Lobaplatin in advanced urothelial tract tumors. The Genitourinary Group of the European Organization for Research and Treatment of Cancer (EORTC)

Lobaplatin-Induced Apoptosis Requires p53-Mediated p38MAPK Activation Through ROS Generation in Non-Small-Cell Lung Cancer

Platinum-based chemotherapy is recommended as the first-line treatment regimen for patients with advanced non-small-cell lung cancer (NSCLC). Lobaplatin (LBP), a third-generation platinum anti-neoplastic agent, has shown an improved efficacy. This study is aimed to investigate the mechanisms of LBP-induced apoptosis in the A549 p53 wild-type cell line. The Cell Counting Kit-8 assay (CCK-8), flow cytometry (FCM), Western blot, xenograft tumor models, terminal deoxynucleotide transferase dUTP nick end labeling (TUNEL), and RNA interference were used in this study. Our results showed that the proliferation of A549 cells could be inhibited by LBP. At lower concentrations, LBP triggered cell cycle arrest at the G1 phase in A549 cells. LBP could also induce apoptosis of A549 cells. LBP also increased the expression of PARP and Bax and the cleavage of caspase-3, caspase-8, and caspase-9 and reduced Bcl-2 expression. In vivo experiment confirmed that LBP could inhibit tumor growth in the A549 xenograft models and induce apoptosis. Apoptosis of A549 cells was decreased after transfected with p53 shRNA or treated with reactive oxygen species inhibitor NAC and p38MAPK inhibitor SB203580, suggesting that the p53/ROS/p38MAPK pathway appeared to mediate the LBP-induced apoptosis of A549 cells. Our data demonstrate that LBP could be a promising candidate for the treatment of NSCLC with wild-type p53.

Retrospective study of the efficacy and toxicity of lobaplatin in combined chemotherapy for metastatic breast cancer

OBJECTIVE

To study the efficacy and adverse reactions of lobaplatin combined with other chemotherapy drugs in the treatment of metastatic breast cancer.

METHODS

This retrospective analysis enrolled 114 patients who were diagnosed with advanced breast cancer from January 2010 to December 2015. Lobaplatin and another chemotherapeutic agent were given to patients. The efficacy and side effects were evaluated after at least two cycles of chemotherapy.

RESULTS

Therapeutic efficacy and adverse reactions could be evaluated in 112 patients with 2 complete response (CR) patients, 31 cases of partial response (PR), 52 cases of stable disease (SD) and 27 cases of progressive disease (PD). The overall response rate (ORR) was 29.5% and the disease control rate (DCR) was 75.9%. The median time to progression (TTP) was 7.7 months, and the median overall survival (OS) was expected to be 28.0 months. The main side effects were myelosuppression. Twenty five patients (21.9%) had grade 3/4 neutrophil suppression, 18 patients (15.8%) had grade 3/4 thrombocytopenia. Other toxicities included gastrointestinal reaction, peripheral neuropathy, stomatitis, hepatic dysfunction, fatigue and skin rashes, which were alleviated by symptomatic treatment.

CONCLUSION

Lobaplatin-based regimen chemotherapy for advanced metastatic breast cancer patients is effective and well tolerated.

Intrapleural or intraperitoneal lobaplatin for treatment of patients with malignant pleural effusion or ascites

AIMS

To explore efficacy and side effects of intrapleural or intraperitoneal lobaplatin for treating patients with malignant pleural or peritoneal effusions.

METHODS

Patients in Jiangsu Cancer Hospital and Research Institute with cytologically confirmed solid tumors complicated with malignant pleural effusion or ascites were enrolled into this study. Lobaplatin (20-30 mg/m2) was intrapleurally or intraperitoneally infused for patients with malignant pleural effusion or ascites.

RESULTS

From 2012 to 2013, intrapleural or intraperitonea lobaplatin was administered for patients with colorectal or uterus cancer who were previous treated for malignant pleural effusion or ascites. Partial response was achieved for them. Main side effects were nausea/vomiting, and bone marrow suppression. No treatment related deaths occurred.

CONCLUSION

Intrapleural or intraperitoneal infusion of lobaplatin is a safe treatment for patients with malignant pleural effusion or ascites, and the treatment efficacy is encouraging.

Antitumor activity of lobaplatin alone or in combination with antitubulin agents in non-small-cell lung cancer

OBJECTIVE

Lobaplatin is used to treat patients with breast cancer, small-cell lung cancer, and chronic myelogenous leukemia in China. In this study, we assessed the in-vitro and in-vivo activities of lobaplatin alone or in combination with antitubulin agents against human non-small-cell lung cancer (NSCLC).

METHODS

The cytotoxicities of lobaplatin against NSCLC cells were determined by the sulforhodamine B (SRB) assay. Cell cycle analysis and apoptosis were assessed using flow cytometry, and the in-vivo antitumor activities were evaluated in human NSCLC xenografts in nude mice.

RESULTS

The cytotoxicity of lobaplatin was similar to or higher than that of cisplatin and carboplatin, with a mean IC(50) of 2.5 μmol/l in a variety of NSCLC cells. In addition, lobaplatin arrested cells in the S phase and triggered apoptosis. The combination of lobaplatin with antitubulin agents yielded synergistic cytotoxic activity in vitro. In NSCLC xenografts, lobaplatin alone showed significant antitumor activity. The combination of lobaplatin with antitubulin agents, especially with paclitaxel, led to significantly enhanced activity, which was superior to that of cisplatin combined with antitubulin agents.

CONCLUSION

These data demonstrate that the use of lobaplatin alone or in combination with antitubulin agents might be a rational and novel therapeutic strategy for human NSCLC and warrants further clinical investigation.

First- and second-line therapy for metastatic urothelial carcinoma of the bladder

Urothelial cancer of the bladder is the 4th most common malignancy in American men and the 9th most common in women. Although it is a chemosensitive disease, advanced bladder cancer seems to have reached a plateau with regard to median survival of patients. Standard first-line therapy remains gemcitabine plus cisplatin (gc) or methotrexate, vinblastine, doxorubicin, and cisplatin (mvac). In patients deemed unfit to receive cisplatin, gemcitabine plus carboplatin or gemcitabine plus paclitaxel can be considered. To date, no standard therapy has been established for patients who recur or are refractory to first-line therapy. Second-line vinflunine, by way of superiority over best supportive care, has shown promise in a phase iii trial. Cisplatin-based therapy (mvac or gc) can also be offered to patients previously treated with cisplatin, especially if they responded previously and are considered platinum-sensitive. Novel targeted therapies are sorely needed to further improve the delivery and efficacy of chemotherapy.

The status of platinum anticancer drugs in the clinic and in clinical trials

Since its approval in 1979 cisplatin has become an important component in chemotherapy regimes for the treatment of ovarian, testicular, lung and bladder cancers, as well as lymphomas, myelomas and melanoma. Unfortunately its continued use is greatly limited by severe dose limiting side effects and intrinsic or acquired drug resistance. Over the last 30 years, 23 other platinum-based drugs have entered clinical trials with only two (carboplatin and oxaliplatin) of these gaining international marketing approval, and another three (nedaplatin, lobaplatin and heptaplatin) gaining approval in individual nations. During this time there have been more failures than successes with the development of 14 drugs being halted during clinical trials. Currently there are four drugs in the various phases of clinical trial (satraplatin, picoplatin, Lipoplatin and ProLindac). No new small molecule platinum drug has entered clinical trials since 1999 which is representative of a shift in focus away from drug design and towards drug delivery in the last decade. In this perspective article we update the status of platinum anticancer drugs currently approved for use, those undergoing clinical trials and those discontinued during clinical trials, and discuss the results in the context of where we believe the field will develop over the next decade.

New agents for treatment of advanced transitional cell carcinoma

The prognosis for any patient with progressive or recurrent invasive transitional cell carcinoma remains poor. In this context, the focus of clinical research in these invasive cancers concentrates on identifying systemic treatment options and new agents in order to improve survival of patients. Cisplatin-based chemotherapy is standard treatment of patients with metastatic urothelial cancer; however, despite regimens as the cisplatin-gemcitabine combination, the overall response rates vary between 40% and 65%, with complete response in 15%-25% with survivals up to 16 months. This survival is frequently achieved with severe and life-threatening side effects. None the less, almost all responding patients relapse within the first year; therefore, the need for development of new and tolerable agents is urgent. This review highlights some new active chemotherapeutic as new platinum compounds (oxaliplatin, lobaplatin), gallium nitrate, ifosfamide, the antifolates piritrexim and pemetrexed (Alimta, LY231514), vinflunine and molecular targeting agents such as farnesyltransferase inhibitors (lonafarnib, R115777, SCH66336), ribozyme (RPI.4610), histone deacetylase inhibitor (CI-994) and monoclonal antibodies (epidermal growth factor receptor, Her 2/neu).

The development of platinum compounds and their possible combination

Cisplatin plays a central role in cancer chemotherapy in spite of its toxicity. To circumvent this toxicity and to enhance its therapeutic index a lot of preclinical and clinical studies have been conducted and several thousand analogues have been synthesized. Much more analysis remains to be done, but nowadays, the absence of any definitive, biologically interpretable molecular predictor of activity is consistent with the idea that platinum compounds have multiple intracellular targets and that cells can have multiple mechanisms of resistance. This review analyses a part of these platinum compounds analyzed to date, their mechanism of action, resistance and the future trends in this sector.

New-generation platinum drugs in the treatment of cisplatin-resistant cancers

Platinum drugs with altered stable ligands, such as oxaliplatin and satraplatin, produce a different DNA-adduct profile to cisplatin. This results in a distinct therapeutic profile, and clinical trials with these agents demonstrate significant anticancer activity in diseases with inherent or acquired resistance to cisplatin, such as colorectal and prostate cancers as well as previously treated ovarian and germ-cell cancer. An alternative approach to increasing the efficacy associated with platinum therapy is to enhance tumour delivery by coupling platinum drugs with a polymer or encapsulating the agent in a liposome. The early clinical trials of these novel delivery formulations are promising but, as yet, have not confirmed that the delivery of platinum to the tumour cell DNA is increased.

New drugs and new approaches in metastatic bladder cancer

The median survival of patients with metastatic cancer of the urothelium who receive best supportive care only in 4-6 months. With the introduction of combination chemotherapy regimens including cisplatin and methotrexate for the management of metastatic urothelial cancer, median overall survival has doubled. Nevertheless, death due to cancer ultimately occurs in more than 80% of these patients, thus more effective therapy is required. The new available treatment modalities range from new combinations of conventional chemotherapeutic agents to combinations incorporating novel drugs like gemcitabine and the taxanes. These new combinations incorporate the new active agents in two, three or multiple drug combinations, administered either in one regimen or sequentially in various combinations and schedules intended to improve the outcome of bladder cancer patients. Ongoing phase III studies will help to define the role of these new combinations in the treatment of advanced bladder cancer. The improved understanding of the molecular biology of urothelial malignancies is helping to define the role of new prognostic indices that can direct the most appropriate choice of treatment for advanced disease. In addition, advances in the molecular biology of urothelial malignancies may allow identification of specific genetic lesions and biochemical pathways upon which future therapeutic approaches can be focused. The integration of newer biologic agents, probably to supplement rather than to supplant chemotherapeutic drugs, should be a primary direction of research with the objective to interfere with multiple aspects of bladder cancer progression.

Lobaplatin: a new antitumour platinum drug

Lobaplatin (D-19466) is a diastereometric mixture of platinum(II) complexes containing a 1,2-bis(aminomethyl)cyclobutane stable ligand and lactic acid as the leaving group. Its antitumour activity results from the formation of DNA-drug adducts, mainly as GG and AG intra-strand cross-links. Lobaplatin influences the expression of the c-myc gene, which is involved in oncogenesis, apoptosis and cell proliferation. Lobaplatin has activity in a wide range of preclinical tumour models and appears to overcome tumour resistance to cisplatin and carboplatin in some of these models. In the body, lobaplatin remains largely intact until removed by glomerular filtration. Exposure of the body to lobaplatin (AUC) correlates with dose, creatinine clearance and the degree of thrombocytopoenia. Phase I clinical trials of three quite different administration schedules found the same dose-limiting toxicity (thrombocytopoenia) and similar maximum tolerated doses (60 mg/m(2) per 3 - 4 weeks). In Phase II trials, lobaplatin showed activity in patients with a variety of tumour types. Many of the patients who responded to lobaplatin may also have responded to cisplatin and carboplatin because they had had no prior chemotherapy or had a prolonged remission after earlier treatment. In conclusion, lobaplatin is a new platinum drug, which overcomes some forms of cisplatin resistance in preclinical tumour models. Several potential clinical applications remain unexplored, such as its use in relapsed testicular cancer and in combination with other cancer chemotherapeutic agents and ionising radiation.

Clinical development of platinum complexes in cancer therapy: an historical perspective and an update

The vast amount of basic research on platinum coordination complexes has produced, over the past 25 years, several thousand new molecules for preclinical screening and 28 compounds which have entered clinical development. The goals of these research activities have been to identify compounds with superior efficacy, reduced toxicity, lack of cross-resistance or improved pharmacological characteristics as compared with the parent compound, cisplatin. After the remarkable therapeutic effects of cisplatin had been established, only a few other platinum compounds succeeded in reaching general availability. Whereas carboplatin is an analogue with an improved therapeutic index (mostly driven by reduced organ toxicity) over that of cisplatin, new compounds clearly more active than or non-cross-resistant with cisplatin have not yet been identified. The platinum analogues that remain under investigation are focusing on expanding the utilisation of platinum therapy to tumour types not usually treated with, or responsive to, cisplatin or carboplatin. In addition, novel routes of administration constitute another avenue of research. The clinical development of platinum coordination complexes, with emphasis on those compounds still under active development, is reviewed.