Quantitative determination of total and unbound paclitaxel in human plasma following Abraxane treatment

Efficacy and safety evaluation of albumin-bound paclitaxel chemotherapy in East Asian patients with gynecological tumors based on the degree of paclitaxel binding to patient plasma

Nab-PTX is a special dosage form of antitumor drug that is different from other injections. In order to explore the efficacy and safety of albumin-bound paclitaxel, we developed an analytical method with UPLC-MS/MS to quantify the total and free paclitaxel in plasma, and prospectively evaluate the impact of unbound fraction fu (%) on the prognosis and adverse reactions of patients with gynecological tumors. From 2020.10 to 2021.10, a total of 116 patients with gynecological tumors were included, application of albumin-bound paclitaxel combined with platinum chemotherapy drugs, the blood collection time is 18-30 h after nab-PTX intravenous infusion. The collection time and the start (end) time of intravenous drip are recorded correctly, and a high-precision and sensitive UPLC-MS/MS method for the simultaneous determination of total and free paclitaxel was established. With fu (%) = Cunbound/Ctotal as the evaluation index, the concentration of total paclitaxel and free paclitaxel were determined by UPLC-MS/MS. The value of fu (%) was closely related to clinical adverse reactions, neutropenia, thrombocytopenia, leukopenia and bone marrow suppression. Neurotoxicity was statistically remarkable (P up0.001), and fu (%) has a significant correlation with clinical efficacy (P up0.001). We have developed a highly precise, highly sensitive and specific UPLC-MS/MS method for the simultaneous determination of binding and free albumin-bound paclitaxel concentrations in patients' serum. In addition, we found that fu (%) could be used as the detection index. The higher the fu (%) was, the more taxol could be free, the more adverse reactions related to toxic events occurred in patients.

Preparation and characterization of paclitaxel palmitate albumin nanoparticles with high loading efficacy: an in vitro and in vivo anti-tumor study in mouse models

BACKGROUND

Combination of the prodrug technique with an albumin nano drug-loaded system is a novel promising approach for cancer treatment. However, the long-lasting and far-reaching challenge for the treatment of cancers lies in how to construct the albumin nanometer drug delivery system with lead compounds and their derivatives.

METHODS

In this study, we reported the preparation of injectable albumin nanoparticles (NPs) with a high and quantitative drug loading system based on the Nab^TM technology of paclitaxel palmitate (PTX-PA).

RESULTS

Our experimental study on drug tissue distribution in vivo demonstrated that the paclitaxel palmitate albumin nanoparticles (Nab-PTX-PA) remained in the tumor for a longer time post-injection. Compared with saline and paclitaxel albumin nanoparticles (Abraxane^®), intravenous injection of Nab-PTX-PA not only reduced the toxicity of the drug in normal organs, and increased the body weight of the animals but maintained sustained release of paclitaxel (PTX) in the tumor, thereby displaying an excellent antitumor activity. Blood routine analysis showed that Nab-PTX-PA had fewer adverse effects or less toxicity to the normal organs, and it inhibited tumor cell proliferation more effectively as compared with commercial paclitaxel albumin nanoparticles.

CONCLUSIONS

This carrier strategy for small molecule drugs is based on naturally evolved interactions between long-chain fatty acids (LCFAs) and Human Serum Albumin (HSA), demonstrated here for PTX. Nab-PTX-PA shows higher antitumor efficacy in vivo in breast cancer models. On the whole, this novel injectable Nab-PTX-PA has great potential as an effective drug delivery system in the treatment of breast cancer.

A phase I pharmacokinetic and safety study of Paclitaxel Injection Concentrate for Nano-dispersion (PICN) alone and in combination with carboplatin in patients with advanced solid malignancies and biliary tract cancers

PURPOSE

Paclitaxel injection concentrate for nano-dispersion (PICN) is a Cremophor-free, nanotechnology-driven paclitaxel formulation. This phase I study examined the safety, tolerability, pharmacokinetics and maximum tolerated dose (MTD) of PICN alone and in combination with carboplatin. Its early efficacy in unresectable biliary tract cancers (BTCs) was also evaluated.

METHODS

This multi-center study comprised two parts. Part A contained a dose-escalation cohort following "3 + 3" design using PICN monotherapy in advanced solid tumors (Part A1); Part A2 dose-expansion cohort was then conducted in advanced BTCs due to observed efficacy in Part A1. Part B1 and B2 evaluated escalating dose of PICN with carboplatin in advanced solid tumors. PICN was administered as a 30 min-infusion every 3 weeks without pre-medications for hypersensitivity reactions.

RESULTS

Thirty-six patients received PICN monotherapy in Part A and 21 received PICN plus carboplatin in Part B. The MTD of PICN was determined to be 295 mg/m² both as a monotherapy and in combination with carboplatin at AUC 5. Dose-proportional exposure in paclitaxel C_max and AUC was observed overdose range from 175 to 325 mg/m² for PICN monotherapy and its combination with carboplatin. Carboplatin did not alter PICN exposure. Clinically significant toxicities mainly include neutropenia and peripheral neuropathy. PICN monotherapy yielded a response rate of 20% in unresectable BTCs.

CONCLUSION

This study demonstrated the safety and stable pharmacokinetics of PICN as a monotherapy and in combination with carboplatin. Single-agent PICN showed promising antitumor activity in advanced BTCs, warranting further studies to investigate its role in gastrointestinal cancers.

Phase I/II Study of the Mesothelin-targeted Immunotoxin LMB-100 with Nab-Paclitaxel for Patients with Advanced Pancreatic Adenocarcinoma

PURPOSE

LMB-100 is a recombinant immunotoxin (iTox) consisting of a mesothelin-binding Fab for targeting and a modified Pseudomonas exotoxin A payload. Preclinical studies showed that combining taxanes with iTox results in synergistic antitumor activity. The objectives of this phase I/II study were to determine the MTD of LMB-100 when administered with nanoalbumin bound (nab)-paclitaxel to patients with previously treated advanced pancreatic adenocarcinoma and to assess the objective response rate.

PATIENTS AND METHODS

Patients (n = 20) received fixed-dose nab-paclitaxel (125 mg/m² on days 1 and 8) with LMB-100 (65 or 100 μg/kg on days 1, 3, and 5) in 21-day cycles for 1-3 cycles.

RESULTS

Fourteen patients were treated on the dose escalation and an additional six in the phase II expansion. MTD of 65 μg/kg was established for the combination. Dose-limiting toxicity resulting from capillary leak syndrome (CLS) was seen in two of five patients treated at 100 μg/kg and one of six evaluable phase I patients receiving the MTD. Severity of CLS was associated with increases in apoptotic circulating endothelial cells. LMB-100 exposure was unaffected by anti-LMB-100 antibody formation in five of 13 patients during cycle 2. Seven of 17 evaluable patients experienced >50% decrease in CA 19-9, including three with previous exposure to nab-paclitaxel. One patient developed an objective partial response. Patients with biomarker responses had higher tumor mesothelin expression.

CONCLUSIONS

Although clinical activity was observed, the combination was not well tolerated and alternative drug combinations with LMB-100 will be pursued.

Bioequivalence of paclitaxel protein-bound particles in patients with breast cancer: determining total and unbound paclitaxel in plasma by rapid equilibrium dialysis and liquid chromatography-tandem mass spectrometry

Background and objective: Paclitaxel protein-bound particles for injectable suspension (nab-paclitaxel) showed many advantages in safety, effectiveness, and convenience. Different from conventional formulations, the bioequivalence evaluation of nab-paclitaxel formulations requires to determine the total amount of paclitaxel in plasma and the unbound paclitaxel to reflect their in vivo disposition. This study aimed to develop an analytical method to quantify the total and unbound paclitaxel in plasma and evaluate the bioequivalence of two formulations of nab-paclitaxel in patients with breast cancer. Materials and methods: An open-label, randomized, two-period crossover study was completed among 24 Chinese patients with breast cancer. The patients were randomized to receive either the test formulation on cycle 1 day 1 and after 21 days in cycle 2 day 1 by the reference formulation (Abraxane®), or vice versa. Rapid equilibrium dialysis was adopted to separate the unbound paclitaxel in human plasma. Total and unbound paclitaxel concentrations were measured by the validated liquid chromatography-tandem mass spectrometry methods over the range of 5.00-15,000 and 0.200-200 ng/mL, respectively. The bioequivalence of the test formulation to the reference formulation was assessed using the Food and Drug Administration and European Medicines Agency guidelines. Results: All the 90% confidence intervals (CIs) of the geometric mean ratios fell within the predetermined acceptance range. The 90% CIs for the area under the concentration-time curve (AUC) from 0 h to 72 h (AUC0-t), AUC from time zero to infinity (AUC0-∞), and peak plasma concentrations (Cmax) for total paclitaxel were 92.03%-98.05%, 91.98%-99.37%, and 91.37%-99.36%, respectively. The 90% CIs of AUC0-t, AUC0-∞, and Cmax for unbound paclitaxel were 86.77%-97.88%, 86.81%-97.88%, and 87.70%-98.86%, respectively. Conclusion: Bioequivalence between the two nab-paclitaxel formulations was confirmed for total and unbound paclitaxel at the studied dose regimen.

In vitro and in vivo Assessment of Keratose as a Novel Excipient of Paclitaxel Coated Balloons

Purpose: Drug coated balloons (DCB) are continually improving due to advances in coating techniques and more effective excipients. Paclitaxel, the current drug choice of DCB, is a microtubule-stabilizing chemotherapeutic agent that inhibits smooth muscle cell proliferation. Excipients work to promote coating stability and facilitate paclitaxel transfer and retention at the target lesion, although current excipients lack sustained, long-term paclitaxel retention. Keratose, a naturally derived protein, has exhibited unique properties allowing for tuned release of various therapeutic agents. However, little is known regarding its ability to support delivery of anti-proliferative agents such as paclitaxel. The goal of this project was to thus demonstrate the feasibility of keratose as a DCB-coating excipient to promote the release and delivery of paclitaxel. Methods: Keratose was combined with paclitaxel in vitro and the release kinetics of paclitaxel and keratose were evaluated through high performance liquid chromatograph-mass spectroscopy (HPLC-MS) and spectrophotometry, respectively. A custom coating method was developed to deposit keratose and paclitaxel on commercially available angioplasty balloons via an air spraying method. Coatings were then visualized under scanning electron microscopy and drug load quantified by HPLC-MS. Acute arterial transfer of paclitaxel at 1 h was assessed using a novel ex vivo model and further evaluated in vivo in a porcine ilio-femoral injury model. Results: Keratose demonstrated tunable release of paclitaxel as a function of keratose concentration in vitro. DCB coated via air spraying yielded consistent drug loading of 4.0 ± 0.70 μg/mm2. Under scanning electron microscopy, the keratose-paclitaxel DCB showed uniform coverage with a consistent, textured appearance. The acute drug transfer of the keratose-paclitaxel DCB was 43.60 ± 14.8 ng/mg at 1 h ex vivo. These measurements were further confirmed in vivo as the acute 1 h arterial paclitaxel levels were 56.60 ± 66.4 ng/mg. Conclusion: The keratose-paclitaxel coated DCB exhibited paclitaxel uptake and achieved acute therapeutic arterial tissue levels, confirming the feasibility of keratose as a novel excipient for DCB.

Liposomal paclitaxel induces fewer hematopoietic and cardiovascular complications than bioequivalent doses of Taxol

Paclitaxel (PTX) exhibits potent antineoplastic activity against various human malignancies; however, clinical application must overcome the inherent hydrophobicity of this molecule. The commercialized Taxol formulation utilizes Cremophor EL (CrEL)/ethanol as a solvent to stabilize and dispense PTX in an aqueous solution. However, adverse CrEL-induced hypersensitivity reactions have been reported in ~30% of recipients, and 40% of patients receiving premedication may also experience this adverse effect. Therefore, the development of a CrEL-free delivery system is crucial, in order to fully exploit the therapeutic efficacy of PTX. In the present study, a novel liposomal PTX (lipo-PTX) formulation was optimized with regards to encapsulation rate and long-term stability, arriving at a molar constituent ratio of soybean phosp hatidylcholine:cholesterol:N-(carbonyl-methoxy-poly-ethylene glycol 2000)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine, sodium salt:PTX at 95:2:1:2. Comparable doses of lipo-PTX and Taxol were bioequivalent in terms of therapeutic efficacy in xenograft tumor models. However, the systemic side effects, including hematopoietic toxicity, acute hypersensitivity reactions and cardiac irregularities, were significantly reduced in lipo-PTX-treated mice compared with those infused with reference formulations of PTX. In conclusion, the present study reported that lipo-PTX exhibited a higher therapeutic index than clinical PTX formulations.

Physiologically-based modeling and interspecies prediction of paclitaxel pharmacokinetics

The objective was to develop a physiologically-based pharmacokinetic (PBPK) model to characterize the whole-body disposition of paclitaxel (formulated in Cremophor EL and ethanol-Taxol^®) in mice and to evaluate the utility of this model for predicting pharmacokinetics in other species. Published studies that reported paclitaxel plasma and tissue concentration-time data following single intravenous bolus administration of Taxol^® to mice were used; and the PBPK model included plasma, liver, lungs, kidneys, spleen, heart, gastrointestinal tract, and remainder compartments. The final model resulted in a good description of the experimental plasma and tissues data in mice, where all tissues were represented by a single compartment, except the remainder that included two sub-compartments. The predictive performance of the PBPK model was assessed by evaluating its utility in predicting pharmacokinetics of paclitaxel in rats and humans. The relationship between species body weights (mice, rats, rabbits, and humans) and plasma clearance was determined by power-based regression, and resulting allometric exponent was 0.86. The model demonstrated reasonable predictions of plasma and tissue paclitaxel concentration-time profiles in rats and plasma profiles in humans. The proposed PBPK model represents an important basis that can be further utilized for characterization of novel formulations of paclitaxel.

A new high-performance liquid chromatography-tandem mass spectrometry method for the determination of paclitaxel and 6α-hydroxy-paclitaxel in human plasma: Development, validation and application in a clinical pharmacokinetic study

Paclitaxel belongs to the taxanes family and it is used, alone or in multidrug regimens, for the therapy of several solid tumours, such as breast-, lung-, head and neck-, and ovarian cancer. Standard dosing of chemotherapy does not take into account the many inter-patient differences that make drug exposure highly variable, thus leading to the insurgence of severe toxicity. This is particularly true for paclitaxel considering that a relationship between haematological toxicity and plasma exposure was found. Therefore, in order to treat patients with the correct dose of paclitaxel, improving the overall benefit–risk ratio, Therapeutic Drug Monitoring is necessary. In order to quantify paclitaxel and its main metabolite, 6α-hydroxy-paclitaxel, in patients’ plasma, we developed a new, sensitive and specific HPLC–MS/MS method applicable to all paclitaxel dosages used in clinical routine. The developed method used a small volume of plasma sample and is based on quick protein precipitation. The chromatographic separation of the analytes was achieved with a SunFire^™ C18 column (3.5 μM, 92 Å, 2,1 x 150 mm); the mobile phases were 0.1% formic acid/bidistilled water and 0.1% formic acid/acetonitrile. The electrospray ionization source worked in positive ion mode and the mass spectrometer operated in selected reaction monitoring mode. Our bioanalytical method was successfully validated according to the FDA-EMA guidelines on bioanalytical method validation. The calibration curves resulted linear (R² ≥0.9948) over the concentration ranges (1–10000 ng/mL for paclitaxel and 1–1000 ng/mL for 6α-hydroxy-paclitaxel) and were characterized by a good accuracy and precision. The intra- and inter-day precision and accuracy were determined on three quality control concentrations for paclitaxel and 6α-hydroxy-paclitaxel and resulted respectively <9.9% and within 91.1–114.8%. In addition, to further verify the assay reproducibility, we tested this method by re-analysing the incurred samples. This bioanalytical method was employed with success to a genotype-guided phase Ib study of weekly paclitaxel in ovarian cancer patients treated with a wide range of drug’s dosages.

Preparation and characterization of an injectable thermosensitive hydrogel for simultaneous delivery of paclitaxel and doxorubicin

In the current study, we aimed to develop a novel injectable thermosensitive hydrogel for simultaneous intra-tumoral administration of paclitaxel (PTX) and doxorubicin hydrochloride (DOX). At first, mixed micelles composed of Pluronic F127 and α-tocopheryl polyethylene glycol 1000 succinate (TPGS) was loaded with PTX and their physicochemical properties including particle size, zeta potential, drug loading content, entrapment efficiency, and the drug release were investigated in details. In the second step, the optimized PTX-loaded micelles prepared in the first step were incorporated into the thermosensitive Pluronic F127/hyaluronic acid (PF127/HA) hydrogel containing fixed amount of DOX. Gel formation temperature, rheological properties, injectability, degradation rates of the hydrogel, and the release rate of PTX and DOX from the hydrogel were examined. The mean particle sizes and zeta potentials of the PTX-loaded micelles were 157.5 ± 20.1 nm and -9.6 ± 1.1 mV, respectively. The entrapment efficiency of the formulation was about 51%. The hydrogel containing PTX-loaded micelles and DOX existed as a solution with low viscosity at 4 °C converted to a semisolid upon increasing the temperature to 35 °C. DOX was completely released from the hydrogel within 12 h, while 40-80% of PTX could be released from the different formulations during 3 days. This novel thermosensitive hydrogel prepared in the current study could be efficiently used for co-delivery of PTX and DOX in solid tumor types.

HPLC-MS/MS method for quantification of paclitaxel from keratin containing samples

Local drug delivery of paclitaxel is becoming ever more prevalent. As complex drug/excipient combinations are being developed and tested, new high performance liquid chromatography-mass spectrometry (HPLC-MS) techniques capable of quantifying paclitaxel from such formulations are needed. Here a method for quantifying paclitaxel from aqueous, protein and oil containing samples was developed and validated. Keratin, derived from human hair, is the protein component/paclitaxel excipient in the development and validation of said method. The novelty of this method is described by its ability to overcome water solubility issues and address clean-up of residual solvents in clinical grade paclitaxel injection composition. The method evaluates tert-butyl methyl ether and ethanol as extraction solvents with an extraction efficiency of 31.9±2.3% and 86.4±4.5% respectively. Upon evaporation and rehydration, samples were evaluated by HPLC-MS and a method was developed for paclitaxel quantification. The method developed had an inter-day precision of 9.1% relative standard deviation and an intra-day precision of 4.3% relative standard deviation normalized to a docetaxel internal standard. The described method is applicable to any aqueous paclitaxel sample containing protein and/or oils.

Mass spectrometry in the pharmacokinetic studies of anticancer natural products

In the history of medicine, nature has represented the main source of medical products. Indeed, the therapeutic use of plants certainly goes back to the Sumerian and Hippocrates and nowadays nature still represents the major source for new drugs discovery. Moreover, in the cancer treatment, drugs are either natural compounds or have been developed from naturally occurring parent compounds firstly isolated from plants and microbes from terrestrial and marine environment. A critical element of an anticancer drug is represented by its severe toxicities and, after administration, the drug concentrations have to remain in an appropriate range to be effective. Anyway, the drug dosage defined during the clinical studies could be inappropriate for an individual patient due to differences in drug absorption, metabolism and excretion. For this reason, personalized medicine, based on therapeutic drug monitoring (TDM), represents one of most important challenges in cancer therapy. Mass spectrometry sensitivity, specificity and fastness lead to elect this technique as the Golden Standard for pharmacokinetics and drug metabolism studies therefore for TDM. This review focuses on the mass spectrometry-based methods developed for pharmacokinetic quantification in human plasma of anticancer drugs derived from natural sources and already used in clinical practice. Particular emphasis was placed both on the pre-analytical and analytical steps, such as: sample preparation procedures, sample size required by the analysis and the limit of quantification of drugs and metabolites to give some insights on the clinical practice applicability. © 2015 Wiley Periodicals, Inc. Mass Spec Rev. 36:213-251, 2017.

Scientific and Regulatory Considerations for Generic Complex Drug Products Containing Nanomaterials

In the past few decades, the development of medicine at the nanoscale has been applied to oral and parenteral dosage forms in a wide range of therapeutic areas to enhance drug delivery and reduce toxicity. An obvious response to these benefits is reflected in higher market shares of complex drug products containing nanomaterials than that of conventional formulations containing the same active ingredient. The surging market interest has encouraged the pharmaceutical industry to develop cost-effective generic versions of complex drug products based on nanotechnology when the associated patent and exclusivity on the reference products have expired. Due to their complex nature, nanotechnology-based drugs present unique challenges in determining equivalence standards between generic and innovator products. This manuscript attempts to provide the scientific rationales and regulatory considerations of key equivalence standards (e.g., in vivo studies and in vitro physicochemical characterization) for oral drugs containing nanomaterials, iron-carbohydrate complexes, liposomes, protein-bound drugs, nanotube-forming drugs, and nano emulsions. It also presents active research studies in bridging regulatory and scientific gaps for establishing equivalence of complex products containing nanomaterials. We hope that open communication among industry, academia, and regulatory agencies will accelerate the development and approval processes of generic complex products based on nanotechnology.

Determination of total and unbound propofol in patients during intensive care sedation by ultrafiltration and LC-MS/MS

For the quantification of propofol total and unbound drug concentrations a sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated. To separate unbound propofol an ultrafiltration step before sample preparation was performed. Both the ultrafiltrate and plasma samples were extracted with solid-phase extraction and substituted with deuterated propofol as an internal standard. Separation was performed by gradient elution using UPLC-like system and analyzed by MS/MS consisting of an electrospray ionization source. To detect low and high concentration levels of propofol two calibration curves were identified and showed linearity within the range of 1-50ng/ml and 50-20000ng/ml. The lower limit of quantification was 1ng/ml. Intra- and interassay precision and accuracy did not exceed ±15%. The method was applied to a clinical study during intensive care treatment of patients after coronary artery bypass grafting.

Abraxane, the Nanoparticle Formulation of Paclitaxel Can Induce Drug Resistance by Up-Regulation of P-gp

P-glycoprotein (P-gp) can actively pump paclitaxel (PTX) out of cells and induces drug resistance. Abraxane, a nanoparticle (NP) formulation of PTX, has multiple clinical advantages over the single molecule form. However, it is still unclear whether Abraxane overcomes the common small molecule drug resistance problem mediated by P-gp. Here we were able to establish an Abraxane-resistant cell line from the lung adenocarcinoma cell line A549. We compared the transcriptome of A549/Abr resistant cell line to that of its parental cell line using RNA-Seq technology. Several pathways were found to be up or down regulated. Specifically, the most significantly up-regulated gene was ABCB1, which translates into P-glycoprotein. We verified the overexpression of P-glycoprotein and confirmed its function by reversing the drug resistance with P-gp inhibitor Verapamil. The results suggest that efflux pathway plays an important role in the Abraxane-resistant cell line we established. However, the relevance of this P-gp mediated Abraxane resistance in tumors of lung cancer patients remains unknown.

Age-related changes in nanoparticle albumin-bound paclitaxel pharmacokinetics and pharmacodynamics: influence of chronological versus functional age

PURPOSE

This study evaluated age-related changes in pharmacokinetic and pharmacodynamic parameters of nanoparticle albumin-bound paclitaxel (nab-paclitaxel) in patients with metastatic breast cancer.

METHODS

Forty patients received nab-paclitaxel (100 mg/m(2) weekly for 3 weeks followed by a 1-week break) as first- or second-line chemotherapy. Blood samples were collected for analysis, and response was assessed every two cycles. Planned statistical analyses included linear regression to examine the relationship between age and pharmacokinetic variables (ln clearance [CL] and ln area under the curve [AUC]) and two-sided two-sample t tests to evaluate age differences in pharmacodynamic variables. The association between chemotherapy toxicity risk scores and pharmacokinetic and pharmacodynamic variables including grade ≥ 3 toxicity were examined post hoc.

RESULTS

Of 40 patients enrolled, 39 (98%) were evaluable (mean age: 60 years; range: 30-81 years). A partial response was achieved in 31%, and 38% had stable disease. There was a borderline positive association between age and 24-hour ln AUC (slope = 0.011; SE = 0.006; p = .055). Grade 3 toxicity was experienced by 26% (8% hematologic, 18% nonhematologic). There were no differences in age based on the presence of grade 3 toxicity (p = .75), dose reductions (p = .38), or dose omissions (p = .15). A significant association was noted between chemotherapy toxicity risk score category and presence of grade 3 toxicity (toxicity rate by risk score category: low, 5 of 30 patients; medium, 3 of 6 patients; high, 2 of 3 patients; p = .041).

CONCLUSION

A borderline significant relationship exists between age and 24-hour AUC, but no differences were noted for pharmacodynamic variables (grade 3 toxicity, dose reductions, or dose omissions) based on age. There is an association between toxicity risk score and grade ≥ 3 chemotherapy toxicity and pharmacokinetic variables. The treatment is well tolerated across all age groups.

Quantification of taxanes in biological matrices: a review of bioanalytical assays and recommendations for development of new assays

Since the isolation of paclitaxel and its approval for the treatment of breast cancer, various taxanes and taxane formulations have been developed. To date, almost 100 bioanalytical assays have been published with the method development and optimization often extensively discussed by the authors. This Review presents an overview of assays published between January 1970 and September 2013 that described method development and validation of assays used to quantify taxanes in biological matrices such as plasma, urine, feces and tissue samples. For liquid chromatography assays, sample pretreatment, chromatographic separation and assay performance are compared. Since this Review discusses the limitations of previously developed liquid chromatography assays and gives recommendations for future assay development, it can be used as a reference for future development of liquid chromatography assays for the quantification of taxanes in various biological matrices to support preclinical and clinical studies.

The role of payload hydrophobicity in nanotherapeutic pharmacokinetics

Although drug delivery with nanovectors is regarded as one of the paradigm-shifting advances in modern medicine, the compatibility and performance of drug-vector formulations have not been systematically studied in terms of their physicochemistry and pharmacokinetics (PKs). The drug delivery systems (DDSs), currently available in clinics or trials, were analyzed based on hydrophobicity and anatomical therapeutic chemical (ATC) classification of drug payloads. Four major types of DDSs differentiated based on DDS structure and drug hydrophobicity, where payload hydrophobicity decreased: micelles, serum albumin, liposome membrane, and liposome interior. A strong relationship between the increase in half-life in DDS formulation and drug hydrophobicity was found with up to 200-fold greater increase for hydrophilic drugs. The analysis results seemingly integrated PKs, ATC, and hydrophobicity to reinforce the development or optimization of drug delivery vectors and their formulations.

Randomised, double-blind trial of carboplatin and paclitaxel with daily oral cediranib or placebo in patients with advanced non-small cell lung cancer: NCIC Clinical Trials Group study BR29

INTRODUCTION

This randomised double-blind placebo-controlled study evaluated the addition of cediranib, an inhibitor of vascular endothelial growth factor receptors 1-3, to standard carboplatin/paclitaxel chemotherapy in advanced non-small cell lung cancer.

METHODS

Eligible patients received paclitaxel (200mg/m(2)) and carboplatin (area under the concentration time curve 6) intravenously every 3 weeks. Daily oral cediranib/placebo 20mg was commenced day 1 of cycle 1 and continued as monotherapy after completion of 4-6 cycles of chemotherapy. The primary end-point of the study was overall survival (OS). The trial would continue to full accrual if an interim analysis (IA) for progression-free survival (PFS), performed after 170 events of progression or death in the first 260 randomised patients, revealed a hazard ratio (HR) for PFS of ⩽ 0.70.

RESULTS

The trial was halted for futility at the IA (HR for PFS 0.89, 95% confidence interval [CI] 0.66-1.20, p = 0.45). A final analysis was performed on all 306 enrolled patients. The addition of cediranib increased response rate ([RR] 52% versus 34%, p = 0.001) but did not significantly improve PFS (HR 0.91, 95% CI 0.71-1.18, p = 0.49) or OS (HR 0.94, 95% CI 0.69-1.30, p=0.72). Cediranib patients had more grade 3 hypertension, diarrhoea and anorexia.

CONCLUSIONS

The addition of cediranib 20mg daily to carboplatin/paclitaxel chemotherapy increased RR and toxicity, but not survival.

Combined quantification of paclitaxel, docetaxel and ritonavir in human feces and urine using LC-MS/MS

A combined assay for the determination of paclitaxel, docetaxel and ritonavir in human feces and urine is described. The drugs were extracted from 200 μL urine or 50 mg feces followed by high-performance liquid chromatography analysis coupled with positive ionization electrospray tandem mass spectrometry. The validation program included calibration model, accuracy and precision, carry-over, dilution test, specificity and selectivity, matrix effect, recovery and stability. Acceptance criteria were according to US Food and Drug Administration guidelines on bioanalytical method validation. The validated range was 0.5-500 ng/mL for paclitaxel and docetaxel, 2-2000 ng/mL for ritonavir in urine, 2-2000 ng/mg for paclitaxel and docetaxel, and 8-8000 ng/mg for ritonavir in feces. Inter-assay accuracy and precision were tested for all analytes at four concentration levels and were within 8.5% and <10.2%, respectively, in both matrices. Recovery at three concentration levels was between 77 and 94% in feces samples and between 69 and 85% in urine samples. Method development, including feces homogenization and spiking blank urine samples, are discussed. We demonstrated that each of the applied drugs could be quantified successfully in urine and feces using the described assay. The method was successfully applied for quantification of the analytes in feces and urine samples of patients.

Simultaneous online SPE-HPLC-MS/MS analysis of docetaxel, temsirolimus and sirolimus in whole blood and human plasma

Docetaxel and temsirolimus are some of the most used drugs in a wide range of solid tumors. In preclinical studies, mTOR inhibitors such as temsirolimus have demonstrated synergistic cytotoxic effects with taxanes providing the rationale for combination studies. These anticancer agents exhibit a narrow therapeutic concentration range and due to their high inter- and intra-individual pharmacokinetic variability, therapeutic dose monitoring by highly sensitive methods as LC-MS/MS are important for clinical research. Therefore, the aim of this study was to develop and validate a sensitive, fast and convenient method for the simultaneous identification and quantification of docetaxel, temsirolimus and its main metabolite, sirolimus, using paclitaxel, another anticancer drug, as the internal standard. These analytes were quantified by an integrated online solid phase extraction-high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS) system. Separation was performed on a Zorbax eclipse XDB-C8 (150mm×4.6mm, 5μm) column. The mass spectrometer tandem quadruple detector was equipped with jet stream electrospray ionization, monitored in multiple reactions monitoring (MRM) and operated in positive mode. A combination of protein precipitation with methanol/zinc sulphate (70:30) (v/v) and online SPE using a Zorbax eclipse plus C8 (12.5mm×4.6mm, 5μm) cartridge was used to extract the compounds. This method allows the use of the same reagents, sample treatment and analytical technique independently of whether the samples are whole blood or plasma. The method has been successfully validated and applied to real samples. It is a suitable method for dose adjustment and for evaluating potential drug interactions during combined treatments.

Perspectives and potential applications of nanomedicine in breast and prostate cancer

Nanomedicine is a branch of nanotechnology that includes the development of nanostructures and nanoanalytical systems for various medical applications. Among these applications, utilization of nanotechnology in oncology has captivated the attention of many research endeavors in recent years. The rapid development of nano-oncology raises new possibilities in cancer diagnosis and treatment. It also holds great promise for realization of point-of-care, theranostics, and personalized medicine. In this article, we review advances in nano-oncology, with an emphasis on breast and prostate cancer because these organs are amenable to the translation of nanomedicine from small animals to humans. As new drugs are developed, the incorporation of nanotechnology approaches into medicinal research becomes critical. Diverse aspects of nano-oncology are discussed, including nanocarriers, targeting strategies, nanodevices, as well as nanomedical diagnostics, therapeutics, and safety. The review concludes by identifying some limitations and future perspectives of nano-oncology in breast and prostate cancer management.

Translational considerations for cancer nanomedicine

There are many important considerations during preclinical development of cancer nanomedicines, including: 1) unique aspects of animal study design; 2) the difficulties in evaluating biological potency, especially for complex formulations; 3) the importance of analytical methods that can determine platform stability in vivo, and differentiate bound and free active pharmaceutical ingredient (API) in biological matrices; and 4) the appropriateness of current dose scaling techniques for estimation of clinical first-in-man dose from preclinical data. Biologics share many commonalities with nanotechnology products with regard to complexity and biological attributes, and can, in some cases, provide context for dealing with these preclinical issues. In other instances, such as the case of in vivo stability analysis, new approaches are required. This paper will discuss the significance of these preclinical issues, and present examples of current methods and best practices for addressing them. Where possible, these recommendations are justified using the existing regulatory guidance literature.

Radiation-guided drug delivery to mouse models of lung cancer

PURPOSE

The purpose of this study was to achieve improved cancer-specific delivery and bioavailability of radiation-sensitizing chemotherapy using radiation-guided drug delivery.

EXPERIMENTAL DESIGN

Phage display technology was used to isolate a recombinant peptide (HVGGSSV) that binds to a radiation-inducible receptor in irradiated tumors. This peptide was used to target nab-paclitaxel to irradiated tumors, achieving tumor-specificity and enhanced bioavailability of paclitaxel.

RESULTS

Optical imaging studies showed that HVGGSSV-guided nab-paclitaxel selectively targeted irradiated tumors and showed 1.48 ± 1.66 photons/s/cm(2)/sr greater radiance compared with SGVSGHV-nab-paclitaxel, and 1.49 ± 1.36 photons/s/cm(2)/sr greater than nab-paclitaxel alone (P < 0.05). Biodistribution studies showed >5-fold increase in paclitaxel levels within irradiated tumors in HVGGSSV-nab-paclitaxel-treated groups as compared with either nab-paclitaxel or SGVSGHV-nab-paclitaxel at 72 hours. Both Lewis lung carcinoma and H460 lung carcinoma murine models showed significant tumor growth delay for HVGGSSV-nab-paclitaxel as compared with nab-paclitaxel, SGVSGHV-nab-paclitaxel,and saline controls. HVGGSSV-nab-paclitaxel treatment induced a significantly greater loss in vasculature in irradiated tumors compared with unirradiated tumors, nab-paclitaxel, SGVSGHV-nab-paclitaxel, and untreated controls.

CONCLUSIONS

HVGGSSV-nab-paclitaxel was found to bind specifically to the tax-interacting protein-1 (TIP-1) receptor expressed in irradiated tumors, enhance bioavailability of paclitaxel, and significantly increase tumor growth delay as compared with controls in mouse models of lung cancer. Here we show that targeting nab-paclitaxel to radiation-inducible TIP-1 results in increased tumor-specific drug delivery and enhanced biological efficacy in the treatment of cancer.

A phase I study of paclitaxel and continuous daily CAI in patients with refractory solid tumors

BACKGROUND

Carboxyamido-triazole (CAI) is a calcium influx inhibitor with anti-angiogenic and anti-invasive properties and stabilizes tumor progression in patients. We hypothesized daily oral micronized CAI with q3 week paclitaxel would be well-tolerated and active.

RESULTS

Twenty-nine heavily pretreated patients [median 3 [0-7]] were enrolled on five dose levels. No additive or cumulative toxicity was observed, and grade III nonhematological toxicity was rare. Neutropenia was the most common hematologic toxicity, seen in 79% of patients, with a trend towards increasing grade with higher paclitaxel doses. The recommended phase II dose defined by the maximum tolerated dose (MTD) was CAI 250 mg daily and paclitaxel 200 mg/m(2) q3weeks. Pharmacokinetic analysis revealed paclitaxel increases CAI trough concentration at all dose levels by over 100% (p < 0.0001). A trend towards higher steady-state CAI trough concentrations was found in patients with a partial response (PR; p = 0.09). Six patients had confirmed PR (24%; 4-67 cycles, median 10); two patients had minor responses.

PATIENTS AND METHODS

Eligible patients with solid tumors received micronized CAI daily (150-250 mg PO) and paclitaxel intravenously q3weeks (175-250 mg/m(2)), sequentially escalating each drug. CAI preceded paclitaxel by one week to permit pharmacokinetic analysis. Patients were assessed for toxicity, pharmacokinetics and disease outcome.

CONCLUSIONS

The MTD of the combination of CAI and paclitaxel is 250 mg daily and 200 mg/m(2) q3weeks, respectively. The combination is tolerable and has potential antitumor activity.

A novel method for the separation and determination of non-encapsulated pyrene in plasma and its application in pharmacokinetic studies of pyrene-loaded MPEG-PLA based nanoparticles

During the pharmacokinetic processes of nanoparticles, encapsulated drugs and non-encapsulated (free and protein-bound) drugs are the drug forms existing in plasma. It is necessary and important to measure the bioavailable drug concentration, namely, the non-encapsulated drug concentration, in pharmacokinetic studies of nanoparticles. A new method using liquid-liquid extraction was first developed and validated for the separate determination of non-encapsulated drugs in plasma. The method was based on the significant difference of extractability between non-encapsulated and encapsulated drugs, and used n-heptane as an extractant. Satisfactory results were obtained with a good linear relationship in the range of 1-80 ng ml(-1) (r = 0.9999) and good reproducibility with coefficients of variation (CVs) less than 10% of intra- and inter-day evaluation results, and the accuracy of intra- and inter-day evaluation results ranged from 92.4% to 109.2%. The extraction recovery was stable in the range 68.6%-75.6%. The developed method had been proven to be an ideal method with high specificity and sensitivity, and the method is simple and rapid. The method described herein has been successfully applied for pharmacokinetic studies in female Wistar rats after the administration of a 5 mg equivalent pyrene kg(-1) dose of pyrene-loaded nanoparticles. The results showed that the non-encapsulated drug had a different pharmacokinetic behavior compared with that of the total drug.

Randomized crossover pharmacokinetic study of solvent-based paclitaxel and nab-paclitaxel

PURPOSE

Abraxane (ABI-007) is a 130-nm albumin-bound (nab) particle formulation of paclitaxel, devoid of any additional excipients. We hypothesized that this change in formulation alters the systemic disposition of paclitaxel compared with conventional solvent-based formulations (sb-paclitaxel; Taxol), and leads to improved tolerability of the drug.

PATIENTS AND METHODS

Patients with malignant solid tumors were randomized to receive the recommended single-agent dose of nab-paclitaxel (260 mg/m(2) as a 30-minute infusion) or sb-paclitaxel (175 mg/m(2) as a 3-hour infusion). After cycle 1, patients crossed over to the alternate treatment. Pharmacokinetic studies were carried out for the first cycle of sb-paclitaxel and the first two cycles of nab-paclitaxel.

RESULTS

Seventeen patients were treated, with 14 receiving at least one cycle each of nab-paclitaxel and sb-paclitaxel. No change in nab-paclitaxel pharmacokinetics was found between the first and second cycles (P = 0.95), suggesting limited intrasubject variability. Total drug exposure was comparable between the two formulations (P = 0.55) despite the dose difference. However, exposure to unbound paclitaxel was significantly higher after nab-paclitaxel administration, due to the increased free fraction (0.063 +/- 0.021 versus 0.024 +/- 0.009; P < 0.001).

CONCLUSION

This study shows that paclitaxel disposition is subject to considerable variability depending on the formulation used. Because systemic exposure to unbound paclitaxel is likely a driving force behind tumoral uptake, these findings explain, at least in part, previous observations that the administration of nab-paclitaxel is associated with augmented antitumor efficacy compared with solvent-based paclitaxel.