MDM2 molecular imaging for the prediction of chemotherapeutic sensitivity in human breast cancer xenograft

The aim of the present study was to investigate the possible use of mouse double-minute 2 (MDM2) molecular imaging to predict chemotherapeutic sensitivity in breast cancer xenografts (BCXs). MCF-7 cells were transfected with MDM2 antisense oligonucleotides (ASONs), and MDM2 expression levels were determined by Western blotting. Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in MCF-7 cells transfected with ASONs and treated with paclitaxel. BCXs were established in nude mice by injection of ASONs, and tumor volumes were measured after paclitaxel treatment. MDM2 ASONs were labeled with 99mTc to generate an MDM2 molecular probe, and MDM2 expression levels were evaluated by imaging and Western blotting. MDM2 ASONs downregulated MDM2 expression in a dose-dependent manner and increased the rate of paclitaxel-induced cell growth inhibition. Imaging of tumors revealed significant differences in the tumor to skeletal muscle (T/M) ratio between groups. Tumor MDM2 protein expression was correlated with T/M ratios at 4 hours (R  =  .880) and 10 hours (R  =  .886). The effect of paclitaxel varied among nude mice bearing BCXs with different concentrations of ASONs, as shown by differences in tumor growth. MDM2 molecular imaging could be a promising method for predicting the sensitivity of BCXs to chemotherapy.

Management of breast cancer with nanoparticle albumin-bound (nab)-paclitaxel combination regimens: a clinical review

BACKGROUND

Monotherapy with nanoparticle albumin-bound (nab)-paclitaxel has demonstrated improved efficacy and safety compared with solvent-based paclitaxel and docetaxel.

DESIGN

A comprehensive review of all reported studies of nab-paclitaxel combinations with other agents in all breast cancer settings was undertaken.

RESULTS

Most studies reviewed are small, phase II and non-comparative. Combinations studied included nab-paclitaxel plus trastuzumab and/or bevacizumab (with or without additional cytotoxic agents), gemcitabine, capecitabine, carboplatin, or lapatinib. The majority of metastatic and neoadjuvant studies demonstrated satisfactory efficacy and safety for nab-paclitaxel combinations, although conclusions regarding comparison with solvent-based taxane (SBT) regimens are not possible. The two adjuvant studies confirmed the safety of nab-paclitaxel combinations in this setting.

CONCLUSIONS

Although results of this review indicate that nab-paclitaxel may be an appropriate substitute for SBTs in combination regimens, additional research is required to confirm the place and cost effectiveness of these combinations before nab-paclitaxel could be recommended routinely in all settings.

A phase II trial of dose-dense neoadjuvant gemcitabine, epirubicin, and albumin-bound paclitaxel with pegfilgrastim in the treatment of patients with locally advanced breast cancer

BACKGROUND

Neoadjuvant anthracycline/taxane combinations, with or without gemcitabine, produce pathologic complete responses (pCRs) in 15%-25% of patients. In this multicenter phase II study, we attempted to increase efficacy and decrease toxicity of a 3-drug gemcitabine-containing neoadjuvant regimen by administering dose-dense therapy with pegfilgrastim, and including albumin-bound paclitaxel as the taxane.

PATIENTS AND METHODS

A total of 123 patients with locally advanced breast cancer were enrolled. Patients were treated with 6 doses of neoadjuvant gemcitabine 2000 mg/m2, epirubicin 50 mg/m2, and albumin-bound paclitaxel 175 mg/m2 intravenously administered at 14-day intervals. Following neoadjuvant chemotherapy, patients underwent either mastectomy or breast conservation surgery; pathologic response to treatment was assessed. Postoperatively, patients received 4 doses of gemcitabine 2000 mg/m2 with albumin-bound paclitaxel 220 mg/m2 at 14-day intervals. Pegfilgrastim 6 mg was administered subcutaneously on day 2 following each dose of chemotherapy.

RESULTS

A total of 116 patients (95%) completed neoadjuvant chemotherapy and had subsequent surgical resection. Twenty-three patients (20%) had a pCR. The estimated 3-year progression-free survival (PFS) and overall survival rates were 48% and 86%, respectively. Neoadjuvant treatment was well tolerated; only 11% of the patients had grade 3/4 neutropenia, with 1 episode of neutropenic fever. Other grade 3/4 toxicities occurred in < 10% of the patients.

CONCLUSION

Neoadjuvant biweekly chemotherapy with gemcitabine/epirubicin/albumin-bound paclitaxel with pegfilgrastim is feasible and well tolerated. The pCR rate of 20% and the 3-year PFS rate of 48% are similar to results achieved with other commonly used neoadjuvant regimens.