Modulation of thymidine phosphorylase by neoadjuvant chemotherapy in primary breast cancer

Thymidine phosphorylase induction by ionizing radiation antagonizes 5-fluorouracil resistance in human ductal pancreatic adenocarcinoma

Chemoresistance in pancreatic ductal adenocarcinoma (PDAC) frequently contributes to failure of systemic therapy. While the radiosensitizing properties of 5-fluorouracil (FU) are well known, it is unknown whether ionizing radiation (IR) sensitizes towards FU cytotoxicity. Here, we hypothesize that upregulation of thymidine phosphorylase (TP) by IR reverses FU chemoresistance in PDAC cells. The FU resistant variant of the human PDAC cell line AsPC-1 (FU-R) was used to determine the sensitizing effects of IR. Proliferation rates of FU sensitive parental (FU-S) and FU-R cells were determined by WST-1 assays after low (0.05 Gy) and intermediate dose (2.0 Gy) IR followed by FU treatment. TP protein expression in PDAC cells before and after IR was assessed by Western blot. To analyze the specificity of the FU sensitizing effect, TP was ablated by siRNA. FU-R cells showed a 2.7-fold increase of the half maximal inhibitory concentration, compared to FU-S parental cells. Further, FU-R cells showed a concomitant IR resistance towards both doses applied. When challenging both cell lines with FU after IR, FU-R cells had lower proliferation rates than FU-S cells, suggesting a reversal of chemoresistance by IR. This FU sensitizing effect was abolished when TP was blocked by anti-TP siRNA before IR. An increase of TP protein expression was seen after both IR doses. Our results suggest a TP dependent reversal of FU-chemoresistance in PDAC cells that is triggered by IR. Thus, induction of TP expression by low dose IR may be a therapeutic approach to potentially overcome FU chemoresistance in PDAC.

Capecitabine + Epirubicin + Cyclophosphamide Combination Therapy (CEX Therapy) as Neoadjuvant Chemotherapy for HER-2-Negative Breast Cancer: A Retrospective, Single-Center Study

BACKGROUND

We modified and administered capecitabine + epirubicin + cyclophosphamide combination therapy (CEX) as neoadjuvant chemotherapy (NAC) for HER-2-negative breast cancer and retrospectively analyzed its effectiveness and tolerability at our center.

METHODS

The inclusion criteria were presence of breast cancer negative for HER-2 and positive lymph node metastasis, or negative lymph node metastasis when tumor diameter was 20 mm or greater without distant metastasis. Additional inclusion criteria were a performance status of 0 or 1, an EF >60%, and an age of 75 years or less. Clinical outcomes were evaluated after 4 courses of epirubicin 80 mg/m2, cyclophosphamide 500 mg/m2 (administered every 3 weeks), and capecitabine 1,500 mg/m2 (administered for 2 weeks and withdrawn for 1 week).

RESULTS

A clinical benefit was noted in all 18 patients who received CEX as neoadjuvant chemotherapy during the period from 2009 through 2013. The clinical response rate was 83.3% (15/18), and the clinical complete response rate was 50%. Aesthetic outcomes of breast-conserving surgery were positive in all patients. Among patients with satisfactory outcomes, 33.3% had a pathologic complete response (triple-negative: 6, luminal: 0) and 68.8% were n0 (triple-negative: 8, luminal: 3). All patients with a pathologic complete response are presently alive, free of recurrence, and currently undergoing follow-up. Adverse events were classified as grade 2 or lower in all patients.

CONCLUSIONS

CEX therapy administered as neoadjuvant chemotherapy could be useful for individualized treatment. In particular, this regimen was effective for triple-negative breast cancer.

Development and validation of a quantitative method for thymidine phosphorylase activity in peripheral blood mononuclear cells

The enzyme thymidine phosphorylase (TP) is important for activation of capecitabine and 5-fluorouracil. Assessment of TP phenotype might be suitable for identification of patients at risk of fluoropyrimidine-induced toxicity. In this paper, we describe the development and validation an assay for TP activity in peripheral blood mononuclear cells (PBMCs). The assay was based on ex vivo conversion of the TP substrate thymidine to thymine. The amount of thymine formed was determined by high-performance liquid chromatography - ultraviolet detection (HPLC-UV) with 5-bromouracil as internal standard. Lymphocytes and monocytes were purified from isolated PBMCs to examine cell-specific TP activity. TP activity in PBMCs demonstrated Michaelis-Menten kinetics. The lower limit of quantification was 2.3 µg PBMC protein and assay linearity was demonstrated up to 22.7 µg PBMC protein. Within-day and between-day precisions were ≤9.2% and ≤6.0%, respectively. Adequate stability TP activity was demonstrated after long-term storage of PBMC dry pellets and lysates at -80 °C. In monocytes, TP activity was approximately 3 times higher than in lymphocytes. Clinical applicability was demonstrated in samples that were collected from five cancer patients. A simple, precise and sensitive HPLC-UV assay for quantification of TP activity in PBMCs was developed that can be applied for clinical research.

A phase II study of capecitabine plus cisplatin in metastatic triple-negative breast cancer patients pretreated with anthracyclines and taxanes

BACKGROUND

Cisplatin is an effective agent for triple-negative breast cancer (TNBC) and synergistic activity between cisplatin and capecitabine has been demonstrated by in vitro and in vivo studies. This study was designed as a prospective clinical trial to evaluate the efficacy and safety of capecitabine plus cisplatin (XP) regimen in metastatic TNBC patients pretreated with anthracyclines and taxanes.

PATIENTS AND METHODS

Thirty-three patients with metastatic TNBC who had anthracyclines and taxanes as prior therapy were treated with capecitabine 2000 mg/m(2) orally on day 1 through 14 plus cisplatin 75 mg/m(2) intravenously on day 1 of a 21-day cycle, followed by capecitabine maintenance medications after a maximum of 6 cycles. The primary end point was objective response rate (ORR) and the secondary end points included progression-free survival (PFS), overall survival (OS) and toxicity profiles.

RESULTS

A total of 162 cycles was given. ORR was 63.6%. Median PFS was 8.2 (95%CI: 4.8-11.6) months in the entire population and 10.8 (95%CI: 6.5-15.1) months in responding patients. Median OS was 17.8 (95%CI: 14.4-21.2) months in all enrolled patients and 25.8 (95%CI: 14.6-37.0) months in responding patients. Most adverse events were mild and manageable, with neutropenia and nausea/vomiting as the most common toxicities. Grade 3/4 toxicities included leukopenia (10, 30.3%), neutropenia (10, 30.3%), anemia (2, 6.1%), thrombocytopenia (1, 3.0%), nausea/vomiting (3, 9.1%), hand-foot syndrome (HFS; 1, 3.0%), and sensory neuropathy (1, 3.0%).

CONCLUSIONS

Capecitabine plus cisplatin demonstrated an excellent activity and an acceptable safety profile in metastatic TNBC patients pretreated with anthracyclines and taxanes.

Single-Agent Therapies After Standard Combination Regimens

Increasingly prolonged survival in metastatic colorectal cancer has paralleled the approval of new agents alone and in combination. Most recently, several new agents have sought approval in the heavily pretreated setting, after treatment with standard chemotherapies, alone and in combination, and with anti-vascular endothelial growth factor receptor and anti-epidermal growth factor receptor (for patients with RAS wild-type tumors). These agents have included the multitargeted tyrosine kinase inhibitor (TKI), regorafenib, and the novel antimetabolite combination, TAS-102. Both of these showed improvement in progression-free survival and overall survival compared with placebo controls and were approved in the United States and the rest of the world. Benefits of treatment and toxicities are discussed. Nintedanib, another multitargeted TKI, is already approved by the European Medicines Evaluation Agency for non-small cell lung cancer and has been studied in a similar phase III trial. Results are pending. The risks and benefits of each agent are discussed.

TAS-102: a novel antimetabolite for the 21st century

TAS-102, a novel antimetabolite combination chemotherapy agent, consists of a rediscovered antimetabolite agent, trifluorothymidine (trifluridine) combined with the metabolic inhibitor of thymidine phosphorylase, tipiracil, in a 1:0.5 molar ratio. Mechanism of action studies suggest that this agent works by incorporation into DNA. Both preclinical and clinical studies demonstrate that this agent is noncross-resistant with 5-fluorouracil. Tipiracil may also have antiangiogenic effects through inhibition of thymidine phosphorylase. Recent randomized Phase II and III trials demonstrate clinical activity (improved progression-free survival, time to decrease in performance status, prolonged overall survival) in metastatic colorectal cancer refractory to all standard agents. Monotherapy with TAS-102 has now been approved for this indication in Japan and in the USA.

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

Background

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

Methods

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

Results

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

Conclusion

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

A phase II study of preoperative capecitabine in women with operable hormone receptor positive breast cancer

Conventional preoperative chemotherapy regimens have only limited efficacy in hormone receptor positive (HR+) breast cancer and new approaches are needed. We hypothesized that capecitabine, which is effective in metastatic breast cancer, may be an active preoperative treatment for HR+ breast cancer. Women with HR+, HER2-negative operable breast cancer received capecitabine, 2000 mg/m² daily in divided doses for 14 days, followed by a 7-day rest period. Treatment was repeated every 21 days for a total of four cycles. The primary endpoint of the study was to determine the rate of pathological complete response (pCR). Because of slow accrual, the study was closed after 24 patients were enrolled. Three patients had a complete clinical response, and eight patients had a partial clinical response, for an overall clinical response rate of 45.8%. There were no cases of pCR. Of the 22 patients who had pathological response assessment by the Miller–Payne grading system, there were six grade 3 responses, and no grade 4 or 5 responses. Toxicity was manageable: the only grade 3 toxicities observed were one case each of diarrhea, palmar plantar erythrodysesthesia, hypokalemia, and mucositis. There was no association between baseline levels, or change in level from baseline to cycle 1, or from baseline to time of surgery, of thymidine phosphorylase (TYMP), thymidylate synthase (TYMS), dihydropyrimidine dehydrogenase (DPYD), or Ki67 and pathological, clinical, or radiographic response. Preoperative capecitabine is a well-tolerated regimen, but appears not lead to pCR when used as monotherapy in HR+ breast cancer.

Phase ii trial of a metronomic schedule of docetaxel and capecitabine with concurrent celecoxib in patients with prior anthracycline exposure for metastatic breast cancer

BACKGROUND

This phase ii clinical trial examined the activity of a metronomic dosing schedule of docetaxel and capecitabine chemotherapy in patients with advanced breast cancer. Patients also received daily oral celecoxib in an effort to improve outcome measures and to ameliorate some of the common side effects of chemotherapy.

METHODS

Patients received docetaxel at a starting dose of 15 mg/m² weekly, oral capecitabine 1250 mg/m² once daily, and oral celecoxib 200 mg twice daily. The primary endpoint was clinical benefit: percentage of patients experiencing either an objective response or stable disease (sd) for more than 6 months. In the absence of significant neutropenia, the dose of docetaxel was escalated after 4 and 8 weeks of treatment. Therapy was given until disease progression or development of unacceptable toxicity. The level of thymidine phosphorylase expression in peripheral white blood cells of patients was measured before and during treatment to determine the effect on this capecitabine-activating enzyme.

RESULTS

Of 47 patients enrolled, 38 (81%) completed treatment to a disease endpoint. No complete responses were achieved, but 13 of the 38 patients (34%) experienced a partial response, and another 3 patients (8%) experienced sd for more than 6 months. The clinical benefit rate was therefore 42% (95% confidence interval: 27% to 57%). The median time to disease progression for all evaluable patients was 3.6 months (range: 0.9-21.7 months). The most common nonhematologic toxicities were diarrhea, plantar- palmar erythrodysesthesia, fatigue, mucositis, and vomiting. Most patients (89%) received combination chemotherapy until disease progression.

CONCLUSIONS

The present study demonstrates that metronomic docetaxel-capecitabine chemotherapy with daily celecoxib can produce significant anticancer activity, with predictable toxicity. Efficacy fell short of expectations, with outcome measures being similar to those obtained when the study agents are given in conventional dosing. Furthermore, there is mounting evidence to indicate that a low dose of taxanes fails to induce thymidine phosphorylase expression, an effect believed to be important in achieving therapeutic synergism when taxanes are given concurrently with capecitabine.

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

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

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.

Adjuvant capecitabine, docetaxel, cyclophosphamide, and epirubicin for early breast cancer: final analysis of the randomized FinXX trial

PURPOSE

Capecitabine is an active agent in the treatment of breast cancer. It is not known whether integration of capecitabine into an adjuvant regimen that contains a taxane, an anthracycline, and cyclophosphamide improves outcome in early breast cancer.

PATIENTS AND METHODS

Women with axillary node-positive or high-risk node-negative breast cancer were randomly assigned to receive either three cycles of docetaxel and capecitabine (TX) followed by three cycles of cyclophosphamide, epirubicin, and capecitabine (CEX; n = 753) or three cycles of docetaxel (T) followed by three cycles of cyclophosphamide, epirubicin, and fluorouracil (CEF; n = 747). The primary end point was recurrence-free survival (RFS).

RESULTS

During a median follow-up time of 59 months, 214 RFS events occurred (local or distant recurrences or deaths; TX/CEX, n = 96; T/CEF, n = 118). RFS was not significantly different between the groups (hazard ratio [HR], 0.79; 95% CI, 0.60 to 1.04; P = .087; 5-year RFS, 86.6% for TX/CEX v 84.1% for T/CEF). Fifty-six patients assigned to TX/CEX died during the follow-up compared with 75 of patients assigned to T/CEF (HR, 0.73; 95% CI, 0.52 to 1.04; P = .080). In exploratory analyses, TX/CEX improved breast cancer-specific survival (HR, 0.64; 95% CI, 0.44 to 0.95; P = .027) and RFS in women with triple-negative disease and in women who had more than three metastatic axillary lymph nodes at the time of diagnosis. We detected little severe late toxicity.

CONCLUSION

Integration of capecitabine into a regimen that contains docetaxel, epirubicin, and cyclophosphamide did not improve RFS significantly compared with a similar regimen without capecitabine.

Individually tailored treatment with epirubicin and paclitaxel with or without capecitabine as first-line chemotherapy in metastatic breast cancer: a randomized multicenter trial

Anthracyclines and taxanes are active cytotoxic drugs in the treatment of early metastatic breast cancer. It is yet unclear whether addition of capecitabine to the combination of these drugs improves the treatment outcome. Patients with advanced breast cancer were randomized to first-line chemotherapy with a combination of epirubicin (Farmorubicin(®)) and paclitaxel (Taxol(®)) alone (ET) or in combination with capecitabine (Xeloda(®), TEX). Starting doses for ET were epirubicin 75 mg/m(2) plus paclitaxel 175 mg/m(2), and for TEX epirubicin 75 mg/m(2), paclitaxel 155 mg/m(2), and capecitabine 825 mg/m(2) BID for 14 days. Subsequently, doses were tailored related to side effects. Primary endpoint was progression-free survival (PFS); secondary endpoints were overall survival (OS), time to treatment failure (TTF), objective response (OR), safety and quality of life (QoL). 287 patients were randomized, 143 to ET and 144 to TEX. Median PFS was 10.8 months for patients treated with ET, and 12.4 months for those treated with TEX (HR 0.84, 95% CI 0.65-1.07, P = 0.16); median OS was 26.0 months for women in the ET versus 29.7 months in the TEX arm (HR 0.84, 95% CI 0.63-1.11, P = 0.22). OR was achieved in 44.8% (ET) and 54.2% (TEX), respectively (χ(2) 3.66, P = 0.16). TTF was significantly longer for patients treated with TEX, 6.0 months, versus 5.2 months following ET (HR 0.73, 95% CI 0.58-0.93, P = 0.009). Severe hematological side effects related to epirubicin and paclitaxel were evenly distributed between the treatment arms, mucositis, diarrhea, and Hand-Foot syndrome were significantly more frequent in the TEX arm. Toxicity-adjusted treatment with ET and TEX showed similar efficacy in terms of PFS, OS, and OR. In this trial with limited power, the addition of capecitabine to epirubicin and paclitaxel as first-line treatment did not translate into clinically relevant improvement of the outcome.

Thymidylate synthase and thymidine phosphorylase as predictive markers of capecitabine monotherapy in patients with anthracycline- and taxane-pretreated metastatic breast cancer

PURPOSE

The primary purpose of this study was to evaluate the role of thymidylate synthase (TS) and thymidine phosphorylase (TP) as biomarkers to predict clinical outcomes of capecitabine monotherapy in patients with anthracycline- and taxane-pretreated metastatic breast cancer (MBC).

METHODS

Of the patients who were previously treated with anthracycline and taxane regimens, 90 patients who had available tissue block for immunohistochemistry with measurable lesions were included. All patients received capecitabine (2,500 mg/m(2)/day) for 14 days every 3 weeks.

RESULTS

High TS expression was more common among patients with triple-negative (TN) subtype than among patients with other subtypes (33% for hormone receptor+, 8% for HER2+, and 58% for TN, P = 0.023). The median PFS was significantly lower in patients with high TS (6.6 vs. 3.0 months; P = 0.017) and low TP expressions (6.0 vs. 3.3 months; P = 0.013). A high TS and a low TP expressions were identified as unfavorable independent risk factors for PFS to capecitabine monotherapy in multivariate analysis (hazard ratio [HR], 1.7, P = 0.037 for high TS score; HR, 1.8, P = 0.014 for low TP score).

CONCLUSIONS

Our data suggest that high TS and low TP scores correlate with a shorter PFS for capecitabine monotherapy in patients with anthracycline- and taxane-pretreated MBC.

Refractory lung metastasis from breast cancer treated with multidisciplinary therapy including an immunological approach

A suggestive case of metastatic disease from breast cancer is reported. The HER-2-positive tumor was refractory to several agents, including anti-HER-2 therapy, trastuzumab, and lapatinib. After re-induction of trastuzumab in combination with activated natural killer (NK) cell injection therapy, tumor markers decreased, and finally a synergistic effect of taxane and capecitabine led to treatment response. This case suggests that multidisciplinary therapy including an immunological approach might be a breakthrough in the treatment of refractory disease.

Adjuvant capecitabine in combination with docetaxel and cyclophosphamide plus epirubicin for breast cancer: an open-label, randomised controlled trial

BACKGROUND

Standard adjuvant chemotherapy regimens for patients with moderate-to-high-risk early breast cancer typically contain a taxane, an anthracycline, and cyclophosphamide. We aimed to investigate whether integration of capecitabine into such a regimen enhances outcome.

METHODS

In this open-label trial, we randomly assigned (centrally by computer; stratified by node status, HER2 status, and centre) 1500 women with axillary node-positive or high-risk node-negative breast cancer to either three cycles of capecitabine and docetaxel followed by three cycles of cyclophosphamide, epirubicin, and capecitabine (capecitabine group, n=753), or to three cycles of docetaxel followed by three cycles of cyclophosphamide, epirubicin, and fluorouracil (control group, n=747). The primary endpoint was recurrence-free survival. A planned interim analysis was done after 3 years' median follow-up. Efficacy analyses were by modified intention to treat. The study is registered with ClinicalTrials.gov, number NCT00114816.

FINDINGS

Two patients in each group were excluded from efficacy analyses because of withdrawal of consent or distant metastases. After a median follow-up of 35 months (IQR 25.5-43.6), recurrence-free survival at 3 years was better with the capecitabine regimen than with control (93%vs 89%; hazard ratio 0.66, 95% CI 0.47-0.94; p=0.020). The capecitabine regimen was associated with more cases of grade 3 or 4 diarrhoea (46/740 [6%] vs 25/741 [3%]) and hand-foot syndrome (83/741 [11%] vs 2/741 [<1%]) and the control regimen with more occurrences of grade 3 or 4 neutropenia (368/375 [98%] vs 325/378 [86%]) and febrile neutropenia (65/741 [9%] vs 33/742 [4%]). More patients discontinued planned treatment in the capecitabine group than in the control group (178/744 [24%] vs 23/741 [3%]). Four patients in the capecitabine group and two in the control group died from potentially treatment-related causes.

INTERPRETATION

The capecitabine-containing chemotherapy regimen reduced breast cancer recurrence compared with a control schedule of standard agents. Capecitabine administration was frequently discontinued because of adverse effects.

FUNDING

Roche, Sanofi-Aventis, AstraZeneca, Cancer Society of Finland.

N(3)-o-toluyl-fluorouracil inhibits human hepatocellular carcinoma cell growth via sustained release of 5-FU

Purpose

N₃-o-toluyl-fluorouracil (TFU), the prodrug of 5-fluorouracil (5-FU), is the metabolite of N₁-acetyl-N₃-o-toluyl-fluorouracil (atofluding). In the present study, we aimed to evaluate the efficacy of TFU on the inhibition of human hepatocellular carcinoma cells via sustained release of 5-FU. The metabolism of TFU underlying the inhibitory effect was also analyzed.

Methods

In vitro assays, inhibition of cell growth by TFU was evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide method. The levels of TFU and 5-FU in the cell culture supernatant fluid were measured by high-performance liquid chromatography (HPLC). In vivo assays, the efficacy of TFU was evaluated in a human hepatocellular carcinoma xenograft mice model after 3 weeks of oral administration. The distributions of TFU and 5-FU in plasma and homogenate tissues including liver, lung and tumor were determined by HPLC.

Results

N₃-o-toluyl-fluorouracil weakly inhibited the proliferation of SMMC-7721 and PLC/PRF/5 cells in the absence of liver microsomal enzymes. In contrast, the inhibition rates were significantly increased in the presence of these enzymes. HPLC results revealed that TFU was metabolized slowly by liver microsomal enzymes and therefore the concentration of 5-FU was gradually increased with a longer retention time in cell culture supernatant fluid. The efficacy of TFU was confirmed in SMMC-7721 xenografts in Balb/c athymic (nu+/nu+) mice model. TFU treatment induced inhibition of SMMC-7721 growth with few side effects. HPLC results showed that high levels of TFU were still in liver 48 h after the end of oral administration, implying that TFU preferentially accumulated in liver with slow conversion to 5-FU by enzymes. This led to a long-lasting concentration of 5-FU in plasma. Further, a high level of 5-FU was found in tumors with a relatively low level in lungs. These results suggest that the metabolite of TFU was preferentially converted or taken up by tumor cells. The distributions of 5-FU may contribute to its high anti-tumor activity and low adverse reactions in vivo.

Conclusion

These results demonstrate that TFU is a promising prodrug of 5-FU for cancer treatment via sustained release of 5-FU in liver.

Sequential administration of dose-dense epirubicin/cyclophosphamide followed by docetaxel/capecitabine for patients with HER2-negative and locally advanced or node-positive breast cancer

PURPOSE

Capecitabine is effective against metastatic breast cancer (MBC). We hypothesized that sequential treatment with dose-dense epirubicin/cyclophosphamide (EC) and docetaxel/capecitabine would be active and tolerable in the adjuvant/neoadjuvant setting.

METHODS

In this prospective phase II clinical trial patients with HER2-negative and node-positive or locally advanced tumors were eligible to receive four cycles of EC (100/600 mg/m2) every 2 weeks with G-CSF on days 3-10, followed by four cycles of docetaxel/capecitabine (75/1,000 mg/m2 b.i.d., days 1-14) every 3 weeks.

RESULTS

Fifty-five patients were enrolled with median age of 49, and 80% had hormone receptor-positive disease. The median tumor size was 2.5 cm, with a median of two axillary nodes involved. Seventy-five percent of the first 20 patients had grade 2/3 hand-foot syndrome (HFS). Dose reduction of capecitabine to 800 mg/m2 reduced the grade 2/3 HFS incidence to 31% in the remaining patients. No grade 4/5 toxicities were observed. All 20 patients treated preoperatively responded, with 5 (25%) pathologic complete responses and 3 additional pT0N1 tumors. At a median follow-up of 48 (range 28-60) months, the event-free and overall survival rates are 91 and 98%, respectively.

CONCLUSIONS

Sequential treatment with dose-dense EC followed by docetaxel/capecitabine, using a lower capecitabine dose than that approved for MBC, has an acceptable toxicity profile and encouraging activity when used as neoadjuvant or adjuvant treatment of breast cancer.

Pharmacology and therapeutic efficacy of capecitabine: focus on breast and colorectal cancer

Capecitabine (N -pentyloxycarbonyl-5-deoxy-5-fluorocytidine), an oral prodrug of 5-fluorouracil, has provided compelling efficacy data for the treatment of metastatic breast cancer and stage III or IV colorectal cancer, both as monotherapy and in combination regimens. The preferential conversion of capecitabine to 5-fluorouracil in neoplastic tissues renders this fluoropyrimidine particularly appealing for clinical use. The enzyme thymidine phosphorylase, which mediates the final step of the capecitabine activation pathway, is expressed in higher concentration in neoplastic than in healthy tissues. This makes capecitabine more tumor specific than other chemotherapeutic agents. Accordingly, capecitabine is generally well tolerated. In particular, the incidence of myelosuppression and alopecia is low, and the most common side effects, hand-foot syndrome and diarrhea, are usually manageable. Given its good toxicity profile, capecitabine was assessed in combination with several chemotherapeutic or biologic agents. In addition, the observation that thymidine phosphorylase is upregulated after treatment with other anticancer drugs, namely taxanes, provided a rationale for the prominent antitumor activity recently observed for the combination of capecitabine with these agents. This review provides an evidence-based update of clinical trials investigating the role of capecitabine in the treatment of breast and colorectal cancer, with special emphasis on pharmacological and safety issues that form the basis of currently used schedules.

Thymidine phosphorylase expression and benefit from capecitabine in patients with advanced breast cancer

BACKGROUND AND AIM

Capecitabine is an orally bioavailable prodrug that is converted to 5-fluorouracil through several enzymatic steps, the last of which is mediated by thymidine phosphorylase (TP). TP has been reported to be expressed at higher levels in cancer tissue compared with normal counterpart. The present study aimed at evaluating the potential relationship between TP expression and benefit from capecitabine in patients with metastatic breast cancer (BC).

METHODS

Immunohistochemistry for TP and other biological markers was carried out on paraffin-embedded cancer tissues of 61 patients with BC treated with at least three cycles of capecitabine as single agent for metastatic disease. All patients had received capecitabine 1000 mg/m(2) b.i.d. days 1-14 every 21 days. The following variables were analyzed as potential determinants of benefit from capecitabine: TP expression, estrogen receptor (ER) and progesterone receptor status, human epidermal growth factor receptor-2 (HER-2) status, MIB-1 expression, performance status at the beginning of capecitabine treatment, stage at diagnosis, grade, presence of visceral metastases at the beginning of capecitabine treatment, and previous chemotherapy.

RESULTS

Overall, median time to progression (TTP) was 6.5 months (range 1.4-33). On multivariate analysis, ER status [hazard ratio (HR) for progression = 0.31; 95% confidence interval (CI) = 0.15-0.64; P = 0.002], presence of visceral metastases at the beginning of capecitabine treatment (HR = 2.30; 95% CI = 1.21-4.39; P = 0.01), and capecitabine as first- or second-line treatment (HR = 2.28; 95% CI = 1.21-4.32; P = 0.01) independently predicted TTP. TP was highly expressed in 34 of 61 cases (55.7%). In the subgroup of patients with TP-expressing tumor, TTP was significantly longer in patients who received anthracyclines and taxanes before capecitabine (median TTP 7.5 versus 3.3 months, P = 0.01, log-rank test). Similarly, patients with a TP-positive tumor showed a longer TTP if they received taxanes before capecitabine than patients with TP-positive tumor who did not receive this treatment (7.3 versus 3.4 months, P = 0.03).

CONCLUSIONS

These data provide further evidence that TP expression in BC could represent a biomarker of sensitivity to capecitabine treatment. Prospective studies with translational approach are desirable to confirm the predictive and prognostic role of TP.

Thymidine phosphorylase and dihydropyrimidine dehydrogenase are predictive factors of therapeutic efficacy of capecitabine monotherapy for breast cancer-preliminary results

Capecitabine monotherapy was administered for 25 patients with advanced or recurrent breast cancer, and the clinical therapeutic efficacy and its relationship to expression of 5-fluorouracil-related enzymes (i. e., thymidine phosphorylase (TP), thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD)) were investigated. The expressions of TP, TS and DPD were determined by immunohistochemical staining techniques and rated using a scoring system of 1~4. The expression score for TP/DPD showed a statistically significant correlation with the clinical response, whereas the expression score for TP/TS also showed a correlation but it was not statistically significant. The number of patients was small, but the results revealed the potential of application of the TP/DPD expression score as a factor for predicting the efficacy of the drug in individual patients.

Thymidine phosphorylase expression is associated with time to progression in patients receiving low-dose, docetaxel-modulated capecitabine for metastatic breast cancer

BACKGROUND

Preclinical data have indicated a synergistic interaction between docetaxel and capecitabine by means of taxane-induced up-regulation of thymidine phosphorylase (TP). On the basis of such premises, we conducted a phase II trial to determine the activity and tolerability of weekly docetaxel plus capecitabine in patients with metastatic breast cancer (MBC). Furthermore, we explored the relationship between TP tumor expression and benefit from this regimen.

PATIENTS AND METHODS

Patients received docetaxel 36 mg/m(2) i.v. on days 1, 8, and 15 and capecitabine orally 625 mg/m(2) b.i.d. from days 8 to 21. Cycles were repeated every 4 weeks. In the correlative study, we evaluated the TP expression by immunohistochemistry and the TP messenger RNA expression by real-time RT-PCR in the primary tumor.

RESULTS

Forty-seven women were enrolled. In the intention-to-treat analysis, objective responses were achieved in 24 patients (51%). Fourteen additional patients (30%) had stable disease. The median time to progression (TTP) was 6 months (range 1-44 months). Median survival was 17 months (range 1-48 months). Overall, the treatment was well tolerated. The most common clinical adverse events (all grades) were alopecia (55%), nail changes (53%), fatigue/asthenia (51%), nausea/vomiting (51%), neutropenia (49%), and neuropathy (49%). A significantly higher TTP was observed in patients with TP-positive tumors (log-rank test, P = 0.009). Interestingly, a subgroup analysis confirmed this TTP benefit in patients with TP-positive tumors obtaining a tumor response (log-rank test, P = 0.03), whereas the statistical significance was lost in nonresponders (log-rank test, P = 0.3).

CONCLUSIONS

This study indicates that a regimen with low doses of capecitabine plus weekly docetaxel is active against MBC. The correlative analysis provides preliminary evidence that TP expression may be a predictive marker for therapeutic benefit.

XeNA: capecitabine plus docetaxel, with or without trastuzumab, as preoperative therapy for early breast cancer

Combinations of capecitabine and a taxane are highly active in metastatic breast cancer, and synergy between capecitabine and docetaxel has also been demonstrated. Such combinations potentially would provide a promising non-anthracycline-based alternative for patients with early breast cancer. Non-anthracycline preoperative regimens are a particularly interesting proposition in human epidermal growth factor receptor 2 (HER2)-positive breast cancer, as they offer less cardiotoxicity and thus can be used concomitantly with preoperative trastuzumab therapy. Capecitabine plus docetaxel (XT) and trastuzumab with XT (HXT) are promising non-anthracycline regimens for the preoperative treatment of women with HER2-negative and HER2-positive breast cancer, respectively. The Xeloda in Neoadjuvant (XeNA) trial, an open-label, multicenter, phase II study, independently assesses the efficacy of preoperative XT in HER2-negative and HXT in HER2-positive breast cancer. A particularly important feature of the XeNA study is the use of pathologic complete response (pCR) plus near pCR (npCR) as the primary endpoint. pCR is associated with long-term survival, and although it is valuable as a surrogate marker, pCR has some limitations. Measurement of residual breast cancer burden (RCB) has been proposed as a more practical alternative to predict survival after preoperative chemotherapy. The combination of RCB-0 and RCB-I (npCR) expands the subset of patients shown to benefit from preoperative chemotherapy, and achievement of pCR or npCR is associated with long disease-free survival. In XeNA, the sum of pCR and npCR will facilitate correlative studies designed to identify patients most likely to benefit from XT and HXT and may expedite the clinical evaluation of these novel preoperative regimens.

Anthracyclines and taxanes induce the upregulation of thymidine phosphorylase in breast cancer cells

We have investigated the immunohistochemical expression of thymidine phosphorylase before and after the administration of anthracycline, and/or anthracycline/taxane-based preoperative chemotherapy in a consecutive series of 55 patients with primary operable breast cancer. Pretreatment, large core breast biopsies and the corresponding surgical samples were retrospectively evaluated for thymidine phosphorylase immunoreactivity. Immunohistochemical expression was evaluated on tumor cells (nuclear and cytoplasmic staining) and on stromal cells (cytoplasmic staining). The cytoplasmic expression of thymidine phosphorylase was enhanced in the tumor cells after treatment (P=0.04). An increase in thymidine phosphorylase cytoplasmic tumor expression was observed in 33% (95% confidence interval: 19-50%) of patients after preoperative chemotherapy (P=0.01). No statistically significant nuclear staining changes were observed in response to treatment. Similarly, no significant changes of the enzyme expression were seen in stromal cells. This study provides further evidence that, at least in breast cancer, thymidine phosphorylase is upregulated after anthracycline and/or taxane-containing chemotherapy. Accordingly, it supports the hypothesis of a synergistic effect between thymidine phosphorylase-modulating and thymidine phosphorylase-targeting anticancer agents. Translational studies, specifically designed on the basis of this rationale, are eagerly waited.

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.

Phase II study of weekly docetaxel and capecitabine in patients with metastatic breast cancer

PURPOSE

This phase II study evaluated the safety and efficacy of weekly docetaxel and capecitabine in patients with metastatic breast cancer.

PATIENTS AND METHODS

Thirty-nine patients with metastatic breast cancer received 30 mg/m2 of docetaxel on days 1, 8, and 15 in combination with capecitabine 800 mg/m2 twice daily on days 1-21, repeated every 28 days.

RESULTS

The median number of treatment cycles was 4 (range, 1-20 cycles). Grade 3 toxicities per patient were asthenia (n = 7; 18%), diarrhea (n = 7; 18%), nausea/vomiting (n = 5; 13%), stomatitis (n = 5; 13%), neutropenia (n = 5; 13%), and hand-foot syndrome (n = 4; 10%). There were only 2 grade 4 toxicities, febrile neutropenia and pulmonary embolism. The overall response rate was 44% (95% confidence interval (CI), 28%-60%), median duration of response was 9.1 months (95% CI, 6.2-12 months), and median time to progression was 5.5 months (95% CI, 3.7-7.3 months).

CONCLUSION

Weekly docetaxel with capecitabine was active with acceptable toxicities. Additional trials to define the optimal schedule of docetaxel and capecitabine are justified.

The future perspectives of breast cancer therapy

Adjuvant therapy after surgery for breast cancer has provided significant benefits to patients at risk of relapse. However, the success of therapy for each individual patient will often take years to reveal. Preoperative therapy has brought about significant advances in the treatment of breast cancer. More breast conservation therapy can be performed and it becomes clear that pathologic complete response (pCR) is a good prognostic marker. Moreover, patients can be segregated into different clinical phenotypes after preoperative therapy: the responder non-recurrent, the responder recurrent, the non-responder non-recurrent and the non-responder recurrent. While conventional therapy and surgery is adequate for the responder non-recurrent and the non-responder non-recurrent cases, modification of conventional therapy, the adoption of a new approach or the incorporation of novel therapeutics may be necessary to improve the pCR and reduce recurrence for the later two groups of patients. Preoperative therapy has also made possible the development of biomarkers to predict response and resistance to treatment. With this translational approach, the therapy for each patient can be more targeted and individualized. A higher rate of success is expected.

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.

Phase II trial of capecitabine in recurrent squamous cell carcinoma of the cervix

PURPOSE

To determine the efficacy and safety of capecitabine in women with inoperable, recurrent, or metastatic squamous cell cervical cancer.

PATIENTS AND METHODS

In a phase II IRB approved trial, capecitabine was given at a dosage of 2000 mg/m2/day orally in a divided dose daily for 14 days followed by a 7-day rest period. A standard dose modification scheme was used with one allowed dose reduction or dose escalation. National Cancer Institute criteria for progression, response, and toxicity were utilized. Quality of life data were obtained using the Memorial Symptom Assessment Scale and Functional Assessment for Cancer Therapy, which included a subscale for cervical cancer.

RESULTS

Twenty of 23 enrolled patients were evaluable for response. Stable disease was noted in 5 patients, with a median duration of response of 3.5 months (range, 3-6.5 months). No partial or complete responses were seen. Common grade 3 toxicities were fatigue (30.4%); abdominal pain, constipation, hand-foot syndrome, nausea, and vomiting (8.7% each); as well as dyspnea, headache, and coagulopathy (4.3% each). There were no grade 4 toxicities. All patients with previous exposure to infused 5-FU had evidence of progression. No statistically significant changes in quality of life were noted from baseline to post-cycle 2.

CONCLUSION

Single-agent capecitabine in patients with recurrent cervical cancer resulted in no objective responses. Although capecitabine is a well-tolerated regimen, as a single agent, it offers minimal benefit in a poor-prognosis cervical cancer population.

Translational research in breast cancer

Translational research (TR) involves both the development of novel diagnostics and novel therapeutics. These two major developmental areas are often associated with each other and these associations often bring new paradigms in the management of cancer patients. For example, the development of trastuzumab-based treatments has been conducted in harmony with the development of new methodologies to assess the expression of the Her-2 gene or protein, and from this, a therapeutic modality was established for breast cancer patients as a novel and individualized treatment system. TR covers a broad spectrum, from diagnosis to treatment, and it seems to act as a catalyst for developing novel paradigms. Therefore, it is crucial to conduct TR in clinical trials, in particular, prospective clinical trials. In this regard, TR can accelerate the development of new methodologies and increase trial efficiency. In this review, we describe the importance of TR, particularly that related to novel therapeutics.

Thymidine phosphorylase (platelet-derived endothelial-cell growth factor) in cancer biology and treatment

Thymidine phosphorylase (TP) is often induced in the tumour microenvironment by physiological and chemical stress. Its induction protects cells from apoptosis and helps cell survival by stimulating nucleoside metabolism and angiogenesis. Chemotherapy often upregulates TP, which acts in cell rescue; this result indicates that TP is a crucial therapeutic target. Clinical trials for metastatic diseases have shown that TP-targeting chemotherapy with fluorouracil derivatives greatly improves the effectiveness of conventional chemotherapy for not only response but also prognosis. This new idea, the improvement of TP-inducible therapy with TP-targeting therapy, should be further investigated for early disease states, and inhibitors of TP warrant extensive investigation.

Phase I study of weekly (day 1 and 8) docetaxel in combination with capecitabine in patients with advanced solid malignancies

PURPOSE

Capecitabine in combination with docetaxel given every 3 weeks has shown a high degree of activity in a number of tumor types, but at the expense of significant toxicity. To improve the therapeutic index, we evaluated a weekly regimen of docetaxel in combination with capecitabine, and determined the maximum tolerated dose, toxicities and pharmacokinetics of this combination.

PATIENTS AND METHODS

Patients with advanced solid malignancies were treated with docetaxel on days 1 and 8, and capecitabine, twice daily on days 1-14, of an every-21-day cycle. Pharmacokinetics of docetaxel were assessed on days 1 and 8 of the first cycle of chemotherapy.

RESULTS

Enrolled in the study were 25 patients. The most frequent toxicities were asthenia, hand-foot syndrome and mucositis. Inability to deliver at least 75% of the planned doses of both drugs during the first two cycles of chemotherapy was noted at dose levels 2, 3 and 4. Dose level 1 (docetaxel 30 mg/m2 and capecitabine 825 mg/m2 twice daily) is the recommended dose for phase II studies. Five patients experienced a partial response, and eight patients had stabilization of disease. Coadministration of capecitabine did not alter the pharmacokinetics of docetaxel.

CONCLUSION

The regimen consisting of docetaxel 30 mg/m2 (days 1, 8) and capecitabine 825 mg/m2 twice daily (days 1-14) was well tolerated. Capecitabine did not alter pharmacokinetics of docetaxel. Further testing of this regimen in tumor-specific trials, especially gastric, lung and breast cancer, is warranted.