Paclitaxel Activity in Anthracycline Refractory Breast Cancer Patients

A phase I and pharmacologic study of capecitabine and paclitaxel in breast cancer patients

BACKGROUND

Based on preclinical studies demonstrating that treatment with paclitaxel upregulates intratumoral thymidine phosphorylase (dTHdPase), which catalyzes the final step in the conversion of the oral fluoropyrimidine capecitabine to 5-fluorouracil (5-FU), as well as the overlapping spectra of activity for these agents, particularly in metastatic breast cancer, this phase I study evaluated the feasibility of administering capecitabine on an intermittent schedule in combination with paclitaxel in previously-treated patients with locally advanced or metastatic breast cancer. The study also sought to recommend doses for subsequent disease-specific studies, identify clinically significant pharmacokinetic interactions, and detect preliminary antitumor activity.

PATIENTS AND METHODS

Nineteen previously treated women with metastatic breast cancer whose prior treatment included neither paclitaxel or capecitabine received one hundred one courses of capecitabine and paclitaxel. Paclitaxel was administered as a three-hour intravenous (i.v.) infusion at a fixed dose of 175 mg/m2 and capecitabine was administered as 2 divided daily doses for 14 days followed by a seven-day rest period every 3 weeks. The dose of capecitabine was increased from a starting dose of 1650 mg/m2/d. The plasma sampling scheme in the first course permitted characterization of the pharmacokinetics of each agent given alone and concurrently to detect major pharmacokinetic interactions.

RESULTS

Palmar plantar erythrodysesthesia (hand foot syndrome) and neutropenia were the principal dose-limiting toxicities (DLT). Other toxicities included diarrhea and transient hyperbilirubinemia. Three of eight new patients treated with capecitabine 2000 mg/m2/d and paclitaxel 175 mg/m2 experienced DLT in the first course, whereas none of eleven new patients treated with capecitabine 1650 mg/m2/d and paclitaxel 175 mg/m2 developed DLT. Pharmacokinetic studies indicated that capecitabine did not grossly affect the pharmacokinetics of paclitaxel, and there were no major effects of paclitaxel on the pharmacokinetics of capecitabine and capecitabine metabolites. However, AUC values for the major 5-FU catabolite, fluorobeta-alanine (FBAL), were significantly lower in the presence of paclitaxel. Two complete and seven partial responses (56% response rate) were observed in sixteen patients with measurable disease; four of six patients whose disease was previously treated with high-dose chemotherapy and hematopoietic stem-cell support had major responses. Seven of nineteen patients had stable disease as their best response.

CONCLUSIONS

Recommended combination doses of capecitabine on an intermittent schedule and paclitaxel are capecitabine 1650 mg/m2/d orally for 14 days and paclitaxel 175 mg/m2 i.v. every 3 weeks. The favorable preclinical interactions between capecitabine and paclitaxel, as well as the acceptable toxicity profile and antitumor activity in patients with metastatic breast cancer, support further clinical evaluations to determine an optimal role for the combination of capecitabine and paclitaxel in breast cancer and other relevant malignancies.

Cost effectiveness of treatment options in advanced breast cancer in the UK

OBJECTIVE

To compare clinical and economic study data for docetaxel, paclitaxel and vinorelbine in the treatment of anthracycline-resistant advanced breast cancer.

STUDY DESIGN AND METHODS

A Markov decision-analysis model to simulate the clinical course of a 'typical' patient with advanced breast cancer during salvage chemotherapy was updated with response rates and adverse effect rates from phase III clinical trial data for docetaxel, paclitaxel and vinorelbine. Costs were taken from UK national databases and hospitals. Utilities were estimated from 30 oncology nurses in the UK using the standard gamble method.

PERSPECTIVE

National Health Service.

RESULTS

When compared with other chemotherapeutic agents, docetaxel has been shown to increase response rate, time to progression and survival in patients with advanced breast cancer. In the base-case analysis, the incremental cost-utility ratio for docetaxel versus paclitaxel was pound1995 per quality-adjusted life year (QALY) gained (1998 values). The incremental cost-utility ratio for docetaxel versus vinorelbine was pound14 055 per QALY gained. In the comparison with vinorelbine, docetaxel provided the equivalent of an additional 92 days of perfect health. Sensitivity analyses confirmed the robustness of the model and the validity of the base-case analysis results. Even in the worst case scenarios, docetaxel remained cost effective compared with paclitaxel and vinorelbine.

CONCLUSIONS

These findings support the use of the taxoids, notably docetaxel, in the management of advanced breast cancer.

Vinorelbine and cisplatin in metastatic breast cancer patients previously treated with anthracyclines

PURPOSE

To assess the antitumor efficacy and safety of a vinorelbine and cisplatin combination in patients with metastatic breast cancer previously treated with anthracyclines.

PATIENTS AND METHODS

Fifty-three patients with assessable metastatic breast cancer with previous exposure to anthracyclines (adjuvant n = 6, palliative n = 47) were studied. Cisplatin 75 mg/m2 on day 1 was given followed by 25 mg/m2 vinorelbine (VNR) on days 1 + 8, in a five-min i.v. infusion. Courses were repeated every three weeks on an outpatient basis. Treatment continued until disease progression, excess toxicity or patient refusal. Patients were classified according to their response to anthracyclines: anthracycline refractory patients were patients who had never responded under an anthracycline regimen. Anthracycline resistant patients were either metastatic patients who progressed within four months of completing anthracycline-based chemotherapy or patients who progressed within six months of completion of an anthracycline adjuvant treatment. Patients who progressed four months after the end of an anthracycline regimen in metastatic setting or six months after the end of an anthracycline regimen in adjuvant setting were considered as patients previously treated with anthracyclines and were called 'relapsed'.

RESULTS

Four patients (8%) achieved a complete response (CR) and twenty-two patients (41%) achieved a partial response (PR) with an overall response rate (OR) of 49% (95% confidence interval (CI): 35-63). Stable disease (SD) was observed in five patients (9%), twenty-two patients had progressive disease (PD). Responses according to previous sensitivity to anthracycline were as follow: 5 refractory patients achieved a PR from 14 patients (36%). Seven of sixteen resistant patients responded (44%), six with PR and one with CR. Among 23 'relapsed' patients, 14 responses were observed (61%), with 3 CR and 11 PR. There was no statistical difference in RR among the three groups. The median duration of response for all patients was 7 months, the median time to progression (TTP) 5 months and median overall survival 12 months. All patients were assessed for toxicity. The main toxicity was neutropenia grade 3 and 4 in 49% of patients. Febrile neutropenia requiring hospitalization was uncommon (2 patients). There were no treatment related deaths. Despite potential overlapping neurologic toxicities of the two drugs, only eight patients (15%) developed neuropathy, which was, however, mild (grades 1 and 2).

CONCLUSIONS

This cisplatin VNR regimen is well tolerated and active in patients who failed anthracyclines. The response rate, TTP and survival data are encouraging and indicate that cisplatin VNR may have a place as second-line treatment alternative to taxanes or other less active regimens. If these results can be verified in multi-institution trials, this combination of drugs would merit investigation as first-line therapy in this patient population.

Chemotherapy of breast cancer: are the taxanes going to change the natural history of breast cancer?

Among the novel chemotherapeutic drugs introduced in the last decade, taxanes have emerged as the most powerful compounds and results available to date suggest that they will be remembered in the future as the breast cancer chemotherapy of the 1990s. The two taxanes (paclitaxel, Taxol, Bristol-Myers Squibb and docetaxel, Taxotere, Rhône-Poulenc Rorer) share some characteristics, but are also significantly different both in preclinical profile and, most importantly, in clinical characteristics. The main clinical differences are related to their different efficacy-toxicity ratio in relation to dose and schedule; the differing integrability of paclitaxel and docetaxel in anthracycline-taxane containing regimens, secondary to major differences in pharmacokinetic interactions between each taxane and the anthracyclines, and; the potential differences in level of synergism between each taxane and herceptin (HeR2Neu antibody/trastuzumab, Genentech/Roche). In clinical practice, the taxanes are now standard therapy in metastatic breast cancer after prior chemotherapy, in particular anthracyclines, has failed. Their role in combination with anthracyclines in first-line therapy of advanced breast cancer is emerging and sheds new light on the potential role of taxanes in the adjuvant setting. However, the impact of taxanes on the natural history of breast cancer is yet to be defined, despite the trend of results suggesting that these agents have the potential for significant improvements in advanced and, most importantly, adjuvant therapy of breast cancer. The results of all completed or ongoing Phase III trials in first-line metastatic and the adjuvant setting will help determine if taxanes will further improve the outcome of breast cancer or not.