Effect of Food on the Pharmacokinetics of the Oral Docetaxel Tablet Formulation ModraDoc006 Combined with Ritonavir (ModraDoc006/r) in Patients with Advanced Solid Tumours.

INTRODUCTION: ModraDoc006 is a novel docetaxel tablet formulation that is co-administrated with the cytochrome P450 3A4 and P-glycoprotein inhibitor ritonavir (r): ModraDoc006/r. OBJECTIVES: This study evaluated the effect of food consumed prior to administration of ModraDoc006/r on the pharmacokinetics of docetaxel and ritonavir. METHODS: Patients with advanced solid tumours were enrolled in this randomized crossover study to receive ModraDoc006/r in a fasted state in week 1 and after a standardized high-fat meal in week 2 and vice versa. Pharmacokinetic sampling was conducted until 48 h after both study drug administrations. Docetaxel and ritonavir plasma concentrations were determined using liquid chromatography with tandem mass spectrometry. Safety was evaluated with the Common Terminology Criteria for Adverse Events, version 4.03. RESULTS: In total, 16 patients completed the food-effect study. The geometric mean ratio (GMR) for the docetaxel area under the plasma concentration-time curve (AUC)0-48, AUC0-inf and maximum concentration (Cmax) were 1.11 (90% confidence interval [CI] 0.93-1.33), 1.19 (90% CI 1.00-1.41) and 1.07 (90% CI 0.81-1.42) in fed versus fasted conditions, respectively. For the ritonavir Cmax, the GMR was 0.79 (90% CI 0.69-0.90), whereas the AUC0-48 and AUC0-inf were bioequivalent. The most frequent treatment-related toxicities were grade ≤ 2 diarrhoea and fatigue. Hypokalaemia was the only observed treatment-related grade 3 toxicity. CONCLUSIONS: The docetaxel and ritonavir exposure were not bioequivalent, as consumption of a high-fat meal prior to administration of ModraDoc006/r resulted in a slightly higher docetaxel exposure and lower ritonavir Cmax. Since docetaxel exposure is the only clinically relevant parameter in our patient population, the overall conclusion is that combined ModraDoc006 and ritonavir treatment may be slightly affected by concomitant intake of a high-fat meal. In view of the small effect, it is most likely that the intake of a light meal will not affect the systemic exposure to docetaxel. CLINICALTRIALS. GOV IDENTIFIER: NCT03147378, date of registration: May 10 2017.

Association of plasma docetaxel levels with ABCB1 gene polymorphisms and tumour response in locally advanced breast cancer patients of South India on neo-adjuvant chemotherapy.

BACKGROUND: Genetic factors could be attributed to the variability in docetaxel plasma levels and its subsequent therapeutic response. The objectives of this study were to assess the effect of ABCB1 gene polymorphisms [SNPs rs1045642 (C3435T) and rs1128503 (C1236T)] on docetaxel plasma levels and also to analyze the influence of docetaxel plasma levels on tumour response in the ethnically distinct South Indian population. METHODS: 104 locally advanced breast cancer (LABC) patients on docetaxel-based neo-adjuvant chemotherapy (NACT) were included. The plasma docetaxel levels were estimated using the validated reverse phase liquid chromatography with mass spectrometry (LC-MS/MS). DNA was extracted (phenol-chloroform extraction method) and the real-time PCR system using validated TaqMan® SNP genotyping assay method was used for genotyping. Tumour response was assessed by RECIST criteria based on the MRI images. RESULTS: Patients with "CT/TT" genotype of the SNP C1236T had a C0/Ct ratio of 1.6 times higher than those with "CC" genotype (13.5 ± 6.5 vs 8.3 ± 3.1, p = 0.002). Though not significant, patients with "CT/TT" genotype had greater initial plasma concentration (C0) and area under the plasma concentration-time curve (AUC0-t). Conversely, the SNP C3435T was not associated with the plasma docetaxel levels. Furthermore, the C0 and normalized C0 were found to be higher in tumour responders compared to non-responders (p < 0.05). CONCLUSIONS: The plasma levels of docetaxel were significantly influenced by the SNP C1236T of ABCB1 gene coding for the MDR1 transporter (P-glycoprotein). The plasma levels of docetaxel were also found to influence its therapeutic effect.

Evaluation of the Physicochemical Properties, Pharmacokinetics, and In Vitro Anticancer Effects of Docetaxel and Osthol Encapsulated in Methoxy Poly(ethylene glycol)-b-Poly(caprolactone) Polymeric Micelles.

Docetaxel (DTX), a taxane-based anticancer drug, and osthol (OTH), a coumarin-derivative compound, have shown anticancer effects against different types of cancers through various mechanisms. However, these drugs have low solubility in water and low oral bioavailability, and thus their clinical application is difficult. To overcome these problems, we encapsulated DTX and OTH in methoxy poly(ethylene glycol)-b-poly(caprolactone) (mPEG-b-PCL) and conducted studies in vitro and in vivo. We selected a 1:4 ratio as the optimal ratio of DTX and OTH, through combination index analysis in A549 cancer cells, and prepared micelles to evaluate the encapsulation efficiency, drug loading, particle size, and zeta potential. The in vitro drug-release profile showed that DTX/OTH-loaded mPEG-b-PCL micelles could slowly release DTX and OTH. In the clonogenic assay, DTX/OTH-loaded mPEG-b-PCL micelles showed 3.7 times higher inhibitory effect than the DTX/OTH solution. Pharmacokinetic studies demonstrated that micelles in combination with DTX and OTH exhibited increased area under curve and decreased clearance values, as compared with single micelles.

Exploring the Promising Potential of High Permeation Vesicle-Mediated Localized Transdermal Delivery of Docetaxel in Breast Cancer To Overcome the Limitations of Systemic Chemotherapy.

The currently available systemic chemotherapy for treating breast cancer often results in serious systemic side effects and compromises patient compliance. The distinct anatomical features of human breasts (e.g., embryological origin of breast skin, highly developed internal lymphatic and venous circulation, and the presence of mammary fat layers) help in preferential accumulation of drugs into breasts after topical application on breast region. This unique feature is termed as localized transdermal delivery which could be utilized for effectively delivering anticancer agents to treat breast cancer and reducing the systemic side effects by limiting their presence in blood. However, the clinical effectiveness of this drug delivery approach is highly limited by barrier properties of skin reducing the permeation of anticancer drugs. In the present work, we have developed high permeation vesicles (HPVs) using phospholipids and synergistic combination of permeation enhancers (SCOPE) to improve the skin permeation of drugs. Docetaxel (DTX) was used as a model drug for hypothesis testing. The optimized SCOPE mixture composed of sodium oleate/sodium lauryl ether sulfate/propylene glycol in 64:16:20% w/w ratio. DTX HPVs were prepared using phospholipid: SCOPE, 8:2% w/w ratio. DTX HPVs exhibited as a uniform deformable vesicles with size range 124.2 ± 7.6 nm, significantly improved skin permeation profile, and sustained drug release until 48 h. Superior vesicle deformability, better vesicle membrane fluidization, and SCOPE mediated enhancement in skin fluidization were the prime factors behind enhancement of DTX permeation. The improved cellular uptake, reduced IC50 values, and higher apoptotic index of DTX HPVs in MCF-7 and MDA-MB-231 cells ensured the therapeutic effectiveness of HPV based therapy. Also, HPVs were found to be predominantly internalized inside cells through clathrin and caveolae-dependent endocytic pathways. Bioimaging analysis in mice confirmed the tumor penetration potential and effective accumulation of HPVs inside tumors after topical application. In vivo studies were carried out in comparison with marketed intravenous DTX injection (Taxotere) to compare the effectiveness of topical chemotherapy. The topical application of DTX HPV gel in tumor bearing mice resulted in nearly 4-fold tumor volume reduction which was equivalent to intravenous Taxotere therapy. Toxicity analysis of DTX HPV gel in comparison with intravenous Taxotere dosing showcased remarkably lower levels of toxicity biomarkers (aspartate transaminase (AST), alanine transaminase (ALT), blood urea nitrogen (BUN), and creatinine), indicating improved safety of topical chemotherapy. Overall results warranted the effectiveness of topical DTX chemotherapy to reduce tumor burden with substantially reduced risk of systemic toxicities in breast cancer.

An improved LC-MS/MS method for determination of docetaxel and its application to population pharmacokinetic study in Chinese cancer patients.

Because of its unpredictable side effects and efficacy, the anticancer drug docetaxel (DTX) requires improved characterisation of its pharmacokinetic profiles through population pharmacokinetic studies. A sensitive and rugged LC-MS/MS method for the detection of DTX in human plasma was developed and optimised using paclitaxel as an internal standard (IS). The plasma samples underwent rapid extraction using hybrid solid-phase extraction-protein precipitation. The analyte and IS were separated with an isocratic system on a Zorbax Eclipse Plus C18 column using water containing 0.05% acetic acid along with 20 µM of sodium acetate and methanol (30/70, v/v) as the mobile phase. Quantification was performed using a triple quadrupole mass spectrometer through multiple reaction monitoring in positive mode, using the m/z 830.3 → 548.8 and m/z 876.3 → 307.7 transitions for DTX and paclitaxel, respectively. The range of the calibration curve was 1-500 ng/mL for DTX, and the linear correlation coefficient was >0.99. The accuracies ranged from -4.6 to 4.2%, and the precision was no higher than 7.0% for the analytes. No significant matrix effect was observed. Both DTX and the IS showed considerable recovery. This method was finally applied to the establishment of a population pharmacokinetic model to optimise the clinical use of DTX.

A Population Pharmacokinetic Model of Oral Docetaxel Coadministered With Ritonavir to Support Early Clinical Development.

Oral administration of docetaxel is an attractive alternative for conventional intravenous (IV) administration. The low bioavailability of docetaxel, however, hinders the application of oral docetaxel in the clinic. The aim of the current study was to develop a population pharmacokinetic (PK) model for docetaxel and ritonavir based on the phase 1 studies and to support drug development of this combination treatment. PK data were collected from 191 patients who received IV docetaxel and different oral docetaxel formulations (drinking solution, ModraDoc001 capsule, and ModraDoc006 tablet) coadministered with ritonavir. A PK model was first developed for ritonavir. Subsequently, a semiphysiological PK model was developed for docetaxel, which incorporated the inhibition of docetaxel metabolism by ritonavir. The uninhibited intrinsic clearance of docetaxel was estimated based on data on IV docetaxel as 1980 L/h (relative standard error, 11%). Ritonavir coadministration extensively inhibited the hepatic metabolism of docetaxel to 9.3%, which resulted in up to 12-fold higher docetaxel plasma concentrations compared to oral docetaxel coadministered without ritonavir. In conclusion, a semiphysiological PK model for docetaxel and ritonavir was successfully developed. Coadministration of ritonavir resulted in increased plasma concentrations of docetaxel after administration of the oral formulations of ModraDoc. Furthermore, the oral ModraDoc formulations showed lower variability in plasma concentrations between and within patients compared to the drinking solution. Comparable exposure could be reached with the oral ModraDoc formulations compared to IV administration.

Effect of the Phragmitis Rhizoma Aqueous Extract on the Pharmacokinetics of Docetaxel in Rats.

BACKGROUND: Traditionally, Phragmitis rhizoma has been prescribed to relive a fever, vomiting, dysuria, and constipation, and to promote secretion of fluids. In addition, recent studies have reported its efficacy as a diuretic and antiemetic. Our previous study demonstrated that the Phragmitis rhizoma aqueous extract (EPR) ameliorates docetaxel (DTX)-induced myelotoxicity. AIM AND OBJECTIVE: This study was aimed to investigate the effects of EPR on the pharmacokinetics of DTX in Sprague-Dawley rats. MATERIALS AND METHODS: The animals received an intravenous injection of DTX (5 mg/kg) with or without oral EPR (100 mg/kg) pretreatment for 1 or 6 days. The pharmacokinetics of plasma DTX was analyzed using an ultra-performance liquid chromatography-tandem mass spectrometry system, and pharmacokinetic parameters were estimated via noncompartmental analysis. RESULTS: Relative to the control group (DTX alone), EPR pretreatment did not affect significantly the overall profiles of plasma DTX levels. Consecutively pretreated EPR for 6 days slightly altered AUC0-t and Cmax of DTX by 122 and 145.9%, respectively, but these data did not reach the threshold of statistical significance (p > 0.05). CONCLUSION: These results indicate that DTX exposure may not be affected by EPR treatment at the dose level used in this study, suggesting that oral EPR can be used safely when taken with intravenously injected DTX. However, further studies under the stringent conditions are needed when chronic treatment of EPR and anticancer drug.

Evaluation of the Synergism Mechanism of Tamoxifen and Docetaxel by Nanoparticles.

BACKGROUND: Our previous studies have shown that Docetaxel (DTX) and Tamoxifen (TMX) loaded nanoparticles(Co-NPs) could exhibit a synergistic effect on estrogen receptor positive cell lines. In the current study，we have studied the synergistic effect of Co-NPs and underlying possible molecular mechanism. METHODS: Cell apoptosis assay, pharmacokinetic experiment and immunohistochemistry experiment were used to explore the synergistic effect and underlying possible mechanism in vitro and in vivo. RESULTS: Cell apoptosis assay revealed that Co-NPs could mediate cell sensitization to a cytotoxic agent, resulting in remarkable cell apoptosis. In addition, pharmacokinetic experiment research showed that Co-NPs have longer circulation time in vivo, which could prolong the treatment time of the chemotherapeutic drugs. Immunohistochemistry experiment revealed that the Co-NPs could downregulate the expression of P-gp level to reduce the drugs' efflux. CONCLUSION: The possible mechanism of the synergistic effect of DTX and TMX by Co-NPs was attributed to the longer in vivo circulation time, significantly increased rate of cell apoptosis and downregulated expression of P-gp level to the tumor cells.

Antitumour activity and tolerability of an EphA2-targeted nanotherapeutic in multiple mouse models.

Antibody-mediated tumour targeting and nanoparticle-mediated encapsulation can reduce the toxicity of antitumour drugs and improve their efficacy. Here, we describe the performance of a nanotherapeutic encapsulating a hydrolytically sensitive docetaxel prodrug and conjugated to an antibody specific for EphA2-a receptor overexpressed in many tumours. Administration of the nanotherapeutic in mice led to slow and sustained release of the prodrug, reduced exposure of active docetaxel in the circulation (compared with administration of the free drug) and maintenance of optimal exposure of the drug in tumour tissue. We also show that administration of the nanotherapeutic in rats and dogs resulted in minimal haematological toxicity, as well as the absence of neutropenia and improved overall tolerability in multiple rodent models. Targeting of the nanotherapeutic to EphA2 improved tumour penetration and resulted in markedly enhanced antitumour activity (compared with administration of free docetaxel and non-targeted nanotherapeutic controls) in multiple tumour-xenografted mice. This nanomedicine could become a potent and safe therapeutic alternative for cancer patients undergoing chemotherapy.

A new method for the determination of total and released docetaxel from docetaxel-entrapped core-crosslinked polymeric micelles (CriPec®) by LC-MS/MS and its clinical application in plasma and tissues in patients with various tumours.

A sensitive, high-performance liquid chromatographic method was developed and validated, for determination of docetaxel from docetaxel-entrapped core-crosslinked polymeric micelles (CriPec®) in human potassium EDTA plasma and released docetaxel to support the clinical development of Cripec® docetaxel. CriPec® docetaxel is a novel formulation of docetaxel - covalently conjugated via a linker agent in a nanoparticle. The analytical characterization of CriPec® docetaxel comprises determination of both released and total docetaxel, the first being the already deconjugated docetaxel, whereas total is representative of all docetaxel (deconjugated as well as CriPec® nanoparticle conjugated material). Total docetaxel was determined by incubation of human plasma with 0.5 M ammonium acetate buffer pH 7.4 for 3-days at 37 °C. Hereafter, a liquid-liquid extraction with 1-chlorobutane was performed using paclitaxel as internal standard. Released docetaxel from CriPec® docetaxel nanoparticles was determined in human plasma stabilized with 5 M ammonium acetate, pH 5.0. Hereafter, a liquid-liquid extraction with 1-chlorobutane was performed using docetaxel-d5 in acetonitrile as internal standard. Released docetaxel and its internal standard were eluted. The validated ranges for total docetaxel were 2,000-100,000 ng/mL for the high concentrations and 2-500 ng/mL for the low concentrations and 0.250-100 ng/mL for released docetaxel. In conclusion the newly developed assay met the required standards for validation and was applied successfully to support pharmacokinetic analysis in both serum and tissue in patients treated with Cripec®.

Determination of total and unbound docetaxel in plasma by ultrafiltration and UPLC-MS/MS: application to pharmacokinetic studies.

A sensitive and specific liquid chromatographic/tandem mass spectrometric (LC-MS/MS) method was developed and validated for quantifying total and unbound docetaxel drug concentrations in plasma. Calibration curves for unbound and total docetaxel were linear over the respective ranges of 0.108~10.8 and 0.54~216 ng/mL. The intra- and interday assay accuracy and precision did not exceed 15%. The methods were validated to show the standard range linearity, sensitivity, selectivity, accuracy, precision, and stability of docetaxel in the matrices tested. In addition, this method is fast and simple with a short run time of 4.5 min and a small plasma sample volume (500 µL). The validated method was successfully applied to a pharmacokinetic study of a docetaxel micelle formulation in rat plasma after intravenous administration at a dose of 10 mg/kg. Docetaxel micelles slowly released their drug payload, and protein-bound, unbound, and micellar drug pools existed simultaneously. These various forms in plasma pools were also measured in the study. We confirmed that most of the docetaxel in plasma was micelle-associated (96.52% at 24 h and 83.14% at 72 h) after micellar docetaxel administration, as a result of sequestration of the drug in long-circulating micelles.