Docetaxel in combination with epirubicin in metastatic breast cancer: pharmacokinetic interactions

Electrochemical Sensor Based on Poly(Azure B)-DNA Composite for Doxorubicin Determination

A new voltammetric DNA sensor has been developed for doxorubicin determination on the platform of a glassy carbon electrode (GCE) covered with electropolymerized Azure B film and physically adsorbed native DNA. The redox properties of polymeric Azure B were monitored at various pH and scan rates. DNA application decreased the peak currents related to polymeric and monomeric forms of the dye, whereas incubation in doxorubicin solution partially restored the peaks in accordance with the drug and DNA concentration. The relative shift of the cathodic peak current caused by doxorubicin depended on the nominal DNA concentration and its application mode. In optimal conditions, the DNA sensor makes it possible to determine between 0.1 μM to 0.1 nM doxorubicin (limit of detection 7×10-11 M). The DNA sensor was tested on commercial doxorubicin formulations and on artificial samples the mimicked electrolyte content of human serum.

A simple method to improve the stability of docetaxel micelles

Self-assembled polymeric micelles have been widely applied in drug delivery systems. In this study, we found that pH value of micellar system solution was the decisive factor of physical stability. Furthermore, the weak basic solution could maintain the solution clarification for a relative long time. To investigate the stability of polymeric micelles in different pH solutions, the micellar particle size and the docetaxel content remaining in solution were detected at predetermined time points. The crystallographic assay of freeze-drying powder was characterized by an X-ray diffractometer. In vitro release results indicated that the PBS had little influence on the sustained-release effect of docetaxel-loaded polymeric micelles (DPM). Besides, the safety of micellar formulation was determined by an MTT assay on HEK293 cells, and the anti-tumor activity was tested on MCF-7 cells. The results demonstrated that DPM adjusted with PBS (DPM (PBS)) was of low toxicity and maintained the effectiveness of docetaxel. In vivo antitumor results indicated that DPM (PBS) had better antitumor efficacy than common docetaxel injection (DTX). Thus it was concluded that regulation of micellar solution PH by PBS is a safe and effective method to improve the physical stability of DPM. It might promote the application of micellar formulation in clinical applications.

Preparation and therapeutic application of docetaxel-loaded poly(d,l-lactide) nanofibers in preventing breast cancer recurrence

The aim of this study was to develop docetaxel (DTX)-loaded poly-d,l-lactide (PDLLA) nanofibers and evaluate their therapeutic effect in preventing local breast cancer recurrence. DTX was incorporated into biodegradable PDLLA nanofibers by electrospinning. The surface morphology of the DTX/PDLLA nanofibers was characterized using scanning electron microscopy and wide angle X-ray diffraction. The in vitro release behavior of DTX from the fiber mats was also studied in detail. The cytotoxicity of DTX/PDLLA nanofibers was evaluated by MTT assay in 4T1 breast cancer cells. Flow cytometry revealed that DTX/PDLLA nanofibers exhibited apoptotic activity in 4T1 cells. In vivo antitumor efficacy of DTX/PDLLA nanofibers was evaluated in BALB/c mice bearing local breast tumors. Locoregional recurrence after primary tumor resection decreased obviously in mice treated with subcutaneously (16.7%) administered DTX-loaded PDLLA nanofibers, compared with the blank PDLLA nanofibers (88.9%), systemic (75.0%) or locally (77.8%) administered DTX and the control group (100%) (p < 0.05). Finally, after subcutaneous transplantation in mice, the DTX/PDLLA scaffolds presented excellent biocompatibility, as exhibited by the minimal presence of inflammatory cells in the region surrounding the scaffolds. Our results suggest that DTX/PDLLA nanofibers could have great potential for clinical application requiring local chemotherapy.

Cytotoxicity of 3,4-dihalogenated 2(5H)-furanones

Mucohalogen acids have been used for the preparation of a variety of 3,4-dihalogenated 2(5H)-furanones. In one synthetic step the carbamates 2a-c and the pseudoanhydrides 4a-e were prepared using isocyanates and acid anhydrides. A series of 5-alkoxylated 3,4-dichloro-2(5H)-furanones 5a-o have been synthesized with a wide range of lipophilicity, using the hydroxy-form of mucohalogen acids 1a and 1b. The 5-allyl-3,4-dichloro-2(5H)-furanone 5f was derived into the dihydro-isoxazol 6 and the oxirane 7. The methyl ester 5a was converted with ammonia into the tetramic acid chloride 11. The pseudo acid chloride 3 was reacted further into the bis aziridine 8. Reduction of the mucochloric acid 1a furnished the trichlorofuranone 3. The cytotoxicity of these simple and bis-cyclic butenolides have been evaluated in tissue culture on MAC13 and MAC16 cancer cell lines using the MTT cytotoxicity assay. The ester 5g, the acetate 4b and the carbamate 2b displayed a cytotoxicity in the low micromolar range. Further, an IC50 (50% inhibitory concentration) of 50 nM and 30 nM was determined for the epoxide 7 and the aziridine 8.

CE-LIF method for the separation of anthracyclines: application to protein binding analysis in plasma using ultrafiltration

Anthracyclines are chemotherapeutic drugs that are widely used in the treatment of cancers such as lung and ovarian cancers. The simultaneous determination of the anthracyclines, daunorubicin, doxorubicin and epirubicin, was achieved using CE coupled to LIF, with an excitation and emission wavelength of 488 and 560 nm, respectively. Using a borate buffer (105 mM, pH 9.0) and 30% MeOH, a stable and reproducible separation of the three anthracyclines was obtained. The method developed was shown to be capable of monitoring the therapeutic concentrations (50-50 000 ng/mL) of anthracyclines. LODs of 10 ng/mL, calculated at an S/N = 3, were achieved. Using the CE method developed, the in vitro protein binding to plasma was measured by ultrafiltration, and from this investigation the estimated protein binding was determined to be in the range of 77-94%.

Docetaxel/anthracycline combinations for breast cancer treatment

Anthracyclines and taxanes represent the most active group of cytotoxic agents for the treatment of breast cancer. Combining docetaxel with anthracyclines is widely used in the clinic, but, due to an overlap in toxicities this strategy remains somewhat challenging. Combinations of docetaxel with doxorubicin, epirubicin or liposomal doxorubicin in conventional or dose-dense cycles are reviewed in this article. A specific focus is given to the three-drug combination of docetaxel, doxorubicin and cyclophosphamide (TAC regimen), as it is registered for the adjuvant treatment of node-positive breast cancer. Febrile neutropenia and associated toxicities are frequently associated with the TAC combination. However, when used as primary prophylaxis with granulocyte growth factors, as well as antibiotics, this regimen is considered as a safely-applicable standard option for early breast cancer treatment.

Model Describing the Relationship Between Pharmacokinetics and Hematologic Toxicity of the Epirubicin-Docetaxel Regimen in Breast Cancer Patients

Purpose

The aims of the present study were (1) to characterize the pharmacokinetics of both component drugs and (2) to describe the relationship between the pharmacokinetics and the dose-limiting hematologic toxicity for the epirubicin (EPI)/docetaxel (DTX) regimen in breast cancer patients.

Patients and Methods

Forty-four patients with advanced disease received EPI and DTX every 3 weeks for up to nine cycles. The initial doses (EPI/DTX) were 75/70 mg/m2. Based on leukocyte (WBC) and platelet counts, the subsequent doses were, stepwise, either escalated (maximum, 120/100 mg/m2) or reduced (minimum, 40/50 mg/m2). Hematologic toxicity was monitored in all patients, whereas pharmacokinetics was studied in 16 patients. A semiphysiological model, including physiological parameters as well as drug-specific parameters, was used to describe the time course of WBC count following treatment.

Results

In the final pharmacokinetic model, interoccasion variability was estimated to be less than interindividual variability in the clearances for both drugs. The sum of the individual EPI and DTX areas under concentration-time curve correlated stronger to WBC survival fraction than did the corresponding sum of doses. A pharmacokinetic-pharmacodynamic (PK-PD) model with additive effects of EPI and DTX could adequately describe the data.

Conclusion

The final PK-PD model might provide a tool for calculation of WBC time course, and hence, for prediction of nadir day and duration of leukopenia in breast cancer patients treated with the EPI/DTX regimen.

Docetaxel, Carboplatin and Concomitant Radiotherapy for Unresectable Squamous Cell Carcinoma of the Head and Neck

Concomitant chemoradiotherapy is the most effective treatment of unresectable head and neck cancer. Docetaxel and carboplatin are two active drugs that potentiate radiotherapy. Thirty patients (median age = 56 years; median Eastern Cooperative Oncology Group performance status = 1) received radiotherapy (70 Gy, 2 Gy/d, 5 d/wk) concurrent with carboplatin AUC 0.3 to 0.5 on day 1-5, weeks 1, 3, 5, 7, and docetaxel 15 to 25 mg/m2 on day 4 of weeks 2, 4, and 6. Site of unresectable squamous cell carcinoma was as follows: oropharynx, 41%; hypopharynx, 27%; oral cavity, 16%; and larynx, 16%. Stage was III in 13% and IV in 87%. In 11 patients, pharmacokinetic parameters were evaluated. Acute G4 toxicity was as follows: neutropenia, 20%; mucositis, 33%. We had the following acute G3 toxicities: mucositis, 40%; neutropenia, 37%; dermatitis, 23%; and anemia, 13%. The maximum tolerated dosage was area under the curve 0.5 for carboplatin and 20 mg/m2 for docetaxel. Median radiotherapy dose was 69 Gy, and 175 out of 210 courses (83%) were administered. At the end of the treatment, we had 20 complete responses (CR) (67%), 9 partial responses (30%), and 1 no change (3%). After radial neck dissection, 2 patients achieved a CR (overall CR = 73%). After a median follow-up of 2.5 years, we had a 3-year local progression-free survival of 85%, failure-free survival of 69%, and overall survival of 60%. A significant increase of Cmax of carboplatin concentration was noted at the beginning of weeks 3, 5, and 7. Total plasma platinum raises during each course of 5 days of carboplatin without reaching a steady state. Carboplatin, docetaxel, and concomitant conventional radiotherapy is a feasible and effective treatment of unresectable head and neck cancer. The concurrent administration of two drugs does not alter pharmacokinetic drug behavior compared with single-agent data.

Clinical data and pharmacokinetics of a docetaxel-vinorelbine combination in anthracycline resistant/ relapsed metastatic breast cancer

The aim of this study was to evaluate the pharmacokinetic parameters, efficacy and toxicity of a docetaxel and vinorelbine combination in metastatic breast cancer patients previously treated with anthracycline. A population of 40 patients was analyzed; 30 patients (75%) had visceral metastases as the dominant site of disease, including 20 patients (50%) with liver metastases. Three or more organs were involved in 43% of patients. All patients had received prior anthracycline therapy. Five patients (12%) had primary resistant disease, 10 patients (25%) secondary resistant disease and 25 patients (63%) had progressive metastatic breast cancer after first-line chemotherapy. Docetaxel and vinorelbine were given at 80 mg/m2 and 20 mg/m2 i.v., respectively, on day 1 every 3 weeks. After a median of 5 cycles, it was found that 5 patients had a complete remission (13%), 19 a partial remission (48%), 9 had stable disease (22%) and 7 had progressive disease (17%). Response rates in patients with visceral and liver metastases were 57% and 50%, respectively. After a median follow-up of 24 months (13-36), median time to progression was 8.5 months and median overall survival 17 months. Grade 4 neutropenia was observed in 78% of courses (febrile neutropenia in 9%). Possible pharmacokinetic interactions were studied in 23 patients by administering docetaxel immediately followed by vinorelbine (protocol A) or vinorelbine followed by docetaxel (protocol B). Patients in protocol B had significantly higher vinorelbine plasma levels and more pronounced neutropenia. Docetaxel plus vinorelbine is an effective combination in anthracycline resistant/relapsed metastatic breast cancer. The administration sequence docetaxel --> vinorelbine is safer than the reverse order.

Phase I pharmacokinetic and sequence finding study of the combination of docetaxel and methotrexate in patients with solid tumours

This phase I study was performed to assess the feasibility and possible enhanced antitumour activity of the sequential administration of methotrexate (MTX) and docetaxel (D) in patients with solid tumours. Pharmacokinetic analysis was performed to investigate the pharmacokinetic interaction of the two agents. A total of 22 patients were enrolled, a total of six dose levels were investigated. MTX (days 1+15) 30, 40 and 50 mg/m(2)+D (day 2 or day 1) 75 and 85 mg/m(2) with supportive care measures. Both haematological and non-haematological toxicities were significant, preventing dose escalation above MTX 40 mg/m(2)+D 75 mg/m(2). Four partial responses were documented, three in patients with breast cancer, one in a patient with urothelial cell cancer. Pharmacokinetic data did not give an explanation for the significant toxicity as they revealed no interaction of D and MTX kinetics. Methotrexate and 7-OH MTX kinetics seemed to be independent of the administration of D and the moment of D administration appeared not to influence MTX kinetics. The sequential administration of MTX and D results in significant toxicity without any evidence of a clinical benefit.

A sequence-dependent combination of docetaxel and vinorelbine: pharmacokinetic interactions

We studied possible pharmacokinetic interactions between docetaxel (DTX) and vinorelbine (VNR) in patients affected by different types of cancer. Patients with metastatic breast cancer or recurrent head and neck cancer received the following schedules: Protocol A: 11 patients were i.v. infused for 1 h with DTX (80 mg/m2) at once, followed by VNR (25 mg/m2) as slow i.v. bolus; Protocol B: VNR (25 mg/m2) as a slow 10 min i.v. bolus was administered to 12 patients, immediately followed by 1 h i.v. infusion of DTX (80 mg/m2). In both schedules, VNR and DTX plasma concentrations versus time were analysed by HPLC obtaining the corresponding non-compartmental pharmacokinetic parameters. VNR appeared pharmacokinetically affected by the sequential administration of DTX, since with protocol B, Cmax and AUC were significantly higher and clearance lower than in protocol A. Moreover, a significant increase in the VNR plasma level was observed in correspondence with the peak plasma level of DTX. By contrast, Cmax, AUC and clearance of DTX did not vary in the two protocols. Also the number of neutrophils at nadir on day 8 of treatment varied significantly in the two schedules. In conclusion we observed altered pharmacokinetic parameters between protocol A (DTX, VNR) and protocol B (VNR/DTX). In particular, patients following protocol B seemed to be exposed to higher VNR plasma concentration and to higher haematological toxicity.

A preliminary pharmacokinetic study of docetaxel, carboplatin and concurrent radiotherapy for regionally advanced squamous cell carcinoma of the head and neck

This work investigates the pharmacokinetics and toxicity resulting from the concomitant use of low dose carboplatin (CBCA)/docetaxel (DTX) plus concurrent radiotherapy in patients with head and neck cancer. The study comprised 11 patients with stage III-IV head and neck cancer. All patients received 2 Gy radiotherapy daily, 5 fractions per week, up to a planned total of 70 Gy over 7 weeks. CBCA (AUC 0.4 mg/ml, min/day) was also administrated as 20 min i.v. infusion, starting 1 day before the first radiotherapy fraction. CBCA was administered for 5 consecutive days every 2 weeks (weeks 1, 3, 5 and 7). DTX 30 mg/m2 (1 h i.v. infusion) was given as a single dose on days 10, 24 and 38. CBCA on day 1 and DTX on day 10 were analysed to determine the concentration-time curves during the first 24 h. CBCA Cmax and Cmin in 2-5 days and on day 15 and 29, as well as total plasma platinum on days 2, 3, 4, 5, 29 and 43 were also assayed. By calculating the non-compartmental pharmacokinetic parameters of the two drugs from the available plasma concentrations we found in the first week values similar to those reported in the literature as single agents. In contrast, during subsequent weeks (weeks 3 and 5), a significant and progressive increase of platinum levels was observed. So, it could be assumed that after 2 weeks of CBCA and DTX treatment a bias in dose calculation occurred because the linear relationship between creatinine clearance (used to calculate the expected AUC through the Calvert formula) and CBCA clearance was no longer observed.

Rapid high-performance liquid chromatographic determination of docetaxel (Taxotere) in plasma using liquid-liquid extraction

A new rapid and sensitive high-performance liquid chromatographic method for analysis of docetaxel (Taxotere) in human plasma was developed and validated. After adding an internal standard (paclitaxel, Taxol), plasma was extracted following a simple liquid-liquid extraction with diethyl ether. Extraction efficiency averaged 95% for docetaxel. Separation was performed using a Nucleosil (C18) 5 microm column, monitored at 227 nm. The isocratic mobile phase consisted of acetonitrile-acetate buffer, pH 5-tetrahydrofuran (45:50:5, v/v) pumped at a flow-rate of 1.8 ml/min. The limit of quantification for docetaxel in plasma was 12.5 ng/ml. Retention times for docetaxel and paclitaxel were 7.7 and 9 min, respectively. Standard curves were linear over a range of 25-1,000 ng/ml. This new method is rapid since it does not require time-consuming extraction procedures, or complex chromatographic conditions. This rapidity, along with the lack of chromatographic interferences with various other drugs likely to be administered to the cancer patients (pain killers, corticoids, antiemetics drugs) make this method suitable for daily routine analysis of Taxotere, a major anticancer drug extensively used in clinical oncology.

Drug interactions of paclitaxel and docetaxel and their relevance for the design of combination therapy

The taxanes' interaction with other anticancer drugs have been extensively investigated in in vitro and in animal models as well as in humans due to the outstanding antitumor activity in a broad range of malignancies. Paclitaxel and docetaxel are endowed of a rich and complex pharmacology whereby different pharmacodynamic effects are observed depending on the sequence of their administration in respect with the companion drug, and the type of drug that is combined. Pharmacokinetic interference is often but not always a basis of the pharmacodynamic effect. In addition, the vehicle of clinical formulation, especially Cremophor EL for paclitaxel, influence the pharmacological effect. Finally, new interaction based on as yet unknown mechanisms drive the two taxanes to multiple additive/synergistic relationships with new signal transduction drugs, such as modulators of the epidermal-growth-factor family of receptors and farnesyl-transferase inhibitors. The ongoing effort to better understanding such a rich pharmacology is worth continuing in view of designing new and better combinations of the taxanes.