The use of oral cytotoxic and cytostatic drugs in cancer treatment

Development and Challenges of Diclofenac-Based Novel Therapeutics: Targeting Cancer and Complex Diseases

Simple Summary

Diclofenac is a widely used drug for its anti-inflammatory and pain alleviating properties. This review summarizes the current understanding about the drug diclofenac. The potential applications of diclofenac beyond its well-known anti-inflammatory properties for other diseases such as cancer are discussed, along with existing limitations.

Abstract

Diclofenac is a highly prescribed non-steroidal anti-inflammatory drug (NSAID) that relieves inflammation, pain, fever, and aches, used at different doses depending on clinical conditions. This drug inhibits cyclooxygenase-1 and cyclooxygenase-2 enzymes, which are responsible for the generation of prostaglandin synthesis. To improve current diclofenac-based therapies, we require new molecular systematic therapeutic approaches to reduce complex multifactorial effects. However, the critical challenge that appears with diclofenac and other drugs of the same class is their side effects, such as signs of stomach injuries, kidney problems, cardiovascular issues, hepatic issues, and diarrhea. In this article, we discuss why defining diclofenac-based mechanisms, pharmacological features, and its medicinal properties are needed to direct future drug development against neurodegeneration and imperfect ageing and to improve cancer therapy. In addition, we describe various advance molecular mechanisms and fundamental aspects linked with diclofenac which can strengthen and enable the better designing of new derivatives of diclofenac to overcome critical challenges and improve their applications.

Boosting the oral bioavailability of anticancer drugs through intentional drug-drug interactions

Oral anticancer drugs suffer from significant variability in pharmacokinetics and pharmacodynamics partially due to limited bioavailability. The limited bioavailability of anticancer drugs is due to both pharmaceutical limitations and physiological barriers. Pharmacokinetic boosting is a strategy to enhance the oral bioavailability of a therapeutic drug by inhibiting physiological barriers through an intentional drug-drug interaction (DDI). This type of strategy has proven effective across several therapeutic indications including anticancer treatment. Pharmacokinetic boosting could improve anticancer drugs lacking or with otherwise unacceptable oral formulations through logistic, economic, pharmacodynamic and pharmacokinetic benefits. Despite these benefits, pharmacokinetic boosting strategies could result in unintended DDIs and are only likely to benefit a limited number of targets. Highlighting this concern, pharmacokinetic boosting has mixed results depending on the boosted drug. While pharmacokinetic boosting did not significantly improve certain drugs, it has resulted in the commercial approval of boosted oral formulations for other drugs. Pharmacokinetic boosting to improve oral anticancer therapy is an expanding area of research that is likely to improve treatment options for cancer patients.

Phase II study of DHP107 (oral paclitaxel) in the first-line treatment of HER2-negative recurrent or metastatic breast cancer (OPTIMAL study)

Background:

Standard intravenous (IV) paclitaxel is associated with hypersensitivity/toxicity. Alternative IV formulations have improved tolerability but still require frequent hospital visits and IV infusion. DHP107 is a novel oral formulation of paclitaxel that is approved in South Korea for the treatment of gastric cancer.

Methods:

This multicenter, phase II study using a Simon’s two-stage design investigated the efficacy and safety of DHP107 200 mg/m² administered orally twice daily on days 1, 8, and 15 every 4 weeks for the first-line treatment of recurrent or metastatic HER2-negative breast cancer.

Results:

Thirty-six patients were enrolled and 31 were assessable for efficacy. Patient median age was 57 years (range = 34–81) and 11 (31%) had triple-negative disease. A median of seven cycles (range = 1–28) of DHP107 was administered. Objective response rate was 55% (17 patients), all partial responses, according to the investigator’s decision and independent central review (ICR), and 44% (4/9 patients) in those with triple-negative disease. Disease control rate (partial response and stable disease) was 74% (23 patients) according to the investigator’s decision and ICR. In the intention-to-treat (ITT) population of all enrolled participants, the objective response rate was 50% (18/36 patients). Median progression-free survival was 8.9 months [95% confidence interval [CI]: 5.2–12.3) and median time to treatment failure was 8.0 months (95% CI: 4.2–10.0). DHP107 had an acceptable toxicity profile. All patients experienced treatment-emergent adverse events; the most common adverse events were decreased neutrophil count (81% all grades and 78% grade ⩾ 3) followed by peripheral sensory neuropathy (61% all grades and 8% grade 3). However, there was no febrile neutropenia or sepsis.

Conclusion:

DHP107 showed promising efficacy and acceptable tolerability in this phase II study and is currently being investigated in the OPTIMAL phase III study (NCT03315364).

Trial registration:

This trial was registered with ClinicalTrials.gov identifier: NCT03315364.

Design and Characterization of Maltoheptaose-b-Polystyrene Nanoparticles, as a Potential New Nanocarrier for Oral Delivery of Tamoxifen

Tamoxifen citrate (TMC), a non-steroidal antiestrogen drug used for the treatment of breast cancer, was loaded in a block copolymer of maltoheptaose-b-polystyrene (MH-b-PS) nanoparticles, a potential drug delivery system to optimize oral chemotherapy. The nanoparticles were obtained from self-assembly of MH-b-PS using the standard and reverse nanoprecipitation methods. The MH-b-PS@TMC nanoparticles were characterized by their physicochemical properties, morphology, drug loading and encapsulation efficiency, and release kinetic profile in simulated intestinal fluid (pH 7.4). Finally, their cytotoxicity towards the human breast carcinoma MCF-7 cell line was assessed. The standard nanoprecipitation method proved to be more efficient than reverse nanoprecipitation to produce nanoparticles with small size and narrow particle size distribution. Moreover, tamoxifen-loaded nanoparticles displayed spherical morphology, a positive zeta potential and high drug content (238.6 ± 6.8 µg mL-1) and encapsulation efficiency (80.9 ± 0.4 %). In vitro drug release kinetics showed a burst release at early time points, followed by a sustained release profile controlled by diffusion. MH-b-PS@TMC nanoparticles showed higher cytotoxicity towards MCF-7 cells than free tamoxifen citrate, confirming their effectiveness as a delivery system for administration of lipophilic anticancer drugs.

Anthracycline-containing regimens or taxane versus S-1 as first-line chemotherapy for metastatic breast cancer

BACKGROUND

We have previously demonstrated S-1 is non-inferior to taxane with respect to overall survival as first-line chemotherapy for HER2-negative metastatic breast cancer. We aimed to confirm whether S-1 is also non-inferior to anthracycline-containing regimens in the same setting.

METHODS

We conducted an open-label, non-inferiority, Phase 3 study. Individuals who had HER2-negative metastatic breast cancer, had received no chemotherapy for advanced disease and had endocrine therapy resistance, were randomly assigned to the anthracycline-containing regimens or S-1. The primary endpoint was overall survival. A pre-planned combined analysis of our two Phase 3 studies was also carried out.

RESULTS

We enrolled 230 patients (anthracycline, n = 115; S-1, n = 115). Median overall survival was 30.1 months (95% CI 24.9-35.8) with the S-1 group and 33.7 months (95% CI 25.5-36.9) with the anthracycline group. The HR for the anthracycline group was 1.09 (95% CI 0.80-1.48). The combined analysis constituted 814 patients (395 assigned to standard treatment (anthracycline or taxane); 419 assigned to S-1). Median overall survival was 36.3 months in the standard treatment group and 32.7 months in the S-1 group. S-1 was non-inferior to standard treatment in terms of overall survival (HR 1.06 (95% CI 0.90-1.25); P non-inferiority = 0.0062).

CONCLUSIONS

S-1 could be considered a new treatment option for first-line chemotherapy for patients with HER2-negative metastatic breast cancer.

CLINICAL TRIAL REGISTRATION

The University Hospital Medical Information Network, Japan: UMIN000005449. This trial was registered on 15 April, 2011.

Probing the interactions of novel europium coordination complexes with serum albumin

Molecular interactions between novel europium coordination complexes (EC) possessing superior cytotoxic activity and bovine serum albumin (BSA), the most prominent representative of plasma proteins, were assessed using fluorescence spectroscopy and molecular docking techniques. Cumulative results from fluorescent probe binding, fluorescence quenching and Förster resonance energy transfer studies revealed that the europium complexes V4 and V8 do not perturb the BSA structure, while V3, V5, and V7 induce partial unfolding of the polypeptide chain. Molecular docking studies coupled with analysis of the three-dimensional structure of the BSA-EC complexes showed that V4 and V8 reside in the vicinity of the protein IIA subdomain (Sudlow's site I), while V3, V5 and V5 were localized predominantly in the BSA IIIA subdomain (Sudlow's site II). Due to the intactness of the protein structure upon association with V4 and V8, these compounds may be recommended for further evaluation as potential antineoplastic agents.

Phase II study of sequential S-1 and cyclophosphamide therapy in patients with metastatic breast cancer

Background

S-1 and cyclophosphamide (CPA) can be given orally, and their combination may have great potential for treating metastatic breast cancer (MBC). A phase I study of sequential S-1 and CPA therapy was conducted in patients with MBC; the recommended doses that were determined for this regimen were 80 mg/m²/day for S-1 and 100 mg/m²/day for CPA. We then conducted a phase II study of this oral S-1 and CPA regimen.

Methods

This was a single-arm, open-label, single-center prospective phase II study to evaluate the efficacy of a sequential S-1 and CPA regimen for MBC. S-1 was administered orally 2×/day for 14 consecutive days, and then CPA was administered orally 2×/day for 14 consecutive days in a repeating 4-week cycle (S-1 for 2 weeks, CPA for 2 weeks). The primary endpoint was the overall response rate (ORR). Secondary endpoints included the overall survival (OS), progression-free survival (PFS), clinical benefit rate (CBR) and safety.

Results

Thirty-six patients were enrolled in this study. The overall response was complete response in 0 (0%), partial response in 12 (33.3%), stable disease in 12 (33.3%), and progressive disease in 11 (30.1%) patients. The ORR was 33.3% (12/36). The CBR was 66.7% (24/36). The median PFS was 9.5 months (95%CI: 7.8–12.6 months). The median OS was 20.2 months (95%CI: 15.0–25.4 months) Grade 3/4 adverse events included leukopenia in seven patients (19.4%). Dose reductions because of adverse events occurred in 12 patients (33.3%). There was no treatment-related mortality.

Conclusion

The combination of sequential therapy with S-1 and CPA was tolerable and had efficacy with good disease control. Sequential therapy with S-1 and CPA may be a feasible new treatment option for patients with MBC; however, further study is warranted to explore the efficacy of this therapy.

Trial registration

JRCT, JRCTs031180296. Registered 2 December 2019 – Retrospectively registered.

Anticancer and radiosensitizing effects of the cyclin-dependent kinase inhibitors, AT7519 and SNS‑032, on cervical cancer

Cyclin-dependent kinases (CDK) are considered to be potential targets of anticancer drugs that can interrupt the uncontrolled division of cancer cells. In this study, we selected two selective CDK inhibitors, AT7519 and SNS‑032, from current clinical trials and examined their anticancer and radiosensitizing effects in a cervical cancer model. SNS‑032 was found to be more potent than AT7519, with a lower half maximal inhibitory concentration (IC50) value. Both AT7519 and SNS‑032 induced the apoptosis, premature senescence and cytostasis of cervical cancer cells, which led to the attenuation of tumor growth in vivo. Moreover, using these CDK inhibitors together with radiation synergistically inhibited tumor growth in a human xenograft tumor model. The concomitant activation of the p53 tumor suppressor and the suppression of cell cycle checkpoint responses mediated by Chk1 led to the cytostasis of cervical cancer cells. Finally, AT7519 and SNS‑032 inhibited cancer cell migration, invasion and angiogenesis in vitro, and suppressed lung metastases in a spontaneous metastasis model. On the whole, the findings of this study indicate that the utilization of AT7519 and SNS‑032 as part of an adjuvant treatment may help control cervical cancer progression.

Determination of Degradation Kinetics and Effect of Anion Exchange Resin on Dissolution of Novel Anticancer Drug Rigosertib in Acidic Conditions

Rigosertib is a novel anticancer drug in clinical development by Onconova therapeutics, Inc. Currently, it is in pivotal phase III clinical trials for myelodysplastic syndrome (MDS) patients. Chemically, it is a sodium salt of weak acid with low solubility in lower pH solutions. In the preliminary studies, it was found that rigosertib is unstable in acidic conditions and forms multiple degradation products. In this research, drug degradation kinetics of rigosertib were studied in acidic conditions. Rigosertib follows pseudo-first-order general acid catalysis reaction. Cholestyramine, which is a strong anion exchange resin, was used to form complex with drug to improve stability and dissolution in acidic conditions. Drug complex with cholestyramine showed better dissolution profile compared to drug alone. Effect of polyethylene glycol was investigated on the release of drug from the drug resin complex. Polyethylene glycol further improved dissolution profile by improving drug solubility in acidic medium.

Galeterone and its analogs inhibit Mnk-eIF4E axis, synergize with gemcitabine, impede pancreatic cancer cell migration, invasion and proliferation and inhibit tumor growth in mice

Survival rate for pancreatic cancer (pancreatic ductal adenocarcinoma, PDAC) is poor, with about 80% of patients presenting with the metastatic disease. Gemcitabine, the standard chemotherapeutic agent for locally advanced and metastatic PDAC has limited efficacy, attributed to innate/acquired resistance and activation of pro-survival pathways. The Mnk1/2-eIF4E and NF-κB signaling pathways are implicated in PDAC disease progression/metastasis and also associated with gemcitabine-induced resistance in PDAC. Galeterone (gal), a multi-target, agent in phase III clinical development for prostate cancer has also shown effects on the aforementioned pathways. We show for the first time, that gal/analogs (VNPT55, VNPP414 and VNPP433-3β) profoundly inhibited cell viability of gemcitabine-naive/resistance PDAC cell lines and strongly synergized with gemcitabine in gemcitabine-resistant PDAC cells. In addition, to inducing G1 cell cycle arrest, gal/analogs induced caspase 3-mediated cell-death of PDAC cells. Gal/analogs caused profound downregulation of Mnk1/2, peIF4E and NF-κB (p-p65), metastatic inducing factors (N-cadherin, MMP-1/-2/-9, Slug, Snail and CXCR4) and putative stem cell factors, (β-Catenin, Nanog, BMI-1 and Oct-4). Gal/analog also depleted EZH2 and upregulated E-Cadherin. These effects resulted in significant inhibition of PDAC cell migration, invasion and proliferation. Importantly, we also observed strong MiaPaca-2 tumor xenograft growth inhibition (61% to 92%). Collectively, these promising findings strongly support further development of gal/analogs as novel therapeutics for PDAC.

Experiences and coping strategies of oncology patients undergoing oral chemotherapy: First steps of a grounded theory study

PURPOSE

Chemotherapies are increasingly available for oral application. Previous studies have focussed on differences between orally and intravenously administered chemotherapies, mostly following quantitative designs surveying patients' preferences and adherence. The lived experience of patients undergoing oral chemotherapy has been rarely explored. Therefore, this study investigates how patients experience oral chemotherapy.

METHOD

We conducted open interviews with six patients and two spouses. Recruitment took place in the outpatient clinic of an urban Swiss hospital. Data collection and analysis followed the principles of Straussian grounded theory.

RESULTS

The participants reported physical and emotional reluctance towards oral chemotherapy as well as toxic side effects. Feeling responsible emerged as a core phenomenon. All participants intended to adhere to the therapy although this was challenging because of the complex medication regimen. Belief in the effectiveness of the therapy was a strengthening factor.

CONCLUSIONS

All participants reported to be highly adherent to oral chemotherapy. Although they experienced some toxic side effects, they did not react. Monitoring toxicities and support in everyday life should be a core feature of care.

Taxanes versus S-1 as the first-line chemotherapy for metastatic breast cancer (SELECT BC): an open-label, non-inferiority, randomised phase 3 trial

BACKGROUND

Oral fluoropyrimidines are used for the first-line treatment of metastatic breast cancer to avoid severe adverse effects, although firm supporting evidence is lacking. We aimed to establish whether S-1 is non-inferior to taxanes in this setting.

METHODS

We did an open-label, non-inferiority, phase 3 trial at 154 hospitals in Japan. We enrolled individuals who had HER2-negative metastatic breast cancer who had received no chemotherapy for advanced disease, and who were resistant to endocrine treatment. Patients were randomly assigned (1:1) either to taxane (docetaxel 60-75 mg/m(2) at intervals of 3-4 weeks; paclitaxel 80-100 mg/m(2) weekly for 3 of 4 weeks; or paclitaxel 175 mg/m(2) at intervals of 3-4 weeks) or to S-1 (40-60 mg twice daily for 28 consecutive days, followed by a 14-day break). Randomisation was done centrally with the minimisation method, with stratification by institution, liver metastasis, oestrogen and progesterone receptor status, previous treatment with taxanes or oral fluorouracil, and time from surgery to recurrence. The primary endpoint was overall survival, with a prespecified non-inferiority margin of 1·333 for the hazard ratio (HR). The primary efficacy analysis was done in the full analysis set, which consisted of all patients who took at least one study treatment and who had all data after randomisation. This trial is registered with the University Hospital Medical Information Network, Japan (protocol ID C000000416).

FINDINGS

Between Oct 27, 2006, and July 30, 2010, we enrolled 618 patients (309 assigned to taxane; 309 assigned to S-1). The full analysis set consisted of 286 patients in the taxane group and 306 in the S-1 group. Median follow-up was 34·6 months (IQR 17·9-44·4). Median overall survival was 35·0 months (95% CI 31·1-39·0) in the S-1 group and 37·2 months (33·0-40·1) in the taxane group (HR 1·05 [95% CI 0·86-1·27]; pnon-inferiority=0·015). The most common grade 3 or worse adverse events were neutropenia (20 [7%] of 307 patients in the S-1 group vs nine [3%] of 290 patients in the taxane group), fatigue (ten [3%] vs 12 [4%]), and oedema (one [<1%] vs 12 [4%]). Treatment-related deaths were reported in two patients in the taxane group.

INTERPRETATION

S-1 is non-inferior to taxane with respect to overall survival as a first-line treatment for metastatic breast cancer. S-1 should be considered a new option for first-line chemotherapy for patients with HER2-negative metastatic breast cancer.

FUNDING

Comprehensive Support Project for Oncology Research of the Public Health Research Foundation, Japan; Taiho.

Therapeutic applications of hydrogels in oral drug delivery

INTRODUCTION

Oral delivery of therapeutics, particularly protein-based pharmaceutics, is of great interest for safe and controlled drug delivery for patients. Hydrogels offer excellent potential as oral therapeutic systems due to inherent biocompatibility, diversity of both natural and synthetic material options and tunable properties. In particular, stimuli-responsive hydrogels exploit physiological changes along the intestinal tract to achieve site-specific, controlled release of protein, peptide and chemotherapeutic molecules for both local and systemic treatment applications.

AREAS COVERED

This review provides a wide perspective on the therapeutic use of hydrogels in oral delivery systems. General features and advantages of hydrogels are addressed, with more considerable focus on stimuli-responsive systems that respond to pH or enzymatic changes in the gastrointestinal environment to achieve controlled drug release. Specific examples of therapeutics are given. Last, in vitro and in vivo methods to evaluate hydrogel performance are discussed.

EXPERT OPINION

Hydrogels are excellent candidates for oral drug delivery, due to the number of adaptable parameters that enable controlled delivery of diverse therapeutic molecules. However, further work is required to more accurately simulate physiological conditions and enhance performance, which is important to achieve improved bioavailability and increase commercial interest.

Oral treatment with etoposide in small cell lung cancer - dilemmas and solutions

Background

Etoposide is a chemotherapeutic agent, widely used for the treatment of various malignancies, including small cell lung cancer (SCLC), an aggressive disease with poor prognosis. Oral etoposide administration exhibits advantages for the quality of life of the patient as well as economic benefits. However, widespread use of oral etoposide is limited by incomplete and variable bioavailability. Variability in bioavailability was observed both within and between patients. This suggests that some patients may experience suboptimal tumor cytotoxicity, whereas other patients may be at risk for excess toxicity.

Conclusions

The article highlights dilemmas as well as solutions regarding oral treatment with etoposide by presenting and analyzing relevant literature data. Numerous studies have shown that bioavailability of etoposide is influenced by genetic, physiological and environmental factors. Several strategies were explored to improve bioavailability and to reduce pharmacokinetic variability of oral etoposide, including desired and undesired drug interactions (e.g. with ketoconazole), development of suitable drug delivery systems, use of more water-soluble prodrug of etoposide, and influence on gastric emptying. In addition to genotype-based dose administration, etoposide is suitable for pharmacokinetically guided dosing, which enables dose adjustments in individual patient.

Further, it is established that oral and intravenous schedules of etoposide in SCLC patients do not result in significant differences in treatment outcome, while results of toxicity are inconclusive. To conclude, the main message of the article is that better prediction of the pharmacokinetics of oral etoposide may encourage its wider use in routine clinical practice.

Bp44mT: an orally active iron chelator of the thiosemicarbazone class with potent anti-tumour efficacy

BACKGROUND AND PURPOSE

Our previous studies demonstrated that a thiosemicarbazone iron chelator (di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone; Dp44mT) possesses potent and selective anti-cancer activity but led to cardiotoxicity at non-optimal doses. In this study, we examined the in vivo anti-tumour efficacy and tolerability of a new-generation 2-benzoylpyridine thiosemicarbazone iron chelator (2-benzoylpyridine-4,4-dimethyl-3-thiosemicarbazone; Bp44mT) administered via the oral or i.v. routes.

EXPERIMENTAL APPROACH

BpT chelators were tested in vitro against human lung cancer cells (DMS-53) and in vivo in DMS-53 tumour xenografts in mice. The toxicity of Bp44mT in vivo and its effects on the expression of iron-regulated molecules involved in growth and cell cycle control were investigated.

KEY RESULTS

Administration of Bp44mT by either route resulted in marked dose-dependent inhibition of tumour growth. When administered at 50 mg·kg(-1) via oral gavage three times per week for 23 days, the net xenograft growth was inhibited by 75%, compared with vehicle-treated mice. Toxicological examination showed reversible alterations including slight reduction of RBC count, with a decrease of liver and splenic iron levels, which confirmed iron chelation in vivo. Importantly, in contrast to Dp44mT, the chelator-treated mice did not show cardiac histological abnormalities. There was also no significant weight loss in mice, suggesting oral administration of Bp44mT was well tolerated.

CONCLUSIONS AND IMPLICATIONS

This is the first study to show that Bp44mT can be given orally with potent anti-tumour efficacy. Oral administration of a novel and effective chemotherapeutic agent provides the benefits of convenience for chronic dosing regimens.

Advanced molecular design of biopolymers for transmucosal and intracellular delivery of chemotherapeutic agents and biological therapeutics

Hydrogels have been instrumental in the development of polymeric systems for controlled release of therapeutic agents. These materials are attractive for transmucosal and intracellular drug delivery because of their facile synthesis, inherent biocompatibility, tunable physicochemical properties, and capacity to respond to various physiological stimuli. In this contribution, we outline a multifaceted hydrogel-based approach for expanding the range of therapeutics in oral formulations from classical small-molecule drugs to include proteins, chemotherapeutics, and nucleic acids. Through judicious material selection and careful design of copolymer composition and molecular architecture, we can engineer systems capable of responding to distinct physiological cues, with tunable physicochemical properties that are optimized to load, protect, and deliver valuable macromolecular payloads to their intended site of action. These hydrogel carriers, including complexation hydrogels, tethered hydrogels, interpenetrating networks, nanoscale hydrogels, and hydrogels with decorated structures are investigated for their ability to respond to changes in pH, to load and release insulin and fluorescein, and remain non-toxic to Caco-2 cells. Our results suggest these novel hydrogel networks have great potential for controlled delivery of proteins, chemotherapeutics, and nucleic acids.

Antibody-targeted nanoparticles for cancer therapy

In recent years, nanoparticulate-mediated drug delivery research has examined a full spectrum of nanoparticles that can be used in diagnostic and therapeutic cancer applications. A key aspect of this technology is in the potential to specifically target the nanoparticles to diseased cells using a range of molecules, in particular antibodies. Antibody–nanoparticle conjugates have the potential to elicit effective targeting and release of therapeutic targets at the disease site, while minimizing off-target side effects caused by dosing of normal tissues. This article provides an overview of various antibody-conjugated nanoparticle strategies, focusing on the rationale of cell-surface receptors targeted and their potential clinical application.

Controlled Release Camptothecin Tablets based on Pluronic and Poly(acrylic acid) Copolymer. Effect of Fabrication Technique on Drug Stability, Tablet Structure, and Release Mode

Poly(ethylene oxide)-b-poly(propylene oxide)-b-(polyethylene oxide)-g-poly(acrylic acid), a graft-comb copolymer of Pluronic 127 and poly(acrylic acid) (Pluronic-PAA), was explored as an excipient for tablet dosage form of camptothecin (CPT). The tablets were prepared by either direct compression of the drug-polymer physical blend, suspension in ethanol followed by evaporation, or compression after kneading and characterized with respect to their physical structures, drug stability, and release behavior. Porosity and water uptake rate were strongly dependent on the fabrication procedure, ranking in the order: direct compression of physical blend > compression after suspension/evaporation in ethanol > compression after kneading. Tablets prepared by compression of physical blends swelled in water with a rapid surface gel layer formation that impeded swelling and disintegration of the tablets core. These tablets were able to sustain the CPT release for a period of time longer than those observed with the tablets made by either suspension/evaporation or kneading, which disintegrated within a few minutes. Despite the tablet disintegration, the CPT release was impeded for at least 6 hr, which was attributed to the ability of the Pluronic-PAA copolymers to form micellar aggregates at the hydrated surface of the particles. Physical mixing did not alter the fraction of CPT being in the pharmaceutically active lactone form, whilst the preparation of the tablets by the other two methods caused a significant reduction in the lactone form content. Tablets prepared from the physical blends demonstrated CPT release rates increasing with the pH due to the PAA ionization leading to the increase in the rate and extent of the tablet swelling. The results obtained demonstrate the potential of the Pluronic-PAA copolymers for the oral administration of chemotherapeutic agents.

Oral Anticancer Drugs in the Elderly

The increasing number of elderly people in the world population has led to a parallel increase in the number of older cancer patients, with over 45% of all cancers in Europe occurring in patients >70 years of age. The increasing tendency to use oral chemotherapy is thus of interest in the elderly, given that both elderly patients and their physicians prefer to use less complex and toxic regimens when such treatments have equivalent efficacy to more complex regimens. However, data from studies designed to evaluate these therapies in the elderly are currently limited. Factors that must be considered before prescribing oral agents to this subset of patients include age-related physiological changes affecting clinical pharmacology, adherence, the patient's capability to self-administer medications, and safety issues concerning the older patient and his or her caregivers. The idea that elderly patients may benefit from the introduction of oral chemotherapy is very fashionable, but to date there is no proof that this approach is as effective as intravenous therapy in this age group, particularly since randomised trials are lacking. This review discusses these issues and reviews current information about the use of specific oral chemotherapeutic drugs for major neoplastic diseases in the elderly.

Protection against radiation oxidative damage in mice by Triphala

Protection against whole body gamma-irradiation (WBI) of Swiss mice orally fed with Triphala (TPL), an Ayurvedic formulation, in terms of mortality of irradiated animals as well as DNA damage at cellular level has been investigated. It was found that radiation induced mortality was reduced by 60% in mice fed with TPL (1g/kg body weight/day) orally for 7 days prior to WBI at 7.5 Gy followed by post-irradiation feeding for 7 days. An increase in xanthine oxidoreductase activity and decrease in superoxide dismutase activity was observed in the intestine of mice exposed to WBI, which, however, reverted back to those levels of sham-irradiated controls, when animals were fed with TPL for 7 days prior to irradiation. These data have suggested the prevention of oxidative damage caused by whole body radiation exposure after feeding of animals with TPL. To further understand the mechanisms involved, the magnitude of DNA damage was studied by single cell gel electrophoresis (SCGE) in blood leukocytes and splenocytes obtained from either control animals or those fed with TPL for 7 days followed by irradiation. Compared to irradiated animals without administering TPL, the mean tail length was reduced about three-fold in blood leukocytes of animals fed with TPL prior to irradiation. Although, similar protection was observed in splenocytes of TPL fed animals, the magnitude of prevention of DNA damage was significantly higher than that observed in leukocytes. It has been concluded that TPL protected whole body irradiated mice and TPL induced protection was mediated through inhibition of oxidative damage in cells and organs. TPL seems to have potential to develop into a novel herbal radio-protector for practical applications.

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.

Cellular evaluation of oral chemotherapy carriers

Hydrogel nanospheres composed of methacrylic acid and poly(ethylene glycol) were loaded with bleomycin and tested as a potential oral delivery system for chemotherapeutic agents. The gastrointestinal epithelium was modeled through the use of Caco-2 monolayers for studies of permeation enhancement by the carriers as well as bleomycin transport. Bleomycin efficacy following release from the carrier was evaluated with a DLD-1 tumor cell model. The nanospheres release bleomycin in response to a pH increase similar to that seen when passing from the stomach into the upper small intestine. These carriers can also increase the permeability of a model of the epithelial barrier, which would hopefully improve drug transport into the bloodstream. Efficacy studies using a tumor cell model showed retention of activity for bleomycin following loading and release from the nanospheres. The carriers described performed well during in vitro evaluation and can hopefully expand the spectrum of chemotherapeutic agents capable of being administered orally.

Alternative administration of camptothecin analogues

In order to improve the therapeutic index of camptothecin (CPT) analogues, alternative administration of CPT analogues is being evaluated. Topotecan, irinotecan, rubitecan, lurtotecan and 9-aminocamptothecin have been administered orally with response rates equivalent to that seen after intravenous administration, where applicable. Oral availability and administration of some of the newer CPT analogues, including diflomotecan (BN80915) and grimatecan (ST1481), have also shown promising results. Aerosolisation of liposomal 9-nitrocamptothecin has been studied in patients with advanced malignancies involving the lung, demonstrating systemic antitumour activity. Intrathecal administration of topotecan has been studied in children with refractory neoplastic meningitis. It is well tolerated and associated with some antitumour activity. Intraperitoneal administration of topotecan as consolidation therapy in patients with ovarian cancer has shown promising results. Transdermal administration of rubitecan has been studied in mice. So far, no CPT has been approved for an alternative route of administration.

Review of the use of topotecan in ovarian carcinoma

Ovarian cancer is the fifth leading cause of cancer deaths in women. The majority of patients present with advanced disease and relapse after first-line platinum-based chemotherapy; therefore, many proceed to treatment with salvage chemotherapy. Currently available treatment options are generally no longer curative in the relapse setting; hence, the emphasis of treatment is towards disease control and palliation of symptoms. There are several agents available for the treatment of relapsed ovarian carcinoma, of which topotecan is one of the most widely studied and characterised. This review aims to evaluate the role of topotecan in the management of this disease by considering the properties of the compound, the clinical efficacy in Phase II and III studies, its role in first- and second-line treatment and alternative dosing strategies to overcome toxicity.

Principles of transmucosal delivery of therapeutic agents

Recent advances in medicine have led to new treatment options for patients and physicians as a more developed understanding of the molecular basis of disease states is translated into new therapeutic agents. Many of these new agents are compounds that are not able to reach the bloodstream when administered by the oral route preventing the ability to enjoy the benefits this delivery route provides such as lower cost and increased quality of life. Our laboratory has focused on the use of hydrogel carriers to increase the bioavailability of orally administered therapeutic agents ranging from proteins such as insulin to chemotherapeutics like bleomycin. The foundations of this research as well as recent advances are reviewed along with a discussion of the challenges of oral administration and other emerging strategies for oral administration.

Phase I and pharmacokinetic study of topotecan administered orally once daily for 5 days for 2 consecutive weeks to pediatric patients with refractory solid tumors

PURPOSE

We conducted a phase I trial of the injectable formulation of topotecan given orally once daily for 5 days for 2 consecutive weeks (qd x 5 x 2) in pediatric patients with refractory solid tumors.

PATIENTS AND METHODS

Cohorts of two to six patients received oral topotecan at 0.8, 1.1, 1.4, 1.8, and 2.3 mg/m(2)/d every 28 days for a maximum of six courses. Twenty patients (median age, 10.6 years) received a total of 51 courses. Eight patients received topotecan capsules during course 2 only.

RESULTS

Dose-limiting toxicity occurred at 2.3 mg/m(2)/d and consisted of prolonged grade 4 neutropenia (n = 2), grade 3 stomatitis as a result of radiation recall (n = 1), grade 3 hemorrhage (epistaxis) in the presence of grade 4 thrombocytopenia (n = 1), and grade 3 diarrhea in the presence of Clostridium difficile infection (n = 1). Dose-limiting, prolonged grade 4 neutropenia and thrombocytopenia occurred in one patient at 1.4 mg/m(2)/d. Infrequent toxicities were mild nausea, vomiting, elevated liver ALT or AST, and rash. The maximum-tolerated dosage was 1.8 mg/m(2)/d; the mean (+/- standard deviation) area under the plasma concentration-time curve for topotecan lactone at this dosage was 20.9 +/- 8.4 ng/mL. h. The population mean (+/- standard error) oral bioavailability of the injectable formulation was 0.27 +/- 0.03; that of capsules was 0.36 +/- 0.06 (P =.16). Disease stabilized in nine of 19 assessable patients for 1.5 to 6 months.

CONCLUSION

Oral topotecan (1.8 mg/m(2)/d) on a qd x 5 x 2 schedule is well tolerated and warrants additional testing in pediatric patients.

Oral vinorelbine in combination with cisplatin: a novel active regimen in advanced non-small-cell lung cancer

BACKGROUND

A phase II trial of alternating i.v. and oral vinorelbine in combination with cisplatin was designed to determine the response rate, safety profile, progression-free survival, overall survival and quality of life (QoL) in advanced non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Fifty-six chemotherapy-naïve patients received cisplatin 100 mg/m(2) and i.v. vinorelbine 25 mg/m(2) on day 1, followed by oral vinorelbine 60 mg/m(2) on days 8, 15 and 22, every 28 days.

RESULTS

After an independent review, the response rate was 33% [95% confidence interval (CI) 20% to 46%]. Median progression-free and overall survival were 5.5 months (95% CI 3.7-6.4) and 8.9 months (95% CI 8.8-11.7), respectively. The most frequent hematological toxicities were neutropenia (grade 3-4 in 73% of patients) and anemia (grade 3-4 in 11% of patients). Grade 3-4 infections and non-hematological toxicities occurred occasionally. QoL for lung cancer related symptoms was stable or improved.

CONCLUSIONS

The efficacy and safety of the alternating vinorelbine schedule (i.v. on day 1, oral on days 8, 15 and 22) in combination with cisplatin in advanced NSCLC are similar to those of the standard regimen using exclusively i.v. vinorelbine, whereas ease of administration and patient comfort may favor the novel approach.