A phase I study of 1,2-diamminomethyl-cyclobutane-platinum (II)-lactate (D-19466; lobaplatin) administered daily for 5 days

Lobaplatin induces apoptosis in T24 and 5637 bladder cancer cells by regulating Bcl-2 and Bax expression and inhibiting the PI3K/Akt signaling pathway

Background

Lobaplatin (LBP) is a third-generation platinum-based drug that has been approved only in China for the treatment of several cancer types. Nonetheless, its efficacy in treating bladder cancer (BC) is unclear thus far. Through in vitro and in vivo experiments, this study aimed to explore whether LBP has an antitumor effect on T24 and 5637 BC cells and whether the effect is related to B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax) and regulation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway.

Methods

For in vitro experiments, the cell counting kit-8 (CCK-8) method was used to determine how different concentrations of LBP affect the viability of two types of BC cells. A wound healing assay was used to test the inhibitory effect of LBP on the migration of the two cell lines. Annexin V-fluorescein isothiocyanate isomer I (V-FITC)/propidium iodide (PI) staining was used to detect changes in cell apoptosis before and after LBP treatment, and Western blotting was used to detect the expression of apoptosis-related proteins and PI3K/Akt pathway proteins. For in vivo experiments, a cell-derived xenograft (CDX) model was employed, and the weight of nude mice and the tumor size were measured. Immunohistochemistry was used to detect the effect of LBP on the expression of apoptosis-related proteins in tumor xenografts.

Results

In vitro, LBP reduced proliferation (P<0.05), inhibited migration (P<0.05), and induced apoptosis in T24 (31.25%±1.20%, P<0.01) and 5637 (14.3%±2.24%, P<0.05) BC cells, in a dose-dependent manner (P<0.05); increased the expression of proapoptotic proteins, including Bax, caspase-3 and cleaved caspase-3 (P<0.05); and suppressed the expression of antiapoptotic proteins, including Bcl-2, PI3K, Akt and phosphorylated Akt (p-Akt). The in vivo experiment confirmed that LBP can reduce the size of subcutaneous tumors in nude mice (P<0.05), increase the expression levels of Bax and cleaved caspase-3 and lower the expression of Bcl-2 (P<0.05) in bladder tumor tissue.

Conclusions

The results obtained from both experiments suggest that LBP can inhibit the proliferation of T24 and 5637 BC cells, which might be credited to its effects in regulating Bcl-2 and Bax expression and inhibiting the PI3K/Akt pathway.

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.

Comparative assessment of clinical trials, indications, pharmacokinetic parameters and side effects of approved platinum drugs

Platinum complexes are among the most commonly applied anticancer agents. The aim of current work is collection, analysing and comparative estimation of clinical trials and pharmacological indications of currently approved for application platinum detivatives: Cisplatin, Carboplatin, Oxaliplatin, Nedaplatin (Japan), Lobaplatin (China), Heptaplatin (North Korea), and Satraplatin. The other aim of the study includes the summarizing of the hystoric data for the stages of the developlement of these drugs, and the comparison of pharmacokimetic parameters, side effecs and the dose-liniting factors of the drugs. The observational study on pharmacokinetic parameters shows that protein binding decreases in order: 95% (Cisplatn); 90% (Oxaliplatin); 50% (Nedaplatin); low (Carboplatin). For every of Cisplatin, Carboplatin, Oxaliplatin have been reported more than 1000 clinical trials; for Lobaplatin, Nedaplatin, Satraplatin - about 10 trials. The differenses in dose-limiting effects are: neuro-, nephro-, ototoxicity (Cisplatin); neurotoxicity (Oxaliplatin); nephrotoxicity (Heptaplatin); myelosuppression: thrombocytopenia, neutropenia, leukopenia (Carboplatin, Nedaplatin, Satraplatin).

Multicentre Comparison of the Toxicity and Effectiveness of Lobaplatin-Based Versus Cisplatin-Based Adjuvant Chemotherapy in Oesophageal Carcinoma

Objectives

Lobaplatin (LBP), a third-generation cisplatin derivative has shown promising activity and few side effects in oesophageal squamous cell carcinoma (ESCC) in previous reports. We compared LBP plus docetaxel with cisplatin plus docetaxel as adjuvant chemotherapy in ESCC patients to determine the effects on overall survival (OS) and toxicity.

Methods

A multicentre retrospective study was performed using propensity score matching (PSM) with the Medicine-LinkDoc database. Patients diagnosed with stage II-III ESCC treated with adjuvant chemotherapy (cisplatin plus docetaxel or LBP plus docetaxel) between January 2013 and December 2016 were selected from 6 centres in China.

Results

There were 733 eligible ESCC patients. After PSM (1:1 ratio), 458 patients remained. The 5-year OS rates of the cisplatin and LBP groups were 25.9% and 23.6%, respectively (P=0.457). Leukopenia (grade III-IV/I-II/0: 2.62%/34.5%/59.39% versus 5.24%/43.23%/45.85%; P=0.0176), neutropenia (grade III-IV/I-II/0: 6.55%/37.56%/51.09% versus 4.37%/53.28%/36.34%; P=0.0015), nephrotoxicity (grade I-II/0: 13.97%/76.86% versus 26.64%/65.94%; P<0.001) and gastrointestinal symptoms (grade III-IV/I-II/0: 2.18%/54.59%/32.31% versus 6.55%/65.07%/20.88%; P=0.0011) were more frequent in the cisplatin group.

Conclusions

Compared with cisplatin plus docetaxel, LBP plus docetaxel provided the same survival benefits but lower side effects of myelosuppression and gastrointestinal symptoms. LBP plus docetaxel might be a choice for adjuvant chemotherapy in ESCC.

Clinical Trial Registration

Lobaplatin or Cisplatin in Adjuvant Chemotherapy for Oesophageal Carcinoma, identifier NCT03413436.

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.

Population pharmacokinetics and individualized lobaplatin regimen for the treatment of Chinese small cell lung cancer in the elderly

BACKGROUND

Lobaplatin (LBP) is a third-generation platinum compound.

MATERIAL AND METHODS

This prospective study was performed in 7 institutions in 2014-2016. Elderly small cell lung cancer (SCLC) patients (≥65 years old) were divided into 2 groups to receive LBP regimens according to endogenous creatinine clearance rate (Ccr). LBP was administered at 30 and 20 mg/m in groups A (Ccr ≥ 80 ml/min) and B (60 ml/min ≤ Ccr < 80 ml/min), respectively. The primary endpoint was plasma LBP concentrations. Secondary endpoints were safety and efficacy parameters, including progression-free survival (PFS) and overall survival (OS).

RESULTS

One-hundred patients were enrolled. Median PFS and OS in groups A and B were 155 vs170 days and 306 vs 272 days, respectively. The rates of grade III/IV AEs in groups A and B were 60.8% (n = 31) and 51.0% (n = 25), respectively. In population pharmacokinetics, the area under the curve (AUC) value for group B was 39% lower than that of group A. With LBP administration based on body surface area (BSA), AUC differences between individuals were small.

CONCLUSION

With Ccr ≥ 60 ml/min, BSA based administration is necessary. Meanwhile, LBP-based regimens are reliable in treating elderly patients with SCLC.

Lobaplatin-based regimens outperform cisplatin for metastatic breast cancer after anthracyclines and taxanes treatment

The goal of this study was to assess the antitumor efficacy and safety of lobaplatin-based regimens as the second line of treatment in patients with metastatic breast cancer (MBC) resistant to anthracyclines and taxanes, compared with that of cisplatin-based regimens. During August 2012 to April 2015, 87 patients who received lobaplatin-based regimens or cisplatin-based regimens were included. Medical records of the patients noted that lobaplatin (30 mg/m2) or cisplatin (25 mg/m2), combined with another chemotherapeutic agent such as Gemcitabine (1000 mg/m2) or Vinorelbine (25 mg/m2), was intravenously given to the patients on a basis of twenty-one days as one treatment cycle. All the patients were followed until August 2017. The endpoint of this study was progression-free survival (PFS), overall survival (OS), and estimated objective response rate (RR). Safety and drug tolerability data were also obtained. Lobaplatin-based regimens prolonged PFS compared to cisplatin-based regimens (median 13.2 vs 4.7 months, hazard ratio = 0.37, 95% confidence intervals: 0.21-0.67, P = .0007), while OS was not significantly different between the two groups (hazard ratio = 0.72, 95% confidence intervals: 0.40-1.30, P = .2767), as was objective RR (37.8% vs 33.4%, x 2 = 0.19, P = .6653). Nausea/vomiting and renal injury were more frequent with cisplatin-based regimens. Our results show that lobaplatin-based regimens are superior to cisplatin in terms of efficacy and are better tolerated.

Lobaplatin promotes radiosensitivity, induces apoptosis, attenuates cancer stemness and inhibits proliferation through PI3K/AKT pathway in esophageal squamous cell carcinoma

Radiotherapy is one of the common treatments for esophageal squamous cell carcinoma (ESCC). Yet, local recurrence led by radioresistance is still not solved. Lobaplatin (LBP) is known to have powerful clinical anti-tumor activities in various tumors, but its effect in radiotherapy is rarely studied. Here we report that LBP is a promising radiosensitizer for ESCC. We treated ESCC cells with LBP and radiation, both separately and in combination. Untreated cells were set as control groups. We found that LBP inhibited ESCC cell growth and enhanced their radiosensitivity. LBP also impeded the tumor growth in vivo. LBP combined with radiation significantly increased ESCC cell apoptosis. Meanwhile, LBP obviously decreased the expression of cancer stem cells biomarker CD271 both in vitro and in vivo. The molecular mechanism was related to the downregulation of Bcl-2/Bax ratio, PI3K and p-AKT (Ser473) expression. Taken together, our findings indicated that LBP could enhance the radiosensitivity of ESCC cells by increasing radiation-induced apoptosis, attenuating cancer stemness and inhibiting PI3K/AKT pathway. These results provide a foundation for the combined therapy of radiation and LBP for ESCC in clinical practice.

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.

The efficacy and toxicities of combined lobaplatin with paclitaxel as a first-line chemotherapy for advanced esophageal squamous cell carcinoma

BACKGROUND

To assess the efficacy and toxicities of combined lobaplatin with paclitaxel (LP) as a first line chemotherapy in esophageal cancer.

METHODS

The clinical data of 45 patients with esophageal squamous cell carcinoma treated initially with lobaplatin-paclitaxel chemotherapy were collected and reviewed retrospectively. The overall response, treatment toxicities and dysphagia relief were analyzed with SPSS software.

RESULTS

The overall response rate was 42.2%, with 1 patient (2.2%) showing complete remission, 18 patients (40.0%) with partial remission, 19 (42.2%) with stable disease (SD), and 7 (15.6%) with progressive disease, respectively. The most common hematological toxicity was leucopenia with grade 0, I, II, III and IV in 16 (35.6%), 10 (22.2%), 11 (24.4%), 7 (15.6%), and 1 patient (2.2%), respectively. Thirty-seven patients (82.2%) experienced grade I-II nausea/vomiting without grade III-IV instances occurring. Four patients (8.9%) experienced grade I hepatotoxicity. No nephrotoxicity was observed. Five in thirteen patients treated with concurrent chemoradiotherapy (CRT) suffered severe radiation pneumonitis. The dysphagia resolved or improved in 32 patients (71%).

CONCLUSIONS

Lobaplatin-paclitaxel showed a significant antitumor effect to squamous esophageal cancer with manageable toxicities. Limitation of the surveillance time and the retrospective nature, the effect that based on these data formal prospective trials appear warranted and are needed prior to routine first line use of this regimen.

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.

Efficacy and toxicity of nimotuzumab combined with radiotherapy in elderly patients with esophageal squamous cell carcinoma

This study was conducted to assess the efficacy and toxicity of nimotuzumab combined with radiotherapy (RT) in elderly patients with esophageal squamous cell carcinoma. The clinical data of 16 esophageal squamous cell carcinoma patients, aged >70 years, who were initially treated with nimotuzumab combined with RT, were collected and retrospectively reviewed. The overall response and treatment toxicity were analyzed using SPSS software. All the patients completed the treatment schedule. The response to treatment was assessed at treatment completion and reassessed after 1-2 months: 1 patient achieved complete response (CR), 10 patients achieved partial response (PR), 4 patients exhibited stable disease and 1 patient developed disease progression and succumbed to radiation pneumonitis (RP) 1 month later. The overall response rate (CR+PR) was 68.8%. All 16 patients experienced grade 1-2 radiation esophagitis; no grade 3-4 toxicities were reported. There was one case of treatment-related mortality due to RP during the study. One patient developed a rash on the forearm. No hematological, gastrointestinal, hepatic or renal toxicities were observed. In conclusion, the toxicity of combined nimotuzumab with RT in elderly patients with esophageal cancer was tolerable. However, due to limitations associated with the retrospective nature of this study, the limited number of enrolled cases and the epidermal growth factor receptor expression determination prior to treatment, the efficacy of this treatment modality requires further investigation.

Lobaplatin-TACE combined with radioactive 125I seed implantation for treatment of primary hepatocellular carcinoma

AIM

To investigate the efficacy and safety of lobaplatin-transcatheter arterial chemoembolization (TACE) combined with radioactive 125I seed implantation in treatment of primary hepatocellular carcinoma (HCC).

METHODS

75 patients with primary HCC were enrolled in the study, among them 43 receiving lobaplatin- TACE (TACE group) and 32 lobaplatin-TACE combined with 125I seed implantation (TACE+125I group). After treatment, the local remission rates and postoperative complications of two groups were compared using the Pearson Chi-square test. Overall survival in the two groups was calculated using Kaplan-Meier survival curves and the differences were tested using Log-rank test.

RESULTS

There were 7 cases of complete response (CR), 13 of partial response (PR), 6 of stable disease (SD) and 17 of progressive disease (PD) in the TACE group, with 13 cases of CR, 9 of PR, 5 of SD and 5 of PD in the TACE+125I group. The disease control rates of TACE and TACE+125I group were 60.5% (26/43) and 84.4% (27/32), respectively, with a significant difference between them (P < 0.05). The survival rates at 6, 12 and 18 months in the TACE group were 100.0%, 81.8% and 50.0%, respectively, and those in TACE+125I group were 100.0%, 93.8% and 65.6%. The mean survival times in the TACE and TACE+125I groups were 19.5 and 22.9 months, respectively. There was a significant difference in the overall survival rate between two groups (P < 0.05). No serious complications were encountered in either group.

CONCLUSION

Lobaplatin-TACE combined with 125I seed implantation is favorable and safe for treatment of primary HCC.

Lobaplatin arrests cell cycle progression, induces apoptosis and impairs migration and invasion in B16-F10 melanoma cell line in vitro

Melanoma is highly resistant to most conventional treatment, and the incidence and mortality rates are increasing rapidly worldwide. The objective of this study was to determine the anticancer effects of lobaplatin on the melanoma carcinoma cell line B16-F10 in vitro, and explored its mechanisms of action. Our results have shown that lobaplatin inhibited cell proliferation in human melanoma A375 and CHL-1 cells and murine melanoma B16-F10 cells in a concentration- and time-dependent manner. Flow cytometry assay confirmed that lobaplatin affected B16-F10 cell survival by blocking cell cycle progression in G2/M phase and inducing apoptosis in a concentration-dependent manner. In addition, the apoptosis was associated with downregulation of anti-apoptotic protein Bcl-2 while upregulation of pro-apoptotic protein Bax. Lobaplatin could also decrease the mitochondrial membrane potential, indicating that lobaplatin may induce apoptosis via mitochondria-mediated apoptotic pathway. Furthermore, lobaplatin blocked B16-F10 cell migration and invasion in vitro. These results suggested that lobaplatin could be an effective chemotherapeutic agent in melanoma treatment by inhibiting proliferation, inducing apoptosis, cell cycle arrest and blocking cell migration and invasion.

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.

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.

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.

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.

Emerging treatments for ovarian cancer

The survival at 5 years, of patients with ovarian cancer, has steadily improved since 1960, when surgery and alkylating agents were the only initial modalities employed to cope with the usual late presentation of the disease. In the 1980s, cisplatin and then carboplatin became established as the most active drugs, alone or in combination with other drugs. In the last decade, the antimicrotubulin drug paclitaxel, and the topoisomerase I inhibitor topotecan were noted to be active after failure of platinum drugs. These drugs, as well as others with known activity in the second-line setting, such as the pegylated liposomal doxorubicin, gemcitabine and oral etoposide, all play a role in the treatment of these patients and likely prolong survival without eradicating the disease. The plight of these patients has stimulated new areas of drug development. Here, the evolution of the current therapeutic strategy, the scientific rationale for cytotoxic and non-cytotoxic agents and their status at present are reviewed. 'Targeted' drug trials, in contrast to trials studying cytotoxic drug analogues, currently represent only a minor portion of clinical trials in ovarian cancer.

Lobaplatin: D 19466

Lobaplatin [D 19466] is a platinum complex with DNA alkylating activity that was developed by ASTA Medica (Degussa) for the treatment of cancer. ASTA Medica discontinued development of lobaplatin, and subsequent development of the compound became the responsibility of Zentaris AG (AEterna Laboratories), which was formed in 2001 from the biopharmaceutical, inhalation technology and gene therapy activities of ASTA Medica. On 30 December 2002, Zentaris was acquired by AEterna Laboratories. Cisplatin, one of the original platinum compounds, has had a major impact on the treatment of solid tumours such as germ cell cancer, ovarian cancer, bladder cancer and bronchial carcinoma, but its clinical usefulness is limited by renal, neurological and gastrointestinal toxicity. This has led to the development of second- and third-generation platinum analogues, such as lobaplatin, with reduced toxicity and a better therapeutic index. In January 2003, Zentaris AG and Hainan Tianwang International Pharmaceutical signed a contract for the manufacture and marketing of lobaplatin in China. The technology transfer agreement provides for Zentaris to receive a one-time payment to the amount of 4.5 million Canadian dollars. In addition, the contract foresees for Tianwang to manufacture and deliver lobaplatin to Zentaris or its partners for marketing in all other countries worldwide. Lobaplatin has been approved in China for the treatment of chronic myelogenous leukaemia (CML) and inoperable, metastatic breast and small cell lung cancer. However, it has not yet been launched there. In June 2003, AEterna reported that it expects lobaplatin to be launched in China by the end of 2003 at the 10th Annual Meeting of the Biotechnology Industry Organization (BIO-2003). Lobaplatin has also completed phase II clinical trials in the US, Australia, EU, Brazil and South Africa for the treatment of various cancers, including breast, oesophageal, lung and ovarian cancers as well as CML.

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.

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.

Phase I trial design: are new methodologies being put into practice?

BACKGROUND

The primary goal of phase I studies is to efficiently and accurately determine the recommended dose of a new agent for further investigation. Issues of concern ranging from the ethics of these trials to selection of starting dose and rapidity of dose escalation, have led to suggested modifications of the traditional phase I design. We wanted to assess the frequency with which these new approaches are being applied to recent phase I trials and, if possible, their impact.

METHODS

Reports of phase I trials of single agent cytotoxics published between 1993 and 1995 were identified by computer search and review of cancer journals. Data on starting dose, toxicology, dose escalation method, definition of dose limiting toxicity (DLT), actual maximum tolerated dose (MTD) and recommended phase II dose were abstracted.

RESULTS

Reports of 46 phase I trials were identified: 27 were the first clinical studies of 17 new cytotoxic agents (group A) and 19 were repeat studies of 14 agents (group B). Starting doses in group A were based on preclinical animal toxicology (usually mouse or dog) and for group B on previous clinical experience. Dog toxicology appropriately influenced starting dose in 3 of 6 trials. The majority of group A (19/27) studies employed modified Fibonacci dose escalation; group B studies commonly escalated doses by fixed increments. The definition of DLT was highly variable across studies. MTD was usually defined as the dose level at which > 2/6 patients experienced DLT but several studies required 3-4/6 patients. In 30 trials, the recommended phase II dose was one dose level below the MTD; but in 10 trials the terms MTD and recommended phase II dose were considered synonymous.

CONCLUSION

Despite proposed new methodologies (particularly dose escalation) for phase I trials, very few are being employed in practice. A concerted effort should be made to prospectively evaluate these to determine which provides the best combination of safety and efficacy. In addition, the lack of standardization in the definition of limiting toxicity is surprising. Those involved in drug development should strive for agreement on the acceptable degree of toxicity for phase II dose selection.

Emerging drug treatments for solid tumours

A number of novel anticancer agents have emerged during the past few decades, which show high activity in preclinical tumour models and promising activity in early trials in patients with solid tumours. Most of the agents have novel and unique mechanisms of action, and show activity against a variety of malignancies, including tumours which are notoriously resistant to systemic treatment. Recently, our understanding of the molecular basis of cancer has increased considerably. This is reflected in the development of agents that are directed at well defined molecular targets, such as the mitotic tubulin/microtubuli system (taxoids), nuclear enzymes (topoisomerase I inhibitors) and cell signal transduction pathways (protein kinase C inhibitors). In addition, significant advances have been made in our understanding of mechanisms of toxicity, especially of cisplatin. This has resulted in the development of agents modulating cisplatin toxicity, among which amifostine (WR-2721) is one of the most promising. The outlined emerging drug therapies with novel anticancer agents and treatment modalities will, it is hoped, result in increased response rates of advanced tumours, longer disease-free and total survival and better palliative care.

Phase II and pharmacokinetic study of lobaplatin in patients with relapsed ovarian cancer

In phase I studies, lobaplatin showed activity in ovarian cancer patients pretreated with platinum. A phase II trial with lobaplatin was performed in patients with refractory or relapsed ovarian cancer to define activity and pharmacokinetics. Twenty-two patients were treated with lobaplatin administered as an intravenous bolus every 4 weeks. Dependent on creatinine clearance (CRCL) patients received 30 or 50 mg m-2 lobaplatin as the starting dose. Twenty-two patients received 78 courses (median 3, range 1-6). In eight patients total platinum (TPt) in plasma and urine, free platinum (FPt) in plasma ultrafiltrate (both measured by atomic absorption spectrometry) and lobaplatin in plasma ultrafiltrate measured (by high-performance liquid chromatography) were measured. Toxicity was confined to mild nausea and vomiting, mild leucocytopenia (WHO grade 3 in 18% of the courses), and renal function-related thrombocytopenia (WHO grade 3/4 in 53% of the courses). A correlation was found between CRCL and reduction in platelet count (r = -0.77; P < 0.01). No renal toxicity was encountered. Five of 21 evaluable patients (24%) achieved a response (four complete remissions and one partial remission). Remissions occurred mainly in patients who relapsed more than 6 months after primary treatment. The median survival from start of lobaplatin treatment was 8 months. The mean areas under the curve (AUCs) were 4.2 +/- 0.5, 3.0 +/- 0.6, and 3.2 +/- 1.1 h mgl-1 for TPt, FPt and lobaplatin respectively. The free platinum fraction (FPt/TPt) was initially very high, indicating low protein binding. FPt was essentially present as intact lobaplatin. Four hours after infusion 54 +/- 5% and 24 h after infusion 74 +/- 3% of the lobaplatin dose was excreted in the urine. In conclusion, lobaplatin is a platinum compound with anti-tumour activity in patients with relapsed ovarian cancer, especially in those who have platinum-sensitive tumours. The main toxicity of lobaplatin is thrombocytopenia and its dose should be corrected according to renal function.

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.

New platinum antitumor complexes

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.

New cisplatin analogues in development. A review

Cisplatin was discovered to have cytotoxic properties in the 1960s, and by the end of the 1970s it had earned a place as the key ingredient in the systemic treatment of germ cell cancers. Since the early seminal work in the preclinical and clinical development of this drug, several thousand analogues have been synthesised and tested for properties that would enhance the therapeutic index of cisplatin. About 13 of these analogues have been evaluated in clinical trials, but only one (carboplatin) has provided definite advantage over cisplatin and achieved worldwide approval. However, carboplatin has afforded benefit only in reducing some cisplatin toxicities; it has not enlarged the spectrum of platinum-sensitive cancers, nor has it proved active in cisplatin-resistant cancers. The major obstacle to the efficacy of cisplatin or carboplatin is platinum resistance, either innate or acquired. The mechanisms of this resistance have been under intense study, and many of the cisplatin analogues synthesised in the past decade have been designed specifically with the hope of overcoming platinum resistance. The mechanism of the cytotoxic activity of platinum complexes has also been studied intensely. Recently synthesised analogues have been designed to interact with DNA in a manner different from cisplatin and carboplatin, with the desire of finding new structures with a superior or wider spectrum of antitumor efficacy. Most recently, water soluble platinum complexes that retain antitumour activity, but that can be effectively absorbed after oral administration, have been synthesised with the goal of improving patient quality of life. Nine platinum analogues are currently in clinical trials around the world (ormaplatin [tetraplatin], oxaliplatin, DWA2114R, enloplatin, lobaplatin, CI-973 [NK-121], 254-S, JM-216 and liposome-entrapped cis-bis-neodecanoato-trans-R,R-1,2-diaminocyclohexane platinum (II) [LNDDP]). Some of these analogues only represent attempts to reduce cisplatin toxicity and/or allow administration without forced hydration and diuresis, which carboplatin already does. Others are 'third generation' complexes shown to have limited or no cross-resistance with cisplatin in preclinical studies. They are being tested clinically with particular attention to this highly desirable property.(ABSTRACT TRUNCATED AT 400 WORDS)

Stability of the new anticancer platinum analogue 1,2-diaminomethyl-cyclobutane-platinum(II)-lactate (lobaplatin; D19466) in intravenous solutions

The chemical stability of the new anticancer platinum analogue 1,2-diaminomethyl-cyclobutane-platinum(II)-lactate (D19466) in infusion media was studied in an accelerated stability testing experiment with a selective HPLC-UV method. Variables were time, temperature, light, concentration, and infusion mixture. Mean reaction rate constants of decomposition were, respectively, 0.9555 *10(-2), 2.127 *10(-2), and 4.221 *10(-2) hr-1 at 37, 56, and 66 degrees C at a concentration of 200 mg/L in normal saline. From the Arrhenius equation, shelf lives (5% loss) at 4, 22, 37, and 121 degrees C were, respectively, calculated to be 41.6, 13.2, 5.7, and 0.15 hr. Mean reaction rate constant in 5% dextrose was 3.106 *10(-2) hr-1 (200 mg/L; 56 degrees C) and differed from that in normal saline (P less than 0.005). Mean reaction rate constant in Ringer lactate was 2.084 *10(-2) hr-1 (200 mg/L; 56 degrees C) (P greater than 0.05). There was no influence of normal daylight on the rate of decomposition. It is recommended to prepare D19466 infusions in normal saline. Chemical stability is then maximal 12 hr at room temperature or 24 hr at 4 degrees C. No protection against normal daylight is required. Sterilization by heat is not possible.