A phase I study of an all-oral combination of vinorelbine/capecitabine in patients with metastatic breast cancer previously treated with anthracyclines and/or taxanes

Senescence sensitivity of breast cancer cells is defined by positive feedback loop between CIP2A and E2F1

Senescence induction contributes to cancer therapy responses and is crucial for p53-mediated tumor suppression. However, whether p53 inactivation actively suppresses senescence induction has been unclear. Here, we show that E2F1 overexpression, due to p53 or p21 inactivation, promotes expression of human oncoprotein CIP2A, which in turn, by inhibiting PP2A activity, increases stabilizing serine 364 phosphorylation of E2F1. Several lines of evidence show that increased activity of E2F1-CIP2A feedback renders breast cancer cells resistant to senescence induction. Importantly, mammary tumorigenesis is impaired in a CIP2A-deficient mouse model, and CIP2A-deficient tumors display markers of senescence induction. Moreover, high CIP2A expression predicts for poor prognosis in a subgroup of patients with breast cancer treated with senescence-inducing chemotherapy. Together, these results implicate the E2F1-CIP2A feedback loop as a key determinant of breast cancer cell sensitivity to senescence induction. This feedback loop also constitutes a promising prosenescence target for therapy of cancers with an inactivated p53-p21 pathway.

SIGNIFICANCE

It has been recently realized that most currently used chemotherapies exert their therapeutic effect at least partly by induction of terminal cell arrest, senescence. However, the mechanisms by which cell-intrinsic senescence sensitivity is determined are poorly understood. Results of this study identify the E2F1-CIP2A positive feedback loop as a key determinant of breast cancer cell sensitivity to senescence and growth arrest induction. Our data also indicate that this newly characterized interplay between 2 frequently overexpressed oncoproteins constitutes a promising prosenescence target for therapy of cancers with inactivated p53 and p21. Finally, these results may also facilitate novel stratification strategies for selection of patients to receive senescence-inducing cancer therapies.

Anticancer oral therapy: emerging related issues

The use of oral anticancer drugs has shown a steady increase. Most patients prefer anticancer oral therapy to intravenous treatment primarily for the convenience of a home-based therapy, although they require that the efficacy of oral therapy must be equivalent and toxicity not superior than those expected with the intravenous treatment. A better patient compliance, drug tolerability, convenience and possible better efficacy for oral therapy as compared to intravenous emerge as the major reasons to use oral anticancer agents among oncologists. Inter- and intra-individual pharmacokinetic variations in the bioavailability of oral anticancer drugs may be more relevant than for intravenous agents. Compliance is particularly important for oral therapy because it determines the dose-intensity of the treatment and ultimately treatment efficacy and toxicity. Patient stands as the most important determinant of compliance. Possible measures for an active and safe administration of oral therapy include a careful preliminary medical evaluation and selection of patients based on possible barriers to an adequate compliance, pharmacologic issues, patient-focused education, an improvement of the accessibility to healthcare service, as well as the development of home-care nursing symptom-focused interventions. Current evidences show similar quality of life profile between oral and intravenous treatments, although anticancer oral therapy seems to be more convenient in terms of administration and reduced time lost for work or other activities. Regarding cost-effectiveness, current evidences are in favor of oral therapy, mainly due to reduced need of visits and/or day in hospital for the administration of the drug and/or the management of adverse events.

Capecitabine and Vinorelbine as an All-Oral Chemotherapy in HER2-Negative Locally Advanced and Metastatic Breast Cancer

BACKGROUND: The oral formulation of vinorelbine together with capecitabine allows for an all-oral combination chemotherapy which promises to raise quality of life of patients with advanced breast cancer. PATIENTS AND METHODS: Patients with HER2-negative, locally advanced, inoperable or metastatic breast cancer were included in this prospective observational trial (treatment schedule: capecitabine 500 mg/m2 twice daily, days 1-14; vinorelbine 60 mg/m2, days 1+8; repeated in 3-week cycles). RESULTS: All 32 patients (median age 50 years) were evaluable for toxicity, and 30 patients for response. Twentyfour patients received therapy as first-line treatment, and 8 patients as beyond first-line treatment. Median time to progression was 8 months, and median overall survival was 32 months. Complete response was observed in 1 patient (3%), partial response in 10 patients (33%), and disease stabilization for more than 6 months (SD > 6) in 10 patients (33%). This results in an overall response rate (ORR) of 37% and a clinical benefit rate (ORR + SD > 6) of 70%. The only grade 3/4 toxicities were neutropenia (19%) and hand-foot syndrome (9%). CONCLUSIONS: The all-oral combination of capecitabine/vinorelbine at this schedule appears to be an effective, well-tolerated regimen for treatment of advanced breast cancer, and offers a promising alternative to single-agent capecitabine and vinorelbine as well as intravenous polychemotherapy.

Intravenous versus oral vinorelbine plus capecitabine as second-line treatment in advanced breast cancer patients. A retrospective comparison of two consecutive phase II studies

Vinorelbine (i.v.) plus capecitabine (oral) combination therapy is active in anthracycline/taxane pretreated patients with metastatic breast cancer. Availability of oral vinorelbine provides this combination in an all-oral formulation. Two consecutive phase II trials differing only in vinorelbine administration routes evaluated their respective activities and tolerabilities in this population. In the i.v. group (n = 38) disease control was 61% (37% PR, 24% SD), median TTP 6.8 months and median survival 11.3 months. In the oral group (n = 38) disease control was 77% (5.4% CR, 34% PR, 38% SD), median TTP 7 months and median survival 10 months. G3-G4 neutropenia was more common in the oral group (p < 0.05); G2-G3 anaemia [5] and G3 thrombocytopenia [1] were observed only in the oral group. Although the comparison between the two regimens was not randomized, the results observed in these two consecutive phase II studies may suggest that oral and iv vinorelbine, in combination with capecitabine, can achieve similar responses in patients with metastatic breast cancer refractory to anthra-taxane combinations.

All-oral combination of oral vinorelbine and capecitabine as first-line chemotherapy in HER2-negative metastatic breast cancer: an International Phase II Trial

BACKGROUND

This multicentre, international phase II trial evaluated the efficacy and safety profile of a first-line combination of oral vinorelbine plus capecitabine for women with metastatic breast cancer (MBC).

METHODS

Patients with measurable, HER2-negative disease received, as a first line in metastatic setting, 3-weekly cycles of oral vinorelbine 80 mg m(-2) (after a first cycle at 60) on day 1 and day 8, plus capecitabine 1000 mg m(-2) (750 if >or=65 years of age) twice daily, on days 1-14. Treatment was continued until progression or unacceptable toxicity.

RESULTS

A total of 55 patients were enrolled and 54 were treated (median age: 58.5 years). Most (78%) had visceral involvement and 63% had received earlier (neo)adjuvant chemotherapy. The objective response rate (RECIST) in 49 evaluable patients was 51% (95% confidence interval (CI), 36-66), including complete response in 4%. The clinical benefit rate (response or stable disease for >or=6 months) was 63% (95% CI, 48-77). The median duration of response was 7.2 months (95% CI, 6.4-10.2). After a median follow-up of 41 months, median progression-free survival was 8.4 months (95% CI, 5.8-9.7) and median overall survival was 29.2 months (95% CI, 18.2-40.1). Treatment-related adverse events were manageable, the main grade 3-4 toxicity was neutropaenia (49%); two patients experienced febrile neutropaenia and three patients had a neutropaenic infection (including one septic death). A particularly low rate of alopaecia was observed.

CONCLUSION

These results show that the all-oral combination of oral vinorelbine and capecitabine is an effective and well-tolerated first-line regimen for MBC.

A population-based clinical trial of irinotecan and Carboplatin

Purpose. Phase I trials of anticancer drugs are commonly conducted using the method of modified Fibonacci. We have developed a population-based design for phase I trials of combining anticancer drugs such as irinotecan and carboplatin. Patients and Methods. Intrapatient dose escalation of irinotecan and carboplatin was performed according to a predetermined schema to reach individual dose-limiting toxicity (DLT) in 50 patients with solid tumors refractory to previous chemotherapy. The individual toxicity-limiting dose levels were analyzed for normal distribution using the method of Ryan-Joiner and subsequently used to determine a population-based maximum tolerated dose (pMTD). For comparison, a simulation study was performed using the method of modified Fibonacci. Results. The most common dose-limiting toxicities (DLTs) included neutropenia (58%), thrombocytopenia (16%), and diarrhea (8%). The frequency of individual toxicity-limiting dose levels of 50 patients approximated a normal distribution. The dose levels associated with individual limiting toxicities ranged from level 1 (irinotecan 100 mg/m² and carboplatin AUC = 4 mg/mL x min) to level 8 (irinotecan 350 mg/m² and carboplatin AUC = 6). The pMTD was determined to be dose level 3 (150 mg/m² for irinotecan and AUC = 5 for carboplatin). In contrast, the MTD was determined to be dose level 4 (200 mg/m² for irinotecan and AUC 5 for carboplatin) by modified-Fibonacci simulation. Conclusions. The population-based design of phase I trial allows optimization of dose intensity and derivation of a pMTD. The pMTD has been applied in phase II trial of irinotecan and carboplatin in patients with small-cell lung cancer.

Effective oral chemotherapy for breast cancer: pillars of strength

Traditionally, anticancer therapy has been dominated by intravenous drug therapy. However, oral agents provide an attractive approach to chemotherapy and use of oral treatments is increasing. We discuss the benefits and challenges of oral chemotherapy from the perspectives of patients, healthcare providers and healthcare funders. Important issues include patient preference, efficacy, compliance, bioavailability, reimbursement, use in special patient populations, financial and staff time savings and flexibility of dosing. We review data for traditional oral agents (e.g. cyclophosphamide, methotrexate), newer oral chemotherapies (e.g. capecitabine), oral formulations of traditionally intravenous agents (e.g. vinorelbine, idarubicin) and new biologic agents under evaluation in breast cancer (e.g. tyrosine kinase inhibitors). Lastly, we review studies of all-oral combination regimens. The wealth of data available and the increasing use of oral agents in breast cancer suggest that many of the concerns and perceptions about oral therapy, including efficacy and bioavailability, have been overcome, and that oral therapy will play a major role in breast cancer management in the future in both the metastatic and adjuvant settings.