The platinum (II) complexes as anticancer agents have been well explored for the development of novel analogs. Yet, none of them achieved clinical importance in oncology. At present, anticancer compounds containing platinum (II) complexes have been employed in the treatment of colorectal, lung, and genitourinary tumors. Among the platinum-based anticancer drugs, Cisplatin (cis-diamine dichloroplatinum (II), cis-[Pt(NH3)2Cl2]) is one of the most potent components of cancer chemotherapy. The nephrotoxicity, neurotoxicity and ototoxicity, and platinum compounds associated resistant cancer are some major disadvantages.

With the rapidly growing interest in platinum (II) complexes in tumor chemotherapy, researchers have synthesized many new platinum analogs as anticancer agents that show better cytotoxicity, and less off-target effects with less cellular resistance. This follows the introduction of oxaliplatin, water-soluble carboplatin, multinuclear platinum and newly synthesized complexes, etc. Method: This review emphasizes recent advancements in drug design and development, the mechanism of platinum (II) complexes, their stereochemistry, current updates, and biomedical applications of platinum-based anticancer agents.

In the last few decades, the popularity of platinum complexes as potent anti-cancer agents has risen as scientists have synthesized many new platinum complexes that exhibit better cytotoxicity coupled with less off-target effects.

Cisplatin plus 5-fluorouracil is regarded as standard neoadjuvant chemotherapy for esophageal squamous cell carcinoma (ESCC) in Japan, but the prognosis remains poor. We have previously described how definitive chemoradiotherapy with docetaxel, nedaplatin, and 5-fluorouracil (DNF) led to a very high response rate and promising survival times. We therefore undertook a phase II trial to evaluate the feasibility and efficacy of neoadjuvant DNF. The study included patients with clinical stage Ib-III ESCC. Chemotherapy consisted of i.v. docetaxel (30 mg/m2 ) and nedaplatin (50 mg/m2 ) on days 1 and 8, and a continuous infusion of 5-fluorouracil (400 mg/m2 /day) on days 1-5 and 8-12, every 3 weeks. After three courses of chemotherapy, esophagectomy was carried out. The primary end-point was the completion rate of the protocol treatment. Twenty-eight patients were enrolled (cStage Ib/II/III, 2/3/23) and all received at least two cycles of chemotherapy. Twenty-five patients underwent surgery, all of whom achieved an R0 resection, leading to a completion rate of 89.3%. The overall response rate was 87.0%. A pathological complete response was confirmed in eight (32.0%) cases. Grade 3/4 adverse events included leukopenia (32.1%), neutropenia (39.3%), febrile neutropenia (10.7%), thrombocytopenia (10.7%), and diarrhea (14.3%), but were manageable. Treatment-related deaths and major surgical complications did not occur. Estimated 2-year progression-free and overall survival rates were 70.4% and 77.2%, respectively. Thus, DNF therapy was well tolerated and deemed feasible, with a strong tumor response in a neoadjuvant setting for ESCC. This trial is registered with the University Hospital Medical Information Network (UMIN ID: 000014305).

To date, no second-line chemotherapy regimen for esophageal squamous cell carcinoma (SCC) has been established. This clinical trial aimed to assess the optimum dose of docetaxel plus nedaplatin (cis-diammine-glycolate platinum) as second-line chemotherapy.

Patients with metastatic or recurrent esophageal SCC after treatment with cisplatin plus 5-fluorouracil received docetaxel (50 or 60 mg/m) plus nedaplatin (70 mg/m²) on day 1 every 4 weeks. The recommended dose was based on dose-limiting toxicities defined during the first cycle.

From February 2009 to November 2011, 9 patients were enrolled in the study. Their median age was 62 years (range, 58 to 72 y). Six patients had undergone radiotherapy and 4 had undergone surgical resection of primary lesions. Dose-limiting toxicities were observed in 2 patients at dose level 1 (60 mg/m² docetaxel, 70 mg/m² nedaplatin) but not at dose level 0 (50 mg/m² docetaxel, 70 mg/m nedaplatin). Thus, the maximum tolerated dose was established at dose level 1. No severe nonhematological toxicity was observed. No patient achieved complete response, but 2 (22%; 95% confidence interval, 0%-49%) achieved partial response and 3 had stable disease. Median progression-free and overall survival times were 2.1 and 9.5 months, respectively.

Docetaxel plus nedaplatin chemotherapy seems to be a safe and feasible second-line regimen for the treatment of esophageal SCC. We recommend the administration of 50 mg/m² docetaxel (day 1) plus 70 mg/m² nedaplatin (day 1) every 4 weeks in a phase II study.

Patient survival in esophageal cancer (EC) remains poor. The purpose of this study was to investigate a regimen of definitive chemoradiation therapy (CRT) that exerts good local control of EC. We performed a phase 1/2 study to assess the safety and efficacy of CRT with docetaxel, nedaplatin, and 5-fluorouracil (DNF-R).

Eligible patients presented with stage IB to IV EC. Patients received 2 cycles of docetaxel (20, 30, or 40 mg/m(2)) and nedaplatin (50 mg/m(2)) on days 1 and 8 and a continuous infusion of 5-fluorouracil (400 mg/m(2)/day) on days 1 to 5 and 8 to 12, every 5 weeks, with concurrent radiation therapy (59.4 Gy/33 fractions). The recommended dose (RD) was determined using a 3 + 3 design.

In the phase 1 study, the dose-limiting toxicities were neutropenia and thrombocytopenia. The RD of docetaxel was determined to be 20 mg/m(2). In the phase 2 study, grade 3 to 4 acute toxicities included neutropenia (42.8%), febrile neutropenia (7.14%), thrombocytopenia (17.9%), and esophagitis (21.4%). Grade 3 to 4 late radiation toxicity included esophagostenosis (10.7%). The complete response rate was 82.1% (95% confidence interval: 67.9-96.3%). Both the median progression-free survival and overall survival were 41.2 months.

DNF-R showed good tolerability and strong antitumor activity, suggesting that it is a potentially effective therapeutic regimen for EC.

To evaluate the efficacy and safety of paclitaxel-nedaplatin combination as a front-line regimen in Chinese patients with metastatic esophageal squamous cell carcinoma (ESCC).

A two-center, open-label, single-arm phase II study was designed. Thirty-nine patients were enrolled and included in the intention-to-treat analysis of efficacy and adverse events. Patients received 175 mg/m² of paclitaxel over a 3 h infusion on 1 d, followed by nedaplatin 80 mg/m² in a 1 h infusion on 2 d every 3 wk until the documented disease progression, unacceptable toxicity or patient's refusal.

Of the 36 patients assessable for efficacy, there were 2 patients (5.1%) with complete response and 16 patients (41.0%) with partial response, giving an overall response rate of 46.1%. The median progression-free survival and median overall survival for all patients were 7.1 mo (95%CI: 4.6-9.7) and 12.4 mo (95%CI: 9.5-15.3), respectively. Toxicities were moderate and manageable. Grade 3/4 toxicities included neutropenia (15.4%), nausea (10.3%), anemia (7.7%), thrombocytopenia (5.1%), vomiting (5.1%) and neutropenia fever (2.6%).

The combination of paclitaxel and nedaplatin is active and well tolerated as a first-line therapy for patients with metastatic ESCC.

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.

We undertook a systematic review of the pre-clinical and clinical literature for studies investigating the relationship between platinum and taxane resistance. Medline was searched for (1) cell models of acquired drug resistance reporting platinum and taxane sensitivities and (2) clinical trials of platinum or taxane salvage therapy in ovarian cancer. One hundred and thirty-seven models of acquired drug resistance were identified. 68.1% of cisplatin-resistant cells were sensitive to paclitaxel and 66.7% of paclitaxel-resistant cells were sensitive to cisplatin. A similar inverse pattern was observed for cisplatin vs. docetaxel, carboplatin vs. paclitaxel and carboplatin vs. docetaxel. These associations were independent of cancer type, agents used to develop resistance and reported mechanisms of resistance. Sixty-five eligible clinical trials of paclitaxel-based salvage after platinum therapy were identified. Studies of single agent paclitaxel in platinum-resistant ovarian cancer where patients had previously recieved paclitaxel had a pooled response rate of 35.3%, n=232, compared to 22% in paclitaxel naïve patients n=1918 (p<0.01, Chi-squared). Suggesting that pre-treatment with paclitaxel may improve the response of salvage paclitaxel therapy. The response rate to paclitaxel/platinum combination regimens in platinum-sensitive ovarian cancer was 79.5%, n=88 compared to 49.4%, n=85 for paclitaxel combined with other agents (p<0.001, Chi-squared), suggesting a positive interaction between taxanes and platinum. Therefore, the inverse relationship between platinum and taxanes resistance seen in cell models is mirrored in the clinical response to these agents in ovarian cancer. An understanding of the cellular and molecular mechanisms responsible would be valuable in predicting response to salvage chemotherapy and may identify new therapeutic targets.

Definitive chemoradiation with cisplatin (CDDP) and 5-fluorouracil (5FU) has been playing an important role in the treatment of esophageal cancer, but some patients are not curable or have recurrent lesions. However, few chemotherapeutic regimens are available for such patients. Docetaxel and nedaplatin are active for esophageal cancer. We conducted a dose-escalation study of docetaxel and nedaplatin as second line-chemotherapy after definitive chemoradiation in patients with relapsed or refractory squamous cell carcinoma of the esophagus after chemoradiation.

Nedaplatin was administered on day 1 and docetaxel was administered on days 1 and 15, every 4 weeks. Dose escalation was based on the dose-limiting toxicity (DLT) observed during the first cycle.

Twelve patients were enrolled. At a docetaxel dose of 30 mg/m(2) and a nedaplatin dose of 80 mg/m(2), one grade 4 neutropenia occurred and caused one treatment break longer than 2 weeks, but there were few DLTs. At doses of 35 and 80 mg/m(2), respectively, two grade 4 neutropenias and one grade 2 thrombopenia occurred and caused three treatment breaks longer than 2 weeks. Therefore, the maximum tolerated dose was established at this dose level. Two grade 3 anorexias and one grade 3 nausea occurred, but other non-hematological toxicities were generally mild. Responses were seen in one-fourth of the 12 patients, including one complete remission.

The recommended doses of docetaxel and nedaplatin were 30 and 80 mg/m(2), respectively. This combination could be a potential second-line treatment for this target population.

To determine the recommended dose (RD) of cis-diammine-glycolatoplatinum (nedaplatin) when given concurrently with 5-FU and high dose radiation therapy in the treatment of esophageal cancer. The purpose of the phase II trial is to determine efficacy and further define the side effect profile.

Twenty-six patients with clinical stage I to IVA squamous cell carcinoma of the esophagus were enrolled in a non-surgical treatment comprised of a fixed dose of fluorouracil (400 mg/m2 administered as continuous intravenous infusion on days 1-5 and days 8-12) plus escalating doses of nedaplatin (40 mg/m2 in level 1, 50 mg/m2 in level 2, or 60 mg/m2 in level 3 on days 1 and 8), repeated twice every 3 weeks with concurrent radiotherapy (60 Gy).

Between July 1998 and February 2004, a total of 26 patients entered this trial, all of whom were considered evaluable for toxicity assessment. In phase I of the study, 12 patients were treated in sequential cohorts of three to six patients per dose level. The maximum tolerated dose was reached at level 3 with two grade 4 neutropenia and one grade 4 thrombocytopenia. Thus, the recommended dosing schedule is level 2. Of the 20 patients treated at the RD level 2, including 6 patients of the RD phase I portion, 8 out of 20 patients (40%) had grade 3-4 neutropenia, 5 patients (25.0%) had grade 3-4 thrombocytopenia, 4 patients (20.0%) had grade 3 anemia and 4 patients (20.0%) had grade 3-4 esophagitis. Other toxicities were relatively mild and usually of grade 2 or less. Objective responses were noted in the 26 patients (overall response rate, 88.5%) including 11 (42.3%) complete remissions. The 1- and 3-year survival rates were 65.1 and 37.2%, respectively, with a median survival time of 21.2 months.

The combination of nedaplatin and 5-FU with radiation is a feasible regimen that shows promising antitumor activity with an acceptable safety profile in patients with esophageal cancer.

To define the most effective combination schedule of paclitaxel and nedaplatin, a new platinum derivative, we investigated the in vitro interaction between these drugs in AZ-521 and NUGC-4 gastric adenocarcinoma and KSE-1 esophageal squamous carcinoma cell lines.

Cytotoxic activity was determined by the WST-1 assay. Different treatment schedules of the two drugs were compared and evaluated for synergism, additivity, or antagonism using a quantitative method based on the median-effect principle of Chou and Talalay. Cell-cycle perturbation and apoptosis were evaluated by means of flow cytometry.

Upon 24-h sequential exposure, the sequence paclitaxel followed by nedaplatin induced greater than additive effects in all of the cell lines, with synergistic interactions in NUGC-4 and KSE-1 cells. By contrast, antagonistic effects were observed with the reverse sequence. Simultaneous treatment resulted in either a synergistic or antagonistic effect, depending on the cell line. Therefore, the sequence paclitaxel followed by nedaplatin appears most active, at least in these three cell lines. Flow cytometric analyses at IC50 indicated that paclitaxel induced G2/M arrest with subsequent induction of apoptosis (56%) in the sub-G1 phase. When paclitaxel preceded nedaplatin, apoptosis was most prominent (70%) with pronounced G2/M arrest. By contrast, the reverse sequence yielded only 28% induction of apoptotic cells, with almost identical cell-cycle distribution patterns to those observed with nedaplatin alone, indicating that the activity of paclitaxel is abolished by pretreatment with nedaplatin.

Our findings suggest that the interaction of nedaplatin and paclitaxel is highly schedule dependent and that the sequential administration of paclitaxel followed by nedaplatin should be thus incorporated into the design of a clinical trial.

The effect of coadministration of fosfomycin (FOM) on nedaplatin-induced nephrotoxicity in rats was investigated for 6 days. FOM decreased nedaplatin-induced nephrotoxicity, as shown by reduced blood urea nitrogen (BUN), serum creatinine levels, and urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG). Further, there were fewer histopathological signs of nephrotoxicity in the groups treated with the combination of nedaplatin and FOM as compared with the nedaplatin-alone group. The concentration of nedaplatin was significantly lower in the renal cortex of rats treated with the combination of nedaplatin and FOM as compared with those treated with nedaplatin alone (p < 0.05). In conclusion, the concomitant administration of FOM and nedaplatin may help to achieve a chemotherapeutic strategy that reduces the nephrotoxic effects of nedaplatin.

The spectroscopic properties of platinum(II) complexes with 2-aminomethyl-derivatives of small-membered 1-aza-cycloalkane, i.e., =2-aminomethylaziridine=azida and S-2-aminomethylazetidine=S-azeda, and the crystal structures of their dichloro complexes demonstrate that the conformation of the fused three- (azida) or four- (S-azeda) and five-membered chelate ring formed by the coordination of S-azida and S-azeda to platinum(II) has an S(N) absolute configuration at the secondary amine site and that the two alkyl groups extend axially from the five-membered chelate ring. The chelate ring of the azida is more planar than the S-azeda or other 2-aminomethyl-1-azacycloalkanes. The anticancer activity reported for azeda and 2-aminomethylpyrrolidine appears to be related to their coordination structure, namely the presence of cis-fused successive rings.

In vivo screening models of a cisplatin (CDDP)-resistant human small-cell lung cancer cell (SCLC) line, H69/CDDP, and a non-small-cell lung cancer cell (NSCLC) line, PC-14/CDDP, were evaluated. The transplantability of the tumor xenografts to SCID mice was more than 90%. Tumor xenografts of H69/CDDP and PC-14/CDDP showed CDDP resistance during in vivo treatment. The novel anticancer agent 254-S showed only a partial effect on the growth of H69/CDDP and PC-14/CDDP while ormaplatin showed no cross resistance to CDDP. The in vivo results correlated well with the results of the in vitro MTT assay. In this in vivo sensitivity test, H69/CDDP and PC-14/CDDP were more sensitive to ormaplatin than its parental cell lines. In vivo sensitivity testing using SCID mice bearing transplanted CDDP-resistant tumors was shown to be useful for evaluating the effects of new anti-cancer drugs, especially those that might overcome CDDP resistance.

Over the past two decades, platinum-based drugs (cisplatin and, latterly, the less toxic analogue carboplatin) have conferred significant therapeutic benefit to a large number of cancer sufferers. However, there remains scope for substantial improvement in the clinical utility of metal coordination complexes through the discovery of additional platinum-based complexes (or possibly alternative metals). Future drug discovery strategies should focus on tumor resistance and its circumvention. To date, only one series of compounds, those containing a 1,2-diaminocyclohexane carrier ligand (e.g., oxaliplatin, tetraplatin), has entered clinical trial based on their circumvention of acquired cisplatin resistance in some (mainly murine) preclinical tumor models. At present these agents are in early clinical trial and thus their true clinical utility in cisplatin/carboplatin refractory disease is not yet determinable (and may not be due to dose-limiting neurotoxicity). Over the past few years, our understanding of mechanisms of resistance to cisplatin and its interaction with DNA has vastly increased. This new information will undoubtedly guide the development of new strategies aimed at the circumvention of intrinsic and acquired tumor resistance to cisplatin. Approaches to circumvent resistance will probably involve not only the rational development of a new generation of platinum-based drugs (e.g., compounds designed to overcome reduced cisplatin accumulation or enhanced removal of cisplatin-induced DNA adducts) but also non-platinum drugs which are capable of modulating resistance (e.g., modulators of signal transduction pathways, ras and myc oncogene expression and glutathione biosynthesis). One may look forward with a great deal of optimism that these promising new approaches will result in clinical benefit by the end of the century. Nevertheless, cisplatin and carboplatin remain the standard anticancer drugs to which novel platinum-based complexes must be compared.