Bioequivalence of two tablet formulations of capecitabine and exploration of age, gender, body surface area, and creatinine clearance as factors influencing systemic exposure in cancer patients

Roll-to-Roll Manufacturing of Breathable Superhydrophobic Membranes

Self-cleaning and anti-biofouling are both advantages for lotus-leaf-like superhydrophobic surfaces. Methods for creating superhydrophobicity, including chemical bonding low surface energy molecular fragments and constructing surface morphology with protrusions, micropores, and trapped micro airbags by traditional physical strategies, unfortunately, have encountered challenges. They often involve complex synthesis processes, stubborn chemical accumulation, brutal degradation, or infeasible calculation and imprecise modulation in fabricating hierarchical surface roughness. Here, a scalable method to prepare high-quality, breathable superhydrophobic membranes is proposed by developing a successive roll-to-roll laser manufacturing technique, which offers advantages over conventional fabrication approaches in enabling automatically large-scale production and ensuring cost-effectiveness. Nanosecond laser writing and femtosecond laser drilling produce surface microstructures and micropore arrays, respectively, endowing the membrane with superior antiwater capability with hierarchical microstructures forming a barrier and blocking water infiltration. The membrane's breathability is carefully optimized by tailoring micropore arrays to allow for the adequate passage of water vapor while maintaining superhydrophobicity. These membranes combine the benefits of anti-aqueous corrosive liquid behaviors, photothermal effects, thermoplastic properties, and stretchable performances as promising comprehensive materials in diverse scenes.

Pharmacokinetic and bioequivalence study of two capecitabine tablets in Chinese patients with solid tumor cancer

Capecitabine (CAP) is one of the fluoropyrimidine deoxynucleoside carbamates, which can be converted to 5-fluorouracil (5-FU) by thymine deoxynucleoside phosphorylase (dThdPase) to exert antitumor effects. The purpose of this study is to compare the pharmacokinetics (PK), bioequivalence (BE), and safety of two CAP tablets in Chinese patients with solid tumor cancer. The results showed that the geometric mean ratios (GMRs) of Cmax, AUC0-t and AUC0-∞ of CAP T/R reagent were 90.26%, 95.27%, and 95.07, respectively. The values and 90% confidence intervals (CI) of AUC0-t, AUC0-∞, and Cmax all fall within the range of 80.00-125.00%. In addition, a total of 22 subjects in this study had 30 adverse events, with an incidence of 45.83%, and there were no serious adverse events and adverse events that led to withdrawal from the trial.

Evaluation of bioequivalence and safety analysis of capecitabine tablets and Xeloda® under postprandial dosing conditions in Chinese patients with solid tumor

OBJECTIVES

To compare the pharmacokinetic and safety of the test group capecitabine tablets (0.5 g) and the reference group capecitabine tablets (0.5 g).

METHODS

This study was registered at www.chinadrugtrials.org.cn under the registration number CTR20220138. 48 subjects with solid tumor were recruited and randomized to receive either the test group or the reference group at a dose of 2 g per cycle for three cycles of the entire trial.

RESULTS

The point estimate of the geometric mean ratio of Cmax for the subject and reference groups was 1.0670, which was in the range of 80.00%-125.00%. And the upper limit of 95% confidence interval was -0.0450 < 0. The statistics of geometric mean ratio of AUC0-t and AUC0-∞ (test group/reference group) and their 90% confidence intervals were in the range of 80.00%-125.00%, thus the test group was bioequivalent to the reference group under the conditions of this postprandial test. There were no major or serious adverse events. Conclusion: The pharmacokinetic profiles of capecitabine under postprandial conditions were consistent between the two groups. The two groups were bioequivalent and had a similar favorable safety profile in Chinese patients with solid tumor.

Biotransformation research advances - 2022 year in review

This annual review is the eighth of its kind since 2016 (Baillie et al. 2016, Khojasteh et al. 2017, Khojasteh et al. 2018, Khojasteh et al. 2019, Khojasteh et al. 2020, Khojasteh et al. 2021, Khojasteh et al. 2022). Our objective is to explore and share articles which we deem influential and significant in the field of biotransformation.

A case report of typhlitis during novel use of ropidoxuridine-capecitabine-radiotherapy for treatment-naïve rectal cancer

BACKGROUND

Rectal carcinomas are tumors that arise from the last 12 cm of the large intestine closest to the anus. They generally have a modest prognosis exacerbated by a high local recurrence rate if radiosensitizing chemotherapy is not given during radiotherapy. This case report discusses the clinical trial treatment of a patient with rectal adenocarcinoma by a new ropidoxuridine-capecitabine-radiotherapy combination. This case report is novel due to the patient's participation in an accelerated titration phase I clinical trial and the resultant rare adverse event of treatment-related sigmoid typhlitis.

CASE PRESENTATION

The patient was an 82-year-old female who noticed hematochezia and change in stool caliber over a period of 3 months. A rectal mass was identified by biopsy as a microsatellite stable adenocarcinoma. A planned total neoadjuvant treatment involved eight cycles of leucovorin calcium (folinic acid)-fluorouracil-oxaliplatin (mFOLFOX6) chemotherapy, followed by a clinical trial combination of ropidoxuridine-capecitabine-radiotherapy, prior to definitive surgery. The patient began daily intensity modulated pelvic radiotherapy with concurrent twice-daily oral ropidoxuridine and twice-daily oral capecitabine to be given over 6 weeks. After 14 days of ropidoxuridine-capecitabine-radiotherapy, the patient developed sigmoid typhlitis requiring a 10-day hospitalization and 14-day disruption of treatment. The patient died 27 days after the start of ropidoxuridine-capecitabine-radiotherapy. This adverse event was listed as a definite attribution to the ropidoxuridine-capecitabine treatment; pharmacokinetic and pharmacodynamic data showed low ropidoxuridine metabolite DNA incorporation and high capecitabine metabolite concentration. The accelerated titration phase I clinical trial has been subsequently closed to accrual (NCT04406857).

CONCLUSIONS

We believe this case report demonstrates the decision-making process for terminating a phase I accelerated titration designed clinical trial. The report also presents the rare complication of sigmoid typhlitis as a treatment-attributed adverse event. In this case, a ropidoxuridine-capecitabine combination was used as an investigational radiosensitizing treatment now with a narrower future clinical development pathway.

Influence of age on pharmacokinetics of capecitabine and its metabolites in older adults with cancer: a pilot study

BACKGROUND

Capecitabine is an oral chemotherapy prodrug of 5-fluorouracil (5-FU) with unpredictable toxicity, especially in older adults. The aim of this study was to evaluate the pharmacokinetics (PK) of capecitabine and its metabolites in younger adults (< 70 years) and older adults (≥ 70 years) receiving capecitabine for solid cancer.

METHODS

Eligible participants receiving capecitabine had 2 venous samples collected on day 14 of cycle 1 and cycle 2 of their treatment. Capecitabine and metabolite concentrations were determined using liquid chromatography with tandem mass spectrometry. A Bayesian estimation approach was used to generate individual estimates of PK parameters for 5-FU. A linear mixed-effect analysis of variance (ANOVA) model was used to compare dose-normalised log-transformed PK parameters between age groups. Correlations were determined by linear regression and logistic regression analyses.

RESULTS

Of the total 26 participants, 58% were male with a median age of 67 years (range, 37-85) with 54% aged < 70 years and 46% aged ≥ 70 years. Participants aged ≥ 70 years, compared to those aged < 70 years, had a greater 5-FU exposure based on area under the concentration-time curve (AUC) of 17% (90% CI 103-134%; 0.893 vs. 0.762 mg h/L) and 14% increase in maximal concentration, C_max (90% CI 82.1-159%; 0.343 vs. 0.300 mg/L). The 5-FU C_max was positively associated with time up and go (TUG) (Pearson's correlation 0.77, p = 0.01), but not other geriatric assessment domains or severe toxicity.

CONCLUSION

5-FU exposure was significantly increased in older adults compared to younger adults receiving equivalent doses of capecitabine, and is a possible cause for increased toxicity in older adults.

Pharmacokinetic and bioequivalence study of two capecitabine tablets in Chinese patients with breast, colorectal or gastric cancer under fed condition: A multicentric, randomized, open-label, single-dose, two-period, two-way crossover clinical trial

OBJECTIVE

The aim of this study was to examine the pharmacokinetics, bioequivalence, and safety of two tablet formulations of capecitabine 500 mg in Chinese patients with breast, colorectal or gastric cancer under fed condition.

METHODS

A multicentric, randomized, open-label, single-dose, two-period, two-way crossover trial was conducted by randomizing a single oral dose of test (T) or reference (R, Xeloda®) capecitabine (500 mg) to patients of either sex with colon, colorectal or breast cancer under fed condition (high-fat and high-calorie diet). Pharmacokinetic parameters were calculated using non-compartmental methods. Patients were monitored for safety and tolerability throughout the study.

RESULTS

74 subjects were randomly enrolled. The T/R geometric mean ratios (GMRs) and 90% confidence intervals (CIs) for C_max, AUC_0-t and AUC_0-∞ of capecitabine were 96.60% (85.87-108.67%), 99.07% (95.40-102.89%), 99.17% (95.29-103.21%), respectively. All 90% CIs fell within the bioequivalence acceptance range of 80.00-125.00%. The common adverse events (AEs) included clinically significant laboratory abnormalities and gastrointestinal diseases. There were no serious adverse events (SAEs) or deaths during the study. No subject withdrew from the study due to AEs.

CONCLUSION

Single oral intake of test and the reference capecitabine tablets were bioequivalent under fed condition and had similar favourable safety profiles in Chinese patients with breast, colorectal or gastric cancer.

TRIAL REGISTRATION

chinadrugtrials.org.cn (CTR20182110).

Evaluation and prediction of oral drug absorption and bioequivalence with food-drug interaction

This article reviews the impacts on the in vivo prediction of oral bioavailability (BA) and bioequivalence (BE) based on Biopharmaceutical classification systems (BCS) by the food-drug interaction (food effect) and the gastrointestinal (GI) environmental change. Various in vitro and in silico predictive methodologies have been used to expect the BA and BE of the test oral formulation. Food intake changes the GI physiology and environment, which affect oral drug absorption and its BE evaluation. Even though the pHs and bile acids in the GI tract would have significant influence on drug dissolution and, hence, oral drug absorption, those impacts largely depend on the physicochemical properties of oral medicine, active pharmaceutical ingredients (APIs). BCS class I and III drugs are high soluble drugs in the physiological pH range, food-drug interaction may not affect their BA. On the other hand, BCS class II and IV drugs have pH-dependent solubility, and the more bile acid secretion and the pH changes by food intake might affect their BA. In this report, the GI physiological changes between the fasted and fed states are described and the prediction on the oral drug absorption by food-drug interaction have been introduced.

Pharmacokinetics and Comparative Bioavailability of Test or Reference Capecitabine and Discrepant Pharmacokinetics Among Various Tumors in Chinese Solid Cancer Patients

The main objective of this study was to compare the pharmacokinetic (PK) bioequivalence of two capecitabine tablets and explore the different PK profiles of various tumors in Chinese patients with cancer. All 76 patients with a confirmed cancer diagnosis were included in this study. A single dose of 2000 mg of test or reference capecitabine (Xeloda, Hoffmann-La Roche) was orally administered postprandially. After 24 hours of washout, the patients were administered the test or the reference capecitabine alternately. PK samples were taken at the time of predose up to 6 hours postdose. Bioequivalence evaluation was performed using the geometric mean ratios of peak concentration in plasma (C_max) , area under the concentration-time curve from time 0 to 6 h (AUC_0-t) , and area under the concentration-time curve from time 0 to infinity (AUC_0-∞ ) for capecitabine and 5-fluorouracil (5-FU). In this study, 90% confidence intervals of test/reference mean ratios of C_max , AUC_0-t , AUC_0-∞ of capecitabine and 5-FU were in the range of 80%-125%. Both the test and reference capecitabine regimens were well tolerated in this study. Furthermore, we found that patients with esophageal-gastrointestinal cancers had higher exposure to capecitabine and a shorter time to C_max (T_max) than those with breast cancer. In conclusion, a single oral dose of 2000 mg of test capecitabine tablets after postprandial administration was bioequivalent to the reference drug.

Fixed dose combination of capecitabine and cyclophosphamide in metastatic breast cancer: Results from THE ENCLOSE phase 2/3 randomized multicenter study

Aim

To evaluate pharmacokinetics, efficacy and safety of fixed-dose combination (FDC) of oral capecitabine + cyclophosphamide in metastatic breast cancer (MBC) patients progressing after anthracycline and/or taxane chemotherapy.

Methods

In this prospective, adaptive, phase-2/3, open-label study (CTRI/2014/12/005234), patients were randomized (1:1:1) to three FDC doses (doses/day: D1, capecitabine + cyclophosphamide 1400 mg + 60 mg; D2, 1800 mg + 80 mg; D3, 2200 mg + 100 mg) for 14 days, in 21-day cycles. In Part-I, multiple-dose pharmacokinetics and optimal dose(s) were evaluated with futility analysis. Group(s) with <3 responders based on best overall response rate (BOR, complete response [CR]+partial response [PR]), were discontinued. Efficacy (BOR, disease control rates [DCR; CR + PR + stable disease]) and safety of optimal dose(s) were evaluated in Part-II.

Results

Of 66 patients (n = 22/group) in Part-I, pharmacokinetics (D1 = 7/22, D2 = 9/22, D3 = 8/22) showed dose-proportionality for cyclophosphamide and greater than dose-proportionality for capecitabine. Modified intent-to-treat (mITT) analysis showed BOR of 7.14% (1/14) in D1 (discontinued), and 22.22% (4/18) each in D2 and D3, respectively. In Part-II, 50 additional patients were randomized in D2 and D3 (n = 144; total 72 [22 + 50] patients/group). mITT analysis in D2 (n = 54) and D3 (n = 58) showed BOR of 29.63% (16/54, 95%CI: 17.45–41.81%) and 22.41% (13/58, 95%CI: 11.68–33.15%), respectively. DCR in D2 and D3 were 87.04% (47/54, 95%CI: 78.08–96.00%) and 82.76% (48/58; 95%CI: 73.04–92.48%) after 3 and 57.41% (31/54; 95%CI: 52.41–79.50%) and 50.00% (29/58; 95%CI: 40.40–67.00%), after 6-cycles, respectively. Hand-foot syndrome (16.67%), vomiting (9.72%) in D2, and hand-foot syndrome (18.06%), asthenia (15.28%) in D3 were most-common adverse events.

Conclusion

FDC of capecitabine + cyclophosphamide (1800 + 80 mg/day) showed high disease control rates and good safety profile in MBC patients.

•

Oral fixed dose combination (FDC) of capecitabine + cyclophosphamide developed.

•

FDC showed high efficacy and good safety profiles.

•

Effective in MBC patients progressing post anthracycline and/or taxane exposure.

•

Oral FDC formulation may reduce pill burden and improve patient compliance.

Pharmacokinetic and Safety Comparison of Two Capecitabine Tablets in Patients with Colorectal or Breast Cancer Under Fed Conditions: A Multicenter, Randomized, Open-Label, Three-Period, and Reference-Replicated Crossover Study

INTRODUCTION

In this study, we assessed the pharmacokinetics (PK), bioequivalence, and safety of 150 mg capecitabine compared to the branded reference formulation in colorectal or breast cancer patients receiving a high-fat diet.

METHODS

This was a multicenter, open, random, balanced, three-period, three-sequence and semi-repetitive cross study with 48 subjects. In each study period, the eligible subject received the test or reference formulation, followed by a 1-day washout period. Serial blood samples for pharmacokinetic assessment were collected at predose up to 8 h postdose. The plasma concentrations of capecitabine were analyzed by LC/MS-MS. Pharmacokinetic parameters (non-compartmental model) were assessed with WinNonlin software. The pharmacokinetic parameters assessed were the area under the plasma concentration-time curve from time 0 to the time of last measurable concentration (AUC_0-t), the AUC from time zero to infinity (AUC_0-∞), the peak plasma concentration of the drug (C_max), the time needed to reach maximum concentration (T_max), the elimination half-life (t_1/2), and the terminal elimination rate (λ_z). All were analyzed using an analysis of variance (ANOVA) model after logarithmic transformation of the data. To establish the bioequivalence (BE) for capecitabine, reference-scaled average bioequivalence (RSABE) acceptance criteria and average bioequivalence (ABE) acceptance criteria were used. Safety and tolerability were assessed during the entire study period.

RESULTS

Reference scaled maximum plasma concentration (C_max) was higher than 0.294, permitting use of RSABE. The within-subject SDs of the reference intervention (S_WR) for AUC_0-t and AUC_0-∞ were < 0.294, meeting ABE criteria. The point estimate for the geometric least squares mean (GLSM) ratio for the point estimate of C_max was 0.962, within the range of 0.80-1.25. The 90% upper confidence boundary for the test/reference of GLSM ratios was 97.84-105.40% for AUC_0-t and 97.33-103.51% for AUC_0-∞, all of which were within the prespecified limits. The 90% confidence intervals for AUC_0-t and AUC_0-∞ and 95% upper confidence limit for C_max indicated bioequivalence. No serious adverse events were found among the subjects.

CONCLUSIONS

According to the criteria for bioequivalence, the test formulation was bioequivalent to the reference formulation in terms of the rate and extent of absorption under fed conditions by measurement of total capecitabine and was safe and well tolerated.

TRIAL REGISTRATION

NCT04420871.

Let's talk about sex: Differences in drug therapy in males and females

Professor Henry Higgins in My Fair Lady said, 'Why can't a woman be more like a man?' Perhaps unintended, such narration extends to the reality of current drug development. A clear sex-gap exists in pharmaceutical research spanning from preclinical studies, clinical trials to post-marketing surveillance with a bias towards males. Consequently, women experience adverse drug reactions from approved drug products more often than men. Distinct differences in pharmaceutical response across drug classes and the lack of understanding of disease pathophysiology also exists between the sexes, often leading to suboptimal drug therapy in women. This review explores the influence of sex as a biological variable in drug delivery, pharmacokinetic response and overall efficacy in the context of pharmaceutical research and practice in the clinic. Prospective recommendations are provided to guide researchers towards the consideration of sex differences in methodologies and analyses. The promotion of disaggregating data according to sex to strengthen scientific rigour, encouraging innovation through the personalisation of medicines and adopting machine learning algorithms is vital for optimised drug development in the sexes and population health equity.

Worse capecitabine treatment outcome in patients with a low skeletal muscle mass is not explained by altered pharmacokinetics

Background

A low skeletal muscle mass (SMM) has been associated with increased toxicity and shorter survival in cancer patients treated with capecitabine, an oral prodrug of 5‐fluorouracil (5‐FU). Capecitabine and its metabolites are highly water‐soluble and, therefore, more likely to distribute to lean tissues. The pharmacokinetics (PK) in patients with a low SMM could be changed, for example, by reaching higher maximum plasma concentrations. In this study, we aimed to examine whether the association between a low SMM and increased toxicity and shorter survival could be explained by altered PK of capecitabine and its metabolites.

Methods

Previously, a population PK model of capecitabine and metabolites in patients with solid tumors was developed. In our analysis, we included patients from this previous analysis for which evaluable abdominal computed tomography (CT)‐scans were available. SMM was measured on CT‐scans, by single slice evaluation at the third lumbar vertebra, using the Slice‐o‐Matic software. The previously developed population PK model was extended with SMM as a covariate, to assess the association between SMM and capecitabine and metabolite PK.

Results

PK and SMM data were available from 151 cancer patients with solid tumors. From the included patients, 55% had a low SMM. No relevant relationships were found between SMM and the PK parameters of capecitabine and, the active and toxic metabolite, 5‐FU. SMM only correlated with the PK of the, most hydrophilic, but inactive and non‐toxic, metabolite α‐fluoro‐β‐alanine (FBAL). Patients with a low SMM had a smaller apparent volume of distribution and lower apparent clearance of FBAL.

Conclusions

No alterations in PK of capecitabine and the active and toxic metabolite 5‐FU were observed in patients with a low SMM. Therefore, the previously identified increased toxicity and shorter survival in patients with a low SMM, could not be explained by changes in pharmacokinetic characteristics of capecitabine and metabolites.

First-in-Human Phase 1b Trial of Quinacrine Plus Capecitabine in Patients With Refractory Metastatic Colorectal Cancer

BACKGROUND

Quinacrine plus a fluoropyrimidine has in vivo efficacy against metastatic colorectal cancer (mCRC). This phase 1b trial evaluated the combination of quinacrine plus capecitabine in patients with treatment-refractory mCRC.

PATIENTS AND METHODS

Using a modified Simon accelerated titration design, adults with treatment-refractory mCRC were treated with capecitabine 1000 mg/m² twice daily for 14/21-day cycle, and escalating doses of quinacrine 100 mg daily, 100 mg twice daily, and 200 mg twice daily for 21 days. The primary endpoint was identifying the maximum tolerated dose, determining tolerability and safety. In an expansion cohort, it was overall response rate and time to tumor progression (TTP).

RESULTS

Ten patients (median age of 60 years) were treated in phase 1b. The first 2 quinacrine dosing levels were well tolerated. Dose-limiting toxicities were seen in 3 patients treated with quinacrine 200 mg twice daily. Five additional patients tolerated quinacrine 100 mg twice daily without further dose-limiting toxicities, thus establishing the maximum tolerated dose. Seven additional expansion-cohort patients enrolled onto the study before quinacrine manufacturing ceased within the United States. Five patients experienced stable disease, 1 partial response, and 10 disease progression. Median TTP overall was 2.12 months and median overall survival 5.22 months for the 17 patients.

CONCLUSION

Capecitabine and quinacrine can be safely administered at the maximum tolerated dose of capecitabine 1000 mg/m² by mouth twice daily on days 1-14 and quinacrine 100 mg by mouth twice daily on days 1-21 of a 21-day cycle in mCRC patients. Although the expansion study was halted early, TTP was in line with other studies of refractory mCRC, suggesting activity of this regimen in heavily pretreated patients.

A Sensitive and Efficient Method for Determination of Capecitabine and Its Five Metabolites in Human Plasma Based on One-Step Liquid-Liquid Extraction

Colorectal cancer is the most common critical disease both in the developed and developing countries. Capecitabine, which has served in clinical practice at least for 10 years, is a first-line antidigestive tract cancer drug for its better efficacy, patient compliance, and lower side effects. An ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method has been developed and completely validated for simultaneous determination of capecitabine and its five metabolites in human plasma from colorectal cancer patients after administration of capecitabine tablet. One-step liquid-liquid extraction was successfully applied using ethyl acetate and isopropanol (19 : 1, V : V) for sample pretreatment. Chromatographic separation was achieved within 5 min based on an Atlantis T3-C₁₈ column (3.0 µm, 2.1 × 100 mm) with gradient elution using mobile phases consisting of 0.0075% formic acid in water (pH 4) and in acetonitrile, and the flow rate was 0.3 mL/min. Linear range was approximately 20.0-5000.0 ng/mL for all analytes. Linear correlation coefficients were >0.99 for all regression curves. The intraday and interday accuracy and precision of the method were within ±15.0% and less than 15.0%, respectively. The mean recovery and matrix effect as well as stability of all the analytes ranged from 59.27% to 90.15% and from 74.84% to 114.48% as well as within ±15.0%. This simple, rapid, and sensitive method was successfully applied in 42 sparse clinical samples to verify its practicability.

Pharmacokinetics of Chemotherapy in the Older Patient

Background

The number of individuals aged 65 years and older is growing rapidly, and the majority of cancers are diagnosed in this age group. Age-related changes in physiology can affect chemotherapy pharmacokinetics and pharmacodynamics in older patients.

Methods

We review the literature regarding the impact of age on the pharmacokinetics of commonly used chemotherapy drugs and discuss age-related changes in physiology and pharmacology that can affect chemotherapy tolerance in older patients.

Results

The data on age-related changes in chemotherapy pharmacokinetics are conflicting. While a few studies report age-related differences in chemotherapy pharmacokinetics, most found no significant difference or subtle differences in pharmacokinetics with aging. A difference in pharmacodynamics was commonly seen, however, with older patients at increased risk of myelosuppression and toxicity from age-related decline in organ function. The majority of these studies were performed in a small cohort of patients, thus limiting the generalizability of these results.

Conclusions

Additional studies are needed to address the pharmacokinetics and pharmacodynamics of cancer therapies in the older patient. Multicenter pharmacokinetic studies of adequate sample size, which include a thorough evaluation of physiologic factors and geriatric assessment parameters, would provide further insight into the factors affecting treatment tolerance. These studies would also help to guide appropriate chemotherapy dosing and interventions in order to maximize efficacy and minimize toxicity in the older patient.

Capecitabine: a novel, orally administered, tumour-activated treatment for breast cancer

Objective. To provide a comprehensive review of the preclinical and clinical pharmacology and toxicology of the fluoropyrimidine, capecitabine, with particular reference to its use in metastatic breast cancer.

Data Sources. A MEDLINE search was conducted using the term ‘capecitabine’ for the period 1995 -2001. The reference lists from retrieved articles were reviewed and other relevant papers identified. The abstract books from the annual meetings of the American Society of Clinical and Oncology and the European Society of Medical Oncology were also reviewed.

Data Extraction. The aim of the review was to be comprehensive and descriptive. All studies containing information deemed to be of interest were reviewed by the author; none was excluded on grounds of quality.

Data Summary. Capecitabine is a prodrug of the widely used cytotoxic agent 5-fluorouracil (5-FU). Unlike 5-FU, it is extensively and reliably absorbed after oral administration and does not require folinate (FA) potentiation. The activation of capecitabine is a three-step enzymatic process. The final activating enzyme - thymidine phosphorylase - is found in unusually high concentrations in many solid tumours including breast cancers, resulting in preferential delivery of 5-FU to tumour tissues, and suggesting a greater potential for selective cytotoxicity than is seen with 5-FU.

Capecitabine has been examined both alone and in combination with a variety of cytotoxic drugs in the treatment of metastatic breast cancer. To date, clinical evidence supports the use of capecitabine monotherapy in patients relapsing after prior treatment with anthracyclines and taxanes and in combination with docetaxel in patients failing anthracycline treatment.

Data from phase II studies indicate that in the first of these situations, capecitabine elicits a response in about one-fifth of patients and that responses are associated with symptomatic relief and extended survival. In the latter situation, a phase III study has shown that the combination of docetaxel and capecitabine elicits superior response rates, remission durations, and overall survival compared with the taxane alone and with no clinically important increase in toxicity.

Used alone or in combination, the most notable adverse effect associated with capecitabine is palmar-plantar erythrodysasthesia (hand -foot syndrome), a characteristic complex of reddening, dryness, and soreness of the palms of the hands and soles of the feet, which is rarely disabling and readily managed by treatment interruption and dose reduction.

Capecitabine: a novel, orally administered, tumour-activated treatment for colorectal cancer

Objective. To provide a comprehensive review of the preclinical and clinical pharmacology and toxicology of the fluoropyrimidine, capecitabine, with particular reference to its use in its new indication, advanced colorectal cancer.

Data sources. A MEDLINE search was conducted using the term ‘‘capecitabine’’ for the period 1995 -2001. The reference lists from retrieved articles were reviewed and other relevant papers identified. The abstract books from the annual meetings of the American Society of Clinical and Oncology and the European Society of Medical Oncology were also reviewed.

Data extraction. The aim of the review was to be comprehensive and descriptive. All studies containing information deemed to be of interest were reviewed by the author, none were excluded on grounds of quality.

Data synthesis. Capecitabine is a prodrug of the widely used cytotoxic agent 5-fluorouracil (5-FU). Unlike 5-FU it is extensively and reliably absorbed after oral administration and does not require folinate (FA) potentiation. Activation of capecitabine is a three-step enzymatic process. The final activating enzyme, thymidine phosphorylase, is found in unusually high concentrations in many solid tumours, resulting in preferential delivery of 5-FU to tumour tissues, including that of colorectal cancers, suggesting therapeutic potential in this malignancy. Large, randomized trials have demonstrated that capecitabine fulfils this potential—compared with the widely used ‘‘Mayo’’ regimen of intravenous 5-FU and folinic acid, oral capecitabine (1250 mg/m2 twice daily) produced a superior response rate and a similar time to disease progression and duration of survival. It was also better tolerated than 5-FU/FA—of seven common fluoropyrimidine-induced toxicities, four were significantly less common with capecitabine. Capecitabine also produced significantly less grade 4 toxicity or toxicity requiring hospitalization, though the hand -foot syndrome that characterizes prolonged, continuous exposure to 5-FU was more common after capecitabine.

Effect of age on drug metabolism in women with breast cancer

INTRODUCTION

The aging of the population will increase the number of breast cancer patients requiring treatment in both the adjuvant and metastatic setting. Hormones, chemotherapy and targeted drugs all have a role in treatment. Older patients have been underrepresented in clinical trials making evidence-based decisions difficult. The increase in comorbidity and aging, polypharmacy and changes in function make pharmacotherapy decisions more complicated. Knowledge of the issues is critical in the prescribing of effective and safe therapy. There are factors associated with advancing age that can result in pharmacokinetic and pharmacodynamic variations in processing of hormonal agents, chemotherapy and targeted drugs.

AREAS COVERED

A review of the literature pertaining to pharmacokinetic changes in aging in breast cancer was untaken. Studies are reviewed involving single agents and some combinations.

EXPERT OPINION

Older patients should be considered for standard therapies. Their specific problems need to be evaluated by geriatric-specific assessment including functional status, end organ dysfunction and polypharmacy. There are few instances for age-related changes in pharmacokinetics and when present are usually not clinically significant. When changes are present, they are often the result of comorbidity, drug interactions and drug scheduling issues. The older patients may be more sensitive to certain toxicities such as cardiac toxicity, neuropathy and myelosuppression.

Pharmacokinetics of Selected Anticancer Drugs in Elderly Cancer Patients: Focus on Breast Cancer

Background: Elderly patients receiving anticancer drugs may have an increased risk to develop treatment-related toxicities compared to their younger peers. However, a potential pharmacokinetic (PK) basis for this increased risk has not consistently been established yet. Therefore, the objective of this study was to systematically review the influence of age on the PK of anticancer agents frequently administered to elderly breast cancer patients. Methods: A literature search was performed using the PubMed electronic database, Summary of Product Characteristics (SmPC) and available drug approval reviews, as published by EMA and FDA. Publications that describe age-related PK profiles of selected anticancer drugs against breast cancer, excluding endocrine compounds, were selected and included. Results: This review presents an overview of the available data that describe the influence of increasing age on the PK of selected anticancer drugs used for the treatment of breast cancer. Conclusions: Selected published data revealed differences in the effect and magnitude of increasing age on the PK of several anticancer drugs. There may be clinically-relevant, age-related PK differences for anthracyclines and platina agents. In the majority of cases, age is not a good surrogate marker for anticancer drug PK, and the physiological state of the individual patient may better be approached by looking at organ function, Charlson Comorbidity Score or geriatric functional assessment.

Pharmacokinetics and pharmacogenetics of capecitabine and its metabolites following replicate administration of two 500 mg tablet formulations

PURPOSE

To describe concentration versus time profiles of capecitabine and its metabolites 5'-DFUR, 5'-DFCR and 5-FU, depending on tablet formulation and on frequent and/or relevant genetic polymorphisms of cytidine deaminase, dihydropyrimidine dehydrogenase, thymidylate synthase and methylenetetrahydrofolate reductase (MTHFR).

METHODS

In 46 cancer patients on chronic capecitabine treatment, who voluntarily participated in the study, individual therapeutic doses were replaced on four consecutive mornings by the study medication. The appropriate number of 500 mg test (T) or reference (R) capecitabine tablets was given in randomly allocated sequences TRTR or RTRT (replicate design). Average bioavailability was assessed by ANOVA.

RESULTS

Thirty female and 16 male patients suffering from gastrointestinal or breast cancer (mean age 53.4 years; mean dose 1739 mg) were included. The T/R ratios for AUC0-t(last) and C max were 96.7 % (98 % CI 90.7-103.2 %) and 87.2 % (98 % CI 74.9-101.5 %), respectively. Within-subject variability for AUC0-t(last) and C max (coefficient of variation for R) was 16.5 and 30.2 %, respectively. Similar results were seen for all metabolites. No serious adverse events occurred. For the MTHFR C677T (rs1801133) genotype, an increasing number of 677C alleles showed borderline correlation with an increasing elimination half-life of capecitabine (p = 0.043).

CONCLUSIONS

The extent of absorption was similar for T and R, but the rate of absorption was slightly lower for T. While such differences are not considered as clinically relevant, formal bioequivalence criteria were missed. A possible, probably indirect role of the MTHFR genotype in pharmacokinetics of capecitabine and/or 5-FU should be investigated in further studies.

Simultaneous determination of capecitabine and its three nucleoside metabolites in human plasma by high performance liquid chromatography-tandem mass spectrometry

Capecitabine (Cape) is a prodrug that is metabolized into 5'-deoxy-5-fluorocytidine (DFCR), 5'-deoxy-5-fluorouridine (DFUR), and 5-fluorouracil (5-FU) after oral administration. A liquid chromatography-tandem mass spectrometry method for the simultaneous determination of capecitabine and its three metabolites in human plasma was developed and validated. The ex vivo conversion of DFCR to DFUR in human blood was investigated and an appropriate blood sample handling condition was recommended. Capecitabine and its metabolites were extracted from 100 μL of plasma by protein precipitation. Adequate chromatographic retention and efficient separation were achieved on an Atlantis dC18 column under gradient elution. Interferences from endogenous matrix and the naturally occurring heavy isotopic species were avoided. Detection was performed in electrospray ionization mode using a polarity-switching strategy. The method was linear in the range of 10.0-5000 ng/mL for Cape, DFCR, and DFUR, and 2.00-200 ng/mL for 5-FU. The LLOQ was established at 10.0 ng/mL for Cape, DFCR, and DFUR, and 2.00 ng/mL for 5-FU. The inter- and intra-day precisions were less than 13.5%, 11.1%, 9.7%, and 11.4%, and the accuracy was in the range of -13.2% to 1.6%, -2.4% to 2.5%, -7.1% to 8.2%, and -2.0% to 3.8% for Cape, DFCR, DFUR, and 5-FU, respectively. The matrix effect was negligible under the current conditions. The mean extraction recoveries were within 105-115%, 92.6-101%, 94.0-100%, and 85.1-99.9% for Cape, DFCR, DFUR, and 5-FU, respectively. Stability testing showed that the four analytes remained stable under all relevant analytical conditions. This method has been applied to a clinical bioequivalence study.

Capecitabine: the new generation of fluoropyrimidines in colorectal cancer

Colorectal cancer is the second leading cause of cancer death in the USA and fluoropyrimidines have been the mainstay of treatment for over 40 years. Currently, capecitabine is the only orally available fluoropyrimidine approved for treatment in the USA. As a single agent it has demonstrated activity and equivalence to 5-fluorouracil (5-FU) intravenous administration via the Mayo Clinic regimen, in both the metastatic and adjuvant settings. Ongoing clinical trials are evaluating the efficacy of capecitabine in combination with oxaliplatin and irinotecan as more convenient substitutes for infusional 5-FU in the 5-FU/leucovorin/oxaliplatin and 5-FU/irinotecan regimens.

Predicting concentrations of the cytostatic drugs cyclophosphamide, carboplatin, 5-fluorouracil, and capecitabine throughout the sewage effluents and surface waters of Europe

The present study evaluated the potential environmental concentrations of 4 cytostatic (also known as cytotoxic) drugs in rivers. The antimetabolite 5-fluorouracil (5FU) and its pro-drug capecitabine were examined based on their very high use rates, cyclophosphamide (CP) for its persistence, and carboplatin for its association with the metal element platinum. The study combined drug consumption information across European countries, excretion, national water use, and sewage removal rates to derive sewage effluent values across the continent. Results showed considerable variation in the popularity of individual cytostatic drugs across Europe, including a 28-fold difference in 5FU use and 15-fold difference in CP use. Such variations could have a major effect on the detection of these compounds in effluent or river water. Overall, capecitabine and CP had higher predicted levels in effluent than 5FU or carboplatin. Predicted effluent values were compared with measurements in the literature, and many non-detects could be explained by insufficient limits of detection. Linking the geographic based water resources model GWAVA with this information allowed water concentrations throughout 1.2 million km of European rivers to be predicted. The 90th percentile (worst case) prediction indicated that, with the exception of capecitabine, more than 99% of Europe's rivers (by length) would have concentrations below 1 ng/L for these cytostatic drugs. For capecitabine, 2.2% of river length could exceed 1 ng/L.

Adherence Issues for Oral Antineoplastics

Nonadherence to antineoplastics is a growing concern because of the increasing number of novel oral targeted anticancer therapies. Many of these agents are administered on a chronic continuous schedule for an indefinite period of time where adherence is crucial to achieve optimal disease control and prolong survival. Many factors are known to contribute to medication nonadherence. Prevention, early detection, and management of adverse drug reactions associated with oral targeted therapies require close vigilance. Knowing how to prevent and manage adverse drug reactions will help clinicians develop strategies to promote patient adherence to oral anticancer treatment regimens. Optimal adherence requires a dynamic patient-provider alliance through education, communication, ongoing monitoring, and follow-up.

Phase II trial of simple oral therapy with capecitabine and cyclophosphamide in patients with metastatic breast cancer: SWOG S0430

BACKGROUND

Interest in oral agents for the treatment of metastatic breast cancer (MBC) has increased because many patients prefer oral to i.v. regimens. We evaluated a simple oral combination of capecitabine with cyclophosphamide (CPA) for MBC.

METHODS

The trial was designed to determine whether or not combination therapy would achieve a 42% response rate (RR) using the Response Evaluation Criteria in Solid Tumors (RECIST) in MBC. Patients with two or fewer prior chemotherapy regimens for MBC were eligible. Those with estrogen receptor-positive MBC had to have progressed on endocrine therapy. Patients had measurable disease or elevated mucin (MUC)-1 antigen and received CPA, 100 mg daily on days 1-14, and capecitabine, 1,500 mg twice daily on days 8-21, in 21-day cycles.

RESULTS

In 96 eligible patients, the median progression-free survival (PFS) interval was 5.9 months (95% confidence interval [CI], 3.7-8.0 months) and median overall survival (OS) time was 18.8 months (95% CI, 13.1-22.0 months). The RR was 36% (95% CI, 26%-48%) in 80 patients with measurable disease. The MUC-1 antigen RR was 33% (95% CI, 20%-48%), occurring in 15 of 46 patients with elevated MUC-1 antigen. Toxicity was mild, with no treatment-related deaths.

CONCLUSIONS

PFS, OS, and RR outcomes with capecitabine plus CPA compare favorably with those of capecitabine monotherapy and combination therapy with bevacizumab, sorafenib, or ixabepilone. The addition of these other agents to capecitabine does not improve OS time in MBC patients, and this single-arm study does not suggest that the addition of CPA to capecitabine has this potential in an unselected MBC population. When OS prolongation is the goal, clinicians should choose single-agent capecitabine.

Pharmacokinetic analysis of capecitabine and cisplatin in combination with trastuzumab in Japanese patients with advanced HER2-positive gastric cancer

PURPOSE

To evaluate the pharmacokinetics (PK) of capecitabine and cisplatin, administered in combination with or without trastuzumab, in Japanese patients with HER2-positive advanced gastric cancer (AGC).

METHODS

Patients eligible for this PK study (study JP19959), which was carried out during treatment Cycle 1 of the ToGA study, received either capecitabine and cisplatin (XP arm) or trastuzumab plus capecitabine and cisplatin (HXP arm). All patients received capecitabine (1,000 mg/m(2) orally, twice daily for 14 days) and cisplatin (80 mg/m(2) intravenous infusion on Day 1). Patients in the HXP arm also received trastuzumab (8 mg/kg intravenous infusion on Day 1), concurrently with capecitabine. No further study medication was administered during study JP19959. Serial plasma samples for PK analysis were obtained at intervals before and after the administration of capecitabine and cisplatin on Day 1.

RESULTS

Twenty-two patients were enrolled in this PK study: eight in the HXP arm and 14 in the XP arm. All blood samples were available for PK analysis. Co-administration of trastuzumab resulted in no statistically or clinically significant changes in the PK profiles of capecitabine or its metabolites, or of cisplatin (total or unbound platinum).

CONCLUSIONS

Variability in the AUC(last) and C (max) values for the capecitabine was consistent with the known PK profile of capecitabine and fell within established limits. Concurrent trastuzumab therapy is unlikely to alter the PK or safety profile of capecitabine or cisplatin in Japanese patients with HER2-positive AGC.

A new, validated HPLC-MS/MS method for the simultaneous determination of the anti-cancer agent capecitabine and its metabolites: 5'-deoxy-5-fluorocytidine, 5'-deoxy-5-fluorouridine, 5-fluorouracil and 5-fluorodihydrouracil, in human plasma

A rapid and selective liquid chromatography/tandem mass spectrometric method was developed for the simultaneous determination of capecitabine and its metabolites 5'-deoxy-5-fluorocytidine (5'-DFCR), 5'-deoxy-5-fluorouracil (5'-DFUR), 5-fluorouracil (5-FU) and dihydro-5-fluorouracil (FUH(2)) in human plasma. A 200 microL human plasma aliquot was spiked with a mixture of internal standards fludarabine and 5-chlorouracil. A single-step protein precipitation method was employed using 10% (v/v) trichloroacetic acid in water to separate analytes from bio-matrices. Volumes of 20 microL of the supernatant were directly injected onto the HPLC system. Separation was achieved on a 30 x 2.1 mm Hypercarb (porous graphitic carbon) column using a gradient by mixing 10 mm ammonium acetate and acetonitrile-2-propanol-tetrahydrofuran (1 : 3 : 2.25, v/v/v). The detection was performed using a Finnigan TSQ Quantum Ultra equipped with the electrospray ion source operated in positive and negative mode. The assay quantifies a range from 10 to 1000 ng/mL for capecitabine, from 10 to 5000 ng/mL for 5'-DFCR and 5'-DFUR, and from 50 to 5000 ng/mL for 5-FU and FUH(2) using a plasma sample of 200 microL. Correlation coefficients (r(2)) of the calibration curves in human plasma were better than 0.99 for all compounds. At all concentration levels, deviations of measured concentrations from nominal concentration were between -4.41 and 3.65% with CV values less than 12.0% for capecitabine, between -7.00 and 6.59% with CV values less than 13.0 for 5'-DFUR, between -3.25 and 4.11% with CV values less than 9.34% for 5'-DFCR, between -5.54 and 5.91% with CV values less than 9.69% for 5-FU and between -4.26 and 6.86% with CV values less than 14.9% for FUH(2). The described method was successfully applied for the evaluation of the pharmacokinetic profile of capecitabine and its metabolites in plasma of treated cancer patients.

Impact of age, sex, and comorbidity on cancer therapy and disease progression

A theme of personalized medicine was highlighted at the 2009 Annual Meeting of the American Society of Clinical Oncology. To this end, the current review focuses on the impact of host characteristics (such as age, sex, and comorbidity) as they pertain to cancer biology, treatment efficacy, and tolerance. Increasing age is associated with complex changes in physiology, including alterations in renal and hepatic function, and decreased bone marrow reserve. These may in turn result in alterations in pharmacokinetics and toxicity related to many commonly used anticancer agents. Using tools, such as the geriatric assessment, may help to elucidate the physiologic age of the patient as opposed to the chronologic age. Increasing age is paralleled by an increase in comorbidity, and comorbidity may have independent prognostic implications and substantially impact medical decision making in the patient with cancer. Numerous biologic ties between cancer and comorbidity exist, one example being an association of diabetes with an increased risk of disease recurrence and mortality in the setting of colon cancer. Biologic features can also vary by sex; several biomarkers with either prognostic or predictive value (ie, excisionrepair cross-complementation group 1 expression, epidermal growth factor receptor mutation, or dihydropyrimidine dehydrogenase polymorphism) may differentiate efficacy or toxicity in males and females. Taken together, age, sex, and comorbidity each encompass a complex array of physiologic and molecular variations that may each aid in personalizing care for the patient with cancer.

Advances in the pharmacological treatment of gastro-oesophageal cancer

Despite a sharp decline in the incidence of gastric cancer during the second half of the 20th century, this malignancy remains the second leading cause of cancer mortality in the world. The incidence and mortality rate of gastric cancer increase with age; at present, the median ages at diagnosis are 67 years for men and 72 years for women in the US. This article reviews and discusses current medical treatment options for both the general population and elderly gastric cancer patients. Management of localized gastric cancer has changed significantly over recent years. Adjuvant chemoradiation is not generally recommended outside the US. After decades of trials of adjuvant chemotherapy with inconclusive results, a significant survival benefit for perioperative combination chemotherapy - as compared with surgery alone - in patients with resectable or locally advanced gastro-oesophageal cancer was recently demonstrated in the UK MAGIC trial. A further large, randomized trial from Japan demonstrated a significant survival benefit for adjuvant chemotherapy with S-1 after D2 resection for gastric cancer. However, both trials are applicable only to the population in which the trials were conducted. Specific data on elderly patients are missing. For patients with metastatic disease, oral fluoropyrimidines, such as capecitabine, have been developed. In Asian patients, treatment with the oral fluoropyrimidine S-1 is safe and effective. Docetaxel, oxaliplatin and irinotecan have demonstrated activity against gastric cancer in appropriately designed, randomized, phase III trials and have increased the available treatment options significantly. In addition, according to preliminary data, trastuzumab in combination with chemotherapy has significantly improved activity when compared to chemotherapy alone in patients with human epidermal receptor (HER)-2-positive gastric and gastro-oesophageal cancers. Thus, therapeutic decisions in patients with advanced gastric cancer may be adapted to the molecular subtype and co-morbidities of the individual patient. Data from retrospective analyses suggest that oxaliplatin seems to be better tolerated than cisplatin in elderly patients.

Anticancer drug therapy in the older cancer patient: pharmacology and polypharmacy

OPINION STATEMENT

Older patients currently are the largest group of oncology patients and their numbers will continue to expand. There has been minimal participation of older patients in clinical trials. This has resulted in a lack of data to make high-level evidence-based decisions with regard to chemotherapy. There has now been a number of clinical trials which have given information with regard to age-related changes and the spectrum of toxicity that occurs with older patients. There is also an expanding literature on organ dysfunction. The overall data seem to indicate that there are a very few age-related changes in the pharmacokinetics of chemotherapy. The small changes that are present have not been clinically significant. It seems that the pattern of toxicity is more reflective of patient selection (functional status, performance status), comorbidity, and drug scheduling. The large number of drugs with significant renal excretion requires careful evaluation of renal function. Future clinical trial design needs to be adapted to older patients. Therefore, drugs, which will be primarily used by older patients, should be studied in older patients. These studies should involve pharmacokinetics, and oral therapies should include measurements of compliance. Phase II trials of new agents should consider prospectively dividing groups of patients by age (i.e., <75 years vs. >or=75 years). Phase I trials should consider accruing older patients. The studies can be performed in the older group by using progressive degrees of functional impairment and increasing comorbidity as a surrogate for dose limiting toxicity. Functional independence as a clinical benefit of cancer treatment in older individuals should be considered as an endpoint. Overall survival may not be an appropriate endpoint in clinical trials in the oldest group. Clinical trials should consider studying long-term functional and medical consequences of cancer treatment in long-term older cancer survivors. Journal editors should encourage the inclusion of age-related analyses in the reporting of clinical trials to provide meaningful information for clinicians caring for older patients. Ideally, the clinical trial design should prospectively incorporate age analysis to maximize clinical benefit of data generated. A careful assessment of medication used in older patients needs to be part of routine evaluation to minimize the adverse effects of polypharmacy.

Optimized blood sampling with cytidine deaminase inhibitor for improved analysis of capecitabine metabolites

The 5FU prodrug capecitabine undergoes a 3-step enzymatic conversion, including the conversion of 5'DFRC into 5'DFUR by cytidine deaminase (CDA). The presence of CDA activity in blood led us to analyze the possible ex vivo conversion of 5'DFCR into 5'DFUR in blood samples. We thus examined the impact of the addition of a CDA inhibitor (tetrahydrouridine (THU) 1 microM final) in blood. Blood samples from 3 healthy volunteers were taken on tubes containing or not THU. Blood was spiked with 5'DFCR (20 microM final) (T0) and was maintained at room temperature for 2 h. Plasma concentrations of 5'DFRC and 5'DFUR were analyzed with an optimized HPLC assay. In the absence of THU, 5'DFUR was detectable as early as T0. The percent of 5'DFUR produced relative to 5'DFCR increased over time, up to 7.7 % at 2h. In contrast, the presence of THU totally prevents the formation of 5'DFUR. The impact of THU for preventing the conversion of 5'DFCR was confirmed by the analysis of blood samples from 2 capecitabine-treated patients. Addition of THU in the sampling-tube before the introduction of blood is thus strongly recommended in order to guarantee accurate conditions for reliable measurement of capecitabine metabolites in plasma, and thus faithful pharmacokinetic data.

A dose-escalation study of indisulam in combination with capecitabine (Xeloda) in patients with solid tumours

This dose escalation study was designed to determine the recommended dose of the multi-targeted cell cycle inhibitor indisulam in combination with capecitabine in patients with solid tumours and to evaluate the pharmacokinetics of the combination. Thirty-five patients were treated with indisulam on day 1 of each 21-day cycle. Capecitabine was administered two times daily (BID) on days 1–14. Plasma concentrations of indisulam, capecitabine and its three metabolites were determined for pharmacokinetic analysis. The main dose-limiting toxicity was myelosuppression. Hand/foot syndrome and stomatitis were the major non-haematological toxicities. The recommended dose was initially established at indisulam 700 mg m⁻² and capecitabine 1250 mg m⁻² BID. However, during cycle 2 the recommended dose was poorly tolerated in three patients. A dose of indisulam 500 mg m⁻² and capecitabine 1250 mg m⁻² BID proved to be safe at cycle 1 and 2 in nine additional patients. Indisulam pharmacokinetics during cycle 1 were consistent with pharmacokinetic data from phase I mono-therapy studies. However, exposure to indisulam was remarkably increased at cycle 2 due to a drug–drug interaction between capecitabine and indisulam. Partial response was confirmed in two patients, one with colon carcinoma and the other with pancreatic carcinoma. Seventeen patients had stable disease. Indisulam (700 mg m⁻²) in combination with capecitabine (1250 mg m⁻² BID) was well tolerated during the first cycle. A dose of indisulam 500 mg m⁻² and capecitabine 1250 mg m⁻² BID was considered safe in multiple treatment cycles. The higher incidence of toxicities observed during cycle 2 can be explained by a time-dependent pharmacokinetic drug–drug interaction.

A phase I safety, tolerability, and pharmacokinetic study of enzastaurin combined with capecitabine in patients with advanced solid tumors

Enzastaurin, an oral inhibitor of protein kinase Cbeta, affects signal transduction associated with angiogenesis, proliferation, and survival. Capecitabine is converted to 5-fluoruracil by thymidine phosphorylase, a putative angiogenic factor. The all-oral combination of the two drugs offers the potential for targeting angiogenesis in capecitabine-sensitive tumors with nonoverlapping toxicities. Patients with advanced cancer initially received single-agent enzastaurin to achieve steady-state concentrations (cycle 1). In subsequent 21-day cycles, enzastaurin was given orally, once daily, on days 1-21 and capecitabine orally, twice daily (b.i.d.), on days 1-14 in three dose-level cohorts. Three dose-escalation cohorts were studied: cohort 1 (n=8), 350 mg of enzastaurin +capecitabine (750 mg/m2 b.i.d.); cohort 2 (n=7), enzastaurin (350 mg)+capecitabine (1000 mg/m2 b.i.d.); cohort 3 (n=12), 525-mg capsules or 500-mg enzastaurin+capecitabine (1000 mg/m2 b.i.d.). Further dose escalation was not pursued because of emerging data that enzastaurin systemic exposure did not increase at doses above 525 mg. Although a traditional toxicity-based maximum tolerated dose was not achieved, the highest dosing cohort represented a biologically relevant dose of enzastaurin, on the basis of preclinical data and correlative pharmacodynamic biomarker assays of protein kinase Cbeta inhibition in peripheral blood mononucleocytes, in combination with a standard dose of capecitabine. For the 500/525-mg dose, ratios of total enzastaurin analyte geometric means (i.e. enzastaurin alone versus enzastaurin with capecitabine) reflected a trend toward decreased enzastaurin exposure, but did not reach statistical significance. The pharmacokinetic parameters of capecitabine with enzastaurin were similar to those previously reported for single-agent capecitabine. The regimen was well tolerated, without any consistent pattern of drug-related grade 3 or grade 4 toxicities being observed. Although no objective tumor responses were documented, five patients maintained stable disease for >or=6 months (range: 6-9.7 months). The recommended phase II dose of this combination, based on the results of this study, is enzastaurin at a daily dose of 500 mg (tablet formulation) and capecitabine (1000 mg/m2, b.i.d.) on days 1-14 every 21 days. Further disease-directed studies are warranted, such as in malignancies in the treatment of which both capecitabine and inhibitors of angiogenesis have previously been benchmarked as being effective.

Neoadjuvant Docetaxel and Capecitabine and the Use of Thymidine Phosphorylase as a Predictive Biomarker in Breast Cancer

PURPOSE

Thymidine phosphorylase (TP) induction by docetaxel is a proposed mechanism for the observed preclinical synergy of docetaxel and capecitabine (DC). We evaluated whether TP protein expression is increased by docetaxel and correlates with pathologic complete response (pCR) in breast cancer patients.

EXPERIMENTAL DESIGN

Women with stage II to III breast cancer were given four cycles of neoadjuvant docetaxel 36 mg/m(2) i.v. over 30 min on days 1, 8, and 15 and capecitabine 2,000 mg/d, in two divided doses, on days 5 to 21 of a 28-day cycle. Radiology-directed biopsies of the breast tumors were done at baseline and 5 days after the first dose of docetaxel to evaluate TP expression. Following DC therapy, patients had core breast biopsies, and if residual disease was present, received four cycles of standard dose-dense doxorubin and cyclophosphamide (AC).

RESULTS

The pCR rate was 26.9% (95% confidence interval, 11.6-47.8). Up-regulation of TP expression was not observed by either quantitative immunofluorescence (QIF) or immunohistochemistry. Radiology-directed core biopsy after neoadjuvant chemotherapy accurately predicted pathologic response in 88% (95% confidence interval, 69.8-97.6) of the cases. Neither level of TP expression nor TP up-regulation correlated with pCR. Significant toxicity resulted in therapy discontinuation in 3 of 26 patients.

CONCLUSIONS

DC chemotherapy exhibited a similar pCR rate compared with standard taxane regimens, with increased toxicity. TP expression was not up-regulated after docetaxel and did not correlate with therapeutic response. Core breast biopsy after neoadjuvant chemotherapy accurately predicted pathologic response.

Cytotoxic therapy for the elderly with metastatic breast cancer: A review on safety, pharmacokinetics and efficacy

As the incidence of invasive breast cancer, mainly developing at older age, is rising, the absolute number of elderly developing metastatic disease is also increasing. In view of improved life expectancy, sociocultural changes and better supportive measures for chemotherapy-induced toxicity, there is an increasing request for the administration of chemotherapy in elderly. At the moment, medical oncologists are still reluctant to use chemotherapy in elderly partly because of concern about increased toxicity and poor tolerability of this patient cohort, and the inability to appropriately select elderly that may benefit from chemotherapy. The question is whether this attitude remains justified. In this review, the current status of clinical research in the area of metastatic breast cancer regarding toxicity and activity of chemotherapy in older breast cancer patients is discussed. Further, data on pharmacokinetics are emphasised as age-related physiologic changes may affect these features with consequences for toxicity and decision-making. Moreover, data on assessment tools trying to characterise the 'functional age' are reviewed. In general, the literature data are scarce and hampered by major limitations, while pharmacokinetic data indicate that a different approach in older breast cancer patients does not always seem justified. To increase our knowledge aiming at optimisation of cancer treatment in elderly, there is a clear necessity for prospective, well-designed studies with emphasis on the particular requirements of older patients and incorporation of pharmacokinetic and -dynamic evaluation of cytotoxic agents used in this specific group. As in other research areas, maximal progress will be achieved by joined efforts of co-operative research groups.

International Society of Geriatric Oncology Chemotherapy Taskforce: evaluation of chemotherapy in older patients--an analysis of the medical literature

The elderly comprise the majority of patients with cancer and are the recipients of the greatest amount of chemotherapy. Unfortunately, there is a lack of data to make evidence-based decisions with regard to chemotherapy. This is due to the minimal participation of older patients in clinical trials and that trials have not systematically evaluated chemotherapy. This article reviews the available information with regard to chemotherapy and aging provided by a task force of the International Society of Geriatric Oncology (SIOG). Due to the lack of prospective data, the conclusions and recommendations made are a consensus of the participants. Extrapolation of data from younger to older patients is necessary, particularly to those patients older than 80 years, for which data is almost entirely lacking. The classes of drugs reviewed include alkylators, antimetabolites, anthracyclines, taxanes, camptothecins, and epipodophyllotoxins. Clinical trials need to incorporate an analysis of chemotherapy in terms of the pharmacokinetic and pharmacodynamic effects of aging. In addition, data already accumulated need to be reanalyzed by age to aid in the management of the older cancer patient.

Optimal time interval between capecitabine intake and radiotherapy in preoperative chemoradiation for locally advanced rectal cancer

PURPOSE

Capecitabine and its metabolites reach peak plasma concentrations 1 to 2 hours after a single oral administration, and concentrations rapidly decrease thereafter. We performed a retrospective analysis to find the optimal time interval between capecitabine administration and radiotherapy for rectal cancer.

METHODS AND MATERIALS

The time interval between capecitabine intake and radiotherapy was measured in patients who were treated with preoperative radiotherapy and concurrent capecitabine for rectal cancer. Patients were classified into the following groups. Group A1 included patients who took capecitabine 1 hour before radiotherapy, and Group B1 included all other patients. Group B1 was then subdivided into Group A2 (patients who took capecitabine 2 hours before radiotherapy) and Group B2. Group B2 was further divided into Group A3 and Group B3 with the same method. Total mesorectal excision was performed 6 weeks after completion of chemoradiation and the pathologic response was evaluated.

RESULTS

A total of 200 patients were enrolled in this study. Pathologic examination showed that Group A1 had higher rates of complete regression of primary tumors in the rectum (23.5% vs. 9.6%, p = 0.01), good response (44.7% vs. 25.2%, p = 0.006), and lower T stages (p = 0.021) compared with Group B1; however, Groups A2 and A3 did not show any improvement compared with Groups B2 and B3. Multivariate analysis showed that increases in primary tumors in the rectum and good response were only significant when capecitabine was administered 1 hour before radiotherapy.

CONCLUSION

In preoperative chemoradiotherapy for rectal cancer, the pathologic response could be improved by administering capecitabine 1 hour before radiotherapy.

Rapid and simultaneous determination of capecitabine and its metabolites in mouse plasma, mouse serum, and in rabbit bile by high-performance liquid chromatography

A rapid high-performance liquid chromatography method has been developed for simultaneous determination of capecitabine and its metabolites: 5'-deoxy-5-fluorocytidine (5'-DFCR), 5'-deoxy-5-fluorouridine (5'-DFUR) and 5-fluorouracil (5-FU). 5'-DFCR was synthesized by hydrolyzing capecitabine using commercially available carboxyl esterase (CES) and characterized by NMR, mass spectrometry and elemental analysis. Base-line separations between capecitabine, 5'-DFCR, 5'-DFUR and 5-FU were found with symmetrical peak shapes on a Discovery RP-amide C16 column using 10 mM ammonium acetate at pH 4.0 and methanol as the mobile phase. The retention times of capecitabine, 5'-DFCR, 5'-DFUR and 5-FU were 8.9, 5.0, 5.3 and 3.0 min, respectively. Linear calibration curves were obtained for each compound across a range from 1 to 500 microg ml(-1). The intra- and inter-day relative standard deviations (%RSD) were <5%. A single-step protein precipitation method was employed for separation of the analytes from bio-matrices. Greater than 85% recoveries were obtained for capecitabine, 5'-DFCR, 5'-DFUR and 5-FU from bio-fluids including mouse plasma, mouse serum and rabbit bile.