Clinical data and pharmacokinetics of a docetaxel-vinorelbine combination in anthracycline resistant/ relapsed metastatic breast cancer

Trastuzumab plus capecitabine vs. lapatinib plus capecitabine in patients with trastuzumab resistance and taxane-pretreated metastatic breast cancer

The purpose of this prospective, nonrandomized, controlled study was to compare the regimen of continuously administering trastuzumab and capecitabine (HX) with the regimen of lapatinib plus capecitabine (LX) for metastatic breast cancer (MBC) patients who are resistant to trastuzumab and have previously received taxane treatment. The patients in the HX group received trastuzumab (6 mg/kg every 21 days following a loading dose of 8 mg/kg on cycle 1) and capecitabine (2,000 mg/m(2)/day, days 1 to 14 every 21 days). The patients in the LX group received lapatinib (1,250 mg/day) and capecitabine (2,000 mg/m(2)/day, days 1 to 14 every 21 days). The median progression-free survival (PFS) of the patients in the HX and LX groups was 4.5 vs. 6.0 months, respectively (p = 0.006). The proportion of patients having a PFS ≥ 6 months in the HX and LX groups was 30 vs. 55 %, respectively (p = 0.005). The incidence rate of new brain metastases during treatment was 12 and 3 % in the HX and LX groups, respectively, which was not significantly different (p = 0.16). In conclusion, application of the lapatinib plus capecitabine regimen in MBC patients with a trastuzumab-resistant tumor can more effectively control the disease compared with continuous administration of trastuzumab plus capecitabine.

Vitamin D(3) cryosensitization increases prostate cancer susceptibility to cryoablation via mitochondrial-mediated apoptosis and necrosis

OBJECTIVES

To investigate the effect and molecular mechanisms of action of Vitamin D(3) (VD(3) ) as a neo-adjunctive agent before cryosurgery in an effort to increase treatment efficacy for prostate cancer (CaP). To eliminate the potential for disease recurrence that exists at the periphery of the freeze lesion, where temperatures may be insufficient to destroy both androgen-sensitive (AS) and androgen-insensitive (AI) CaP.

METHODS

Human CaP cells, LNCaP, were each genetically altered to express the AS and AI phenotypes and subjected to VD(3) treatment and freezing in an in vitro and tissue-engineered model. Cell viability, caspase inhibitor and western blot studies were used to determine the basis of the different responses of AI and AS cells to VD(3) cryosensitization.

RESULTS

VD(3) was found to be a highly effective cryosensitizer, resulting in a >50% overall increase in cell death after -15 °C freezing. Fluorescence microscopy, western blot analysis and caspase protease assays confirmed that the increased activation of apoptosis was modulated through a mitochondrial-mediated pathway. Caspase inhibition studies showed that apoptosis played an integral role in cell death, with VD(3) cryosensitivation-induced apoptotic events responsible for >30% of the overall cell death after -15 °C freezing.

CONCLUSIONS

The present study suggests that the use of VD(3) as a cryosensitizer increases cryoablation efficacy through the increased activity of apoptosis as well as through necrosis. The data show that through VD(3) treatment the overall level of AI CaP cell tolerance to freezing is reduced to a level similar to that of AS CaP. VD(3) pre-treatment in conjunction with cryoablation may increase treatment efficacy and reduce disease recurrence for CaP patients.

Colchitaxel, a coupled compound made from microtubule inhibitors colchicine and paclitaxel

BACKGROUND

Tumor promoters enhance tumor yield in experimental animals without directly affecting the DNA of the cell. Promoters may play a role in the development of cancer, as humans are exposed to them in the environment. In work based on computer-assisted microscopy and sophisticated classification methods, we showed that cells could be classified by reference to a database of known normal and cancerous cell phenotypes. Promoters caused loss of properties specific to normal cells and gain of properties of cancer cells. Other compounds, including colchicine, had a similar effect. Colchicine given together with paclitaxel, however, caused cells to adopt properties of normal cells. This provided a rationale for tests of microtubule inhibitor combinations in cancer patients. The combination of a depolymerizing and a stabilizing agent is a superior anti-tumor treatment. The biological basis of the effect is not understood.

RESULTS

A single compound containing both colchicine and paclitaxel structures was synthesized. Colchicine is an alkaloid with a trimethoxyphenyl ring (ring A), a ring with an acetamide linkage (ring B), and a tropolone ring (ring C). Although rings A and C are important for tubulin-binding activity, the acetamide linkage on ring B could be replaced by an amide containing a glutamate linker. Alteration of the C-7 site on paclitaxel similarly had little or no inhibitory effect on its biological activity. The linker was attached to this position. The coupled compound, colchitaxel (1), had some of the same effects on microtubules as the combination of starting compounds. It also caused shortening and fragmentation of the + end protein cap.

CONCLUSION

Since microtubule inhibitor combinations give results unlike those obtained with either inhibitor alone, it is important to determine how such combinations affect cell shape and growth. Colchitaxel shows a subset of the effects of the inhibitor combination. Thus, it may be able to bind the relevant cellular target of the combination. It will be useful to determine the basis of the shape reversal effect and possibly, the reasons for therapeutic efficacy of microtubule inhibitor combinations.

Vinorelbine in the management of breast cancer: New perspectives, revived role in the era of targeted therapy

Vinorelbine is a semi-synthetic vinca alkaloid that has been shown active in many tumour types and is currently registered for the treatment of advanced breast cancer (ABC) and non-small cell lung cancer (NSCLC). This agent has a generally favourable safety profile, and may be suitable for use in special populations such as the elderly and/or frail patient. However, with the taxanes firmly established as standard second line treatment for ABC after failure of an anthracycline, vinorelbine has been generally relegated for use as third line therapy, in competition with the oral compound capecitabine. More recently, the exciting results observed with the combination of vinorelbine and trastuzumab in patients with Her-2 overexpressing/amplified tumours, as well as the development of a reliable formulation and revised schedule of oral vinorelbine with proven activity in ABC appear to have revived the interest in this compound in the management of this disease. There are still a number of unanswered questions that will have to be addressed by properly designed, adequately powered randomised clinical trials.

Docetaxel in the treatment of breast cancer: current experience and future prospects

It has become clear over the past 10 years that docetaxel, a semisynthetic taxoid antineoplastic agent, is among the most promising compounds to have been developed in the 1990s for the treatment of breast cancer. Data indicate that this drug became standard therapy in the treatment of patients with metastatic disease who have failed anthracycline treatment, and secondarily showed very encouraging results in the first-line metastatic setting either in monochemotherapy or when docetaxel was combined with an anthracycline. More recently, docetaxel also became one of the standard therapies in the adjuvant and neoadjuvant settings, and a promising partner for novel biologic therapies. Current research is further exploring the effect of docetaxel on outcome of early breast cancer in order to fully determine the extent that this chemotherapeutic agent will change the natural history of breast cancer.

Paclitaxel and vinorelbine cause synergistic increases in apoptosis but not in microtubular disruption in human lung adenocarcinoma cells (A-549)

Concurrent administration of paclitaxel and vinorelbine results in cytotoxicity in vivo and in vitro in a number of tumor cell lines, yet the mechanisms of enhanced cell killing are undefined. In studies here, we show that low concentrations (1 nM) of paclitaxel and vinorelbine in combination result in enhanced cell killing by apoptosis ( P<0.05) in the human lung adenocarcinoma cell line, A-549. In contrast, necrotic cell death and formation of multinucleated cells, which were significantly increased by paclitaxel ( P<0.05) alone, but not vinorelbine, were not increased synergistically by both drugs. Paclitaxel also caused microtubular disruption which was not observed with vinorelbine. These data provide further rationale for the combined use of paclitaxel and vinorelbine in clinical trials, and suggest that the cooperative effects of drugs on apoptosis are not mediated through similar disruptional effects on microtubules.