AST concentrations>150 U l-1. In the external validation, epirubicin concentrations were over-predicted by 81.4% using the population model and clearance values were also poorly predicted (imprecision 43%).

CONCLUSIONS

The results of internal validation of population pharmacokinetic models should be interpreted with caution, especially when the dataset is relatively small.

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.

Dose and schedule as determinants of outcomes in chemotherapy for breast cancer

Many cytotoxic agents for the adjuvant treatment of breast cancer are available, but they have produced only modest results, even when the tumor burden is low. This relative lack of efficacy may be attributed, in part, to the nonspecificity of the current regimens. Additionally, there is evidence that the chemotherapy doses used in clinical practice are not optimal, which potentially compromises the outcomes when the thresholds of dose intensity are not reached. Variations in treatment underscore the need to return to the basics of chemotherapy administration: dose, schedule, concentration threshold, and therapeutic index. In patients with metastatic breast cancer a clear dose-response curve has been shown with some agents, including anthracyclines. The E-max model, which in its simplest form assumes a direct relation between the dose of a drug and its effect, may be used to improve dosing in the adjuvant treatment of breast cancer. Consistent with this model, threshold effects have been observed in treatment with both anthracyclines and paclitaxel for breast cancer. There is also evidence that using dose-dense schedules may produce better outcomes with some regimens. Maintaining chemotherapy agents at full dose on schedule is crucial to treatment success, especially in adjuvant therapy. Consequently, treatment practices should use both dose intensity and dose compression to increase the likelihood of positive outcomes in patients with breast cancer.

Maximum a posteriori Bayesian estimation of epirubicin clearance by limited sampling

AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Cardiotoxicity of doxorubicin/paclitaxel combination in rats: Effect of sequence and timing of administration

The higher incidence of cardiotoxicity of doxorubicin (DOX)/paclitaxel (PTX) combination compared with DOX alone remains to be a major obstacle against effective chemotherapeutic treatment. We investigated the effect of sequence and time interval between administration of both drugs on the severity of cardiotoxicity of the combination. Male Wistar rats were divided into seven groups. DOX was administered intraperitoneally (i.p.) at a single dose of 5 mg x kg(-1) every other 2 days, 2 doses per week for a total cumulative dose of 20 mg x kg(-1). PTX was administered by an i.p. route at a dose of 20 mg x kg(-1) every other 2 days. Both drugs were injected either alone or sequentially in combination. In one case, DOX preceded PTX by 30 min and 24 h and in the other case, PTX preceded DOX by 30 min and 24 h. Cardiotoxicity was evaluated by both biochemical and histopathological examination, 48 h after the last DOX dose. DOX-induced cardiotoxicity was manifested by abnormal biochemical changes including marked increases in serum creatine phosphokinase isoenzyme (CK-MB), lactate dehydrogenase (LDH), glutathione peroxidase (GSH-Px), and aspartate aminotransferase (AST) activity levels. Myocardial tissue from DOX-treated rats showed significant increases in malondialdehyde (MDA) production and total nitrate/nitrite (NOx) levels, parallel with depletion of "endogenous antioxidant reserve," including GSH contents and GSH-Px activity level. PTX treatment produced significant changes in the biochemical parameters measured by a lower magnitude than those changes produced by DOX alone. Combination of both drugs resulted in aggravation of DOX-induced cardiotoxicity regardless the sequence and time interval between administration of either drug. Administration of PTX 30 min and 24 h after DOX treatment showed exaggeration of combination-induced cardiotoxicity compared with the reverse sequence. This exacerbation was manifested by much more pronounced changes in serum and cardiac tissue parameters measured. Histopathological examination of ventricles of rat's heart revealed that DOX treatment produced myo-cytolysis and myocardial necrosis. Administration of PTX following DOX treatment showed extensive myocardial necrosis compared with those rats treated with either DOX alone or the reverse sequence of administration. Moreover, rats treated with PTX 24 h after DOX treatment showed exaggeration of the combination-induced cardiotoxicity. In conclusion, PTX might synergistically aggravate DOX-induced cardiotoxicity. The effect might be much more pronounced with those rats treated with PTX 24 h after DOX treatment.

Concomitant versus sequential administration of epirubicin and paclitaxel as first-line therapy in metastatic breast carcinoma

BACKGROUND

The authors performed a randomized trial comprising patients with metastatic breast carcinoma (MBC). They used a noninferiority design to evaluate whether the results of sequential administration of epirubicin and paclitaxel were not markedly worse than the concomitant administration in terms of objective response rates (ORRs). Toxicity profile, quality of life (QOL), and pharmacoeconomic evaluations were evaluated as well.

METHODS

In the current study, 202 patients with MBC were randomized to receive either the combination of epirubicin at a dose of 90 mg/m2 plus paclitaxel at a dose of 200 mg/m2 for 8 cycles (concomitant arm, n = 108) or epirubicin at a dose of 120 mg/m2 for 4 cycles followed by paclitaxel at a dose of 250 mg/m2 over 3 hours for 4 cycles every 21 days (sequential arm, n = 94).

RESULTS

The authors rejected the null hypothesis that the sequential treatment is less active than the standard concomitant regimen (ORRs: concomitant = 58.5%, sequential = 57.6%). The median progression-free and overall survival periods were 11.0 months (95% confidence interval [95% CI], 9.7-12.3) and 20.0 months (95% CI, 17.2-22.6), respectively, in the concomitant arm and 10.8 months (95% CI, 7.9-13.6) and 26 months (95% CI, 18.1-33.8), respectively, in the sequential arm (P = not significant). Patients who received the sequential regimen experienced a higher incidence of Grade 3/4 (according to the World Health Organization grading system) neutropenia (62.2% of courses vs. 50.62%; P = 0.003) and Grade > or = 2 neuropathy (45.5% vs. 30.4% of patients; P = 0.03), whereas 6 patients who received the concomitant regimen developed Grade II cardiotoxicity according to New York Heart Association criteria. QOL analyses failed to provide clear differences.

CONCLUSIONS

The sequential administration of epirubicin and paclitaxel at full doses was found to be as active as their association. Therefore, both the sequential and the combined administration were acceptable options.

Relationship between anti-oxidant activities and doxorubicin-induced lipid peroxidation in P388 tumour cells and heart and liver in mice

1. The present study found that, compared with mouse heart and liver, P388 ascitic tumour had significantly lower superoxide dismutase (SOD) activity and that compared with the mouse liver, the heart had significantly lower SOD and catalase activities, as well as a lower glutathione content. 2. At 7.5 mg/kg, doxorubicin (DOX), a superoxide radical inducer, induced significant lipid peroxidation only in the tumour, whereas 15.0 mg/kg DOX induced lipid peroxidation in both the tumour and heart, but not in the liver. 3. Overall, the results of the present study suggest that the differential anti-oxidant activities in P388 ascitic tumour, heart and liver in mice may explain their differential responses and, hence, susceptibility to DOX-induced lipid peroxidation.

Pharmacokinetic-pharmacodynamic relationships of the anthracycline anticancer drugs

The anthracycline glycoside antibiotics represent a group of potent anticancer agents with a wide spectrum of activity against solid tumours and haematological malignancies, and are the mainstay of a large number of clinical protocols for the treatment of adult and childhood neoplastic diseases. Their clinical activity is limited, however, by acute and chronic adverse effects. Myelosuppression, predominantly neutropenia and leucopenia, is the dose-limiting toxicity; in addition to this, mucositis, nausea, vomiting and alopecia are frequent, whereas hepatopathy, characterised by elevated bilirubin concentrations, occurs less frequently. Cardiotoxicity is a major adverse effect of the anthracycline antibiotics and can be acute or chronic; in the acute setting, electrocardiographic abnormalities may be seen, including ST-T elevations and arrhythmias, but chronic cardiotoxicity represents a serious adverse effect that may be lethal due to the development of irreversible, cumulative dose-dependent, congestive cardiomyopathy. The occurrence of toxicity displays a marked interindividual variation, and for this reason the pharmacokinetics and pharmacodynamics of anthracyclines have been extensively investigated in order to identify integrated models that can be used in the clinical setting to prevent the development of serious toxicity, mainly leucopenia, and maximise tumour exposure. Pharmacokinetics has been recognised to influence both the toxicity and the activity of anthracyclines; in particular, there is increasing evidence that the mode of administration plays an important role for cumulative cardiotoxicity and data indicate that bolus administration, rather than continuous infusion, appears to be an important risk factor for anthracycline-induced cardiomyopathy, thus implying that this type of toxicity is maximum concentration-dependent. On the contrary, exposure to the drug, as measured by area under the curve, seems best related to the occurrence of leucopenia. Finally, the development of pharmacokinetic-pharmacodynamic models allows the simulation of drug effects and ultimately dose optimisation in order to anticipate important toxicities and prevent their occurrence by the administration of prophylactic treatments.

Gemcitabine, epirubicin and paclitaxel: pharmacokinetic and pharmacodynamic interactions in advanced breast cancer

BACKGROUND

The objectives of this study were to investigate the disposition of gemcitabine, epirubicin, paclitaxel, 2',2'-difluorodeoxyuridine and epirubicinol, and characterize the pharmacokinetic and pharmacodynamic profile of treatment in patients with breast cancer.

PATIENTS AND METHODS

The drug dispostion in 15 patients who received gemcitabine 1000 mg/m2, epirubicin 90 mg/m2 and paclitaxel 175 mg/m2 (GEP) on day 1 of a 21-day cycle, was compared with that of patients treated with epirubicin 90 mg/m2 and paclitaxel 175 mg/m2 (EP, n = 6) and epirubicin 90 mg/m2 alone (n = 6). Drug and metabolite levels in plasma and urine were assessed by high-performance liquid chromatography and parameters of drug exposure were related to hematological toxicity by a sigmoid-maximum effect (Emax) model.

RESULTS

Paclitaxel administration significantly increased the epirubicinol area under the concentration-time curve, from 357+/-146 (epirubicin) to 603+/-107 (EP) and 640+/-81 h x ng/ml (GEP), and reduced the renal clearance of epirubicin and epirubicinol by 38 and 52.2% and 34.5 and 53% in GEP- and EP-treated patients, respectively, compared with epirubicin alone. Gemcitabine had no apparent effect on paclitaxel and epirubicin pharmacokinetics, and renal clearance of epirubicin and epirubicinol. The only pharmacokinetic/pharmacodynamic relationship observed was between neutropenia and the time spent above the threshold plasma level of 0.1 micromol/l (tC0.1) of paclitaxel, with the time required to obtain a 50% decrease in neutrophil count (Et50) of GEP being 7.8 h, similar to that of EP.

CONCLUSIONS

Paclitaxel and/or its vehicle, Cremophor EL, interferes with the disposition and renal excretion of epirubicin and epirubicinol; gemcitabine has no affect on epirubicin and paclitaxel plasma pharmacokinetics and renal excretion of epirubicin, while neutropenia is not enhanced by gemcitabine.

Drug distribution and pharmacokinetic/pharmacodynamic relationship of paclitaxel and gemcitabine in patients with non-small-cell lung cancer

BACKGROUND

Gemcitabine and paclitaxel are two of the most active agents in non-small-cell lung cancer (NSCLC), and pharmacologic investigation of the combination regimens including these drugs may offer a valuable opportunity in treatment optimization. The present study investigates the pharmacokinetics and pharmacodynamics of paclitaxel and gemcitabine in chemotherapy-naive patients with advanced NSCLC within a phase I study.

PATIENTS AND METHODS

Patients were given i.v. paclitaxel 100 mg/m2 by one-hour infusion followed by gemcitabine 1,500, 1,750 and 2,000 mg/m2 by 30-min administration. Plasma levels of paclitaxel, gemcitabine and its metabolite 2',2'-difluorodeoxyuridine (dFdU) were determined by high-performance liquid chromatography (HPLC). Concentration-time curves were modeled by compartmental and non-compartmental methods and pharmacokinetic/pharmacodynamic (PK/PD) relationships were fitted according to a sigmoid maximum effect (Emax) model.

RESULTS

Paclitaxel pharmacokinetics did not change as a result of dosage escalation of gemcitabine from 1,500 to 2,000 mg/m2. A nonproportional increase in gemcitabine peak plasma levels (Cmax, from 18.56 +/- 4.94 to 40.85 +/- 14.85 microg/ml) and area under the plasma concentration-time curve (AUC, from 9.99 +/- 2.75 to 25.01 +/- 9.87 h x microg/ml) at 1,500 and 2,000 mg/m, respectively, was observed, suggesting the occurrence of saturation kinetics at higher doses. A significant relationship between neutropenia and time of paclitaxel plasma levels > or = 0.05 micromol/l was observed, with a predicted time of 10.4 h to decrease cell count by 50%. A correlation was also observed between percentage reduction of platelet count and gemcitabine Cmax, with a predicted effective concentration to induce a 50% decrease of 14.3 microg/ml.

CONCLUSION

This study demonstrates the lack of interaction between drugs, the nonproportional pharmacokinetics of gemcitabine at higher doses and the Emax relationship of paclitaxel and gemcitabine with neutrophil and platelet counts, respectively. In addition, gemcitabine 1,500 mg/m2 is the recommended dosage in combination with paclitaxel 100 mg/m2 for future phase II studies, due to its predictable kinetic behaviour and less severe thrombocytopenia than expected.

Gemcitabine plus epirubicin plus taxol (GET) in advanced breast cancer: a phase II study

PURPOSE

To investigate the activity of the combination of gemcitabine (G) plus epirubicin (E) and taxol (T), (GET), in metastatic breast cancer, to evaluate the feasibility of this regimen as induction before high dose chemotherapy and to study the pharmacokinetic interactions of these three drugs.

PATIENTS AND METHODS

Metastatic breast cancer patients, with bidimensionally measurable disease were eligible. Treatment consisted of G 1000 mg/sqm days 1 and 4 plus E 90 mg/sqm day 1 plus T 175 mg/sqm/3 h day 1, every 21 days. After six courses of GET, patients aged less than 60 years, in complete or partial remission or stable disease entered a programme of high dose chemotherapy (HDCT), as consolidation treatment.

RESULTS

Thirtysix patients were included in this study. Grade 4 neutropenia was observed in 64% of the patients, with four episodes of febrile neutropenia; 39% of the patients experienced mild to moderate peripheral neuropathy; grade 2 and 3 mucositis occurred respectively in 9 (25%) and 6 (17%) patients. The overall response rate to GET was 92% (95% CI, 77.53%-98.25%); CR 31% and PR 61%. After six courses of GET, 25 patients received HDCT, leading to an overall response rate of 96% with 58% CR. At a median follow up of 25 months (range 8-39), 13 out of 36 patients are progression free and 26 alive. Median progression free survival is 21 months, while median overall survival has not yet been reached. The pharmacokinetic data show that G does not influence the interactions between E and T, while gemcitabine kinetics remains unchanged.

CONCLUSIONS

The results of the present study indicate that the addition of G to E plus T as front line treatment for advanced breast cancer is well tolerated with an ORR of 92%. On the basis of the high activity and interesting progression free and overall survival rates, the GET combination deserves further evaluation in randomized trials.

The relevance of drug sequence in combination chemotherapy

The concept of combining chemotherapeutic agents to increase the cytotoxic efficacy has evolved greatly over the past several years. In the past, the rationale for combination chemotherapy centered on attacking different biochemical targets, overcoming drug resistance in heterogenous tumors, and increasing the dose-density of combination chemotherapy to take advantage of tumor growth kinetics. The overall goal was to improve clinical efficacy with acceptable clinical toxicity. It is now apparent that the sequence of drug administration can significantly enhance the therapeutic effect of chemotherapy. These sequence-dependent effects can be explained by chemotherapy-induced cell cycle perturbations, or by pharmacodynamic interactions between the agents in combination. In this review, we focus on drug combinations with taxanes and camptothecins, which we believe best illustrate the importance of the cell cycle and pharmacologic interactions in the sequential administration of chemotherapy. As our understanding of the cell cycle grows, our ability to appropriately sequence chemotherapy can have a great impact on the treatment of human cancers. Copyright 2000 Harcourt Publishers Ltd.

Role of epirubicin in advanced breast cancer

Anthracyclines were first introduced for the treatment of metastatic breast cancer in the 1970s and are still among the most active single agents for the treatment of this disease. Unfortunately, their clinical value is limited by late-onset ventricular dysfunction. Epirubicin, an anthracycline analogue, does not eliminate the risk of cardiotoxicity but is less cardiotoxic and myelotoxic than doxorubicin at equimolar doses, thereby allowing the safe administration of cumulative doses between 950 and 1000 mg/m2. The inclusion of epirubicin in combination regimens, such as fluorouracil/epirubicin/cyclophosphamide (FEC), has been shown to be safe and active as first-line treatment for metastatic breast cancer. In the past few years, new drugs, including taxanes, have shown a high level of activity as single agents in the treatment of advanced breast cancer. Doxorubicin/paclitaxel combinations have shown high overall response rates (90%) as first-line chemotherapy of advanced breast cancer; however, congestive heart failure has been reported in up to 20% of patients. Epirubicin/paclitaxel combinations have been associated with grade 3 cardiotoxicity (6%) in only one study. We report findings of a trial of combination epirubicin/paclitaxel as first-line treatment of advanced breast cancer, with overall response rates (ORRs) of 84% and a complete response (CR) rate of 19%. Achieving a CR to first-line chemotherapy for advanced breast cancer appears to predict survival, and adding an active drug with a different mechanism of action and nonoverlapping toxicity might increase the percentage of CRs. We therefore tested the feasibility and activity of 6 to 8 courses of first-line treatment with a three-drug combination (gemcitabine 1000 mg/m2 days 1 and 4, epirubicin 90 mg/m2 day 1, and paclitaxel 175 mg/ m2 over 3 hours on day 1) in a phase II study of 36 metastatic breast cancer patients. Treatment was well tolerated, with an ORR of 92% (95% confidence interval: 77.53%-98.25%) and a CR of 31%. In considering retreating patients who progress or relapse after receiving an anthracycline-/taxane-containing regimen with the same active drugs, epirubicin appears ideal in both the adjuvant and metastatic breast cancer settings.

Sequence-dependent toxicity profile in modified FAMTX (fluorouracil-adriamycin-methotrexate) chemotherapy with lenograstim support for advanced gastric cancer: a feasibility study

For advanced irresectible gastric cancer, sequential high-dose methotrexate and 5-fluorouracil (both on day 1) combined with adriamycin on day 15 (FAMTX regimen), cycled every 28 days, is a fairly effective but toxic treatment, with a high incidence of neutropenic fever, dose reductions and dose delays. In order to improve FAMTX toxicity, we studied the feasibility of two modified FAMTX regimens with lenograstim support. Seven advanced gastric cancer patients were treated with all three FAMTX drugs on day 1 followed by lenograstim 150 microgm(-2)for 10 days, in 21-day cycles (FUMA regimen). The next seven patients were treated with the same drugs at the same doses, but with adriamycin 1 day prior to methotrexate and 5-fluorouracil administration (AFUM regimen). Patients were monitored for toxicity, response, and survival. The total number of courses was 27 for FUMA and 35 for AFUM with a median of four courses per patient in each cohort. In the FUMA regimen, considerable toxicity consisting of mucositis and fatigue as well as grade 4 neutropenia occurred, and forced four out of seven patients to stop treatment. The consecutive AFUM regimen showed only mild toxicity, and all patients could finish treatment without dose reductions or delays. We found unanticipated and probably sequence-dependent toxicity profiles in two investigational, modified FAMTX schedules with lenograstim support, leading to high rates of dose-limiting toxicity in the FUMA regimen as opposed to mild toxicity in the AFUM regimen, even though the same total drug doses and treatment cycle length (dose intensity) were employed.

Cardiotoxicity of epirubicin/paclitaxel-containing regimens: role of cardiac risk factors

PURPOSE

To evaluate the incidence of clinically relevant cardiac toxicity after treatment with epirubicin/paclitaxel-containing regimens in patients with metastatic breast cancer and to identify high-risk patients in whom the benefit of chemotherapy may be negated by the occurrence of congestive heart failure (CHF).

PATIENTS AND METHODS

A total of 105 patients who were referred for epirubicin/paclitaxel treatment were included in this study. Treatment regimens were as follows: (1) epirubicin 90 mg/m(2) plus paclitaxel 135 to 225 mg/m(2) over 3 hours (n = 76); and (2) gemcitabine 1,000 mg/m(2) on days 1 and 4 plus epirubicin/paclitaxel (n = 29). The occurrence of CHF was detected by physical examination, and left ventricular function was evaluated by bidimensional echocardiography to support the diagnosis. Cardiac risk factors examined in this study included age, prior radiotherapy to the chest, hypertension, and diabetes.

RESULTS

No patient experienced CHF while on treatment. Nine patients (9%) developed CHF after cumulative epirubicin doses of 1,080 mg/m(2) (n = 4), 720 mg/m(2) (n = 2), 630 mg/m(2) (n = 1), and 540 mg/m(2) (n = 2). One of the two patients who developed CHF after a cumulative epirubicin dose of 540 mg/m(2) had received consolidation with high-dose chemotherapy. Median time to appearance of cardiologic symptoms was 3 months after the end of treatment (range, 3 to 6 months). Overall, the incidence of CHF was 13% and 4% in patients with or without cardiac risk factors, respectively. The cumulative risk of developing CHF was estimated as 7.7% at a cumulative doses of 720 mg/m(2) and 48.7% at a cumulative dose of 1,080 mg/m(2).

CONCLUSION

This study shows that the incidence of CHF after an epirubicin/paclitaxel regimen is low up to cumulative epirubicin doses of 990 mg/m(2), thus allowing the safe administration of this regimen even in patients who received epirubicin in the adjuvant setting. However, the risk of developing CHF increases when a cumulative dose exceeding 990 mg/m(2) is reached, concomitantly with the presence of an additional cardiac risk factor.