Multicenter phase II study of a 28-day regimen of orally administered eniluracil and fluorouracil in the treatment of patients with anthracycline- and taxane-resistant advanced breast cancer

Cabazitaxel: more than a new taxane for metastatic castrate-resistant prostate cancer?

The taxanes are recognized as a major class of chemotherapeutic agents; however, mechanisms of innate and acquired resistance can limit their usefulness. Cabazitaxel, a novel taxane with microtubule-stabilizing potency similar to docetaxel, exhibits activity against tumor cell lines resistant to paclitaxel and docetaxel. Cabazitaxel showed linear pharmacokinetics and a terminal elimination half-life comparable with that of docetaxel, findings which support dosing as a single infusion in three-week treatment cycles. Dose-ranging studies recommended doses of 20 or 25 mg/m(2) every three weeks. Antitumor activity was shown in patients with advanced cancer and chemotherapy failure (including taxane failure). Other early studies investigated the efficacy of cabazitaxel in pretreated metastatic breast cancer, either as a single agent or in combination with capecitabine. Objective antitumor response rates of up to 24% and sustained tumor stabilizations were also observed. The TROPIC phase III study, conducted in patients with metastatic castrate-resistant prostate cancer previously treated with docetaxel, established cabazitaxel as the first chemotherapeutic agent to offer a survival advantage in this patient population. Across these studies, the dose-limiting hematologic toxicity was neutropenia (including febrile neutropenia), usually controllable with colony-stimulating factor/granulocyte-colony stimulating factor support.

Association of the ABCB1 gene polymorphisms 2677G>T/A and 3435C>T with clinical outcomes of paclitaxel monotherapy in metastatic breast cancer patients

BACKGROUND

ABCB1 is responsible for multidrug resistance, the principal mechanism by which many cancers develop resistance to chemotherapeutic drugs. There is a controversy whether ABCB1 gene polymorphisms correlate with survival and response in cancer patients treated with chemotherapy. We evaluated the association between clinical outcome (safety and efficacy) of paclitaxel monotherapy in metastatic breast cancer patients with ABCB1 gene polymorphisms 2677G>T/A or 3435C>T.

PATIENTS AND METHODS

Patients with metastatic breast cancer were treated with 175 mg/m(2) paclitaxel per 3-week cycle. Peripheral blood mononuclear cells from patients were used to genotype ABCB1 2677G>T/A and 3435C>T polymorphisms. Genotypes were investigated for their association with tumor response, survival, toxicity, and chemoresistance.

RESULTS

ABCB1 3435 CT showed a significantly lower disease control rate than the CC genotype (P = 0.025). ABCB1 3435 CT was correlated with shorter overall survival (OS) in Cox regression analysis (P = 0.026). The 2677 GG genotype showed a significant association with chemoresistance to paclitaxel and anthracycline (P = 0.04 and 0.04, respectively). None of the ABCB1 genotypes correlated with toxicity.

CONCLUSIONS

ABCB1 genotypes may be a predictor of paclitaxel activity as well as a prognostic factor in metastatic breast cancer patients.

Can inhibiting dihydropyrimidine dehydrogenase limit hand-foot syndrome caused by fluoropyrimidines?

Hand-foot syndrome (HFS) is a cutaneous adverse event that occurs in some patients treated with fluoropyrimidines. Although it is not life threatening, HFS can severely disrupt the daily lives of patients. HFS appears more frequently with 5-fluorouracil (5-FU) delivered by continuous infusion or with the 5-FU oral derivative capecitabine than with bolus 5-FU therapy. HFS is a leading cause of treatment interruption, dosage reduction, or, even, therapy discontinuation for patients on a capecitabine regimen. Interestingly, addition of a dihydropyrimidine dehydrogenase (DPD) inhibitor, such as uracil, 5-chloro-2,4-dihydroxypyridine, or eniluracil, to the fluoropyrimidine treatment regimen significantly diminishes the incidence of HFS. DPD inhibitors were initially combined with fluoropyrimidines to increase the efficacy of the drugs by impairing the DPD-mediated catabolism of 5-FU. However, with the accumulating findings from clinical trials that show the benefits of DPD inhibition on decreasing the risk of HFS, consideration should be given to changing the recommendations for the treatment of cancer patients with fluoropyrimidines to include DPD inhibitor components as standard therapy.

A phase II study of S-1 in patients with metastatic breast cancer — A Japanese trial by the S-1 cooperative study group, breast cancer working group

BACKGROUND

S-1 is a newly developed novel oral dihydrouracil dehydrogenase inhibiting fluoropyrimidine drug consisting of 1 M tegafur (FT), 0.4 M 5-chloro-2, 4-dihydroxypyrimidine (gimeracil), and 1 M potassium oxonate (oteracil), with efficient antitumor activity and low gastrointestinal toxicity which is widely used in Japan against advanced gastric, head and neck cancers. We investigated its clinical efficacy against metastatic breast cancer.

METHODS

A non-blind phase II study was carried out to evaluate the efficacy and toxicity in metastatic breast cancer patients. Patients with measurable metastasis foci (n=111) were enrolled, and 108 patients were regarded as eligible. S-1 was administered orally at a standard dose of 80 mg/m2/day b.i.d. One course consisted of 28 consecutive days of administration followed by a 14-day rest, and courses were repeated up to six times.

RESULTS

Among the eligible patients, 10 had a complete response and 35 had a partial response, with an overall response rate (CR+PR) of 41.7% (95% confidence interval: CI, 32.3-51.5%). The incidences of toxicity (> or =grade 3) were neutropenia 9.1%, anemia 0.9%, anorexia 3.6%, stomatitis 1.8%, nausea/vomiting 1.8%, diarrhea 0.9%, and fatigue 2.7%, however no treatment-related deaths were observed. The median survival time was 872 days (95% CI, 572-1,110 days). There was no difference in response rate or toxicity between the under 65-year-old group and the older group.

CONCLUSION

S-1 was demonstrated to have high efficacy with low gastrointestinal toxicity even in older patients and will be a promising new chemotherapy drug for metastatic breast cancer.

Single-agent capecitabine: a reference treatment for taxane-pretreated metastatic breast cancer?

The treatment of patients with metastatic breast cancer that has progressed despite previous anthracycline- and taxane-based therapy is a challenge for oncologists. Several agents, including vinorelbine, gemcitabine, pemetrexed, and particularly capecitabine, have been evaluated in this setting, either alone or in combination with other cytotoxic agents. The efficacy of many of these agents has not yet been clearly established in this setting, as the majority have been evaluated in a limited number of patients and predominantly in single-center trials. Furthermore, some agents with clinically meaningful activity are often associated with significant toxicity, particularly myelosuppression and neuropathy, while less toxic agents/regimens often exchange improved tolerability for reduced activity. Capecitabine, an oral chemotherapeutic, is the agent that has been evaluated most extensively in this setting. A large, phase II trial (n = 163) conducted in North America demonstrated a disease control rate of 63%, including an objective response rate of 20%, median time to disease progression of 3.0 months, and median survival of approximately 1 year. Adverse events were typically mild to moderate in intensity and could be controlled with treatment interruption or, if necessary, dose adjustment to each individual's tolerable dose. Data recently reported from three other large trials in taxane-pretreated patients have revealed similar efficacy and tolerability. Together, these four trials show that single-agent capecitabine, in a population of 500 patients, consistently produced clinically meaningful efficacy, including median survival of approximately 1 year, with a favorable safety profile. Myelosuppression and alopecia were particularly rare. In addition, the oral administration of capecitabine, which enables convenient, patient-oriented therapy, makes it an attractive treatment for patients. Based primarily on the results of the pivotal trial, capecitabine received regulatory approval as treatment for anthracycline- and taxane-pretreated (paclitaxel-pretreated in the U.S.) metastatic breast cancer. In light of the confirmatory results of subsequent large trials, capecitabine is now considered a reference treatment in this setting, as no other agent has consistently demonstrated such high efficacy in as large a patient population.