Pharmacology and therapeutic efficacy of capecitabine: focus on breast and colorectal cancer. Anticancer Drugs. 2009;20:217-229. [PMID: 19247178 DOI: 10.1097/cad.0b013e3283293fd4]

Bruceine D Identified as a Drug Candidate against Breast Cancer by a Novel Drug Selection Pipeline and Cell Viability Assay

The multi-target effects of natural products allow us to fight complex diseases like cancer on multiple fronts. Unlike docking techniques, network-based approaches such as genome-scale metabolic modelling can capture multi-target effects. However, the incompleteness of natural product target information reduces the prediction accuracy of in silico gene knockout strategies. Here, we present a drug selection workflow based on context-specific genome-scale metabolic models, built from the expression data of cancer cells treated with natural products, to predict cell viability. The workflow comprises four steps: first, in silico single-drug and drug combination predictions; second, the assessment of the effects of natural products on cancer metabolism via the computation of a dissimilarity score between the treated and control models; third, the identification of natural products with similar effects to the approved drugs; and fourth, the identification of drugs with the predicted effects in pathways of interest, such as the androgen and estrogen pathway. Out of the initial 101 natural products, nine candidates were tested in a 2D cell viability assay. Bruceine D, emodin, and scutellarein showed a dose-dependent inhibition of MCF-7 and Hs 578T cell proliferation with IC50 values between 0.7 to 65 μM, depending on the drug and cell line. Bruceine D, extracted from Brucea javanica seeds, showed the highest potency.

Low skeletal muscle mass is a predictor of treatment related toxicity in oncologic patients. A meta-analysis

BACKGROUND & AIMS

The purpose of this meta-analysis was to summarize the published data regarding associations between occurrence of severe treatment related toxicity and low skeletal muscle mass (LSMM) in oncologic patients and to perform a meta-analysis based on a large sample.

METHODS

MEDLINE, Cochrane, and SCOPUS databases were screened for associations between LSMM and treatment related toxicity in oncologic patients up to June 2021. Overall, 48 studies met the inclusion criteria. The following data were extracted: authors, year of publication, study design, number of patients, influence of LSMM on treatment toxicity (odds ratios and confidence intervals). The methodological quality of the involved studies was checked according to the QUADAS instrument. The meta-analysis was undertaken by using RevMan 5.4 software. DerSimonian and Laird random-effects models with inverse-variance weights were used to account for the heterogeneity between the studies.

RESULTS

The included 48 studies comprised 4803 patients with different malignant diseases. LSMM occurred in 1966 patients (40.9%). LSMM was associated with therapy toxicity (simple logistic regression) with an odds ratio OR = 2.19, CI95%= (1.78-2.68). LSMM was associated with DLT in patients underwent curative treatment (16 studies, 2381 patients) with OR = 2.48, CI95%= (1.77-3.48). LSMM predicted DLT in patients underwent palliative chemotherapy (30 studies, 2337 patients)with OR = 2.06, CI95%= (1.56-2.74). In the subgroups received different palliative therapies, relationships between LSMM and DLT were as follows: conventional chemotherapies (7 studies, 600 patients) OR = 2.14, CI95%= (1.38-3.31); different kinases inhibitors (13 studies, 906 patients) OR = 3.08, CI95%= (1.87-5.09); checkpoint inhibitors (7 studies, 557 patients) OR = 1.30, CI95%= (0.79-2.11).

CONCLUSIONS

LSMM is an essential factor of treatment toxicity in oncologic patients. Association between LSMM and DLT is strongest in patients received therapy with kinases inhibitors. The influence of LSMM on DLT is lowest in patients underwent treatment with checkpoint inhibitors. The presence of LSMM should be included into radiological reports and provided to oncologists to optimize chemotherapy. LSMM should be included into dose calculation for chemotherapy.

Choice of Capecitabine or S1 in Combination with Oxaliplatin based on Thymidine Phosphorylase and Dihydropyrimidine Dehydrogenase Expression Status in Patients with Advanced Gastric Cancer

Purpose

To study the efficacy of capecitabine or S-1 plus oxaliplatin (CAPOX or SOX) for treating thymidine phosphorylase (TP)- or dihydropyrimidine dehydrogenase (DPD)-positive advanced gastric cancer.

Materials and Methods

Eighty-six patients with stage IIIC to IV gastric cancer were assessed for TP and DPD expression by immunohistochemistry. The association between CAPOX or SOX efficacy and TP/DPD expression was retrospectively analyzed.

Results

There were no significant differences in the objective remission rate (ORR, 52.27% vs. 47.62%; P>0.05), disease control rate (72.73% vs. 73.81%, P>0.05), progression-free survival (hazard ratio [HR], 1.119; 95% confidence interval [CI], 0.739-1.741; P=0.586), and overall survival (OS; HR, 0.855; 95% CI, 0.481-1.511; P=0.588) between CAPOX and SOX. A higher number of stage IV patients showed TP positivity, while DPD-positive patients predominantly showed intestinal type of gastric cancer. In TP-positive patients, the ORRs associated with CAPOX and SOX treatments were 57.14% and 38.10%, respectively; OS was better with CAPOX than with SOX (HR, 0.447; 95% CI, 0.179-0.978; P=0.046). Among DPD-positive patients, the SOX treatment-associated ORR (60.87%) was significantly higher than the CAPOX treatment-associated ORR (43.48%). Furthermore, SOX treatment resulted in better OS than did CAPOX treatment (HR, 2.020; 95% CI, 1.019-4.837; P=0.049).

Conclusions

No significant difference in clinical efficacy was found between CAPOX and SOX. TP-positive patients might respond better to CAPOX while DPD-positive patients may respond better to SOX. Our findings might serve as a guide for personalized chemotherapy for gastric cancer.

5-fluorouracil and other fluoropyrimidines in colorectal cancer: Past, present and future

5-Fluorouracil (5-FU) is an essential component of systemic chemotherapy for colorectal cancer (CRC) in the palliative and adjuvant settings. Over the past four decades, several modulation strategies including the implementation of 5-FU-based combination regimens and 5-FU pro-drugs have been developed and tested to increase the anti-tumor activity of 5-FU and to overcome the clinical resistance. Despite the encouraging progress in CRC therapy to date, the patients' response rates to therapy continue to remain low and the patients' benefit from 5-FU-based therapy is frequently compromised by the development of chemoresistance. Inter-individual differences in the treatment response in CRC patients may originate in the unique genetic and epigenetic make-up of each individual. The critical element in the current trend of personalized medicine is the proper comprehension of causes and mechanisms contributing to the low or lack of sensitivity of tumor tissue to 5-FU-based therapy. The identification and validation of predictive biomarkers for existing 5-FU-based and new targeted therapies for CRC treatment will likely improve patients' outcomes in the future. Herein we present a comprehensive review summarizing options of CRC treatment and the mechanisms of 5-FU action at the molecular level, including both anabolic and catabolic ways. The main part of this review comprises the currently known molecular mechanisms underlying the chemoresistance in CRC patients. We also focus on various 5-FU pro-drugs developed to increase the amount of circulating 5-FU and to limit toxicity. Finally, we propose future directions of personalized CRC therapy according to the latest published evidence.

From Molecular Mechanisms to Clinical Management of Antineoplastic Drug-Induced Cardiovascular Toxicity: A Translational Overview

Significance: Antineoplastic therapies have significantly improved the prognosis of oncology patients. However, these treatments can bring to a higher incidence of side-effects, including the worrying cardiovascular toxicity (CTX). Recent Advances: Substantial evidence indicates multiple mechanisms of CTX, with redox mechanisms playing a key role. Recent data singled out mitochondria as key targets for antineoplastic drug-induced CTX; understanding the underlying mechanisms is, therefore, crucial for effective cardioprotection, without compromising the efficacy of anti-cancer treatments. Critical Issues: CTX can occur within a few days or many years after treatment. Type I CTX is associated with irreversible cardiac cell injury, and it is typically caused by anthracyclines and traditional chemotherapeutics. Type II CTX is generally caused by novel biologics and more targeted drugs, and it is associated with reversible myocardial dysfunction. Therefore, patients undergoing anti-cancer treatments should be closely monitored, and patients at risk of CTX should be identified before beginning treatment to reduce CTX-related morbidity. Future Directions: Genetic profiling of clinical risk factors and an integrated approach using molecular, imaging, and clinical data may allow the recognition of patients who are at a high risk of developing chemotherapy-related CTX, and it may suggest methodologies to limit damage in a wider range of patients. The involvement of redox mechanisms in cancer biology and anticancer treatments is a very active field of research. Further investigations will be necessary to uncover the hallmarks of cancer from a redox perspective and to develop more efficacious antineoplastic therapies that also spare the cardiovascular system.

Associations of Genetic Variations in MicroRNA Seed Regions With Acute Adverse Events and Survival in Patients With Rectal Cancer Receiving Postoperative Chemoradiation Therapy

PURPOSE

The aim of this study was to investigate the associations between single nucleotide polymorphisms (SNPs) in the seed regions of microRNAs and acute adverse events (AEs) and survival in patients with rectal cancer receiving postoperative chemoradiation therapy.

METHODS AND MATERIALS

Eighteen SNPs were genotyped in 365 patients with rectal cancer receiving postoperative chemoradiation therapy. The associations between genotypes and AEs were estimated by odds ratios and 95% confidence intervals (CIs), which were computed by using multivariate logistic regression models. The hazard ratios and 95% CIs to assess the death of patients for different genotypes were calculated by Cox proportional regression models. Overall survival and disease-free survival of patients with different genotypes were estimated by Kaplan-Meier plots, and the statistical significance was determined by using the log-rank test.

RESULTS

In these patients, the most common grade ≥2 AEs were diarrhea (44.1%), leukopenia (29.6%), and dermatitis (18.9%). With false discovery rate correction, SNP rs2273626 was significantly associated with a decreased risk of grade ≥2 leukopenia (odds ratio, 0.48; 95% CI, 0.31-0.74; P = .0009). In addition, SNP rs202195689 was associated with overall survival and disease-free survival in patients receiving postoperative chemoradiation therapy, with the hazard ratios for death being 2.02 (95% CI, 1.36-3.01; P = .0006) and 1.91 (95% CI, 1.36-2.70; P = .0002), respectively. However, no significant association between these SNPs and diarrhea and dermatitis was observed.

CONCLUSIONS

These results suggest that rs2273626 and rs202195689 in microRNA seed regions might serve as independent biomarkers for predicting AEs and prognosis in patients with rectal cancer receiving postoperative chemoradiation therapy. Independent replication of these findings is required to confirm these results.

Antineoplastic Drug-Induced Cardiotoxicity: A Redox Perspective

Antineoplastic drugs can be associated with several side effects, including cardiovascular toxicity (CTX). Biochemical studies have identified multiple mechanisms of CTX. Chemoterapeutic agents can alter redox homeostasis by increasing the production of reactive oxygen species (ROS) and reactive nitrogen species RNS. Cellular sources of ROS/RNS are cardiomyocytes, endothelial cells, stromal and inflammatory cells in the heart. Mitochondria, peroxisomes and other subcellular components are central hubs that control redox homeostasis. Mitochondria are central targets for antineoplastic drug-induced CTX. Understanding the mechanisms of CTX is fundamental for effective cardioprotection, without compromising the efficacy of anticancer treatments. Type 1 CTX is associated with irreversible cardiac cell injury and is typically caused by anthracyclines and conventional chemotherapeutic agents. Type 2 CTX, associated with reversible myocardial dysfunction, is generally caused by biologicals and targeted drugs. Although oxidative/nitrosative reactions play a central role in CTX caused by different antineoplastic drugs, additional mechanisms involving directly and indirectly cardiomyocytes and inflammatory cells play a role in cardiovascular toxicities. Identification of cardiologic risk factors and an integrated approach using molecular, imaging, and clinical data may allow the selection of patients at risk of developing chemotherapy-related CTX. Although the last decade has witnessed intense research related to the molecular and biochemical mechanisms of CTX of antineoplastic drugs, experimental and clinical studies are urgently needed to balance safety and efficacy of novel cancer therapies.

The Role of Fluoropirimidines in Gastrointestinal Tumours: from the Bench to the Bed

PURPOSE

Gastrointestinal tumours are one of the most common types of cancer. Therapeutic options include surgery, radiotherapy, local ablation techniques, targeted agents, and chemotherapy. Fluoroprimidines are one of the most active drug families in digestive tumours and remains the cornerstone of the most commonly used chemotherapy schemes.

METHODS

We review the molecular basis of thymidylate synthase inhibition and the mechanisms of action of 5-fluorouracil, next generation oral fluoropyrimidines (capecitabine, tegafur and the latest S-1 and TAS-102) and antifolates.

RESULTS

In addition, mechanisms and biomarkers of resistance and toxicity are explored. Finally, new fluoropyrimidines development and clinical trials ongoing in digestive tumours are reviewed.

CONCLUSIONS

Further research is necessary to avoid resistance mechanisms, improve clinical outcomes and continue reducing toxicities. Until new drugs become available, the optimization of current therapies should be a priority.

Inside the biochemical pathways of thymidylate synthase perturbed by anticancer drugs: Novel strategies to overcome cancer chemoresistance

Our current understanding of the mechanisms of action of antitumor agents and the precise mechanisms underlying drug resistance is that these two processes are directly linked. Moreover, it is often possible to delineate chemoresistance mechanisms based on the specific mechanism of action of a given anticancer drug. A more holistic approach to the chemoresistance problem suggests that entire metabolic pathways, rather than single enzyme targets may better explain and educate us about the complexity of the cellular responses upon cytotoxic drug administration. Drugs, which target thymidylate synthase and folate-dependent enzymes, represent an important therapeutic arm in the treatment of various human malignancies. However, prolonged patient treatment often provokes drug resistance phenomena that render the chemotherapeutic treatment highly ineffective. Hence, strategies to overcome drug resistance are primarily designed to achieve either enhanced intracellular drug accumulation, to avoid the upregulation of folate-dependent enzymes, and to circumvent the impairment of DNA repair enzymes which are also responsible for cross-resistance to various anticancer drugs. The current clinical practice based on drug combination therapeutic regimens represents the most effective approach to counteract drug resistance. In the current paper, we review the molecular aspects of the activity of TS-targeting drugs and describe how such mechanisms are related to the emergence of clinical drug resistance. We also discuss the current possibilities to overcome drug resistance by using a molecular mechanistic approach based on medicinal chemistry methods focusing on rational structural modifications of novel antitumor agents. This paper also focuses on the importance of the modulation of metabolic pathways upon drug administration, their analysis and the assessment of their putative roles in the networks involved using a meta-analysis approach. The present review describes the main pathways that are modulated by TS-targeting anticancer drugs starting from the description of the normal functioning of the folate metabolic pathway, through the protein modulation occurring upon drug delivery to cultured tumor cells as well as cancer patients, finally describing how the pathways are modulated by drug resistance development. The data collected are then analyzed using network/netwire connecting methods in order to provide a wider view of the pathways involved and of the importance of such information in identifying additional proteins that could serve as novel druggable targets for efficacious cancer therapy.

Pilot study investigating the prognostic significance of thymidine phosphorylase expression in patients with metastatic breast cancer: a single institution retrospective analysis

Background

The thymidine phosphorylase (TP) enzyme is expressed in higher levels in cancer tissue when compared with normal tissue. It is involved in the intratumoral activation of widely prescribed pyrimidine-derived antimetabolites such as 5′-deoxy-5-fluorouridine and capecitabine (Xeloda^®). The purpose of this study was to determine the clinical correlation between TP expression in tumor tissue and the clinical outcome of capecitabine-based therapy in patients with locally advanced (stage III) or metastatic breast cancer (stage IV).

Methods

The following variables were analyzed as potential determinants of benefit from a capecitabine-based therapy: TP expression, estrogen receptor (ER) and progesterone receptor (PR) status, human epidermal growth factor receptor-2 status, and Ki67 status. This was accomplished by immunohistochemical analysis of paraffin-embedded cancer tissues from 18 patients with breast cancer treated with at least one cycle of capecitabine. Clinical outcome was measured as time to progression.

Results

TP staining intensities in both the invasive and in situ components in patients with lobular and ductal carcinomas were reported. Higher levels of TP in the invasive component were expressed in ER-negative tumors when compared with ER-positive tumors (P<0.05). The ER-positive group expressing lower levels of TP had a median time to progression of 13 months compared with the ER-negative group expressing higher levels of TP which had a median time to progression of 7.5 months (P=0.14).

Conclusion

Patients with ER-positive tumors expressing lower levels of TP exhibit a longer time to progression when compared with patients with ER-negative tumors. Consequently, tumor TP expression does not seem to predict the outcome of capecitabine-based chemotherapy.

Capecitabine-induced cardiotoxicity: more evidence or clinical approaches to protect the patients' heart?

Fluoropyrimidines, such as capecitabine and 5-fluorouracil, may cause cardiac toxicity. In recent years, the incidence of this side effect has increased and it is expected to further rise due to the population aging and the disproportionate incidence of breast and gastrointestinal cancers in older individuals. The spectrum of cardiac manifestations includes different signs and symptoms and the diagnosis may be difficult. Here, we report the case of a 43-year-old woman with advanced breast cancer who was rechallenged with a capecitabine-based regimen after experiencing a cardiac adverse event during the first fluoropyrimidine exposure. This real-practice case serves as a springboard for discussion about the current evidence on differential diagnosis of capecitabine-related cardiac toxicity, its risk factors, and the underpinning mechanisms of early onset. Moreover, we discussed whether a rechallenge with fluoropyrimidines could be safe in patients who had experienced a previous cardiac adverse event.

Pharmacogenetics research on chemotherapy resistance in colorectal cancer over the last 20 years

During the past two decades the first sequencing of the human genome was performed showing its high degree of inter-individual differentiation, as a result of large international research projects (Human Genome Project, the 1000 Genomes Project International HapMap Project, and Programs for Genomic Applications NHLBI-PGA). This period was also a time of intensive development of molecular biology techniques and enormous knowledge growth in the biology of cancer. For clinical use in the treatment of patients with colorectal cancer (CRC), in addition to fluoropyrimidines, another two new cytostatic drugs were allowed: irinotecan and oxaliplatin. Intensive research into new treatment regimens and a new generation of drugs used in targeted therapy has also been conducted. The last 20 years was a time of numerous in vitro and in vivo studies on the molecular basis of drug resistance. One of the most important factors limiting the effectiveness of chemotherapy is the primary and secondary resistance of cancer cells. Understanding the genetic factors and mechanisms that contribute to the lack of or low sensitivity of tumour tissue to cytostatics is a key element in the currently developing trend of personalized medicine. Scientists hope to increase the percentage of positive treatment response in CRC patients due to practical applications of pharmacogenetics/pharmacogenomics. Over the past 20 years the clinical usability of different predictive markers has been tested among which only a few have been confirmed to have high application potential. This review is a synthetic presentation of drug resistance in the context of CRC patient chemotherapy. The multifactorial nature and volume of the issues involved do not allow the author to present a comprehensive study on this subject in one review.

Triple-negative breast cancer possibly transforming into malignant melanoma due to targeted therapy? A case report and review of literature

BACKGROUND

Triple-negative breast cancer (TNBC) is characterized by lacking expression of estrogen receptor and progesterone receptor as well as absence of human epidermal growth factor receptor 2 overexpression and is an aggressive clinical phenotype.

PATIENTS AND METHODS

We report the case of a 33-year-old woman who has been treated using a targeted approach for TNBC and developed a malignant melanoma metastasis without any primary.

RESULTS AND CONCLUSION

Using targeted therapies, tumors can be treated much more effectively, but up to now, we do not know much about potential adverse reactions. Due to the targeted therapy, tumors may be pressurized for transformation. We call for further investigations to rule out the potential risks of targeted therapy in TNBC. This is the first report of a potential transforming of one tumor entity to another by a targeted therapy.

Preliminary estimation of the prevalence of chemotherapy-induced dysgeusia in Japanese patients with cancer

Background

Although dysgeusia is a common adverse event in chemotherapy patients; it has not been evaluated using objective methods, and its prevalence and frequency have not been quantified.

Methods

Salt-impregnated taste strips were used to objectively assess dysgeusia in patients receiving chemotherapy at Akita University (n = 38) and those off chemotherapy (n = 9). Participant characteristics, and ongoing and previous chemotherapies were evaluated, and their associations with dysgeusia analyzed.

Results

Dysgeusia developed in 38.8% (14/38) of chemotherapy patients, and was most prevalent in patients receiving 5-fluorouracil (5-FU) or its oral analogs (48.1%, 13/27). Particularly, dysgeusia developed in 55.6% (10/18) of patients receiving oral 5-FU analogs; however, prevalence in patients receiving and off chemotherapy was not significantly different. Patients aged ≥70 years also tended to experience dysgeusia (75.0%, 6/8).

Conclusions

Association with dysgeusia may be higher for some chemotherapeutic drugs. Dysgeusia should be routinely assessed in chemotherapy patients with objective methods such as paper strips; interventions for its prevention may be required.

The use of capecitabine in daily practice: a study on adherence and patients' experiences

BACKGROUND

Adherence to pharmacological therapy is a complex and multifactorial issue that can substantially alter the outcome of treatment. Especially when using long-term medication, cancer patients have adherence rates similar to those of patients with other diseases. The consequences of poor adherence are poor health outcomes and increased health care costs. Only few studies have focused on the use of oral anticancer agents in daily practice. Information about the reasons for nonadherence is essential for the development of interventions that may improve adherence. This report presents the CAPER-capecitabine protocol, which is designed to study the adherence to capecitabine and the influence of patient attitudes towards medication and self-reported side effects. Furthermore, the relationships between patient characteristics, disease characteristics, side effects, quality of life, patient beliefs and attitudes towards disease and medication, dose adjustments, reasons for discontinuation, and plasma concentration of three of the main metabolites, including the active compound 5-fluorouracil, will be explored.

METHODS

In this multicenter, prospective, observational cohort study, 90 patients aged 18 years or older starting treatment with capecitabine will be included and followed for a period up to five cycles. The main study parameters are adherence, patient attitudes towards medication, and the number and grade of patient-reported side effects. At baseline and during week 2 of cycles 1, 3 and 5, patients will be asked to donate blood and fill out a questionnaire. Blood samples will be analyzed for plasma concentration of the metabolites, 5'-deoxy-5-fluorouridine, 5-fluorouracil, and α-fluoro-β-alanine. The CAPER-capecitabine trial is closely related to the CAPER-erlotinib trial.

DISCUSSION

The aim of the present study is to get more insight into patient experiences with the use of capecitabine in daily practice and the various aspects that govern adherence. We hypothesize that patient attitudes towards medication and the side effects experienced play an important role in the way patients use capecitabine. We expect that our findings will be useful for health care professionals in developing interventions to support patients in improving adherence and persistence with the use of capecitabine.

Evaluations of biomarkers associated with sensitivity to 5-fluorouracil and taxanes for recurrent/advanced breast cancer patients treated with capecitabine-based first-line chemotherapy

The aim of the present study was to investigate the gene expression of biomarkers associated with the sensitivity to fluoropyrimidine and taxanes in recurrent/advanced breast cancer patients treated with first-line capecitabine chemotherapy. We evaluated the clinicopathological/prognostic significance of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP), class III β-tubulin (βIII-tubulin), and stathmin-1 or oncoprotein-18 (STMN1). Formalin-fixed, paraffin-embedded tumor specimens from 42 patients were used for analysis of TS, DPD, TP, βIII-tubulin, and STMN1 expression with a real-time reverse transcription-PCR technique. Patients were classified into the high-expression and low-expression groups according to the median value of the expression level of each biomarker. There was a significantly longer time to progression (TTP) in the high-TP group (P=0.018). The multivariate analysis revealed that the TP expression (hazard ratio for the low-TP group vs. the high-TP group, 2.873; 95% confidence interval, 1.143-7.223; P=0.025) is independent of prognostic factors for TTP. In the subgroup of patients treated with capecitabine plus taxanes as first-line chemotherapy, TTP was significantly longer in the low-βIII-tubulin group (P=0.047). The gene expression of TS, DPD, and STMN1 failed to have any significant impact on the outcome. These results provide further evidence that the TP expression may be a prognostic factor in breast cancer patients treated with capecitabine-based first-line chemotherapy, and βIII-tubulin can be used to predict the outcome of capecitabine in combination with taxanes as first-line chemotherapy. Therefore, these potential biomarkers should be further evaluated.

Strategies of targeting oral drug delivery systems to the colon and their potential use for the treatment of colorectal cancer

Colorectal cancer (CRC) is the third most common cause of cancer-related death in both men and women. Often, surgical intervention remains the choice in treating CRC. Traditional dosage forms used for treating CRC deliver drug to wanted as well as unwanted sites of drug action resulting in several adverse side effects. Targeted oral drug delivery systems are being investigated to target and deliver chemotherapeutic and chemopreventive agents directly to colon and rectum. Site-specific delivery of a drug to colon increases its concentration at the target site, and thus requires a lower dose with reduced incidence of side effects. The major obstacle to be overcome for successful targeting of drug to colon through oral route is that drug absorption/degradation must be avoided in stomach and small intestine before the dosage form reaches colon. The review includes discussion of physiological factors that must be considered when targeting drugs directly to colorectal region, an outline on drugs used for treatment and prevention of CRC, and a brief description of various types of colon-targeted oral drug delivery systems. The focus is on the assessment of various formulation approaches being investigated for oral colon-specific delivery of drugs used in the treatment and prevention of CRC.

Capecitabine-phenytoin interaction is dose dependent with an unexpected time course

The main objective of this study was to further analyze the drug interaction between capecitabine and phenytoin with special emphasis on magnitude, timing, and the dose effect. A single patient had multiple phenytoin levels at various doses of capecitabine. Phenytoin levels were subjected to analysis of variance and the dose effect was approached using a multiple comparison test. All phenytoin levels meeting the criteria for steady state were subjected to box plot analysis. Analysis of 35 phenytoin levels over a 25-month period demonstrated a statistically significant interaction between the medications. The interaction onset was delayed by 4 weeks and persisted up to 9 weeks after capecitabine dose increases or decreases. The magnitude of interaction was directly proportional to the capecitabine dosage. We concluded that capecitabine caused a marked increase in phenytoin levels that was capecitine dose dependent, with a delayed time course not predicted by phenytoin kinetics, suggesting a novel interaction mechanism. The magnitude and complexity of this interaction suggest that alternate antiepileptic medications should be used in combination with capecitabine.

Identification of novel germline polymorphisms governing capecitabine sensitivity

BACKGROUND

Capecitabine, an oral 5-fluorouracil (5-FU) prodrug, is widely used in the treatment of breast, colorectal, and gastric cancers. To guide the selection of patients with potentially the greatest benefit of experiencing antitumor efficacy, or, alternatively, of developing toxicities, identifying genomic predictors of capecitabine sensitivity could permit its more informed use.

METHODS

The objective of this study was to perform capecitabine sensitivity genome-wide association studies (GWAS) using 503 well genotyped human cell lines from individuals representing multiple different world populations. A meta-analysis that included all ethnic populations then enabled the identification of novel germline determinants (single nucleotide polymorphisms [SNPs]) of capecitabine susceptibility.

RESULTS

First, an intrapopulation GWAS of Caucasian individuals identified reference SNP 4702484 (rs4702484) (within adenylate cyclase 2 [ADCY2]) at a level reaching genome-wide significance (P = 5.2 × 10(-8) ). This SNP is located upstream of the 5 methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR) gene, and it is known that the enzyme for MTRR is involved in the methionine-folate biosynthesis and metabolism pathway, which is the primary target of 5-FU-related compounds, although the authors were unable to identify a direct relation between rs4702484 and MTRR expression in a tested subset of cells. In the meta-analysis, 4 SNPs comprised the top hits, which, again, included rs4702484 and 3 additional SNPs (rs8101143, rs576523, and rs361433) that approached genome-wide significance (P values from 1.9 × 10(-7) to 8.8 × 10(-7) ). The meta-analysis also identified 1 missense variant (rs11722476; serine to asparagine) within switch/sucrose nonfermentable-related, matrix-associated, actin-dependent regulator of chromatin (SMARCAD1), a novel gene for association with capecitabine/5-FU susceptibility.

CONCLUSIONS

Toward the goal of individualizing cancer chemotherapy, the current study identified novel SNPs and genes associated with capecitabine sensitivity that are potentially informative and testable in any patient regardless of ethnicity.

Use and costs of oral anticancer agents in the Netherlands in the period 2000-2008

PURPOSE

In recent years, the number of oral anticancer agents has increased substantially. Although these agents have quickly been incorporated in the treatment of a variety of malignancies, data on their incidence, prevalence and costs are lacking. The objective of the present study was to obtain insight into the use and the costs of oral anticancer agents (with Anatomical Therapeutic Chemical classification system (World Health Organisation) code L01) in the Netherlands between 2000 and 2008.

METHODS

Incidence and prevalence were determined using community pharmacy dispensing records obtained from the PHARMO Record Linkage System database. The data of costs were provided by the Genees- en hulpmiddelen Informatie Project of the Dutch Health Care Insurance Board (CVZ, Diemen, The Netherlands).

RESULTS

In the years 2000-2008, the use of oral anticancer agents has more than doubled from 64 to 140 users per 100 000 inhabitants. The increase is mainly caused by the prescription of capecitabine for various indications. There was a 50-fold rise in costs on oral anticancer agents from €2 m in 2000 to approximately €100 m in 2008. The share in the costs of tyrosine kinase inhibitors (TKIs) in 2008 was 67% (€70 m) with the oldest TKI, imatinib, having a share of more than 50% within the group of TKIs.

CONCLUSIONS

The increased use of oral anticancer agents is mainly due to the frequent prescription of capecitabine. The increased costs are caused by the registration of a variety of TKIs, in particular imatinib. The costs of new agents with an orphan drug status are very high as compared with those of capecitabine, a newer agent for which there are alternative treatment options.

Phase II study of capecitabine as palliative treatment for patients with recurrent and metastatic squamous head and neck cancer after previous platinum-based treatment

BACKGROUND

Platinum-based therapy (PBT) is the standard therapy for recurrent and/or metastatic head and neck cancer (HNC), but the incidence of recurrence remains high. This study evaluates the efficacy and tolerability of capecitabine as palliative monotherapy for recurrent HNC previously treated with PBT.

METHODS

Patients aged 18-75 years, with Eastern Cooperative Oncology Group performance status 0-2, squamous HNC with locoregional and/or metastatic recurrence previously treated with PBT and adequate organ functions, were included. Capecitabine (1.250 mg m(-2) BID) was administered on days 1-14 every 21 days for at least two cycles.

RESULTS

A total of 40 male patients with a median age of 58 years were analysed. All patients received a median number of four cycles of capecitabine (range: 1-9) and the median relative dose intensity was 91%. Seven patients were not evaluable for response. Overall response rate was 24.2%. Median time to progression and overall survival were 4.8 and 7.3 months, respectively. Haematological adverse events (AEs) grade 3/4 were reported in six patients. Most common grade 3/4 non-haematological AEs were asthenia (12.5%), palmar-plantar eritrodisestesia (10%), mucositis (10%), dysphagia (10%) and diarrhoea (7.5%).

CONCLUSIONS

Capecitabine seems to be an active, feasible and well-tolerated mode of palliative treatment for advanced HNC patients who have previously received PBT schedules.

A dose escalation study of docetaxel plus capecitabine in combination with oxaliplatin in patients with advanced solid tumors

OBJECTIVES

Capecitabine (CAP), Oxaliplatin (OX) and Docetaxel (DOC) have shown considerable activity in a wide range of solid tumors. A phase I study was conducted in order to determine the maximum-tolerated dose (MTD) and dose-limiting toxicities (DLTs) of their combination in patients with advanced solid tumors.

PATIENTS AND METHODS

Twenty-one patients were enrolled. The patient's median age was 68 years, 15 were male, and 12 were chemo-naïve. DOC was administered on day 1 as an 1-hour (iv) infusion at a standard dose of 50 mg/m(2). OX was administered on day 1 as a 2-hour (iv) infusion at escalating doses ranging from 70-80 mg/m(2). CAP was administered orally on days 1 to 7 at escalating doses ranging from 2,000-2,750 mg/m(2) given as two daily divided doses. Treatment was repeated every two weeks.

RESULTS

Six different dose-levels were examined. At dose-level VI, two of three enrolled patients presented DLTs (one patient diarrhea and asthenia grade 3 and another grade 3 diarrhea), and thus, the recommended MTD for future phase II studies is CAP 2,750 mg/m(2) , DOC 50 mg/m(2) and OX 75 mg/m(2). A total of 121 treatment cycles were administered. Grade 3 neutropenia was observed in six (5%) treatment cycles and grade 3 thrombocytopenia in one (1%). There was no febrile episode. Grade 3 asthenia was observed in three (14%) patients, grade 3 diarrhea in four (19%), grade 3 neuropathy in one (5%), and grade 1/2 hand-foot syndrome in three (14%). Other toxicities were uncommon. There was no treatment related death. Four (29%) PRs and seven (50%) SD were observed among 14 evaluable patients. Responses were seen in patients with renal (n = 1), gastric (n = 2) and pancreatic (n = 1) cancer.

CONCLUSIONS

These results demonstrate that CAP, DOC and OX can be safely combined at clinically relevant doses and this regimen merits further evaluation.