Capecitabine: a review

Hand-foot syndrome with sclerodactyly-like changes in a patient treated with capecitabine

Capecitabine, a fluoropyrimidine carbamate with antineoplastic activity, is an oral agent that was developed as a prodrug of 5-fluorouracil and is used in the treatment of metastatic colorectal and breast cancers. Multiple cutaneous adverse effects had been described with the use of this drug, but to our knowledge, specific association with capecitabine and hand-foot syndrome with sclerodactyly-like changes has been described only once. We report a patient with a colon adenocarcinoma who presented with hand-foot syndrome, with sclerodactyly-like changes induced by capecitabine.

Prodrugs: design and clinical applications

Prodrugs are bioreversible derivatives of drug molecules that undergo an enzymatic and/or chemical transformation in vivo to release the active parent drug, which can then exert the desired pharmacological effect. In both drug discovery and development, prodrugs have become an established tool for improving physicochemical, biopharmaceutical or pharmacokinetic properties of pharmacologically active agents. About 5-7% of drugs approved worldwide can be classified as prodrugs, and the implementation of a prodrug approach in the early stages of drug discovery is a growing trend. To illustrate the applicability of the prodrug strategy, this article describes the most common functional groups that are amenable to prodrug design, and highlights examples of prodrugs that are either launched or are undergoing human trials.

Candidate mechanisms for capecitabine-related hand-foot syndrome

AIMS

The oral fluoropyrimidine prodrug capecitabine is widely used in oncology. Capecitabine was designed to generate 5FU via the thymidine phosphorylase (TP) enzyme, preferentially expressed in tumoral tissues. Hand-foot syndrome (HFS) is a limiting toxicity of capecitabine. A pilot study on healthy volunteers was conducted in order to test the hypothesis that the occurrence of HFS could be related to tissue-specific expression of drug-metabolizing enzymes in the skin of the palm and sole. To this end, the expression of TP (activating pathway), dihydropyrimidine dehydrogenase (DPD, catabolic pathway) and cell proliferation (Ki67) were measured in the skin of the palm (target tissue for HFS) and of the lower back (control area).

METHODS

Two paired 4-mm diameter punch biopsy specimens (palm and back) were taken in 12 healthy volunteers. Immunohistochemical analyses were performed on frozen tissues.

RESULTS

Proliferation rate (Ki67 staining) was significantly higher in epidermal basal cells of the palm compared with the back (P = 0.008). Also, TP and DPD expression were significantly greater in the palm relative to the back (P = 0.039 and 0.012, respectively). TP and Ki67 expression were positively and significantly correlated in the palm.

CONCLUSIONS

The high proliferation rate of epidermal basal cells in the palm could make them more sensitive to the local action of cytotoxic drugs. TP-facilitated local production of 5FU in the palm during capecitabine treatment could explain the occurrence of HFS. This observation may support future strategies to limit the occurrence of HFS during capecitabine therapy.

Onycholysis Associated with Capecitabine in Patients with Breast Cancer

Background:

Onycholysis, which is separation of the nail plate from the nail bed at its distal and lateral attachments, can cause pain and impair function and is a well-known side effect of traditional chemotherapeutic agents.

Objectives:

We present two cases of onycholysis associated with capecitabine in women with advanced breast cancer, who were initially referred for evaluation of onychomycosis and review the literature on capecitabine.

Conclusion:

Owing to the increased frequency of use of capecitabine for different cancers, physicians should be aware of this side effect.

Prodrugs of nucleoside analogues for improved oral absorption and tissue targeting

Nucleoside analogues are widely used for the treatment of antiviral infections and anticancer chemotherapy. However, many nucleoside analogues suffer from poor oral bioavailability due to their high polarity and low intestinal permeability. In order to improve oral absorption of these polar drugs, prodrugs have been employed to increase lipophilicity by chemical modification of the parent. Alternatively, prodrugs targeting transporters present in the intestine have been exploited to facilitate the transport of the nucleoside analogues. Valacyclovir and valganciclovir are two successful valine ester prodrugs transported by the PepT1 transporter. Recently, research efforts have focused on design of prodrugs for tissue specific delivery to improve efficacy and safety. This review presents advances of prodrug approaches for improved oral absorption of nucleoside analogues and recent developments in tissue targeting.

Capecitabine in combination with leucovorin and oxaliplatin as adjuvant chemotherapy in the treatment of advanced gastric cancer

AIM: To evaluate the efficacy and toxicity of capecitabine in combination with leucovorin and oxaliplatin regimen (CAPE-LV-OXA) as the adjuvant chemotherapy in the treatment of patients with advanced gastric cancer.

METHODS: Twenty-eight patients with advanced gastric cancer were enrolled in the study. Patients were administrated with oral capecitabine 1250 mg/(m²·d) (d1-14) and oral leucovorin 90 mg/d (d1-14), and intravenous oxaliplatin 85 mg/m² (d1) in a 21-day cycle regimen for 2-6 cycles.

RESULTS: Twenty-five patients were evaluable for efficacy and toxicity. There was no complete response, while 13 patients had partial responses, with an overall response rate of 52%. The median time to progression (TTP) was 5.4 months (range 2-13 months). The median survival time was 10.3 months (range 3-25 months). Therapy was generally well tolerated, and the most common adverse effects were gastrointestinal response, neutropenia, and hand-foot syndrome. There was no chemotherapy-related death.

CONCLUSION: CAPE-LV-OXA regimen is an effective and well-tolerated chemotherapy regimen for advanced gastric cancer.

Factors that affect cancer patient compliance to oral anti-neoplastic therapy

OBJECTIVES: To identify factors that can affect compliance to treatment with neoplastic oral drugs in a group of cancer patients. METHODS: Interviews were performed on 61 patients diagnosed with cancer and under anti-neoplastic oral therapy in a private hospital. The interviews were carried out using instruments to assess compliance. RESULTS: Most patients (95%) reported the oral treatment was not difficult. The Morisky and Green Test were positive in 28% of the patients. Factors that may affect following the treatment were significantly (p<0.05) associated with the time variable; patients who presented more difficulty had more treatment time. CONCLUSIONS: Patients presented positive attitudes toward the use of this anti-neoplastic oral treatment therapy, however 28% were considered non-compliant in the Morisky and Green Test.

Redistribution of nucleoside transporters to the cell membrane provides a novel approach for imaging thymidylate synthase inhibition by positron emission tomography

Thymidylate synthase (EC 2.1.1.45) is a key enzyme for the de novo synthesis of DNA and as such a target for anticancer drug development. There is a need to develop noninvasive methods for assessing thymidylate synthase inhibition in tumors. The aim of this study was to assess the potential of 3'-deoxy-3'-[(18)F]fluorothymidine ([(18)F]FLT) positron emission tomography (PET) for early measurement of thymidylate synthase inhibition and to elucidate the cellular mechanisms involved. Radiation-induced fibrosarcoma-1 tumor-bearing mice were injected with a single i.p. dose of the thymidylate synthase inhibitor 5-fluorouracil (5-FU; 165 mg/kg) and imaged by [(18)F]FLT-PET at 1 to 2 hours after treatment. Deoxyuridine, thymidine kinase 1 (cytoplasmic thymidine kinase; EC2.7.1.21), and ATP levels in excised tumors were measured. Cellular assays for membrane transport were also done. There was a 1.8-fold increase in the 60-minute [(18)F]FLT tumor/heart radioactivity ratio in drug-treated mice compared with vehicle controls (P = 0.0016). Plasma and tumor deoxyuridine levels increased significantly but thymidine kinase and ATP levels were unchanged. Whole-cell assays implicated a (low level) functional role for the type-1 equilibrative nucleoside transporter (ENT). There was an increase in type-1 ENT-binding sites per cell from 49,110 in untreated cells to 73,142 (P = 0.03) in cells treated with 10 microg/mL 5-FU for 2 hours, without a change in transporter affinity (P = 0.41). We conclude that [(18)F]FLT-PET can be used to measure thymidylate synthase inhibition as early as 1 to 2 hours after treatment with 5-FU by a mechanism involving redistribution of nucleoside transporters to the plasma membrane.

Effects of capecitabine and vinorelbine on cell proliferation, metabolism and COX2 and p16 expression in breast cancer cell lines and solid tumour tissues

BACKGROUND

Capecitabine is a recently developed oral antineoplastic prodrug of 5-fluorouracil. It has demonstrated a favorable tolerability profile, with low incidence of myelosuppression. Vinorelbine, a third generation vinca alkaloid, works by inhibiting mitosis and interfering with cells' ability to synthesize DNA and RNA. The present study investigates the therapeutic value of single use capecitabine on solid tumour tissues in vitro using breast cancer cell lines and as reference. The data is to be compared with the use of vinorelbine which is a conventionally applied drug for advanced breast cancer patients.

METHODS

The trucut biopsies of 35 metastatic breast tumour patients were obtained. The tissues were cultured for 24h. Capecitabine and vinorelbine were added according to the corresponding groups to be cultured by another 24h. Plain medium was added for control group. The two cell lines chosen were BT-783 and MB-MDA-231 to act as a reference group. The metabolic rate of the tissues and cell lines were measured by ATP bioluminescence assay and the proliferation rate was measured by WST-1. The level of COX2 and p16 after capecitabine and vinorelbine treatment was assessed with immunohistochemical methods.

RESULTS

One-way ANOVA revealed lower metabolic rate in test groups than control in cell lines and tumour tissues. WST-1 showed similar trend in both cell lines. COX2 and p16 staining showed decreases in cell size and number after drug use.

CONCLUSIONS

Capecitabine demonstrated similar inhibitory effects as vinorelbine in breast cancer cell lines and solid tumour tissues at decreasing cell proliferation and metabolism as well as decreasing the expression of metabolic proteins and tumor suppressor genes. Capecitabine also has the added benefits of convenient oral administration and lower cost.

Capecitabine plus oxaliplatin and irinotecan regimen every other week: a phase I/II study in first-line treatment of metastatic colorectal cancer

BACKGROUND

A phase I/II study was performed to determine the safety and activity of a capecitabine plus oxaliplatin and irinotecan (COI) regimen using capecitabine concurrently with oxaliplatin and irinotecan in previously untreated patients with metastatic colorectal cancer.

PATIENTS AND METHODS

Patients received irinotecan on day 1, oxaliplatin (85 mg/m(2)) on day 2 and capecitabine (1000 mg/m(2) orally twice daily) on days 2-6 of a biweekly schedule. Three dose levels ranging from 150 to 180 mg/m(2) were explored for irinotecan in sequential cohorts of three to six patients. Once the recommended dose was determined, a total of 28 eligible patients were planned at this dose level.

RESULTS

Thirty-eight patients received a median of six cycles. The recommended phase II dose of irinotecan was 180 mg/m(2). Toxicity was manageable: the most common severe toxicities were diarrhoea (24%) and nausea (16%). Of 27 assessable patients treated at the recommended dose, 17 achieved a partial response (overall response rate (ORR) 63%; 95% confidece interval (CI), 44 to 78%), with eight patients undergoing liver metastasectomy. Estimated progression-free survival and overall median survival were 8.5 and 23.5 months, respectively.

CONCLUSIONS

Biweekly COI is feasible and active. Tolerability and ease of administration make the regimen well suited for downsizing hepatic colorectal metastases before curative surgery.

Medullary thyroid cancer treated by capecitabine

Medullary thyroid carcinoma with distant metastases is generally incurable, with 20% overall survival at 10 years. The treatment goal is palliative. Chemotherapy has a limited role, with low response rates and high toxicities with the different regimens. Here, we report the case of 64-year-old man with metastatic medullary thyroid carcinoma in progression after primary treatment with cisplatin-doxorubicin. The patient received capecitabine 2000 mg/m total per day x 14 days followed by 1-week rest. He received 41 cycles, and presented prolonged and objective tumor response (30 months), without any toxicity.

Systemic anticancer therapy in gynecological cancer patients with renal dysfunction

Chronic kidney disease is a common occurrence in patients with gynecological cancer. Systemic anticancer treatment in such patients is a challenge for clinicians because of altered drug pharmacokinetics. For those drugs that are excreted mainly by the kidneys, decreased renal function may lead to increased systemic exposure and increased toxicity. Dose adjustment based on pharmacokinetic changes is required in this situation to avoid life-threatening toxicity. In this review, we summarize the nephrotoxicity and pharmacokinetic data of agents commonly used in systemic anticancer treatment of gynecological cancers and dose adjustment guidelines in the presence of impaired renal function. We review 17 medications that need dose adjustment (cisplatin, carboplatin, doxorubicin, epirubicin, cyclophosphamide, ifosfamide, topotecan, irinotecan, etoposide, capecitabine, bleomycin, methotrexate, actinomycin D, granulocyte-macrophage colony-stimulating factor, metoclopramide, cimetidine, and diphenhydramine) as well as 27 drugs that do not (paclitaxel, docetaxel, pegylated liposomal doxorubicin, gemcitabine, oxaliplatin, fluorouracil, vincristine, letrozole, anastrozole, tamoxifen, leuprorelin, megestrol, gefitinib, erlotinib, trastuzumab, leucovorin, granulocyte colony-stimulating factor, erythropoietin, ondansetron, granisetron, palonosetron, tropisetron, dolasetron, aprepitant, dexamethasone, lorazepam, and diazepam). We also review the formulae commonly used to estimate creatinine clearance, including Cockcroft-Gault, Chatelut, Jelliffe, Wright, and the Modification of Diet in Renal Disease study formulae.

Unilaterale akrale Nekrosen als Abortivform einer palmoplantaren Erythrodysästhesie

Hand-foot syndrome is a common toxic side-effect, particularly during chemotherapy, with an incidence of 6-64% overall and 10-24% for capecitabine (Xeloda) monotherapy. Consequently, differential diagnostic considerations should include hand-foot syndrome when acral skin lesions appear, particularly during capecitabine monotherapy. The dosage should be reduced or therapeutic regimen changed. We present a unique patient who while on capecitabine developed unilateral acral necrosis which should be classified as a minor form of hand-foot syndrome.

Acute myeloid leukaemia secondary to treatment with capecitabine for metastatic colorectal cancer

A 63-year-old woman was diagnosed with acute myelo-monocytic leukaemia, associated with MLL gene rearrangement, 16 months after completion of oral capecitabine for metastatic colon cancer. Capecitabine, recommended for use in metastatic breast and colon cancer and more recently as adjuvant treatment of colon cancer, has not previously been reported to be associated with secondary cancer.

The role of nucleoside transporters in cancer chemotherapy with nucleoside drugs

Nucleoside analogs are important components of treatment regimens for various malignancies. Nucleoside-specific membrane transporters mediate plasma membrane permeation of physiologic nucleosides and most nucleoside analogs, for which the initial event is cellular conversion of nucleosides to active agents. Understanding of the roles of nucleoside transporters in nucleoside drug toxicity and resistance will provide opportunities for potentiating anticancer efficacy and avoiding resistance. Because transportability is a possible determinant of toxicity and resistance of many nucleoside analogs, nucleoside transporter abundance might be a prognostic marker to assess drug resistance. Elucidation of the structural determinants of nucleoside analogs for interaction with transporter proteins as well as the structural features of transporter proteins required for permeant interaction and translocation will lead to "transportability guidelines" for the rational design and therapeutic application of nucleoside analogs as anticancer drugs. It should eventually be possible to develop clinical assays that predict sensitivity and/or resistance to nucleoside anti-cancer drugs and thus to identify those patient populations that will most likely benefit from optimal nucleoside analog treatments. This review discusses recent results from structure/function studies of human nucleoside transporters, the role of nucleoside transport processes in the cytotoxicity and resistance of several anticancer nucleoside analogs and strategies to improve the nucleoside transporter-related anticancer effects of nucleoside analogs.

Gemcitabine plus capecitabine compared with gemcitabine alone in advanced pancreatic cancer: a randomized, multicenter, phase III trial of the Swiss Group for Clinical Cancer Research and the Central European Cooperative Oncology Group

PURPOSE

This phase III trial compared the efficacy and safety of gemcitabine (Gem) plus capecitabine (GemCap) versus single-agent Gem in advanced/metastatic pancreatic cancer.

PATIENTS AND METHODS

Patients were randomly assigned to receive GemCap (oral capecitabine 650 mg/m2 twice daily on days 1 to 14 plus Gem 1,000 mg/m2 by 30-minute infusion on days 1 and 8 every 3 weeks) or Gem (1,000 mg/m2 by 30-minute infusion weekly for 7 weeks, followed by a 1-week break, and then weekly for 3 weeks every 4 weeks). Patients were stratified according to center, Karnofsky performance score (KPS), presence of pain, and disease extent.

RESULTS

A total of 319 patients were enrolled between June 2001 and June 2004. Median overall survival (OS) time, the primary end point, was 8.4 and 7.2 months in the GemCap and Gem arms, respectively (P = .234). Post hoc analysis in patients with good KPS (score of 90 to 100) showed a significant prolongation of median OS time in the GemCap arm compared with the Gem arm (10.1 v 7.4 months, respectively; P = .014). The overall frequency of grade 3 or 4 adverse events was similar in each arm. Neutropenia was the most frequent grade 3 or 4 adverse event in both arms.

CONCLUSION

GemCap failed to improve OS at a statistically significant level compared with standard Gem treatment. The safety of GemCap and Gem was similar. In the subgroup of patients with good performance status, median OS was improved significantly. GemCap is a practical regimen that may be considered as an alternative to single-agent Gem for the treatment of advanced/metastatic pancreatic cancer patients with a good performance status.

Capecitabine-induced headache responding to diltiazem

BACKGROUND

Headaches have been reported as a potential side effect of capecitabine therapy. However, severe limiting headaches are rarely experienced in this setting and no known therapy has been described for such a serious side effect.

RESULTS

We report the case of a patient treated with capecitabine and radiation for rectal adenocarcinoma. The patient developed grade 3 capecitabine-induced headache. A cause-effect relationship to capecitabine was suggested due to resolution of headache with capecitabine withdrawal and reappearance with capecitabine rechallenge. The patient's headache resolved with diltiazem therapy and she was able to complete capecitabine and radiation therapy without further adverse events.

CONCLUSIONS

Capecitabine and 5-fluorouracil (5-FU) are known vasospasm inducers. We hypothesize that capecitabine-induced headache is vascular in nature. This likely explains the noted response to a calcium channel blocker (CCB), namely diltiazem. CCBs should be considered in the treatment of 5-FU or capecitabine-induced headaches.

Targeting platelet-derived endothelial cell growth factor/thymidine phosphorylase for cancer therapy

Thymidine phosphorylase (TP) is a key enzyme in the pyrimidine nucleoside salvage pathway, but it also recognizes and inactivates various anti-cancer chemotherapeutic agents. Moreover, TP is identical to platelet-derived endothelial cell growth factor (PD-ECGF), an angiogenic factor with anti-apoptotic properties. Increased expression of PD-ECGF/TP is found in many tumor and stromal cells, and elevated TP levels are associated with aggressive disease and/or poor prognosis. Thus, progression and metastasis of TP-expressing tumors might be abrogated by TP inhibitors that are used as single agents or in combination with (TP-sensitive) nucleoside analogues. On the other hand, increased TP activity in tumors may be exploited for the tumor-specific activation of fluoropyrimidine prodrugs, such as capecitabine. This review will focus on the different biological activities of PD-ECGF/TP and their implications for cancer progression and treatment.

Capecitabine-induced diffuse palmoplantar keratoderma: is it a sequential event of hand-foot syndrome?

Capecitabine was developed as a prodrug of 5-fluorouracil (FU), with the goal of improving tolerability and intratumour drug concentrations through tumour-specific conversion to the active drug against numerous types of neoplasms. The most frequent adverse cutaneous reaction associated with capecitabine is hand foot syndrome (HFS), presented with symmetrical erythema, dysaesthesia, and desquamation on the palms and soles. Acquired palmoplantar keratoderma (PPK) can occur in various dermatoses associated with metabolic abnormalities, malignancies, and toxic agents. However, there has been no report of PPK after capecitabine chemotherapy. We report two cases of diffuse PPK, which developed in patients with metastatic breast cancer after one cycle of capecitabine chemotherapy. Because oral capecitabine is increasingly used for various solid tumours, clinicians should be aware that keratoderma can develop during capecitabine chemotherapy as a sequential event of HFS.

First-line treatment strategies for elderly patients with metastatic colorectal cancer

Colorectal cancer ranks third in incidence in both men and women after lung, breast and prostate cancer. The prevalence of colorectal cancer increases significantly with age, with 40% of patients in Europe being >75 years of age at the time of initial diagnosis. Furthermore, the number of elderly patients with colorectal cancer is expected to increase significantly over the next two decades. Treatment of advanced colorectal cancer has evolved dramatically over the last decade. Advances in surgery and chemotherapy are effective in prolonging time to disease progression and survival in patients with advanced colorectal cancer. For >40 years, fluorouracil has been the mainstay of chemotherapy for advanced colorectal cancer. Recently, however, newer cytotoxic chemotherapies and biological agents effective against colorectal cancer have been shown to improve overall survival in metastatic disease. Thus, a patient with metastatic colorectal cancer today has an expected median survival of 20 months compared with 10 months only a few years ago. There is evidence that elderly individuals derive as much survival benefit from standard chemotherapy approaches in metastatic colorectal cancer as younger patients. Unfortunately, most older patients who might benefit from chemotherapy are not offered this treatment, and the fraction who are not offered it increases with increasing age. Treatment decisions should not be made on the basis of age. Rather, they should be based on functional status, the presence of co-morbidities, and consideration of drug-specific toxicities that can be aggravated in older individuals because of decreased functional reserve. Although the elderly have been under-represented in clinical trials, studies also support the effectiveness of combination chemotherapy in elderly patients with advanced colorectal cancer. This article reviews current optimal first-line treatment strategies for elderly patients with metastatic colorectal cancer.

A case of capecitabine-induced coronary microspasm in a patient with rectal cancer

5-Fluorouracil (5-FU) is the most frequently used chemotherapy agent concomitant with radiotherapy in the management of patients with rectal cancer. Capecitabine is an oral fluoropyrimidine that mimics the pharmaconkinetics of infusional 5-FU. This new drug is replacing 5-FU as a part of the combined-modality treatment of a number of gastrointestinal cancers. While cardiac events associated with the use of 5-FU are a well known side effect, capecitabine-induced cardiotoxicity has been only rarely reported. Here, we reviewed the case of a patient with rectal cancer who had a capecitabine-induced coronary vasospasm. The most prominent mutation of the dihydropyrimidine dehydrogenase gene was also analyzed.

Capecitabine in Combination with Novel Targeted Agents in the Management of Metastatic Breast Cancer: Underlying Rationale and Results of Clinical Trials

At present there is no established standard of care for metastatic breast cancer and prognosis remains poor, although the use of newer chemotherapeutic regimens has led to modest improvements in survival. Capecitabine, an oral prodrug of 5-fluorouracil, is a promising addition to these approaches, having already shown single-agent activity against metastatic breast cancer. Following a pivotal trial demonstrating that capecitabine confers increased survival when used in combination with docetaxel, it is being investigated intensively in combined regimens using other standard chemotherapeutic agents, as well as with novel molecularly targeted therapies. Among the novel agents, the most intensively studied in combination with capecitabine is trastuzumab. Despite preclinical data suggesting that these two agents might not show additive effects, clinical trials have been very encouraging for both heavily pretreated patients and for patients receiving first-line therapy in the metastatic setting. This work is being further extended in an ongoing trial in the neoadjuvant setting. An initial trial in combination with bevacizumab, enrolling heavily pretreated patients, was less successful, but following the example of the E2100 trial, this combination is being re-examined in less heavily treated patients. In addition, this review discusses ongoing trials with an array of newer molecularly targeted agents. Significant improvement in time to progression has already been demonstrated in the combination of lapatinib and capecitabine compared with capecitabine monotherapy; for the most part, however, these trials are still in early stages.

International Society of Geriatric Oncology (SIOG) recommendations for the adjustment of dosing in elderly cancer patients with renal insufficiency

A SIOG taskforce was formed to discuss best clinical practice for elderly cancer patients with renal insufficiency. This manuscript outlines recommended dosing adjustments for cancer drugs in this population according to renal function. Dosing adjustments have been made for drugs in current use which have recommendations in renal insufficiency and the elderly, focusing on drugs which are renally eliminated or are known to be nephrotoxic. Recommendations are based on pharmacokinetic and/or pharmacodynamic data where available. The taskforce recommend that before initiating therapy, some form of geriatric assessment should be conducted that includes evaluation of comorbidities and polypharmacy, hydration status and renal function (using available formulae). Within each drug class, it is sensible to use agents which are less likely to be influenced by renal clearance. Pharmacokinetic and pharmacodynamic data of anticancer agents in the elderly are needed in order to maximise efficacy whilst avoiding unacceptable toxicity.

Should DPD analysis be required prior to prescribing fluoropyrimidines?

Dihydropyrimidine dehydrogenase (DPD) is a key enzyme in the metabolic catabolism of chemotherapeutic agent 5-fluorouracil (5FU) and its derivatives, including capecitabine. Numerous genetic mutations have been identified in the DPD gene locus (DPYD), with a few key variants having functional consequences on enzymatic activity. Deficiencies in DPD activity have been shown to cause 5FU-treated cancer patients to experience severe drug-related toxicities, often requiring extensive medical intervention. We review the performance of assays that assess DPD and DPYD status, with an emphasis on the robustness for routine clinical applications. None of the current strategies are adequate to mandate routine DPD testing prior to starting a fluoropyrimidine-based therapy. However, further research and technological improvements will hopefully allow prospective identification of potentially toxic patients, in order to reduce the number of patients with severe, life-threatening side effects to 5FU treatment.

Design, synthesis, and preliminary evaluation of doxazolidine carbamates as prodrugs activated by carboxylesterases

The synthesis and tumor cell growth inhibition by doxazolidine carbamate prodrugs are reported. The carbamates were designed for selective hydrolysis by one or more human carboxylesterases to release doxazolidine (Doxaz), the formaldehyde-oxazolidine of doxorubicin that cross-links DNA to trigger cell death. Simple butyl and pentyl, but not ethyl, carbamate prodrugs inhibited the growth of cancer cells that overexpress carboxylesterase CES1 (hCE1) and CES2 (hiCE). Relative CES1 and CES2 expression levels were determined by reverse transcription of the respective mRNAs, followed by polymerase chain reaction amplification. More complex structures with a p-aminobenzyl alcohol (PABA) self-eliminating spacer showed better growth inhibition (IC50=50 nM for Hep G2 liver cancer cells) while exhibiting reduced toxicity toward rat cardiomyocytes, relative to the parent drug doxorubicin. Pentyl 4-(N-doxazolidinylcarbonyloxymethyl)phenylcarbamate, the lead compound for further investigation, appears to be activated in Hep G2 cells that express both CES1 and CES2.

Capecitabine/Cyclophosphamide/Methotrexate for patients with metastatic breast cancer: a dose-finding, feasibility, and efficacy study

BACKGROUND

Capecitabine is a fluoropyrimidine carbamate that acts as a prodrug, mimics continuous infusion of 5-fluorouracil (5-FU), and has encouraging antitumor activity in women with metastatic breast cancer. We performed a feasibility study in which the 5-FU of the cyclophosphamide/methotrexate/5-FU regimen was substituted with capecitabine in a novel regimen applicable to women with breast cancer. Three doses of capecitabine were explored (1650 mg/m2, 1850 mg/m2, and 2000 mg/m2 per day from day 1 to day 14) in combination with intravenous bolus cyclophosphamide (600 mg/m2) and methotrexate (40 mg/m2), given on day 1 and day 8 every 4 weeks.

PATIENTS AND METHODS

From June 2002 to August 2004, 39 women with metastatic breast cancer were enrolled and were evaluable for toxicity and response.

RESULTS

Hematologic toxicity was mild for the majority of patients: grade 4 neutropenia and anemia and grade 3 thrombocytopenia occurred in 1 patient. Nonhematologic toxicity of grade > or = 3 occurred only at the highest dose level. Overall response rate was 44% (complete response rate, 13%; partial response rate, 31%). Clinical benefit including long-lasting (> or = 6 months) stable disease overall accounted for 82%. Responses were observed at each dose level. The median duration of response was 14 months (95% confidence interval, 10-28 months). At a median observation of 24 months (range, 8-36 months), time to progression was 13 months (95% confidence interval, 9-24 months).

CONCLUSION

The data of our study show that cyclophosphamide/methotrexate/capecitabine is feasible and active. The capecitabine dose of 1850 mg/m(2) orally on days 1-14 every 28 days was selected as the recommended dose in view of the higher likelihood of "on time" chronic therapy compared with the 2000-mg/m(2) dose.

Pharmacokinetic and safety study of weekly irinotecan and oral capecitabine in patients with advanced solid cancers

BACKGROUND

Capecitabine and irinotecan have demonstrated in vitro synergistic anti-cancer activity, and both are substrates for carboxyl esterases (CES). We conducted a study to identify a safe dose and potential drug-drug interactions of this combination.

METHODS

This was an open-label phase I dose escalation trial. Irinotecan was given as a 30 min infusion on days 1 and 8, and capecitabine on days 1-14 of a 21-day cycle. Plasma for pharmacokinetic analyses was drawn on days 1 and 8.

RESULTS

Forty-seven patients with advanced solid tumors received 202 cycles of chemotherapy in 6 dose cohorts. At the highest dose tested, 1 of 3 patients developed fatal neutropenia and gram-negative sepsis. At dose level 5 (100/2000), 2 of 28 patients developed cycle 1 DLT-grade 3 diarrhea/vomiting, and grade 3 diarrhea. Responses were observed in 9 of 35 (5 of 9 ovarian cancer) evaluable patients. The AUC((0-last)) of irinotecan, SN-38G, and APC were similar on days 1 and 8. However, SN-38 T(max) was longer on Day 8 (0.88 h vs. 1.23 h, p = 0.012). While SN-38 AUC((0-last)) was lower on day 8 by 35%, this was not statistically significant (p = 0.123).

CONCLUSIONS

Capecitabine results in a significantly delayed conversion of irinotecan to SN-38, suggesting drug-drug interaction at the level of CES. This suggests caution should be used when irinotecan is combined with substrates of CES, and warrants further study. The combination of irinotecan and capecitabine is safe and well tolerated at 100/2000, and warrants further evaluation in ovarian and breast cancer.

The Hollow Fibre Assay as a model for in vivo pharmacodynamics of fluoropyrimidines in colon cancer cells

The Hollow Fibre Assay (HFA) is usually applied as an early in vivo model for anti-cancer drug screening, but is potentially an excellent model for short-term in vivo pharmacodynamic studies. We used the model to study the in vivo role of thymidine phosphorylase/platelet-derived endothelial cell growth factor (TP/PD-ECGF) in the cytotoxicity and pharmacodynamics of TAS-102 in colon cancer cells. TAS-102 is a new oral drug formulation, which is composed of trifluorothymidine (TFT) and thymidine phosphorylase inhibitor (TPI), which prevents TFT degradation. We compared the activity with Xeloda (capecitabine), which is activated by TP into 5FU. Hollow fibres filled with human Colo320 or Colo320TP1 colorectal cancer cells with deficient or high TP expression, respectively, were implanted subcutaneously (s.c.) at both flanks of BALB/c mice. The mice were treated orally over 5 days with TAS-102, TFT alone, 5′DFUR±TPI or capecitabine at their maximum tolerated dose (MTD). The cells were retrieved from the fibres and assayed for growth (MTT assay), cell cycle distribution (flow cytometry) and apoptosis induction (FragEL method). TAS-102 induced considerable growth inhibition (50%, P<0.01) to both cell lines, which was completely abolished in the absence of TPI. Capecitabine and its metabolite 5′DFUR reduced proliferation of Colo320TP1 cells in the fibres significantly (down to 25–40%), but much less in Colo320 cells, whereas addition of TPI reduced the effect of 5′DFUR, although not completely. These differences in cytotoxic effects were reflected in the pharmacodynamic evaluation. TAS-102 induced a G2M-phase arrest (from 25 to 40%) and apoptosis (>8-fold), which was more pronounced in Colo320 than in Colo320TP1. Again, omission of TPI neutralised the effect of TAS-102. Similarly, 5′DFUR and capecitabine induced a significant G2M-phase arrest (up to 45%) in the Colo320TP1 cell line, but less pronounced in the parental Colo320. Addition of TPI to 5′DFUR reduced this effect to control levels. Also induction of apoptosis was reduced in the presence of TPI. The data demonstrated that the HFA is excellently suited for studying short-term pharmacodynamic effects of fluoropyrimidines in vivo. TAS-102 is only effective in inducing cytotoxicity when systemic TPI is present, but acts against both low and high TP expressing colon cancer cells, while 5′DFUR needs cellular TP to exert significant activity.

Pharmacogenetics of capecitabine in advanced breast cancer patients

PURPOSE

Germinal gene polymorphisms can explain a part of the interpatient pharmacodynamic variability of anticancer drugs, particularly fluoropyrimidines. Genes for which polymorphisms may potentially influence pharmacodynamics of fluoropyrimidines, including capecitabine, are thymidylate synthase (TS), methylenetetrahydrofolate reductase (MTHFR), and dihydropyrimidine dehydrogenase (DPD).

EXPERIMENTAL DESIGN

The aim of this prospective pilot study was to analyze the effect of TS, MTHFR, and DPD gene polymorphisms on toxicity and efficacy in advanced breast cancer patients receiving capecitabine as monotherapy. Germinal polymorphisms of TS (6 bp deletion in the 3' region and 28 bp repeats, including G>C mutation in the 5' region), MTHFR (677C>T and 1298A>C), and DPD (IVS14+1G>A) were determined in 105 consecutive patients.

RESULTS

A trend toward a higher global toxicity grade 3 and 4 was observed in patients homozygous for the TS 3RG allele compared with patients heterozygous for the 3RG allele or patients not carrying the 3RG allele (50% versus 19% versus 13% respectively, P=0.064). The sole patient bearing the DPD IVS14+1G>A mutation (heterozygous) deceased from hematologic toxicity. The median response duration was 5.8 months (95% confidence interval, 4.3-7.2). Duration of response was significantly shortened in patients homozygous for the 3RG allele compared with others (P=0.037).

CONCLUSIONS

The present data suggest that 3RG3RG breast cancer patients are not good candidates for capecitabine therapy. In addition, attention should be paid to DPD deficiency in breast cancer patients receiving capecitabine. These preliminary data require further confirmation on a larger number of patients.

Phase II study of capecitabine and cisplatin in previously untreated advanced biliary tract cancer

BACKGROUND

Biliary tract cancer is one of the most aggressive and chemotherapy-refractory tumors. Although only curative treatment modality is surgery, most patients are not suitable for surgery due to advanced stage of the disease at diagnosis. Thus most patients with biliary tract cancer are possible candidates for palliative chemotherapy. The standard chemotherapeutic regimen is still to be defined, however. We performed a phase II study of combination chemotherapy with capecitabine and cisplatin in these patients to evaluate efficacy and toxicity of the regimen.

METHODS

Patients with previously untreated metastatic, recurrent, or inoperable biliary tract cancer were enrolled. Eligible patients were screened as following: (1) histologically confirmed, (2) age between 18 and 75 years, (3) at least one measurable lesion according to RECIST criteria, (4) ECOG performance status <or=2, (5) a life expectancy of at least 3 months, and (6) adequate laboratory values. Patients received capecitabine (2,500 mg/m2/day, days 1 to 14) and cisplatin (60 mg/m2, day 1) every 3 weeks. Response was assessed for every two cycles of chemotherapy and treatment was stopped when tumor had progressed or stable with no further response.

RESULTS

Thirty-two patients were enrolled, 20 (62.5%) were male and 12 (37.5%) were female and the median age was 54 years (33-71 years). Fifteen patients (46.9%) had gallbladder cancer, 13 (40.6%) had intrahepatic cholangiocarcinoma, and 4 (12.5%) had extrahepatic biliary cancer. The most frequent metastatic sites were lymph nodes (20/32, 62.5%) and liver (28/32, 56.3%). No complete response was observed and partial response was observed in 13/32 patients. By the intent-to-treat analysis, the overall response rate was 40.6% (95% CI, 23.7-59.4) with 0 CR and 13 PRs. Stable disease was observed in 3 patients (9.4%), and 11 patients (34.4%) had progressive disease. The median time to progression was 3.5 months (95% CI, 1.3-5.8), and the median overall survival was 12.4 months (95% CI, 6.3-18.5) after the median follow-up duration of 9.5 months (4.8-26.1 months). A total of 108 cycles of chemotherapy was delivered. Grade 3 hematologic toxicities included neutropenia (5, 15.6%), anemia (1, 3.1%), and thrombocytopenia (1, 3.1%) per patient, and no grade 4 hematologic toxicities were observed. Grade 3 non-hematologic toxicities included hyperbilirubinemia (2, 6.3%), increase of alkaline phosphatase (2, 6.3%), hand-foot syndrome (2, 6.3%), anorexia, and diarrhea (1, 3.1%) per patient, respectively. There was no treatment-related death.

CONCLUSION

The combination chemotherapy of capecitabine and cisplatin demonstrated a promising antitumor activity with mild toxicity profile in patients with advanced biliary tract cancer.

Paraneoplastic neurological syndromes and breast cancer. Regression of paraneoplastic neurological sensorimotor neuropathy in a patient with metastatic breast cancer treated with capecitabine: a case study and mini-review of the literature

Paraneoplastic neurological syndromes are a rare complication of breast cancer. Nevertheless, they may be clinically relevant leading to neurological impairment. Clinicians should be aware that these neurological disorders could even precede the diagnosis of breast cancer. Here we present the case of a female patient with advanced breast cancer who developed paraneoplastic sensorimotor neuropathy. Treatment with capecitabine lead to clinical amelioration. A review of the literature on the paraneoplastic neurological syndromes in breast cancer is also included.

Relationship between AUC of 5'-DFUR and toxicity of capecitabine, fluoropyrimidine carbamate analogs, and 5'-DFUR in monkeys, mice, and rats

Capecitabine is an oral fluoropyrimidine carbamate which is converted to 5-fluorouracil (5-FU) via 3 enzymatic step to 5'-deoxy-5-fluorocytidine (5'-DFCR), 5'-deoxy-5-fluorouridine (5'-DFUR), and finally 5-FU. We performed 4-week toxicity studies of capecitabine (N(4)-pentyloxycarbonyl-5'-deoxy-5-fluorouridine), galocitabine (trimethoxybenzyl-5'-deoxy-5-fluorocytidine), 4 different fluoropyrimidine carbamate analogs (R=butyl, isopentyl, propyl, or phenethyl), and 5'-DFUR in cynomolgus monkeys with toxicokinetic measurements of intact molecules, 5'-DFCR, and 5'-DFUR. Four-week toxicity data for capecitabine in rats and mice were also obtained for comparison. Capecitabine, galocitabine, butyl, and isopentyl analogs showed similar toxicities in hematopoietic and intestinal organs at 1.0 mmol/kg and the AUCs of 5'-DFUR were approximately 40 to 60 microg*hr/ml. These compounds showed slight toxicity at 0.5 mmol/kg and no toxicity at 0.1 mmol/kg, and AUCs of 5'-DFUR were approximately 30 and 5 microg*hr/ml, respectively. Propyl and phenethyl analogs showed slight toxicity at 1.0 mmol/kg and no toxicity at 0.5 mmol/kg, and AUCs of 5'-DFUR were approximately 30 and 10 microg*hr/ml, respectively. On the other hand, severe and slight-to-moderate toxicity was observed at 0.5 and 0.25 mmol/kg in 5'-DFUR-treated monkeys and AUCs of 5'DFUR were 35.6 and 5.2 microg*hr/ml, respectively. In mice and rats, the toxicity of capecitabine was less than in monkeys relative to dose, but 5'-DFUR AUCs were almost the same. In conclusion, 5'-DFUR AUC correlated with toxicity following oral administration of capecitabine and its analogs in monkeys, mice, and rats, although this relationship is not seen in humans. Capecitabine was less toxic in monkeys than oral 5'-DFUR according to dose (mmol/kg) and 5'-DFUR AUC.

Activity and substrate specificity of pyrimidine phosphorylases and their role in fluoropyrimidine sensitivity in colon cancer cell lines

Thymidine phosphorylase (TP) and uridine phosphorylase (UP) are often upregulated in solid tumors and catalyze the phosphorolysis of natural (deoxy)nucleosides and a wide variety of fluorinated pyrimidine nucleosides. Because the relative contribution of each of the two enzymes to these reactions is still largely unknown, we investigated the substrate specificity of TP and UP in colon cancer cells for the (fluoro)pyrimidine nucleosides thymidine (TdR), uridine (Urd), 5'-deoxy-5-fluorouridine (5'DFUR), and 5FU. Specific inhibitors of TP (TPI) and UP (BAU) were used to determine the contribution of each enzyme in relation to their cytotoxic effect. The high TP expressing Colo320TP1 cells were most sensitive to 5'DFUR and 5FU, with IC50 values of 1.4 and 0.2 microM, respectively, while SW948 and SW1398 were insensitive to 5'DFUR (IC50>150 microM for 5'DFUR). TPI and BAU only moderately affected sensitivity of Colo320, SW948, and SW1398, whereas TPI significantly increased IC(50) for 5'DFUR (50-fold) and 5FU (11-fold) in Colo320TP1 and BAU that in C26A (9-fold for 5'DFUR; p<0.01). In the epithelial skin cell line HaCaT both inhibitors were able to decrease sensitivity to 5'DFUR and 5FU separately. HaCaT might be a model for 5'DFUR toxicity. In the colon cancer cells 5'DFUR degradation varied from 0.4 to 50 nmol 5FU/h/10(6)cells, that of TdR from 0.3 to 103 nmol thymine/h/10(6)cells, that of Urd from 0.8 to 79 nmol uracil/h/10(6)cells, while conversion of 5FU to FUrd was from 0.3 to 46 nmol/h/10(6)cells. SW948 and SW1398 were about equally sensitive to 5'DFUR and 5FU, but SW1398 had higher phosphorylase activity (>65-fold) compared to SW948. In SW948 and HaCaT TPI and BAU inhibited TdR and Urd phosphorolysis (>80%), respectively. Both TP and UP contributed to the phosphorolysis of 5'DFUR and 5FU. In the presence of both inhibitors, still phosphorolysis of 5FU (>40%) was detected in the tumor and HaCaT cell lines, and remarkably, that of all four substrates in SW1398 cells. 5'DFUR phosphorolysis was also measured in situ, where Colo320TP1, SW1398, and HaCaT cells produced significant amounts 5FU from 5'DFUR (>10 nmol/24h/10(6)cells). In Colo320TP1 and in HaCaT cells TPI completely prevented 5FU production, but not in SW1398 cells, where BAU decreased this by 67% (p<0.01). High uracil and dUrd levels were detected in the medium. Uracil accumulation was heavily reduced in the presence of TPI for Colo320TP1 and HaCaT cells, whereas 5FU-induced dUrd production by these cell lines increased (p<0.01). In contrast, for SW1398 cells only BAU was able to reduce uracil levels, and dUrd production remained unchanged. In conclusion, overlapping substrate specificity was found for TP and UP in the cell lines, in which both enzymes were responsible for converting TdR and Urd, and 5'DFUR. 5'DFUR and 5FU were converted to their products in both the colon cancer cells and keratinocytes.

Onicolisis con exudado del hiponiquio secundaria a quimioterapia con paclitaxel y capecitabina

A 39-year-old female patient who consulted due to onycholysis, subungual hyperkeratosis and presence of exudate in the big toe of the right foot. The lesions appeared during oncology treatment of bilateral breast cancer with lymphatic metastases with paclitaxel every three weeks and capecitabine daily. Clinical manifestations are due to the involvement of the nail bed caused by the chemotherapy. These should be known and taken into account due to the increased use of this type of cytotoxic agents.

5′-O-Tritylated Nucleoside Derivatives: Inhibition of Thymidine Phosphorylase and Angiogenesis

Thymidine phosphorylase (TPase) is one of the key enzymes involved in the pyrimidine nucleoside salvage pathway. However, TPase also stimulates angiogenesis, and its expression correlates well with microvessel density and metastasis in a variety of human tumors. We have shown recently that 5'-O-trityl-inosine (KIN59) allosterically inhibits TPase enzymatic activity. KIN59 also inhibits TPase-induced angiogenesis in the chick chorioallantoic membrane (CAM) assay. The trityl group was found to be instrumental to preserve both the anti-TPase and antiangiogenic effect. We have now synthesized a variety of novel 5'-O-trityl nucleoside derivatives. Enzyme activity studies showed that the anti-TPase activity is significantly improved by replacement of the hypoxanthine base by thymine [3.5-fold; i.e., 5'-O-tritylthymidine (KIN6)] and the introduction of chloride on the trityl group [7-fold; i.e., 5'-O-(4-chlorotrityl)-inosine (TP136)], whereas removal of 2'-hydroxyl in the ribose did not significantly alter the anti-TPase activity. Enzyme kinetic studies also demonstrated that 1-(5'-O-trityl-beta-d-ribofuranosyl)-thymine (TP124), like KIN59, inhibits TPase in a noncompetitive fashion both with respect to phosphate and thymidine. Most KIN59 analogs markedly inhibited TPase-induced angiogenesis in the CAM assay. In vitro studies showed that the antiangiogenic effect of these compounds is not attributed to endothelial cell toxicity. For several compounds, there was no stringent correlation between their anti-TPase and antiangiogenic activity, indicating that these compounds may also act on other angiogenesis mediators. The antiangiogenic 5'-O-trityl nucleoside analogs also caused degradation of pre-existing, immature vessels at the site of drug exposure. Thus, 5'-O-trityl nucleoside derivatives combine antiangiogenic and vascular-targeting activities, which opens perspectives for their potential use as anticancer agents.

Acute coronary syndrome induced by oral capecitabine

A 41-year-old woman who was undergoing oral chemotherapy with capecitabine for metastatic breast cancer presented with recurrent episodes of chest pain associated with electrocardiographic signs of diffuse ST segment elevation. After spontaneous pain relief, the electrocardiogram showed ischemic evolution in the anterior precordial leads. Coronary and ventricular angiography, performed 24 h later, showed normal coronary arteries and normal left ventricular function. After therapy with capecitabine was discontinued, the patient did not experience further episodes of chest pain. After a nine-month follow-up, she remains alive, with a good performance status and without clinical evidence of persistent ischemia.

Radiation Modifiers: Treatment Overview and Future Investigations

Many radiosensitizers are in current clinical use. In addition, a myriad of potential new targeted therapies, which may also interact with radiation, are in clinical development. The clinical utility of new targeted therapies, in combination with existing radiation sensitizers (chemotherapies) requires further evaluation, as does the understanding of their acute and late radiation effects. Free radical scavengers appear to show promise as radioprotectors, but data for mucoprotection are less convincing.

Evidence of activity of Irinotecan in patients with advanced AIDS-related Kaposi's sarcoma

Fourteen HIV-infected patients with advanced Kaposi's sarcoma (KS) received Irinotecan 150 mg/m intravenously on days 1 and 10. All patients were relapsed/progressed during highly active antiretroviral therapy, administered as primary antineoplastic therapy. An objective response, all partial remissions, occurred in 75% of patients. Irinotecan was well tolerated, severe leukopenia occurred in only 33% of patients. In HIV-infected patients with advanced KS, irinotecan is active and well tolerated.