Randomized phase II trial of iproplatin and carboplatin in advanced breast cancer. The EORTC Early Clinical Trials Group and the EORTC Data Center

Emerging platinum(IV) prodrug nanotherapeutics: A new epoch for platinum-based cancer therapy

Owing to the unique DNA damaging cytotoxicity, platinum (Pt)-based chemotherapy has long been the first-line choice for clinical oncology. Unfortunately, Pt drugs are restricted by the severe dose-dependent toxicity and drug resistance. Correspondingly, Pt(IV) prodrugs are developed with the aim to improve the antitumor performance of Pt drugs. However, as "free" molecules, Pt(IV) prodrugs are still subject to unsatisfactory in vivo destiny and antitumor efficacy. Recently, Pt(IV) prodrug nanotherapeutics, inheriting both the merits of Pt(IV) prodrugs and nanotherapeutics, have emerged and demonstrated the promise to address the underexploited dilemma of Pt-based cancer therapy. Herein, we summarize the latest fronts of emerging Pt(IV) prodrug nanotherapeutics. First, the basic outlines of Pt(IV) prodrug nanotherapeutics are overviewed. Afterwards, how versatile Pt(IV) prodrug nanotherapeutics overcome the multiple biological barriers of antitumor drug delivery is introduced in detail. Moreover, advanced combination therapies based on multimodal Pt(IV) prodrug nanotherapeutics are discussed with special emphasis on the synergistic mechanisms. Finally, prospects and challenges of Pt(IV) prodrug nanotherapeutics for future clinical translation are spotlighted.

Recent Advances in Platinum (IV) Complex-Based Delivery Systems to Improve Platinum (II) Anticancer Therapy

Cisplatin and its platinum (Pt) (II) derivatives play a key role in the fight against various human cancers such as testicular, ovarian, head and neck, lung tumors. However, their application in clinic is limited due to dose- dependent toxicities and acquired drug resistances, which have prompted extensive research effort toward the development of more effective Pt (II) delivery strategies. The synthesis of Pt (IV) complex is one such an area of intense research fields, which involves their in vivo conversion into active Pt (II) molecules under the reducing intracellular environment, and has demonstrated encouraging preclinical and clinical outcomes. Compared with Pt (II) complexes, Pt (IV) complexes not only exhibit an increased stability and reduced side effects, but also facilitate the intravenous-to-oral switch in cancer chemotherapy. The overview briefly analyzes statuses of Pt (II) complex that are in clinical use, and then focuses on the development of Pt (IV) complexes. Finally, recent advances in Pt (IV) complexes in combination with nanocarriers are highlighted, addressing the shortcomings of Pt (IV) complexes, such as their instability in blood and irreversibly binding to plasma proteins and nonspecific distribution, and taking advantage of passive and active targeting effect to improve Pt (II) anticancer therapy.

Platinum-based compounds for the treatment of metastatic breast cancer

The role of platinum-based compounds (PBCs) in the treatment of metastatic breast cancer (MBC) has been extensively studied. As single agents, high response rates have been observed in first-line therapy, while results in pretreated patients were discouraging. Regimens containing cisplatin/carboplatin together with taxanes showed the highest efficacy and safety as both first-line and second-line therapy. When administered with vinorelbine, the combination was also active and well tolerated in anthracycline- and taxane-pretreated patients. Combining PBCs with etoposide or nucleoside analogues showed moderate activity, yet high toxicity in the case of etoposide. The overall results for the combination with anthracyclines were disappointing. Addition of trastuzumab to PBC combinations showed remarkable activity and good tolerability in patients with HER2/neu overexpression. The use of cisplatin or carboplatin alongside novel targeted therapeutics for patients with triple-negative MBC seems promising and is being further evaluated. The use of PBCs against MBC requires careful patient selection and combination with the right chemotherapeutic agent.

Platinum-based chemotherapy in metastatic breast cancer: current status

Cisplatin and carboplatin are active in previously untreated patients with metastatic breast cancer (MBC) with mean response rates (RRs) of 50 and 32%, respectively. In pretreated patients the RR to cisplatin/carboplatin monotherapy declines markedly to <10%. Cisplatin and carboplatin have been combined with many other cytotoxics. In first-line setting high activity has been observed in combination with taxanes or vinorelbine (RRs consistently approximately 60%). It appears that these newer combinations are superior to older regimens with etoposide (RRs 30 to 50%) or 5-fluorouracil (RRs 40 to 60%). Cisplatin-/carboplatin-based regimens with infusional 5-FU and epirubicin/paclitaxel/vinorelbine achieve high RRs of around 60 to 80%. However these regimens are difficult to administer in all patients because they require central venous access for continuous 5-FU infusion. In pretreated MBC the combinations of cisplatin-taxane/vinorelbine/gemcitabine or carboplatin-docetaxel/vinorelbine yield RRs of 40 to 50%, which are higher than those achieved with platinum-etoposide/5-FU. In locally advanced disease cisplatin-based regimens achieve very high RRs (>80%). This would suggest that in chemotherapy-naïve patients platinum-based therapy might have an important role to play. Additionally the synergy demonstrated between platinum compounds, taxanes and herceptin, in preclinical and clinical studies is of immense importance and the results of the two ongoing Breast Cancer International Research Group randomized phase III studies are eagerly awaited. These studies may help clarify the role of platinum compounds in the treatment of metastatic and possibly early breast cancer.

Platinum compounds in the treatment of advanced breast cancer

Interest in platinum compounds for the treatment of breast cancer has been reawakened because of preclinical studies indicating synergy of platinum salts with the monoclonal antibody trastuzumab in human breast cancer cell lines that overexpress HER2/neu. Cisplatin, carboplatin, and iproplatin are not very active as single agents in patients with previously treated metastatic breast cancer (MBC). The activity of oxaliplatin has not been adequately tested in refractory MBC. On the other hand, cisplatin is very active as first-line chemotherapy, with response rates (RR) of 50%; carboplatin appears to be moderately active in patients without prior chemotherapy (RR around 30%). The clinical effectiveness of the other platinum compounds (iproplatin, oxaliplatin, and others) has not yet been fully tested as first-line chemotherapy. Platinum compounds have been extensively tested in combination with other antitumoral agents. Cisplatin combinations have been employed as neoadjuvant chemotherapy in women with locally advanced breast cancer. These combinations are very active, although the precise contribution of cisplatin to the overall activity is not known. Combinations with cisplatin have been investigated, essentially, as salvage therapy for patients with previously treated MBC. The combinations of cisplatin with older pharmacological agents (5-fluorouracil, etoposide) have moderate activity, while the combinations of cisplatin with the newer agents (vinorelbine, paclitaxel, docetaxel, gemcitabine) appear to be more active. The combinations of carboplatin with the classical agents (5-fluorouracil, etoposide) are poorly active in previously treated MBC; however, the combination of carboplatin with the taxanes (docetaxel, paclitaxel) is more active. Of greatest interest is the synergy between the platinum derivatives and the monoclonal antibody trastuzumab demonstrated in vitro in breast cancer cell lines overexpressing HER2/neu. Currently, several combinations of platinum compounds (either cisplatin or carboplatin) with docetaxel and trastuzumab are under clinical testing in patients with MBC who overexpress HER2/neu. The preliminary results are very promising, and these combinations will soon be tested in the adjuvant setting. Cisplatin, carboplatin, and perhaps, oxaliplatin appear to have some antitumor activity in MBC and can be combined safely with other agents that are active in this disease. However, the precise role that platinum compounds play in the treatment of breast cancer remains to be defined.

Constipation and diarrhea: the neglected symptoms

OBJECTIVE

To review the symptom experience of constipation and diarrhea related to cancer and its treatment.

DATA SOURCES

Published articles and book chapters relating to constipation and diarrhea in patients with cancer.

CONCLUSIONS

Constipation and diarrhea often represent a major concern and source of discomfort for the cancer patients. Research is needed to establish prevention and treatment protocols for patients at risk for constipation or diarrhea.

IMPLICATIONS FOR NURSING PRACTICE

Oncology nurses are in an excellent position to recognize individuals who are at high risk for constipation and diarrhea. Preventive strategies and treatment protocols are of utmost importance.