A multifunctional nanoplatform for cancer chemo-photothermal synergistic therapy and overcoming multidrug resistance.

The integration of various therapy strategies into a single nanoplatform for synergistic cancer treatment has presented a great prospect. Herein, docetaxel (DTX)-loaded poly lactic-co-glycolic acid (PLGA)-coated polydopamine modified with d-α-tocopherol polyethylene glycol 1000 succinate (TPGS) was synthesized for chemo-photothermal synergistic therapy against cancer. Firstly, the DTX-loaded PLGA NPs were prepared by a facile and robust nanoprecipitation method. Then, they were coated with dopamine to achieve the photothermal effects and to be further modified with TPGS, which can inhibit the P-glycoprotein-mediated multidrug resistance (MDR). The near-infrared (NIR) laser irradiation triggered DTX release from DTX-loaded PLGA NPs@PDA-TPGS, and then the chemo-photothermal therapy effect could be enhanced. The in vitro experimental results illustrated that DTX-loaded PLGA NPs@PDA-TPGS exhibits excellent photothermal conservation properties and remarkable cell-killing efficiency. In vivo antitumor studies further confirmed that DTX-loaded PLGA NPs@PDA-TPGS could present an outstanding synergistic antitumor efficacy compared with any monotherapy. This work exhibits a novel nanoplatform, which could not only load chemotherapy drugs efficiently, but could also improve the therapeutic effect of chemotherapy drugs by overcoming MDR and light-mediated photothermal cancer therapy.

P-gp modulatory acetyl-11-keto-ß-boswellic acid based nanoemulsified carrier system for augmented oral chemotherapy of docetaxel.

In spite of being a very potent and promising drug against many types of cancer, docetaxel suffers the disadvantage of low solubility and poor bioavailability rendering it unsuitable for oral administration. Also, the available marketed formulation for intravenous administration has its inherent drawbacks owing to the presence of polysorbate 80. Here, we exploited the anticancer and P-gp inhibitory potential of naturally occurring frankincense oil to fabricate a stable docetaxel loaded nanoemulsified carrier system for oral delivery. The nanoemulsion possessing desirable particle size (122±12nm), polydispersity (0.086±0.007) and zeta potential (-29.8±2.1mV) was stable against all type of physical stresses and simulated physiological conditions tested. The formulation showed higher uptake in Caco-2 cells and inhibited P-gp transporter significantly (P<0.05). In MDA-MB-231 cells, it showed less IC50, arrested cells in G2-M phase and exhibited higher degree of apoptosis than marketed formulation Taxotere®. The 182.58±4.16% increment in relative oral bioavailability led to higher in vivo anti-proliferative activity manifesting 19% more inhibition than Taxotere®. Conclusively, it is revealed that the developed nanoemulsion will be a propitious approach towards alternative docetaxel therapy.

Gold nanorod-based poly(lactic-co-glycolic acid) with manganese dioxide core-shell structured multifunctional nanoplatform for cancer theranostic applications.

Recently, photothermal therapy has become a promising strategy in tumor treatment. However, the therapeutic effect was seriously hampered by the low tissue penetration of laser. Therefore, in this study, radiofrequency (RF) with better tissue penetration was used for tumor hyperthermia. First, one type of gold nanorods (AuNRs) suitable for RF hyperthermia was selected. Then, poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) loaded with AuNRs and docetaxel (DTX) (PLGA/AuNR/DTX) NPs were constructed. Finally, manganese dioxide (MnO2) ultrathin nanofilms were coated on the surfaces of PLGA/AuNR/DTX NPs by the reduction of KMnO4 to construct the PLGA/AuNR/DTX@MnO2 drug delivery system. This drug delivery system can not only be used for the combined therapy of chemotherapy and RF hyperthermia but can also produce Mn2+ to enable magnetic resonance imaging. Furthermore, the RF hyperthermia and the degradation of MnO2 can significantly promote the controlled drug release in a tumor region. The in vitro and in vivo results suggested that the PLGA/AuNR/DTX@MnO2 multifunctional drug delivery system is a promising nanoplatform for effective cancer theranostic applications.

Polymeric nanoparticle-docetaxel for the treatment of advanced solid tumors: phase I clinical trial and preclinical data from an orthotopic pancreatic cancer model.

We assessed the efficacy of the polymeric nanoparticle containing docetaxel (PNP-DTX) in preclinical mouse models and determined the maximum tolerated dose (MTD) through clinical study. Subcutaneous and orthotopic mouse models were dedicated. Tumor growth delay in orthotopic model and quantification of in vivo imaging in orthotopic model were evaluated. Phase I clinical study was a single-center, prospective, open-label trial in advanced solid tumors. PNP-DTX was injected intravenously and the starting dose was 20 mg/m2 escalated to 35 mg/m2, 45 mg/m2, 60 mg/m2 and 75 mg/m2. Pharmacokinetics, tumor response, toxicities were evaluated. Preclinical result revealed the more potent cytotoxic effect of PNP-DTX than docetaxel (DTX). However, there was no difference between PNP-DTX and DTX in subcutaneous model. Tubulin polymerization assay showed that PNP-DTX preserved original mode of action of DTX. For phase I clinical trial, 18 patients were analyzed. The dose of 75 mg/m2 was tentatively determined as the MTD and the most common toxicity was grade 4 neutropenia not lasting over 7days. The Cmax of 60 mg/m2 PNP-DTX and AUClast of 45 mg/m2 PNP-DTX were measured to be comparable to those of 75 mg/m2 DTX. Partial remission (PR) was achieved in 4 (22%) patients. The potency of PNP-DTX was revealed especially in orthotopic mouse model. The MTD of PNP-DTX could not be confirmed, but 75 mg/m2 was tentatively determined. The PNP-DTX of 45 mg/m2 had the same pharmacokinetic profile with that of 75 mg/m2 DTX.

Non-linear pharmacokinetics of piperine and its herb-drug interactions with docetaxel in Sprague-Dawley rats.

Piperine (PIP), the major alkaloid component from Piper longum L. and Piper nigrum L., could enhance the bioavailabilities of other drugs including rosuvastatin, peurarin and docetaxel (DOX) via inhibition of CYP3A and P-glycoprotein activity. Nevertheless, the effect of such drug combination usage on the in vivo exposure of PIP has not been investigated due to lack of assay for the simultaneous determination of PIP and other drugs such as DOX. Besides, the reported pharmacokinetics of PIP varied a lot without appropriate bioavailability determined from the same dose. In the current study, an LC/MS/MS method has been developed to simultaneously determine the plasma concentrations of PIP and DOX and further applied to investigate the pharmacokinetics properties of PIP after oral and intravenous administrations as well as the pharmacokinetics interactions between PIP and DOX after their co-administration. A simple protein precipitation method was employed for plasma sample treatment by adding a mixture of methanol and acetonitrile (1:1, v/v) with glibenclamide as internal standard (IS). The LC/MS/MS system consisted of Agilent 6430 series LC pumps and auto-sampler. The chromatographic separation was carried out in 15min on a Waters C18 column (150×3.9mm i.d., 4µm) with a mobile phase containing 0.2% formic acid and acetonitrile (1:1, v/v) at a flow rate of 0.4ml/min. The detection was performed using the positive ion electrospray ionization (ESI) in multiple reaction monitoring (MRM) mode with precursor-to-product ion transitions at m/z 286.1→201.1 for PIP, m/z 830.3→548.9 for DOX and m/z 494.2→369.0 for IS. The method demonstrated good linearity for both PIP and DOX over the concentration range of 2.5-1280ng/ml with LLOD at 2.5ng/ml. The intra-day and inter-day precisions were less than 13.34% and relative error (R.E.) representing accuracy was in the range of -11.38 to 3.15%. The recoveries of PIP, DOX and IS were above 75% and there was no matrix effect. PIP and DOX exhibited good stabilities under various conditions. PIP was administrated via intravenous bolus at 3.5mg/kg and via oral administration at 35mg/kg and 3.5mg/kg, while DOX was intravenously administrated at 7mg/kg to Sprague-Daley rats. The plasma concentrations of PIP and DOX were determined using the above developed and validated method. At the dose of 3.5mg/kg, the bioavailability of PIP was calculated to be 25.36%. Its AUC0→t was unproportionally increased with doses, indicating a potential non-linear pharmacokinetics profile of PIP. It was found that the AUC0→t and C0 of DOX and t1/2 of PIP were significantly increased after their combination use, suggesting potential enhanced bioavailability of not only DOX but also PIP, which may lead to the overall enhanced pharmacological effects.

Design, Synthesis, and Biological Evaluation of a Novel Water-soluble Prodrug of Docetaxel with Amino Acid as a Linker.

The synthesis and preliminary evaluation of derivatives of docetaxel with novel amino acid as a linker named as LK-193˜LK-196 was described. The C2'-modified compound LK-196 behaves as a prodrug; that is, docetaxel is generated upon exposure to human plasma. The compound was also found to have greatly improved water solubility. The pharmacodynamic results showed LK-196 had the self-evident inhibitory effect on tumor growth in vivo, which is a promising candidate for further biological evaluation.

Comparison of Pharmacokinetics and Biodistribution of 10-Deacetylbaccatin III after Oral Administration as Pure Compound or in Taxus chinensis Extract: A Pilot Study.

Taxanes are a class of bioactive compounds isolated from the Taxus species. 10-Deacetylbaccatin III is one of the popular taxane compounds with antitumor activity, but the pharmacokinetic profile of this compound remains elusive. Previously, we prepared the taxane fractions from the twigs and leaves of Taxus chinensis var. mairei containing 20.4 % 10-deacetylbaccatin III. This study aimed to investigate the pharmacokinetics of 10-deacetylbaccatin III and biodistribution, and explore the potential changes when it was administered in the form of taxane extracts. A simple, sensitive, and reliable liquid chromatography-tandem mass spectrometry method was developed and validated for the quantitative determination of 10-deacetylbaccatin III in biosamples. The results showed that 10-deacetylbaccatin III, after oral dosing, displayed a quick absorption into the blood and distribution into major organs. Oral administration of 10-deacetylbaccatin III in the form of taxane mixtures led to a 16-fold increase in the systemic exposure of pure 10-deacetylbaccatin III, with the AUC0-U in the plasma increasing from 25.75 ± 11.34 to 231.36 ± 70.12 µg h/L (p < 0.0001). Moreover, the concentrations of 10-deacetylbaccatin III in major tissues were significantly enhanced when given in taxane extracts. These findings revealed pharmacokinetic interactions in the taxane components from T. chinensis var. mairei, which contributed to an enhanced systemic exposure of pharmacologically active taxanes.

Development and evaluation of co-formulated docetaxel and curcumin biodegradable nanoparticles for parenteral administration.

CONTEXT: Technology for development of biodegradable nanoparticles encapsulating combinations for enhanced efficacy. OBJECTIVE: To develop docetaxel (DTX) and curcumin (CRM) co-encapsulated biodegradable nanoparticles for parenteral administration with potential for prolonged release and decreased toxicity. MATERIALS AND METHODS: Modified emulsion solvent-evaporation technique was employed in the preparation of the nanoparticles optimized by the face centered-central composite design (FC-CCD). The uptake potential was studied in MCF-7 cells, while the toxicity was evaluated by in vitro hemolysis test. In vivo pharmacokinetic was evaluated in male Wistar rats. RESULTS AND DISCUSSION: Co-encapsulated nanoparticles were developed of 219 nm size, 0.154 PDI, -13.74 mV zeta potential and 67.02% entrapment efficiency. Efficient uptake was observed by the nanoparticles in MCF-7 cells with decreased toxicity in comparison with the commercial DTX intravenous injection, Taxotere®. The nanoparticles exhibited biphasic release with initial burst release followed by sustained release for 5 days. The nanoparticles displayed a 4.3-fold increase in AUC (391.10 ± 32.94 versus 89.77 ± 10.58 µg/ml min) in comparison to Taxotere® with a 6.2-fold increase in MRT (24.78 ± 2.36 versus 3.58 ± 0.21 h). CONCLUSION: The nanoparticles exhibited increased uptake, prolonged in vitro and in vivo release, with decreased toxicity thus exhibiting potential for enhanced efficacy.

Targeted Imaging and Chemo-Phototherapy of Brain Cancer by a Multifunctional Drug Delivery System.

The aim of this study was to develop multifunctional poly lactide-co-glycolide (PLGA) nanoparticles with the ability to simultaneously deliver indocyanine green (ICG) and docetaxel (DTX) to the brain by surface decoration with the brain-targeting peptide angiopep-2 to achieve combined chemo-phototherapy for glioma under near-infrared (NIR) imaging. ICG was selected as a near-infrared imaging and phototherapy agent and DTX was employed as a chemotherapeutic agent. ICG and DTX were simultaneously incorporated into PLGA nanoparticles with higher stability. These nanoparticles were further decorated with angiopep-2 via the outer maleimide group of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)-2000]-maleinimide incorporated in the nanoparticles. The NIR image-guided chemo-phototherapy of the angiopep-2 modified PLGA/DTX/ICG nanoparticles (ANG/PLGA/DTX/ICG NPs) not only highly induced U87MG cell death in vitro, but also efficiently prolonged the life span of the brain orthotopic U87MG glioma xenograft-bearing mice in vivo. Thus, this study suggests that ANG/PLGA/DTX/ICG NPs have the potential for combinatorial chemotherapy and phototherapy for glioma.

Pharmacokinetic synergy from the taxane extract of Taxus chinensis improves the bioavailability of paclitaxel.

BACKGROUND: Taxus chinensis (Pilger) Rehd is widely distributed in China and the northern hemisphere, and the most popular medicinal component isolated from Taxus chinensis is paclitaxel (PTX), which has now become the first-line chemotherapeutic drug for breast cancer and ovarian cancer. Oral administration of pure PTX as a potential anti-cancer agent is compromised by low bioavailability. HYPOTHESIS/PURPOSE: In the clinical practice of traditional Chinese medicine, drug co-administration in the form of mixtures or formula could achieve pharmacokinetic/pharmacodynamic synergies. In this study, we aimed to investigate whether there exist any 'inherent' phytochemical synergy from Taxus chinensis extract that could improve PTX bioavailability. STUDY DESIGN: Pharmacokinetic study of PTX after oral administration of Taxus chinensis extracts or single PTX was performed. In addition, comparative cytotoxic studies were carried out on the MCF-7 breast cancer cell lines. METHODS: The plasma concentrations of PTX were determined using a validated high performance chromatography tandem mass spectrometry method. The cytotoxicity was compared using the MTT assay. RESULTS: Oral administration of taxane fractions isolated from Taxus chinensis (containing 17.2% PTX) could achieve remarkably higher blood concentration and systemic exposure of PTX in rats, while the retention of PTX was significantly improved. Further tissue distribution analysis revealed that the penetration of PTX into major tissues was drastically increased compared with that of single PTX. In addition, in MCF-7 cells, the co-existing components in taxane mixtures could strengthen the inhibitory effects of PTX on tumor cell proliferation. CONCLUSION: Together, these results support that administration of PTX in the form of taxane mixtures may become a novel approach to improve the poor bioavailability of PTX. Moreover, the inherent synergy from Taxus chinensis taxane extracts promises a novel strategy to strengthen PTX efficacy.

Biocompatible amphiphilic pentablock copolymeric nanoparticles for anti-cancer drug delivery.

A pentablock copolymer of Poly(Lactide-co-Glycolide) and Pluronic F68 was synthesized using ring-opening polymerization and characterized by NMR and FTIR for confirming the structure of the block copolymer. TG-DTA studies showed PLGA:Pluronic ratio to be 4:1. As the PLGA-PEO-PPO-PEO-PLGA Pentablock Copolymer (PPPC) prepared is amphiphilic, its Critical Vesicular Concentration, was measured, which was lower at 37 degrees C than at 25 degrees C, which could provide better stability to the system at physiological temperature. The nanoparticles of PPPC vary in topographyand range from 150 to 500 nm in size, according to the synthesis route used viz Emulsion Solvent Evaporation and simple dialysis. Pentablock copolymer nanoparticles were found to entrap about 84% of hydrophobic drug, docetaxel. Drug release profile of docetaxel showed about 50% release in first 2 hours at pH 4.6 and about 80% docetaxel was released at pH 7.4, at the end of 2 days. The PPPC nanoparticles was found to be biocompatible to L929 cell lines up to 1 mg/ml concentration. Preliminary in vitro cytotoxic effect of docetaxel loaded PPPC nanoparticles against four different cancer cell lines showed 50% inhibitory concentration of 6 nM in A431 (Squamous cell carcinoma), 250 nM in HeLa (Cervical carcinoma), 800 nM in PC3 (Prostate carcinoma) and 1 microM in KB (Epidermoid carcinoma) cells.

The effect of St John's wort on the pharmacokinetics of docetaxel.

BACKGROUND AND OBJECTIVE: St John's wort (SJW), a herbal antidepressant, is commonly used by cancer patients, and its component hyperforin is a known inducer of the cytochrome P450 (CYP) isoenzyme 3A4. Here, the potential pharmacokinetic interaction between SJW and the sensitive CYP3A4 substrate docetaxel was investigated. METHODS: In ten evaluable cancer patients, the pharmacokinetics of docetaxel (135 mg administered intravenously over 60 min) were compared before and after 14 days of supplementation with SJW (300 mg extract [Hyperiplant(®)] three times daily). RESULTS: SJW supplementation resulted in a statistically significant decrease in the mean area under the docetaxel plasma concentration-time curve extrapolated to infinity (AUC∞) from 3,035 ± 756 to 2,682 ± 717 ng · h/mL (P = 0.045). Furthermore, docetaxel clearance significantly increased from 47.2 to 53.7 L/h (P = 0.045) after SJW intake. The maximum plasma concentration and elimination half-life of docetaxel were (non-significantly) decreased after SJW supplementation. In addition, the incidence of docetaxel-related toxicities was lower after SJW supplementation. CONCLUSION: These results suggest that concomitant use of docetaxel and the applied SJW product should be avoided to prevent potential undertreatment of cancer patients.

Pharmacokinetics of docetaxel during hyperthermic intraperitoneal chemotherapy for peritoneal metastasis.

UNLABELLED: The purpose of this manuscript is to report the pharmacokinetics of docetaxel during hyperthermic intraperitoneal chemotherapy (HIPEC) after peritonectomy. MATERIALS AND METHODS: Eleven patients with peritoneal metastasis (PM) underwent peritonectomies combined with 40 min of HIPEC with 40 mg/body of docetaxel. The pharmacokinetics of docetaxel were studied by using high-performance liquid chromatography. RESULTS: The docetaxel concentration at the start of HIPEC (0 min) was 9.084 ± 0.972 mg/L. The concentration gradually decreased to 5.599 ± 0.458 mg/L 40 min after HIPEC. In contrast, serum docetaxel levels increased during HIPEC, reaching a maximum level of 0.1334 ± 0.0726 mg/L at 40 min. The clearance (CLp) was 3.164 ± 1.383 L/hr, and the area under the curve (AUC) ratio was 95.12 ± 87.32. The AUC ratio of less-extensive peritonectomies was significantly higher than that of extended peritonectomies. The docetaxel concentration in the tumor tissue increased at 40 min (4.45 mg/gr). The apparent permeability (Papp, 40 min) was 1.47 ± 0.67 mm/40 min. No severe adverse effects were observed after HIPEC. CONCLUSION: From these results, 40 mg is a safe dose for docetaxel combined with HIPEC, and the locoregional intensity of docetaxel is enough to control PM less than 1.47 mm in diameter.

Intravenous microemulsion of docetaxel containing an anti-tumor synergistic ingredient (Brucea javanica oil): formulation and pharmacokinetics.

The purpose of this study was to develop a docetaxel microemulsion containing an anti-tumor synergistic ingredient (Brucea javanica oil) and to investigate the characteristics of the microemulsion. Brucea javanica oil contains oleic acid and linoleic acids that have been shown by animal and human studies to inhibit tumor formation. The microemulsion containing Brucea javanica oil, medium-chain triglyceride, soybean lecithin, Solutol®HS 15, PEG 400, and water was developed for docetaxel intravenous administration. A formulation with higher drug content, lower viscosity, and smaller particle size was developed. The droplet size distribution of the dispersed phase of the optimized microemulsion was 13.5 nm, determined using a dynamic light scattering technique. The small droplet size enabled the microemulsion droplets to escape from uptake and phagocytosis by the reticuloendothelial system and increased the circulation time of the drug. The zeta potential was -41.3 mV. The optimized microemulsion was pale yellow, transparent, and non-opalescent in appearance. The value of the combination index was 0.58, showing that there was a synergistic effect when docetaxel was combined with Brucea javanica oil. After a single intravenous infusion dose (10 mg/kg) in male Sprague Dawley rats, the area under the curve of the microemulsion was higher and the half-time was longer compared with that of docetaxel solution alone, and showed superior pharmacokinetic characteristics. These results indicate that this preparation of docetaxel in emulsion is likely to provide an excellent prospect for clinical tumor treatment.

The effect of Echinacea purpurea on the pharmacokinetics of docetaxel.

AIMS: The herbal medicine Echinacea purpurea (E. purpurea) has been shown to induce cytochrome P450 3A4 (CYP3A4) both in vitro and in humans. This study explored whether E. purpurea affects the pharmacokinetics of the CYP3A4 substrate docetaxel in cancer patients. METHODS: Ten evaluable cancer patients received docetaxel (135 mg, 60 min IV infusion) before intake of a commercially available E. purpurea extract (20 oral drops three times daily) and 3 weeks later after a 14 day supplementation period with E. purpurea. In both cycles, pharmacokinetic parameters of docetaxel were determined. RESULTS: Before and after supplementation with E. purpurea, the mean area under the plasma concentration-time curve of docetaxel was 3278 ± 1086 and 3480 ± 1285 ng ml(-1) h, respectively. This result was statistically not significant. Nonsignificant alterations were also observed for the elimination half-life (from 30.8 ± 19.7 to 25.6 ± 5.9 h, P = 0.56) and maximum plasma concentration of docetaxel (from 2224 ± 609 to 2097 ± 925 ng ml(-1) , P = 0.30). CONCLUSIONS: The multiple treatment of E. purpurea did not significantly alter the pharmacokinetics of docetaxel in this study. The applied E. purpurea product at the recommended dose may be combined safely with docetaxel in cancer patients.

Preclinical antitumor activity of cabazitaxel, a semisynthetic taxane active in taxane-resistant tumors.

PURPOSE: Taxanes are important chemotherapeutic agents with proven efficacy in human cancers, but their use is limited by resistance development. We report here the preclinical characteristics of cabazitaxel (XRP6258), a semisynthetic taxane developed to overcome taxane resistance. EXPERIMENTAL DESIGN: Cabazitaxel effects on purified tubulin and on taxane-sensitive or chemotherapy-resistant tumor cells were evaluated in vitro. Antitumor activity and pharmacokinetics of intravenously administered cabazitaxel were assessed in tumor-bearing mice. RESULTS: In vitro, cabazitaxel stabilized microtubules as effectively as docetaxel but was 10-fold more potent than docetaxel in chemotherapy-resistant tumor cells (IC50 ranges: cabazitaxel, 0.013-0.414 µmol/L; docetaxel, 0.17-4.01 µmol/L). The active concentrations of cabazitaxel in these cell lines were achieved easily and maintained for up to 96 hours in the tumors of mice bearing MA16/C tumors treated with cabazitaxel at 40 mg/kg. Cabazitaxel exhibited antitumor efficacy in a broad spectrum of murine and human tumors (melanoma B16, colon C51, C38, HCT 116, and HT-29, mammary MA17/A and MA16/C, pancreas P03 and MIA PaCa-2, prostate DU 145, lung A549 and NCI-H460, gastric N87, head and neck SR475, and kidney Caki-1). Of particular note, cabazitaxel was active in tumors poorly sensitive or innately resistant to docetaxel (Lewis lung, pancreas P02, colon HCT-8, gastric GXF-209, mammary UISO BCA-1) or with acquired docetaxel resistance (melanoma B16/TXT). CONCLUSIONS: Cabazitaxel is as active as docetaxel in docetaxel-sensitive tumor models but is more potent than docetaxel in tumor models with innate or acquired resistance to taxanes and other chemotherapies. These studies were the basis for subsequent clinical evaluation.

Cabazitaxel in metastatic castration-resistant prostate cancer.

Metastatic castration-resistant prostate cancer (CRPC) has a poor prognosis and remains a significant therapeutic challenge. Prior to 2010, docetaxel chemotherapy was the only treatment shown to improve overall survival, symptom control and quality of life in patients with CRPC. Research efforts focused on overcoming chemoresistance to taxanes eventually led to the development of multiple novel anti-tumor agents, including cabazitaxel. Cabazitaxel has recently been shown to significantly improve overall survival compared with mitoxantrone in a large multicenter Phase III study. This article details the preclinical and clinical development of cabazitaxel and discusses the importance of this novel chemotherapy in CRPC. The authors also discuss the challenges now facing the future use of cabazitaxel in CRPC, including the determination of the optimal dose of cabazitaxel in patients with advanced CRPC, the ideal sequencing of cabazitaxel relative to other anti-tumor treatments, appropriate patient selection and novel strategies for the assessment of treatment response.

Enhanced oral bioavailability of docetaxel by lecithin nanoparticles: preparation, in vitro, and in vivo evaluation.

The aim of this research work was to investigate the potential of lecithin nanoparticles (LNs) in improving the oral bioavailability of docetaxel. Docetaxel-loaded LNs (DTX-LNs) were prepared from oil-in-water emulsions and characterized in terms of morphology, size, zeta potential, and encapsulation efficiency. The in vitro release of docetaxel from the nanoparticles was studied by using dialysis bag method. Caco-2 cell monolayer was used for the in vitro permeation study of DTX-LNs. Bioavailability studies were conducted in rats and different pharmacokinetic parameters were evaluated after oral administration of DTX-LNs. The results showed that DTX-LNs had a mean diameter of 360 ± 8 nm and exhibited spherical shape with smooth surface under transmission electron microscopy. The DTX-LNs showed a sustained-release profile, with about 80% of docetaxel released within 72 hours. The apical to basolateral transport of docetaxel across the Caco-2 cell monolayer from the DTX-LNs was 2.14 times compared to that of the docetaxel solution (0.15 × 10⁻5 ± 0.016 × 10⁻5 cm/second versus 0.07 × 10⁻5 ± 0.003 × 10⁻5 cm/second). The oral bioavailability of the DTX-LNs was 3.65 times that of docetaxel solution (8.75% versus 2.40%). These results indicate that DTX-LNs were valuable as an oral drug delivery system to enhance the absorption of docetaxel.

Phase I trial to investigate the safety, pharmacokinetics and efficacy of sorafenib combined with docetaxel in patients with advanced refractory solid tumours.

AIM: The safety, pharmacokinetics and efficacy of sorafenib plus docetaxel in patients with advanced refractory cancer were investigated in a phase I, dose-escalation trial. METHODS: Twenty-seven patients in four cohorts received docetaxel on day 1 (cohorts 1 and 4: 75 mg/m2; cohorts 2 and 3: 100 mg/m2) plus sorafenib on days 2-19 (cohorts 1 and 2: 200 mg twice-daily (bid); cohorts 3 and 4: 400 mg bid) in 21-day cycles. RESULTS: Most common adverse events (AEs) (grade 3-5) included neutropenia (89%), leucopaenia (81%), hand-foot skin reaction (30%) and fatigue (30%). The most common drug-related AEs leading to dose reduction/interruption or permanent discontinuation were dermatologic (41%), gastrointestinal (26%) and constitutional (22%). Coadministration of sorafenib altered the pharmacokinetics of docetaxel. On average, docetaxel area under the concentration-time curve (AUC)(0-24) increased by 5% (cohort 1), 54% (cohort 2), 36% (Cohort 3) and 80% (cohort 4) with docetaxel plus sorafenib, while C(max) increased by 16-32%, independent of sorafenib/docetaxel doses. Three of 25 evaluable patients (11%) had partial responses; 14 (52%) had stable disease. CONCLUSION: Dose-limiting dermatologic AEs were more common than expected for either therapy alone. A starting dose of docetaxel 75 mg/m2 plus sorafenib 400mg bid (with dose reductions for dermatological toxicities) is proposed for phase II.

From mouse to man: predictions of human pharmacokinetics of orally administered docetaxel from preclinical studies.

Intravenously administered docetaxel is approved for the treatment of various types of cancer. An oral regimen, in combination with ritonavir, is being evaluated in clinical trials. The pharmacokinetics of docetaxel are determined by the activity of the metabolizing enzyme cytochrome P450 3A (CYP3A) and the drug efflux transporter P-glycoprotein (P-gp). The effects of these proteins on the pharmacokinetics of docetaxel were investigated in different mouse models that lack 1 or both detoxifying systems. Docetaxel was given to these mice orally or intravenously with or without a strong CYP3A inhibitor, ritonavir. The data of these 2 preclinical studies were pooled and analyzed using nonlinear mixed-effects modeling. The results of the preclinical studies could be integrated successfully, with only a small difference in residual error (33% and 26%, respectively). Subsequently, the model was used to predict human exposure using allometric scaling and this was compared with clinical trial data. This model led to adequate predictions of docetaxel exposure in humans.