The effect of different doses of cyclosporin A on the systemic exposure of orally administered paclitaxel

Oral Conventional Synthetic Disease-Modifying Antirheumatic Drugs with Antineoplastic Potential: a Review

There is an increasing trend of malignancy worldwide. Disease-modifying antirheumatic drugs (DMARDs) are the cornerstones for the treatment of immune-mediated inflammatory diseases (IMIDs), but risk of malignancy is a major concern for patients receiving DMARDs. In addition, many IMIDs already carry higher background risks of neoplasms. Recently, the black box warning of malignancies has been added for Janus kinase inhibitors. Also, the use of biologic DMARDs in patients with established malignancies is usually discouraged owing to exclusion of such patients in pivotal studies and, hence, lack of evidence. In contrast, some conventional synthetic DMARDs (csDMARDs) have been reported to show antineoplastic properties and can be beneficial for patients with cancer. Among the csDMARDs, chloroquine and hydroxychloroquine have been the most extensively studied, and methotrexate is an established chemotherapeutic agent. Even cyclosporine A, a well-known drug associated with cancer risk, can potentiate the effect of some chemotherapeutic agents. We review the possible mechanisms behind and clinical evidence of the antineoplastic activities of csDMARDs, including chloroquine and hydroxychloroquine, cyclosporine, leflunomide, mycophenolate mofetil, mycophenolic acid, methotrexate, sulfasalazine, and thiopurines. This knowledge may guide physicians in the choice of csDMARDs for patients with concurrent IMIDs and malignancies.

Oral bioavailability of a novel paclitaxel formulation (Genetaxyl) administered with cyclosporin A in cancer patients

The formulation excipient Cremophor EL (CrEL) is known to limit the absorption of oral paclitaxel given together with cyclosporin A. We hypothesized that the use of oral Genetaxyl, a paclitaxel formulation containing only 20% CrEL would have an improved oral bioavailability. Cohorts of six patients were treated with oral Genetaxyl at a dose of 60, 120, or 180 mg/m2 and 10 mg/kg of oral cyclosporin A in cycle 1. In cycle 2, patients received intravenous (i.v.) Genetaxyl (175 mg/m2, 3-h infusion). Three additional patients received one dose of generic i.v. paclitaxel (Genaxol, containing 50% CrEL; 175mg/m2, 3-h infusion). The median area under the plasma concentration-time curve (AUC) and peak concentration of total paclitaxel following i.v. Genetaxyl were lower than those for i.v. Genaxol, as a result of significantly increased clearance (P = 0.017), and the AUC ratio for unbound to total paclitaxel for i.v. Genetaxyl was about two times higher than that for i.v. Genaxol (P = 0.0077). After oral administration of Genetaxyl at doses of 60, 120, and 180 mg/m2, the median total paclitaxel AUCs were 1.29, 1.60, and 1.85 microg x h/ml, respectively, suggesting a less than proportional increase in systemic exposure with increasing doses. The corresponding median values for the apparent bioavailability of oral Genetaxyl were similar when compared with i.v. Genetaxyl, when calculated either on the basis of data for total paclitaxel (30.1%) or unbound paclitaxel (30.6%).

Arsenite-induced mitotic death involves stress response and is independent of tubulin polymerization

Arsenite, a known mitotic disruptor, causes cell cycle arrest and cell death at anaphase. The mechanism causing mitotic arrest is highly disputed. We compared arsenite to the spindle poisons nocodazole and paclitaxel. Immunofluorescence analysis of alpha-tubulin in interphase cells demonstrated that, while nocodazole and paclitaxel disrupt microtubule polymerization through destabilization and hyperpolymerization, respectively, microtubules in arsenite-treated cells remain comparable to untreated cells even at supra-therapeutic concentrations. Immunofluorescence analysis of alpha-tubulin in mitotic cells showed spindle formation in arsenite- and paclitaxel-treated cells but not in nocodazole-treated cells. Spindle formation in arsenite-treated cells appeared irregular and multi-polar. gamma-tubulin staining showed that cells treated with nocodazole and therapeutic concentrations of paclitaxel contained two centrosomes. In contrast, most arsenite-treated mitotic cells contained more than two centrosomes, similar to centrosome abnormalities induced by heat shock. Of the three drugs tested, only arsenite treatment increased expression of the inducible isoform of heat shock protein 70 (HSP70i). HSP70 and HSP90 proteins are intimately involved in centrosome regulation and mitotic spindle formation. HSP90 inhibitor 17-DMAG sensitized cells to arsenite treatment and increased arsenite-induced centrosome abnormalities. Combined treatment of 17-DMAG and arsenite resulted in a supra-additive effect on viability, mitotic arrest, and centrosome abnormalities. Thus, arsenite-induced abnormal centrosome amplification and subsequent mitotic arrest is independent of effects on tubulin polymerization and may be due to specific stresses that are protected against by HSP90 and HSP70.

Polymeric micelles in oral chemotherapy

Oral administration of anticancer agents is preferred by patients for its convenience and potential for use in outpatient and palliative setting. In addition, oral administration facilitates a prolonged exposure to the cytotoxic agents. Enhancement of bioavailability of emerging cytotoxic agents is a pre-requisite for successful development of oral modes of cancer treatment. Over the last decade, our studies have focused specifically on the utilization of large (MW>10(5)) and non-degradable polymers in oral chemotherapy. A family of block-graft copolymers of the poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) Pluronic(R) polyethers and poly(acrylic acid) (PAA) bound by carbon-carbon bonds emerged, wherein both polymeric components are generally recognized as safe. Animal studies with Pluronic-PAA copolymers demonstrated that these molecules are excreted when administered orally and do not absorb into the systemic circulation. The Pluronic-PAA copolymers are surface-active and self-assemble, at physiological pH, into intra- and intermolecular micelles with hydrophobic cores of dehydrated PPO and multilayered coronas of hydrophilic PEO and partially ionized PAA segments. These micelles efficiently solubilize hydrophobic drugs such as paclitaxel and steroids and protect molecules such as camptothecins from the hydrolytic reactions. High surface activity of the Pluronic-PAA copolymers in water results in interactions with cell membranes and suppression of the membrane pumps such as P-glycoprotein. The ionizable carboxyls in the micellar corona facilitate mucoadhesion that enhances the residence time of the micelles and solubilized drugs in the gastrointestinal tract. Large payloads of the Pluronic-PAA micelles with weakly basic and water-soluble drugs such as doxorubicin and its analogs, mitomycin C, mitoxantrone, fluorouracil, and cyclophosphamide are achieved through electrostatic interactions with the micellar corona. Mechanical and physical properties of the Pluronic-PAA powders, blends, and micelles allow for formulation procedures where an active is simply dispersed into an aqueous Pluronic-PAA micellar formulation followed by optional lyophilization and processing into a ready dosage form. We review a number of in vivo and in vitro experiments demonstrating that that the oral administration of the cytotoxics formulated with the Pluronic-PAA copolymer micelles results in enhanced drug bioavailability.

Novel paclitaxel formulations for oral application: a phase I pharmacokinetic study in patients with solid tumours

PURPOSE

To explore the pharmacokinetics (PKs) of paclitaxel and two major metabolites after three single oral administrations of a novel drinking solution and two capsule formulations in combination with cyclosporin A (CsA) in patients with advanced cancer. Moreover, the tolerability and safety of the formulations was studied. In addition, single nucleotide polymorphisms in the multidrug resistance (MDR1) gene were determined.

PATIENTS AND METHODS

Ten patients were enrolled and randomized to receive CsA 10 mg/kg followed by oral paclitaxel 180 mg given as (1) drinking solution (formulation 1), (2) capsule formulation 2B, and (3) capsule formulation 2C on day 1, 8, or 15.

RESULTS

The median C (max) of paclitaxel was 0.42 (0.23-0.96), 0.48 (0.08-0.59), and 0.39 (0.11-1.03) microg/ml and the area under the plasma concentration-time curve was 2.83 (1.69-5.12), 2.01 (1.57-3.04), and 2.67 (1.05-3.61) mug h/ml following administration of formulations 1, 2B, and 2C, respectively. The novel formulations were tolerated after single oral dose without causing relevant gastrointestinal or haematological toxicity.

CONCLUSIONS

The PK and metabolism of paclitaxel were comparable between the oral formulations co-administered with CsA.

Phase II and pharmacological study of oral paclitaxel (Paxoral) plus ciclosporin in anthracycline-pretreated metastatic breast cancer

Paclitaxel is an important chemotherapeutic agent for breast cancer. Paclitaxel has high affinity for the P-glycoprotein (P-gp) (drug efflux pump) in the gastrointestinal tract causing low and variable oral bioavailability. Previously, we demonstrated that oral paclitaxel plus the P-gp inhibitor ciclosporin (CsA) is safe and results in adequate exposure to paclitaxel. This study evaluates the activity, toxicity and pharmacokinetics of paclitaxel combined with CsA in breast cancer patients. Patients with measurable metastatic breast cancer were given oral paclitaxel 90 mg m⁻² combined with CsA 10 mg kg⁻¹ (30 min prior to each paclitaxel administration) twice on one day, each week. Twenty-nine patients with a median age of 50 years were entered. All patients had received prior treatments, 25 had received prior anthracycline-containing chemotherapy and 19 had three or more metastatic sites. Total number of weekly administrations was 442 (median: 15/patient) and dose intensity of 97 mg m⁻² week⁻¹. Most patients needed treatment delay and 17 patients needed dose reductions. In intention to treat analysis, the overall response rate was 52%, the median time to progression was 6.5 months and overall survival was 16 months. The pharmacokinetics revealed moderate inter- and low intrapatient variability. Weekly oral paclitaxel, combined with CsA, is active in patients with advanced breast cancer.

A novel self-microemulsifying formulation of paclitaxel for oral administration to patients with advanced cancer

To explore the parmacokinetics, safety and tolerability of paclitaxel after oral administration of SMEOF#3, a novel Self-Microemulsifying Oily Formulation, in combination with cyclosporin A (CsA) in patients with advanced cancer. Seven patients were enrolled and randomly assigned to receive oral paclitaxel (SMEOF#3) 160 mg+CsA 700 mg on day 1, followed by oral paclitaxel (Taxol®) 160 mg+CsA 700 mg on day 8 (group I) or vice versa (group II). Patients received paclitaxel (Taxol®) 160 mg as 3-h infusion on day 15. The median (range) area under the plasma concentration–time curve of paclitaxel was 2.06 (1.15–3.47) μg h ml⁻¹ and 1.97 (0.58–3.22) μg h ml⁻¹ after oral administration of SMEOF#3 and Taxol®, respectively, and 4.69 (3.90–6.09) μg h ml⁻¹ after intravenous Taxol®. Oral SMEOF#3 resulted in a lower median T_max of 2.0 (0.5–2.0) h than orally applied Taxol® (T_max=4.0 (0.8–6.1) h, P=0.02). The median apparent bioavailability of paclitaxel was 40 (19–83)% and 55 (9–70)% for the oral SMEOF#3 and oral Taxol® formulation, respectively. Oral paclitaxel administered as SMEOF#3 or Taxol® was safe and well tolerated by the patients. Remarkably, the SMEOF#3 formulation resulted in a significantly lower T_max than orally applied Taxol®, probably due to the excipients in the SMEOF#3 formulation resulting in a higher absorption rate of paclitaxel.

Phase I and pharmacokinetic evaluation of the combination of orally administered docetaxel and cyclosporin A in tumor-bearing dogs

OBJECTIVE

To determine the maximum tolerated dose and characterize the pharmacokinetic disposition of an orally administered combination of docetaxel and cyclosporin A (CSA) in dogs with tumors.

ANIMALS

16 client-owned dogs with metastatic or advanced-stage refractory tumors.

PROCEDURES

An open-label, dose-escalation, single-dose, phase I study of docetaxel administered in combination with a fixed dose of CSA was conducted. Docetaxel (at doses of 1.5, 1.625, or 1.75 mg/kg) and CSA (5 mg/kg) were administered concurrently via gavage twice during a 3-week period. Plasma docetaxel concentrations were quantified by use of high-performance liquid chromatography, and pharmacokinetic disposition was characterized by use of noncompartmental analysis. Dogs' clinical signs and results of hematologic and biochemical analyses were monitored for evidence of toxicosis.

RESULTS

No acute hypersensitivity reactions were observed after oral administration of docetaxel. Disposition of docetaxel was dose independent over the range evaluated, and pharmacokinetic variables were similar to those reported in previous studies involving healthy dogs, with the exception that values for clearance were significantly higher in the dogs reported here. The maximum tolerated dose of docetaxel was 1.625 mg/kg. Gastrointestinal signs of toxicosis were dose limiting.

CONCLUSIONS AND CLINICAL RELEVANCE

The absence of myelosuppression suggested that the docetaxel-CSA combination may be administered more frequently than the schedule used. Further studies are warranted to evaluate combination treatment administered on a biweekly schedule in dogs with epithelial tumors.

A pharmacokinetic and safety study of a novel polymeric paclitaxel formulation for oral application

PURPOSE

To investigate the pharmacokinetics, safety, and tolerability of a new oral formulation of paclitaxel containing the polymer polyvinyl acetate phthalate in patients with advanced solid tumors.

PATIENTS AND METHODS

A total of six patients received oral paclitaxel as single agent given as a single dose of 100 mg on day 1, oral paclitaxel 100 mg in combination with cyclosporin A (CsA) 10 mg/kg both given as a single dose on day 8, and i.v. paclitaxel (Taxol) 100 mg as a 3-h infusion on day 15.

RESULTS

The AUC (mean +/- standard deviation) values of paclitaxel after oral administration without CsA and with CsA were 476 +/- 254 and 967 +/- 779 ng/ml h, respectively. T (max) was 4.0 +/- 0.9 h after oral paclitaxel without CsA, and 6.0 +/- 3.1 h after oral paclitaxel with CsA. The mean AUC after oral administration as single agent was 13% of the AUC after i.v. administration of paclitaxel, and increased to 26% after co-administration with CsA. No haematological toxicities were observed, and only mild (CTC-grade 1 and 2) non-hematological toxicities occurred after oral intake of paclitaxel with or without CsA.

CONCLUSION

The AUC of the new polymeric paclitaxel formulation increased a factor 2 in combination with CsA, which confirms that CsA co-administration can also improve exposure to paclitaxel after oral administration of a polymeric formulation. Because of the delayed release of paclitaxel from this formulation, we hypothesize that a split-dose regimen of CsA where it is administered before and after paclitaxel administration will further increase the systemic exposure to paclitaxel up to therapeutic levels. The formulation was well tolerated at the dose of 100 mg without induction of severe toxicities.

Effects of particle size and surface coating on cellular uptake of polymeric nanoparticles for oral delivery of anticancer drugs

This study evaluated cellular uptake of polymeric nanoparticles by using Caco-2 cells, a human colon adenocarcinoma cell line, as an in vitro model with the aim to apply nanoparticles of biodegradable polymers for oral chemotherapy. The feasibility was demonstrated by showing the localization and quantification of the cell uptake of fluorescent polystyrene nanoparticles of standard size and poly(lactic-co-glycolic acid) (PLGA) nanoparticles coated with polyvinyl alcohol (PVA) or vitamin E TPGS. Coumarin-6 loaded PLGA nanoparticles were prepared by a modified solvent extraction/evaporation method and characterized by laser light scattering for size and size distribution, scanning electron microscopy (SEM) for surface morphology, zeta-potential for surface charge, and spectrofluorometry for fluorescent molecule release from the nanoparticles. The effects of particle size and particle surface coating on the cellular uptake of the nanoparticles were quantified by spectrofluorometric measurement. Cellular uptake of vitamin E TPGS-coated PLGA nanoparticles showed 1.4 folds higher than that of PVA-coated PLGA nanoparticles and 4-6 folds higher than that of nude polystyrene nanoparticles. Images of confocal laser scanning microscopy, cryo-SEM and transmission electron microscopy clearly evidenced the internalization of nanoparticles by the Caco-2 cells, showing that surface modification of PLGA nanoparticles with vitamin E TPGS notably improved the cellular uptake. It is highly feasible for nanoparticles of biodegradable polymers to be applied to promote oral chemotherapy.

Population pharmacokinetics of orally administered paclitaxel formulated in Cremophor EL

AIM

The vehicle Cremophor EL (CrEL) has been shown to impair the absorption of paclitaxel by micellar entrapment of the drug in the gastrointestinal tract. The goal of this study was to develop a semimechanistic population pharmacokinetic model to study the influence of CrEL on the oral absorption of paclitaxel.

METHOD

Paclitaxel plasma-concentration time profiles were available from 55 patients (M:F, 17 : 38; total 67 courses; 797 samples), receiving paclitaxel orally once or twice daily (dose range 60-360 mg m(-2)) together with 12-15 mg kg(-1) cyclosporin A. A population pharmacokinetic model was developed using the nonlinear mixed effect modelling program NONMEM.

RESULTS

After absorption, paclitaxel pharmacokinetics were best described using a two-compartment model with linear distribution from the central compartment into a peripheral compartment and first-order elimination. Paclitaxel in the gastrointestinal tract was modelled as free fraction or bound to CrEL, with only the free fraction available for absorption into the central compartment. The equilibrium between free and bound paclitaxel was influenced by the concentration of CrEL present in the gastrointestinal tract. The concentration of CrEL in the gastrointestinal tract decreased with time with a first order rate constant of 1.73 h(-1). The bioavailability of paclitaxel was independent of the dose and of CrEL. Estimated apparent paclitaxel clearance and volume of distribution were 127 l h(-1) and 409 l, respectively. Large interpatient variability was observed. Covariate analysis did not reveal significant relationships with any of the pharmacokinetic parameters.

CONCLUSION

A pharmacokinetic model was developed that described the pharmacokinetics of orally administered paclitaxel. CrEL strongly influenced paclitaxel absorption from the gastrointestinal tract resulting in time-dependent but no significant dose-dependent absorption over the examined dose range studied.

Improvement of oral drug treatment by temporary inhibition of drug transporters and/or cytochrome P450 in the gastrointestinal tract and liver: an overview

The oral bioavailability of many cytotoxic drugs is low and/or highly variable. This can be caused by high affinity for drug transporters and activity of metabolic enzymes in the gastrointestinal tract and liver. In this review, we will describe the main involved drug transporters and metabolic enzymes and discuss novel methods to improve oral treatment of affected substrate drugs. Results of preclinical and clinical phase I and II studies will be discussed in which affected substrate drugs, such as paclitaxel, docetaxel, and topotecan, are given orally in combination with an inhibitor of drug transport or drug metabolism. Future randomized studies will, hopefully, confirm that this strategy for oral treatment is at least as equally effective and safe as standard intravenous administration of these drugs.

Weekly oral paclitaxel as first-line treatment in patients with advanced gastric cancer

BACKGROUND

Pharmacokinetic study has shown that co-administration of cyclosporin A (CsA), which acts as a P-glycoprotein (P-gp) and CYP-3A blocker, resulted in an 8-fold increase in the systemic exposure of oral paclitaxel. Two doses of oral paclitaxel on 1 day in combination with CsA resulted in higher systemic exposure than single dose administration.

PATIENTS AND METHODS

In this phase II study, chemonaïve patients with advanced gastric cancer received oral paclitaxel weekly in two doses of 90 mg/m(2) on the same day; CsA (10 mg/kg) was given 30 min before each dose of oral paclitaxel.

RESULTS

In 25 patients, the main toxicities were: nausea CTC grade 2/3, 10 patients (40%); vomiting grade 2/3, 4 patients (20%); diarrhea grade 2/3, 6 patients (24%); neutropenia grade 3/4, 5 patients (20%). In the 24 evaluable patients, eight partial responses were observed, resulting in an overall response rate (ORR) of 33% [95% confidence interval (CI) 18% to 52%]. Eleven patients had stable disease (46%) and 5 patients showed progressive disease (21%). The ORR in the total population was 32% (95% CI 17% to 50%). The median time to progression was 16 weeks (95% CI 9-22). Pharmacokinetic analyses revealed that the mean area under the plasma concentration-time curve (AUC) of orally administered paclitaxel (+/- standard deviation) was 3757.6 +/- 939.4 ng.h/ml in week 1 and 3928.4 +/- 1281 ng.h/ml in week 2. The intrapatient variability in the AUC was 12%.

CONCLUSIONS

Oral paclitaxel in combination with CsA is both active and safe in chemonaïve patients with advanced gastric cancer. Toxicities were mainly gastrointestinal.

Phase II and pharmacologic study of weekly oral paclitaxel plus cyclosporine in patients with advanced non-small-cell lung cancer

PURPOSE

A phase II study was performed to assess the efficacy and toxicity of oral cyclosporine (CsA) plus paclitaxel in advanced non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Chemotherapy-naive or previously treated patients (one regimen) with measurable disease and World Health Organization performance status <or= 2 were eligible. Oral paclitaxel was given weekly in a dose of 90 mg/m(2) bid. CsA (10 mg/kg) was given 30 minutes before each dose of oral paclitaxel.

RESULTS

Twenty-six patients with a median age of 54 years (range, 32 to 77 years) were entered onto this study. Eighteen patients (69%) had received one prior chemotherapy regimen. The most frequently recorded toxicities were as follows: National Cancer Institute common toxicity criteria grade 3 neutropenia, eight patients (31%); grade 4, six patients (23%); grade 4 febrile neutropenia, three patients (12%); grade 2/3 neurotoxicity, three patients (12%); and grade 2 nail changes, four patients (15%). The overall response rate (ORR) of the 23 assessable patients was 26% (95% confidence interval [CI], 10% to 48%). In the intention-to-treat population, the ORR was 23% (95% CI, 9% to 44%). The median time to progression was 3.5 months (95% CI, 1.2 to 3.9 months), and median overall survival was 6.0 months (95% CI, 2.3 months to not available). Pharmacokinetics revealed that the mean area under the concentration-time curve (AUC) of oral paclitaxel was 5.0 +/- 2.3 micro mol/L/h in week 1 and 4.6 +/- 2.0 micro mol/L/h in week 2, with interpatient variabilities (coefficient of variation [%CV]) of 45% and 42%, respectively. The intrapatient variability (%CV) of the AUC was 14.5%.

CONCLUSION

Oral paclitaxel plus CsA is active and safe in advanced NSCLC, including in patients previously treated with chemotherapy.