Preclinical activity of a new platinum analogue, lobaplatin, in cisplatin-sensitive and -resistant human testicular, ovarian, and gastric carcinoma cell lines

Lobaplatin-based neoadjuvant chemotherapy for triple-negative breast cancer: a 5-year follow-up of a randomized, open-label, phase II trial

Purpose:

We report the 5-year follow-up findings of a randomized, open-label, phase II trial of lobaplatin-based neoadjuvant chemotherapy plus adjuvant therapy for triple-negative breast cancer (TNBC).

Patients and methods:

This study included patients aged ⩾18 years with untreated, operable stage I–III TNBC and an Eastern Cooperative Oncology Group performance status of 0 or 1. One group of patients (TE group, n = 99) received four cycles of docetaxel (T, 75 mg/m²) plus epirubicin (E, 80 mg/m²) every 3 weeks, and another group (TEL group, n = 101) received the same treatment with the addition of lobaplatin (L, 30 mg/m²). Two cycles of the corresponding treatments were administered after surgery in both groups. The primary endpoints were total pathological complete response (tpCR) rate and overall response rate (ORR), and the secondary endpoints were disease-free survival, overall survival, and long-term safety. This trial is registered with the Chinese Clinical Trial Registry (ChiCTR-TRC-14005019).

Results:

The median follow-up was 48.2 months (interquartile range: 31.1–60.0). The tpCR rate was 41.4% and 17.8% in the TEL group and TE group, respectively (p < 0.001). The HR for comparison of DFS between the TEL group and TE group was 0.44 (95% CI: 0.21–0.90, P p = 0.028). The addition of lobaplatin resulted in an HR of 0.44 (95% CI: 0.18–1.02, P = 0.061) for the difference in OS between the two groups. The ORR, which included complete response and partial response, was 92.9% in the TEL group and 74.3% in the TE group (p = 0.001). The TEL group patients were more likely to develop grade III–IV anemia and thrombocytopenia. No lobaplatin-related deaths or increased risk of long-term toxicity was observed.

Conclusion:

Neoadjuvant lobaplatin therapy can improve the tpCR and ORR rates of TNBC with tolerable side effects and have a tendency to improve the long-term survival.

The role of hyperthermic intraperitoneal chemotherapy in the treatment of spontaneously ruptured hepatocellular carcinoma: a pilot study

Background

Spontaneous tumor rupture is a distinctive disease pattern in patients with hepatocellular carcinoma (HCC). The application of hyperthermic intraperitoneal chemotherapy (HIPEC) in spontaneously ruptured hepatocellular carcinoma (srHCC) is debatable. Our study aimed to compare the long-term outcomes of srHCC vs. nrHCC and to test the role of postoperative HIPEC in patients with srHCC after hepatectomy.

Methods

From 2014 to 2018, PSM was performed to compare 57 patients who performed liver resection for srHCC and met the research criteria with 57 nrHCC patients selected from 446 consecutive patients. Then patients with srHCC were divided into two groups according to whether they underwent HIPEC after hepatectomy.

Results

After 1:1 PSM, the clinical characteristics of the patients with srHCC and nrHCC were comparable. In terms of long-term outcomes, the nrHCC group had significantly longer OS (P=0.026) and DFS (P<0.001) than the srHCC group. Of the 57 srHCC patients, the HIPEC group showed added complications compared to the non-HIPEC group, including an increased length of hospital stay and higher in-hospital costs. However, there were no significant differences in the metastatic patterns of these recurrent patients, and there was no statistically significant difference in DFS (P=0.28) or OS (P=0.56) between the two groups.

Conclusions

The prognosis of ruptured HCC patients were worse than those of non-ruptured HCC patients. HIPEC may not be a robust treatment for srHCC now.

Lobaplatin in Prophylactic Hyperthermic Intraperitoneal Chemotherapy for Advanced Gastric Cancer: Safety and Efficacy Profiles

Objective

This study aims to evaluate the safety and efficacy of lobaplatin in prophylactic hyperthermic intraperitoneal chemotherapy (HIPEC) for advanced gastric cancer.

Methods

Advanced gastric cancer patients who underwent radical gastric resection and/or prophylactic HIPEC were systematically reviewed in our department from January 2016 to June 2017. All enrolled patients were grouped in either HIPEC or non-HIPEC groups. Clinical data were collected and analyzed.

Results

A total of 129 patients were enrolled with 61 cases in the HIPEC group and 68 in the non-HIPEC group. The two groups were well balanced in terms of clinical characteristics. In patients of the HIPEC group, three suffered leakage from the duodenal stump or anastomosis, one suffered abnormal bleeding and two were found to have abnormal routine blood tests; no significant difference in adverse events between groups, however, was noted (p > 0.05) and most patients recovered uneventfully. During follow-up, peritoneal recurrence was significantly less among HIPEC patients (p = 0.029), with only three suffering peritoneal recurrence, as compared to 12 non-HIPEC patients. In addition, the estimated illness-specific 3-year disease-free survival rate was significantly higher in the HIPEC group as compared to the non-HIPEC group (89.4% vs.73.9%; p = 0.031).

Conclusion

Lobaplatin in prophylactic HIPEC is safe for advanced gastric cancer patients after treatment by radical resection and can effectively improve illness-specific 3-year disease-free survival.

Blood-triggered generation of platinum nanoparticle functions as an anti-cancer agent

Since the discovery of metal nanoparticles (NPs) in the 1960s, unknown toxicity, cost and the ethical hurdles of research in humans have hindered the translation of these NPs to clinical use. In this work, we demonstrate that Pt NPs with protein coronas are generated in vivo in human blood when a patient is treated with cisplatin. These self-assembled Pt NPs form rapidly, accumulate in tumors, and remain in the body for an extended period of time. Additionally, the Pt NPs are safe for use in humans and can act as anti-cancer agents to inhibit chemotherapy-resistant tumor growth by consuming intracellular glutathione and activating apoptosis. The tumor inhibitory activity is greatly amplified when the Pt NPs are loaded in vitro with the chemotherapeutic drug, daunorubicin, and the formulation is effective even in daunorubicin-resistant models. These in vivo-generated metal NPs represent a biocompatible drug delivery platform for chemotherapy resistant tumor treatment.

Platinum based drugs like cisplatin are common chemotherapy treatments for cancer. Here, the authors report on the in situ formation of platinum nanoparticles in patients and demonstrated how platinum nanoparticles can be synthesized using patients’ blood and provide effective drug delivery and cancer treatments.

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.

The antitumor effect of lobaplatin against Ishikawa endometrial cancer cells in vitro and in vivo

The new effective chemotherapeutic drugs are required urgently for advanced and recurrent endometrial carcinoma (EC), which is one of the most common gynaecological tumors among women worldwide. Preclinical studies have shown that lobaplatin, one of the third-generation platinum compounds, has possessed powerful anti-cancer efficacy on a series of tumors. The purpose of this study is to investigate its effect and molecular mechanism on the growth of endometrial cancer cell line Ishikawa in vitro and in vivo. The results of cell counting kit-8 (CCK-8) shown that lobaplatin concentration-dependent inhibited cell proliferations in human endometrial carcinoma ishikawa cells. Flow cytometry (FCM) assay demonstrated that lobaplatin affected the survival of endometrial carcinoma cell by arresting cell cycle at S phase and G2/M phase and inducing apoptosis in dose-dependent manner. Moreover, Western blot analysis also showed that the apoptosis-inducing effects of lobaplatin was associated with the reduction of Bcl-2 expression while upregulation of cleaved-caspase-3, cleaved-caspase-8, cleaved-caspase-9 and Bax. Meanwhile, lobaplatin significantly suppressed tumor growth of human Ishikawa xenograft models and terminal deoxynucleotidyl trans-ferase dUTP nick end labeling confirmed the significant occurrence of lobaplatin-treated tumor tissues of apoptosis. Therefore, lobaplatin could be an effective chemotherapeutic agent for human endometrial carcinoma and warrants further clinical investigation.

Randomized controlled trial of lobaplatin plus etoposide vs. cisplatin plus etoposide as first-line therapy in patients with extensive-stage small cell lung cancer

The majority of previous studies of lobaplatin in small cell lung cancer (SCLC) are small phase I-II studies. The present study aimed to verify the non-inferiority (in terms of efficacy) of lobaplatin plus etoposide (EL) vs. cisplatin plus etoposide (EP) in patients with previously untreated extensive-stage SCLC (ES-SCLC). This phase III non-inferiority randomized clinical trial enrolled patients at 17 sites between September 2010 and May 2013. Patients were randomized to EL (30 mg/m² lobaplatin on day 1 and 100 mg/m² etoposide on days 1-3, for 21-day cycles) or EP (80 mg/m² cisplatin on day 1 and 100 mg/m² etoposide on days 1-3, for 21-day cycles). The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), objective response rate, disease control rate (DCR), toxicity and quality of life (QoL). A total of 234 patients were randomized to the EL (n=122) and EP (n=112) treatment groups. The median PFS, median OS and DCR were 5.1 vs. 5.3 months (P=0.786), 10.6 vs. 9.7 months (P=0.701) and 85.5 vs. 86.7% (P=0.848) in the EL vs. EP groups, respectively. Patients in the EL group had significantly lower frequencies of nephrotoxicity (2.5 vs. 11.7%; P=0.008), nausea (22.3 vs. 40.5%; P=0.003) and vomiting (14.1 vs. 35.1%; P<0.001) than those in the EP group. Overall, EL was not inferior to EP in terms of PFS and OS. The tolerance and QoL of the EL regimen were better than those of the EP regimen. EL is thus an alternative choice for the first-line treatment of ES-SCLC.

A randomized and open-label phase II trial reports the efficacy of neoadjuvant lobaplatin in breast cancer

Currently, one sixth of triple-negative breast cancer (TNBC) patients who receive docetaxel (T) and epirubicin (E) as neoadjuvant chemotherapy achieve a pathologic complete response (pCR). This study evaluates the impact of adding lobaplatin (L) to the TE regimen. Here, we show data from 125 patients (63 TE and 62 TEL patients). Four patients did not complete all the cycles. Two-sided P values show that the addition of L (38.7% vs. 12.7%, P = 0.001) significantly increases the rate of pCR in the breast and the axilla (TpCR) and the overall response rate (ORR; 93.5% vs. 73.0%, P = 0.003). The occurrence of grade 3–4 anemia and thrombocytopenia is higher in the TEL group (52.5% vs. 10.0% and 34.4% vs. 1.7% respectively). These results demonstrate that the addition of L to the TE regimen as neoadjuvant chemotherapy improves the TpCR and the ORR rates of TNBC but with increased side effects.

Triple-negative breast cancer (TNBC) is one of the most aggressive and difficult to treat types of breast cancer. Here, a phase 2 clinical trial in TNBC patients reveals that the addition of lobaplatin to docetaxel and epirubicin regime improves pCR and ORR rates with tolerable side-effects.

Lobaplatin induces BGC-823 human gastric carcinoma cell apoptosis via ROS- mitochondrial apoptotic pathway and impairs cell migration and invasion

Human gastric cancer is the fifth common cancer with considerable metastasis potential, and its high incidence and mortality rate threaten public health. In this study, we examined the anticancer effects of lobaplatin on the human gastric carcinoma cell line BGC-823 in vitro, and explored its relative mechanisms. The results of MTT assay showed dose- and time-dependent cytotoxicity in BGC-823 cells with lobaplatin. Flow cytometry (FCM) assay indicated that lobaplatin affected BGC-823 cells' survival by inducing apoptosis. Western blot analysis also demonstrated that the occurrence of its apoptosis was associated with activation of Cleaved caspase-3 and Bax, downregulation of Bcl-2. Moreover, lobaplatin could also increase the reactive oxygen species (ROS) slightly and decrease the mitochondrial membrane potential (ΔYm) obviously, elucidating that lobaplatin may induce apoptosis via mitochondria-dependent apoptotic pathway. Furthermore, lobaplatin markedly blocked BGC-823 cells migration and invasion, and the reduction of matrix metalloproteinase (MMP) MMP-2 and MMP-9 expression were also observed in vitro. Our findings demonstrated the chemotherapeutic potential of lobaplatin for treatment of human gastric carcinoma cell line BGC-823 by inhibiting proliferation, inducing apoptosis and attenuating cell migration and invasion.

Lobaplatin for the treatment of SK-MES-1 lung squamous cell line in vitro and in vivo

Lung squamous cell carcinoma is the second-largest histological subtype of lung cancer, which is the leading cause of cancer-related death worldwide. Lobaplatin, one of the third-generation platinum compounds, has shown encouraging anticancer activity in a variety of tumors. The aim of this study was to determine the therapeutic efficacy of lobaplatin on p53-mutant lung squamous cancer cells SK-MES-1. In order to evaluate the antitumor effect of lobaplatin, several in vitro and in vivo analyses were carried out, including Cell Counting Kit-8 (CCK-8), fluorescence-activated cell sorter, Western blot, and terminal deoxynucleotidyl transferase dUTP nick end labeling. Findings showed that lobaplatin could inhibit cell proliferation and induce apoptosis of SK-MES-1 cells in vitro through both intrinsic and extrinsic apoptotic pathways in a time- and dose-dependent manner. In addition, lobaplatin could arrest cell cycle at S phase in SK-MES-1. Lobaplatin has obvious antitumor efficacy in human SK-MES-1 xenograft models; therefore, it seems to be a promising candidate in lung squamous cancer therapy.

Lobaplatin inhibits growth of gastric cancer cells by inducing apoptosis

AIM: To assess the anti-cancer effect of lobaplatin on human gastric cancer cells, and to explore the underlying molecular mechanisms.

METHODS: The human gastric cancer cell lines MKN-28, AGS and MKN-45 were used. The cytotoxicity of lobaplatin was detected using an MTS cell proliferation assay. Flow cytometry was used to detect cell apoptosis using Annexin V-FITC Apoptosis Detection Kit. The expression of apoptosis-regulated genes was examined at the protein level using Western blot.

RESULTS: Lobaplatin inhibited the proliferation of human gastric cancer cells and induced apoptosis, which may be associated with the up-regulation of Bax expression, poly(ADP-ribose) polymerase (PARP) cleavage, p53 expression and the reduction of Bcl-2 expression.

CONCLUSION: The cytotoxicity of lobaplatin may be due to its ability of inducing apoptosis of gastric cancer cells, which would support the potential use of lobaplatin for the therapy of gastric cancer.

A phase I clinical trial of dose escalation of lobaplatin in combination with fixed-dose docetaxel for the treatment of human solid tumours that had progressed following chemotherapy

In this study, the maximum tolerated dose (MTD) of lobaplatin (LBP) when it was combined with docetaxel (TXT) for the treatment of solid tumours that had progressed following chemotherapy was determined, and toxicities to this regimen were evaluated. A modified Fibonacci method was used for the dose escalation of LBP. The patients received TXT (at a fixed dose of 60 mg/m²) on day one (d1) and LBP (at an initial tested dose of 30 mg/m²) on day two (d2) of a treatment cycle that was repeated every 21 days. Each dose group consisted of at least three cases. In the absence of dose-limiting toxicity (DLT), we proceeded to the next dose group, with a dose increment of 5 mg/m² between groups, until DLT occurred. The dose immediately below the dose that produced DLT was regarded as the MTD. The 17 patients examined in this study completed a total of 58 cycles of chemotherapy, and a total of three dose-escalation groups (30 mg/m² LBP, 35 mg/m² LBP, and 40 mg/m² LBP) were established. The main adverse event that was observed was myelosuppression. DLT occurred in four patients, including three patients in the 40 mg/m² LBP group and one patient in the 35 mg/m² LBP group. In total, three out of the four patients in the 40 mg/m² LBP group exhibited DLT. We determined that the treatment administered to the 35 mg/m² LBP group represented the MTD. Thus, our phase I trial revealed that the MTD for the tested LBP combination regimen was 35 mg/m² LBP and 60 mg/m² TXT. This regimen resulted in mild adverse reactions and favourable patient tolerance. Therefore, we recommend the use of these dosages in phase II clinical trials.

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.

Platinum anticancer drugs. From serendipity to rational design

The discovery of cis-platin was serendipitous. In 1965, Rosenberg was looking into the effects of an electric field on the growth of Escherichia coli bacteria. He noticed that bacteria ceased to divide when placed in an electric field but what Rosenberg also observed was a 300-fold increase in the size of the bacteria. He attributed this to the fact that somehow the platinum-conducting plates were inducing cell growth but inhibiting cell division. It was later deduced that the platinum species responsible for this was cis-platin. Rosenberg hypothesized that if cis-platin could inhibit bacterial cell division it could also stop tumor cell growth. This conjecture has proven correct and has led to the introduction of cis-platin in cancer therapy. Indeed, in 1978, six years after clinical trials conducted by the NCI and Bristol-Myers-Squibb, the U.S. Food and Drug Administration (FDA) approved cis-platin under the name of Platinol(®) for treating patients with metastatic testicular or ovarian cancer in combination with other drugs but also for treating bladder cancer. Bristol-Myers Squibb also licensed carboplatin, a second-generation platinum drug with fewer side effects, in 1979. Carboplatin entered the U.S. market as Paraplatin(®) in 1989 for initial treatment of advanced ovarian cancer in established combination with other approved chemotherapeutic agents. Numerous platin derivatives have been further developed with more or less success and the third derivative to be approved in 1994 was oxaliplatin under the name of Eloxatin(®). It was the first platin-based drug to be active against metastatic colorectal cancer in combination with fluorouracil and folinic acid. The two others platin-based drugs to be approved were nedaplatin (Aqupla(®)) in Japan and lobaplatin in China, respectively. More recently, a strategy to overcome resistance due to interaction with thiol-containing molecules led to the synthesis of picoplatin in which one of the amines linked to Pt was replaced by a bulky methyl substituted pyridine allowing the drug more time to reach its target, DNA. On the other hand, efforts which were made to find new orally administered analog led to satraplatin bearing to axial acetate groups. Both drugs are still under clinical trials. An alternatively route to the discovery of new derivatives turns to the development of improved delivery strategies such as liposomes and polymers. Liposomal cis-platin or lipoplatin in under a phase III randomized clinical trial for patients suffering from small cell lung cancer whereas polymer-based drug, Prolindac™ is currently under investigation for pretreated ovarian cancers in up to eight European centers.

Lobaplatin arrests cell cycle progression in human hepatocellular carcinoma cells

BACKGROUND

Hepatocellular carcinoma (HCC) still is a big burden for China. In recent years, the third-generation platinum compounds have been proposed as potential active agents for HCC. However, more experimental and clinical data are warranted to support the proposal. In the present study, the effect of lobaplatin was assessed in five HCC cell lines and the underlying molecular mechanisms in terms of cell cycle kinetics were explored.

METHODS

Cytotoxicity of lobaplatin to human HCC cell lines was examined using MTT cell proliferation assay. Cell cycle distribution was determined by flow cytometry. Expression of cell cycle-regulated genes was examined at both the mRNA (RT-PCR) and protein (Western blot) levels. The phosphorylation status of cyclin-dependent kinases (CDKs) and retinoblastoma (Rb) protein was also examined using Western blot analysis.

RESULTS

Lobaplatin inhibited proliferation of human HCC cells in a dose-dependent manner. For the most sensitive SMMC-7721 cells, lobaplatin arrested cell cycle progression in G1 and G2/M phases time-dependently which might be associated with the down-regulation of cyclin B, CDK1, CDC25C, phosphorylated CDK1 (pCDK1), pCDK4, Rb, E2F, and pRb, and the up-regulation of p53, p21, and p27.

CONCLUSION

Cytotoxicity of lobaplatin in human HCC cells might be due to its ability to arrest cell cycle progression which would contribute to the potential use of lobaplatin for the management of HCC.

Efficacy of lobaplatin plus 5-fluorouracil and leucovorin in the treatment of advanced gastric cancer: a report of 30 cases

AIM: To evaluate the efficacy and safety of lobaplatin (LBP) plus 5-fluorouracil (5-FU) and leucovorin (CF) in the treatment of advanced gastric cancer.

METHODS: The clinical data for 30 patients with advanced gastric cancer treated with LBP plus 5-FU and CF from March 2004 to September 2008 were retrospectively reviewed. All patients received at least two cycles of chemotherapy, each lasting 21 days and consisting of LBP 30 mg/m² IV d 1, 5-FU 300 mg/m² IV d 1-5, and CF 100 mg/m² IV d 1-5.

RESULTS: Thirty patients received 2 to 6 cycles of chemotherapy, with a median of three cycles. All patients were evaluable for efficacy and toxicity. No patients obtained a complete response. Partial response was achieved in 12 patients, stable disease in 5 patients, and progressive disease in 13 patients. The objective response rate was 40% (12/30). The tumor control rate was 56.7% (17/30). Therapy was generally well tolerated. Major toxicity was myelosuppression and gastrointestinal sensitivity, including anaemia, thrombocytopenia, leukocytopenia, and nausea and vomiting. No chemotherapy-related death occurred.

CONCLUSION: LBP plus 5-FU and CF regimen is effective and safe for patients with advanced gastric cancer.

A systematic review of platinum and taxane resistance from bench to clinic: An inverse relationship

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.

Recent insights into platinum drug resistance in cancer

Cisplatin and its analogs have become important components of chemotherapeutic regimens for the treatment of solid tumors, however, their overall effectiveness is limited by the emergence of drug-resistant tumor cells. Resistance to the platinum drugs is multifactorial consisting of mechanisms that prevent the formation of lethal platinum-DNA adducts and mechanisms that operate downstream of the drug/target interaction to promote cell survival. Continued progress in the study of the drug resistance phenotype as well as the development of new platinum analogs may eventually lead to improved therapies and increased survival rates.

Synthesis and in vitro cytotoxicity of novel lipophilic (diamine)platinum(II) complexes of salicylate derivatives

Novel lipophilic (diamine)platinum(II) complexes of salicylate derivatives as the leaving groups were synthesized and characterized by elemental analysis, FAB(+)-MS, FT-IR, and (1)H NMR spectroscopy. Most of the resulting platinum complexes had high solubility in organic solvents such as ethanol, acetone, and ether, and had right partition coefficient suited to be encapsulated in liposomes. The pertinent complexes were evaluated for their in vitro cytotoxicity against A549 human lung carcinoma and SGC-7901 human gastric carcinoma cell lines. They showed better cytotoxic activity than carboplatin and oxaliplatin.

Clinical observation on adverse reaction of combination chemotherapy of lobaplatin, fluorouracil and calcium leucovorin

AIM: To evaluate the adverse reaction of combination chemotherapy of obaplatin, fluorouracil and calcium leucovorin.

METHODS: Combination chemotherapy of obaplatin, fluorouracil and calcium leucovorin was used in 26 colorectal cancer patients after operation, and a total of 30 courses were completed. The adverse reaction was evaluated according to the standard from World Health Organization.

RESULTS: The adverse reactions that occurred frequently were myelosuppression and gastrointestinal tract reaction. The decrease of white cell and platelet count was significant in myelosuppression. Of the 30 treatment courses, white cell count was decreased to gradeⅠor Ⅱ in 18 courses (60.0%), and grade Ⅲ in 2 courses (6.7%); Thrombocytopenia of gradeⅠor Ⅱ achieved in 20 courses (66.7%), and grade Ⅲ in 3 courses (10.0%). Nausea was the dominant gastrointestinal tract reaction, which covered a percentage of 16.7%, and vomiting occurred in only 3.3% of the cases.

CONCLUSION: Combination of lobaplatin, fluorouracil and calcium leucovorin is safe in post-operative chemotherapy.

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 prospects for the treatment of germ-cell tumours

Germ-cell tumours are rare tumours of testicular, ovarian and extra-gonadal origins. Most are curable by cisplatin-based chemotherapy regimens and surgery. Treatment strategy is based on risk factor assessment. The standard cytotoxic drugs used for the treatment of this disease are: etoposide, cisplatin, bleomycin and ifosfamide. More than 80% of patients are cured by standard treatment. There is a dose-response relationship for cisplatin, up to standard 33 mg/m2/week/dose-intensity. However, further dose escalation has failed to demonstrate an increased response. Carboplatin has been shown to be less active than cisplatin. Activity has been demonstrated with nitrogen mustard, actinomycin, mithramycin, vinblastine, methotrexate and recently with paclitaxel and gemcitabine. Activity is questionable with carboplatin, oxaliplatin, lobaplatin, mitomycin and anthracyclins. No activity has been reported with vindesine, vinorelbine, mitoxantrone, AMSA and topotecan. New treatment strategies are developed in poor-risk group patients and in patients who fail to achieve complete remission status or whom experience recurrent disease. Intensification of chemotherapy is one of the tested strategies. Consolidation high-dose chemotherapy with haematopoietic stem-cell support is under evaluation. Until now, no trial has proven its superiority over standard chemotherapy regimens. Other studies concern the role of repeated cycles of high-dose chemotherapy with haematological support. Innovative strategies consist of introducing new drugs or new schedules: paclitaxel in combination with either ifosfamide and cisplatin or epirubicin, short, recycled chemotherapy regimens, use of cisplatin non-cross-resistant drugs and different time infusion administration of drugs. The aim of these studies is to decrease the residual proportion of treatment failures in this highly curable disease, which constitutes a good model for clinical research in cancer chemotherapy.

Tumour-inhibiting platinum complexes--state of the art and future perspectives

Thirty years after the onset of the first clinical studies with cisplatin, the development of antineoplastic platinum drugs continues to be a productive field of research. This article reviews the current preclinical and clinical status, including a discussion of the molecular basis for the activity of the parent drug cisplatin and platinum drugs of the second and third generation, in particular their interaction with DNA. Further emphasis is laid on the development of third generation platinum drugs with activity in cisplatin-resistant tumours, particularly on chelates containing 1,2-diaminocyclohexane (DACH) and on the promising and more recently evolving field of non-classic ( trans- and multinuclear) platinum complexes. The development of oral platinum drugs and drug targeting strategies using liposomes, polymers or low-molecular-weight carriers in order to improve the therapeutic index of platinum chemotherapy are also covered.

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.

Linkage Isomerism Dependent on Solvent and Temperature. Synthesis and Structural Properties of Diamineplatinum(II) Complexes of Allyl- and Diallylmalonate Ligands

The linkage isomerism between (O,O')- and (O,alkene)-chelates has been investigated for the complexes A(2)PtL(2) (A(2) = 2,2-dimethyl-1,3-propanediamine (DMPDA), trans-(+/-)-1,2-diaminocyclohexane (DACH); L(2) = allylmalonate (AM), diallylmalonate (DAM)). The crystal structures of (DMPDA)Pt(AM).2H(2)O (tetragonal P4(2)/m, a = 13.614(3) Å, b = 13.614(3) Å, c = 8.451(4) Å, V = 1566.3(9) Å(3), Z = 4, R = 0.0472) and (DMPDA)Pt(DAM).2H(2)O (monoclinic P2(1)/n, a = 11.021(3) Å, b = 8.996(2) Å, c = 18.765(7) Å, beta = 106.92(3) degrees, V = 1780.0(9) Å(3), Z = 4, R = 0.0531) have been solved. Each platinum atom adopts a typical square planar arrangement with two nitrogen atoms in cis positions. However, surprisingly, the AM anionic ligand is coordinated to the platinum atom via (O,O')-chelation mode through its two carboxylate groups with the alkene group uncoordinated in the solid state, breaking the hard/soft rule. The tetradentate DAM ligand is chelated to the platinum atom through one carboxylate and one alkene group resulting in (O,alkene)-chelation mode with another uncoordinated carboxylate and alkene group. Multinuclear ((1)H, (13)C, and (195)Pt) NMR studies clearly disclose that the linkage isomerism depends on the solvents employed. Both allyl- and diallylmalonate ligands are chelated exclusively to the platinum(II) atom via (O,O')-mode in dimethylformamide or Me(2)SO solution whereas only (O,alkene)-chelation mode is observed in an aqueous solution. At room temperature, the complexes both of the AM and DAM ligands exist in methanol as a mixture of (O,O')- and (O,alkene)-modes. Furthermore, interconversion between the two isomers occurs reversibly depending on temperature: the (O,alkene)-chelate is predominant at low temperatures while the (O,O')-chelate is favorable at elevated temperatures.

Pre-clinical activity of taxol in non-seminomatous germ cell tumor cell lines and nude mouse xenografts

Taxol (Paclitaxel) is a novel anti-cancer drug which has shown excellent clinical activity in a variety of solid tumors, particularly in metastatic breast and ovarian cancer. 70-80% of patients with metastatic non-seminomatous germ cell tumor (NSGCT) attain disease-free status with standard cisplatin-based combination chemotherapy but the emergence of drug resistance still prevents a small proportion of these patients from achieving long-term remission. Here we report the results of pre-clinical studies investigating whether taxol exhibits cross-resistance to cisplatin or ifosfamide in human NSGCT cell lines and in a cisplatin refractory xenograft model of human NSGCT. Following 96-h drug exposure in a 5-day sulphohodamine B (SRB) in vitro assay, taxol demonstrated potent cytotoxicity in cell lines which were cisplatin sensitive (577 LM, H32, H12.1; mean IC50s 1.5-3.0 nM) or those with acquired or intrinsic cisplatin resistance (H12DDP, H23.1; mean IC50s 2.5 nM). Compared to the drug-sensitive cell line, H12.1, the IC50 values of taxol were increased in cell line 1777NRp Cl-A with intermediate level resistance to cisplatin and ifosfamide (4.7 nM; p > 0.05) and significantly elevated in cell line 1411HP, with a high level of cisplatin resistance (6.9 nM; p < 0.01). The latter 2 cell lines may represent models corresponding to patients relapsing after high-dose platinum-based chemotherapy who seem to be resistant to taxol therapy. The IC50s of taxol in H32 and H12DDP were approximately 100-fold lower following drug exposure times exceeding 24 hours compared with short exposure times (1-6 h). Dose-dependent anti-tumor activity was observed with taxol in a cisplatin-refractory xenograft model of NSGCT (H23.1), with significant anti-tumor activity observed at a dose of 15 mg/kg/d injected intravenously on days 1 through 5. The results of this study are in accordance with the most recent clinical data which showed that taxol is a useful drug in relapsed or cisplatin-refractory testicular germ cell cancer, with significant anti-tumor activity being observed in 25% of patients, but poor activity in patients previously treated with high-dose therapy. Further pre-clinical research, especially using models such as 1411HP and 1777NRp Cl-A, on the combinations of taxol with other regimens are required to enable successful treatment of the most drug-resistant relapsed germ cell tumors.

Comparative cytotoxicity of oxaliplatin and cisplatin in non-seminomatous germ cell cancer cell lines

Approximately 70-80% of patients with metastatic testicular cancer will become disease free with cisplatin-based chemotherapy and most of these patients will be long-term survivors. Despite these impressive results, the two limitations of cisplatin are its severe and potentially long-term side-effects, and the emergence of drug resistance which prevents a small proportion of these patients from achieving long-term remission. Oxaliplatin has an improved toxicity profile compared to cisplatin and contains the diaminocyclohexane (DACH) substituent known to be correlated with a lack of cross-resistance with cisplatin. A phase II study has shown interesting activity when used in combination with cisplatin in cisplatin-refractory testicular cancer patients. Here we report the results of the first in vitro study investigating whether oxaliplatin as a single agent exhibits cross-resistance to cisplatin in a panel of non-seminomatous germ cell tumor (NSGCT) cell lines using short and long-term drug exposures in a five-day sulfhodamine B in vitro cytotoxicity assay. Oxaliplatin cytotoxicity was significantly superior to cisplatin in cell lines with both acquired (H12DDP) and intrinsic (1777NRp Cl-A) intermediate level resistance to cisplatin. Following 24 h or 96 h drug exposure the fold resistance in H12DDP and 1777NRp Cl-A was 1.7-2.2 with oxaliplatin compared to 3.9-6.1 with cisplatin. The cytotoxic activity of oxaliplatin was not significantly different from that of cisplatin in cisplatin-sensitive cell lines or in cell lines with a high level (10-20 fold) of cisplatin resistance. The results of this study suggest that further preclinical studies in NSGCT are of interest, particularly in combination with cisplatin, ifosfamide and etoposide. Furthermore, the in vitro results support the use of an oxaliplatin administration schedule giving prolonged drug exposure, such as the flat or circadian rhythm-modulated schedule already under investigation for oxaliplatin.

Unique Fluxional Behavior. Synthesis, Structure, and Properties of Novel (Diamine)platinum(II) Complexes of 9-Fluorenylidene- and Benzhydrylidenemalonate Ligands

New (diamine)platinum(II) complexes A(2)PtX(2) (A(2) = trans-(+/-)-1,2-diaminocyclohexane (DACH), tetrahydro-4H-pyran-4,4-diylbis(methylamine)(THPDMA); X(2) = 9-fluorenylidenemalonate(FM), benzhydrylidenemalonate(BHM)) have been synthesized and characterized by means of multinuclear NMR spectroscopy and X-ray analysis. (DACH)Pt(FM) crystallizes in space group P2(1)/c with eight formula units in a cell of dimensions a = 20.071(7) Å, b = 12.717(3) Å, c = 24.512(6) Å, beta = 103.25(2) degrees, and V = 6090(3) Å.(3) (DACH)Pt(BHM) crystallizes in space group P&onemacr; with four molecular units in a cell of dimensions a = 11.048(3) Å, b = 13.639(3) Å, c = 14.043(6) Å, alpha = 90.17(3) degrees, beta = 91.31(4) degrees, gamma = 89.98(3) degrees, and V = 2116(1) Å(3). The platinum atom in both complexes adopts a typical square planar arrangement with two nitrogen atoms in cis position. The 9-fluorenylidene and benzhydrylidene groups of the amine ligands chelated to platinum are strikingly bent up by 88.8(3) and 80.8(2) degrees, respectively, from the platinum square plane in the solid state. Variable temperature (1)H NMR spectra of the title complexes in dimethyl sulfoxide solution reveals that the amine proton resonances are sensitive to the fluxional motion of the remote arylidene groups, and suggests that interconversion occurs between two "bent-up" and "bent-down" forms. The prominent difference between the FM and BHM complexes is observed in solution, due to the presence or absence of the angle constraint of the anionic coligands.

Schedule-dependent antagonism of paclitaxel and cisplatin in human gastric and ovarian carcinoma cell lines in vitro

Paclitaxel has demonstrated broad clinical activity in a variety of malignancies both alone and in combination with other chemotherapeutic agents. The in vitro cytotoxicity of paclitaxel and cisplatin alone, in combination and in sequence, were evaluated against established human gastric and ovarian carcinoma cell lines using 2-h drug exposure. The combination of cisplatin and paclitaxel was found to be additive or even synergistic when paclitaxel was given 24 h prior to cisplatin as demonstrated by isobologram analysis. However, when both drugs were given simultaneously or when cisplatin was given prior to paclitaxel, a strong antagonistic interaction was observed. This antagonism was evident for up to 72 h after a 2-h exposure to cisplatin. Pretreatment with cisplatin caused no alteration in [3H]paclitaxel uptake in HM2 gastric carcinoma cells, but resulted in decreased intracellular retention of paclitaxel. Since cisplatin treatment led to a reduction in cellular glutathione content in these cells and reduced levels of glutathione have been associated with protection against cytotoxicity of paclitaxel, cells were pretreated with L-buthionine sulfoximine (L-BSO). However, depletion of glutathione had no influence on the activity of paclitaxel. A significant accumulation of cells in S-phase was observed 24 h after cisplatin, which resolved after 48 h and resulted in a pronounced increase of G2M phase. These data demonstrate that the interactions of paclitaxel and cisplatin are highly schedule-dependent and applications of cisplatin simultaneously with or prior to paclitaxel may result in pronounced antagonism. These findings could have implications for the design of further clinical protocols.

A clinical screening cooperative group phase II evaluation of lobaplatin (ASTA D-19466) in advanced head and neck cancer

We evaluated the efficacy and tolerability of lobaplatin, a new platinum compound, given at the dose of 50 mg/m2 by i.v. bolus every 4 weeks, in 49 patients with advanced and/or metastatic squamous cell carcinoma of the head and neck (SCCHN). One complete and 2 partial responses were observed in 43 eligible patients for an overall response rate of 7% (95% confidence interval: 1-19%). The duration of responses was 11, 16 and 32 weeks. Toxicities of WHO grade > or = 3 were hematologic: thrombocytopenia in 26%, granulocytopenia in 12% and anemia in 12% of patients. There was no therapy-related death. Nausea/vomiting, diarrhoea and paresthesia were mild and rare. In conclusion, lobaplatin was well tolerated, but its efficacy in advanced SCCHN at the presented dose and schedule, was marginal.