Sequence-dependent antitumour efficacy of combination chemotherapy of nedaplatin, a novel platinum complex, with 5-fluorouracil in an in vivo murine tumour model

Phase I trial of nedaplatin chemotherapy concurrent with radiotherapy for untreated locoregionally advanced nasopharyngeal carcinoma

PURPOSE

In this phase I study, single-agent chemotherapy was conducted in patients with locoregionally advanced nasopharyngeal carcinoma (NPC) using nedaplatin (NDP) and concomitant radiotherapy. The study sought to determine the maximum tolerated dose (MTD), recommended dose (RD) and the clinical efficacy of this treatment in locoregionally advanced NPC patients.

EXPERIMENTAL DESIGN

Twenty patients were enrolled. The eligibility criteria included local advanced NPC (stage III or IVa) without any previous treatment and an expected survival of ≥ 3 months. The regimen consisted of 1.8-2.0 Gy daily radiation for 5 days a week and NDP with dose escalation of 70-100 mg/m(2) on day 1. The cycles were repeated every 21 days (day 1, day 22 and day 43) until the completion of chemoradiation. Dose-limiting toxicities (DLTs) included: grade 4 anemia; grade 4 neutropenia lasting for ≥ 5 days; grades 3 and 4 febrile neutropenia; grade 4 thrombocytopenia; grades 3-4 non-hematological toxicity (with the exception of alopecia, nausea) and any of the grade 5 responses.

RESULTS

Ninety-five percent of the assessed patients experienced a treatment response. The median time to progression among all patients was 41.9 months. Two-year overall survival was 95%, while the progression-free survival was 85%. DLT included febrile neutropenia of grade 3. The RD of NDP was 90 mg/m(2) during cycles 1-3.

CONCLUSION

NDP combined with radiotherapy and administered every 21 days for three cycles was active in patients with locoregionally advanced NPC. The regimen resulted in mild adverse effects and good patient compliance. Based on the findings from the study, the RD of NDP for phase II trial was found to be 90 mg/m(2).

Efficacy and feasibility of ambulatory treatment-based monthly nedaplatin plus S-1 in definitive or salvage concurrent chemoradiotherapy for early, advanced, and relapsed esophageal cancer

BACKGROUND

Standard chemoradiotherapy (CRT) using cisplatin (CDDP) and 5-fluorouracil (5-FU) is an optional treatment for patients with stage II-III esophageal cancer. However, there are some demerits in this regimen because CDDP administration requires a large transfusion volume and 5-FU must be continuously infused over 24 h. Therefore, hospitalization is unavoidable. We collected retrospectively the data of definitive CRT with nedaplatin and S-1 as carried out in our institution.

METHODS

Patients with early and advanced esophageal cancer and relapsed esophageal cancer after radical surgery were included. Nedaplatin 80 mg/m(2) was given on days 1 and 29, and S-1 80 mg/m(2) on days 1-14 and 29-42. No prophylactic treatment with granulocyte colony stimulating factor was administered. Patients received two courses of concurrent radiotherapy of more than 50 Gy with or without two additional courses as adjuvant therapy every 4 weeks.

RESULTS

Between August 2011 and June 2015, 89 patients (age range, 44-86 years; K-PS 90-100, 81 %; squamous cell carcinoma histology, 97 %; definitive/salvage CRT, 75/25 %) were collected. Twenty-one (24 %) patients completed four cycles, and 94 % received two or more cycles. Grade 4 leukopenia, thrombocytopenia, and anemia occurred in 12, 7, and 10 % of the patients, respectively. Five patients developed febrile neutropenia. Grade 3 non-hematological toxicity included infection in 12 %, mucositis/esophagitis in 3 %, kidney in 3 %, and fatigue in 3 %. Sixty-four patients (72 %) received the prescribed full dose and full cycles of chemotherapy. A complete response was achieved in 76 patients (85 %). The 3-year overall survival rate was 54.4 % in definitive CRT and 39.8 % in salvage CRT, respectively. Sixty-two subjects (70 %) received treatment as outpatients.

CONCLUSIONS

Nedaplatin and S-1 in combination with radiotherapy is feasible, and toxicity is tolerable. This treatment method has the potential to shorten hospitalization without impairing the efficacy of CRT.

Clinical outcomes of nedaplatin and S-1 treatment with concurrent radiotherapy in advanced head and neck cancer

CONCLUSION

Nedaplatin and S-1 treatment with concurrent radiotherapy was effective, with acceptable toxicities. This regimen does not require extensive intravenous hydration and continuous infusion. Nedaplatin and S-1 may contribute to better clinical outcomes and improve quality of life for patients.

OBJECTIVES

We retrospectively analyzed the clinical efficacy and toxicity of concurrent chemoradiotherapy with nedaplatin and S-1 for head and neck squamous cell cancer.

METHODS

Forty-six patients with oropharyngeal, hypopharyngeal, and laryngeal cancer were treated with S-1 on days 1 through 14 and nedaplatin on day 1 every 4 weeks for two cycles of radiotherapy. Therapeutic responses and adverse events were assessed.

RESULTS

Primary site tumors and neck lymph nodes exhibited complete response rates of 91% and 64.3%, respectively. The 4-year relapse-free survival and overall survival rates were 76.2% and 85.3%, respectively. The main grade 3 and 4 toxicities were mucositis (30%), leukopenia (30%), anorexia (22%), dermatitis (15%), and thrombocytopenia (9%).

Results of chemoradiotherapy for stage I esophageal cancer in medically inoperable patients compared with results in operable patients

The purpose of the present study was to evaluate long-term results of chemoradiotherapy for clinical T1b-2N0M0 esophageal cancer and to compare outcomes for operable and inoperable patients. Patients with stage I esophageal cancer (Union for International Cancer Control [UICC] 2009), excluding patients with cT1a esophageal cancer, were studied. All patients had histologically proven squamous cell carcinoma. Operable patients received cisplatin and 5-fluorouracil with concurrent radiotherapy of 60 Gy including a 2-week break. Inoperable patients received nedaplatin and 5-fluorouracil with concurrent radiotherapy of 60-70 Gy without a pause. End-points were overall survival rate (OS), cause-specific survival rate (CSS), progression-free survival rate (PFS), and locoregional control rate (LC). Thirty-seven operable patients and 30 medically inoperable patients were enrolled. There was a significant difference in only age between the operable group and inoperable group (P = 0.04). The median observation period was 67.9 months. In all patients, 5-year OS, CSS, PFS, and LC were 77.9%, 91.5%, 66.9%, and 80.8%, respectively. Comparison of the operable group and inoperable group showed that there was a significant difference in OS (5-year, 85.5% vs. 68.7%, P = 0.04), but there was no difference in CSS, PFS, or LC. Grade 3 or more late toxicity according to Common Terminology Criteria for Adverse Events v 3.0 was found in seven patients. Even in medically inoperable patients with stage I esophageal cancer, LC of more than 80% can be achieved with chemoradiotherapy. However, OS in medically inoperable patients is significantly worse than that in operable patients.

Multicenter phase II study of capecitabine combined with nedaplatin for recurrent and metastatic nasopharyngeal carcinoma patients after failure of cisplatin-based chemotherapy

PURPOSE

There is no standard second-line regimen for recurrent and metastatic nasopharyngeal carcinoma patients after failure of cisplatin-based chemotherapy. A multicenter phase II study was conducted to evaluate the efficacy and toxicity of capecitabine combined with nedaplatin for these patients.

PATIENTS AND METHODS

In the multicenter, open-label, single-arm phase II study, patients with recurrent and metastatic nasopharyngeal carcinoma who failed to previous cisplatin-based chemotherapy were enrolled. Patients received oral capecitabine (1,000 mg/m(2) twice daily from day 1 to 14) and intravenous nedaplatin (80 mg/m(2), day 1) every 3 weeks for two cycles at least.

RESULTS

A total of forty-eight patients were enrolled and included in the intention-to-treat analysis of efficacy and adverse events. Treatment was well tolerated. Grade 3/4 toxicities included neutropenia (8.4 %), anemia (2.1 %), diarrhea (4.2 %), stomatitis (6.3 %), and hand-foot syndrome (HFS) (4.2 %). There were two complete response (4.2 %), eighteen partial responses (37.5 %), giving an overall response rate of 41.7 % [95 % confidence interval (CI) 27.7-55.8]. With a median follow-up period of 12.1 months, the median time to progression was 5.8 months (95 % CI 3.9-7.8 months) and median overall survival was 12.4 months (95 % CI 9.6-16.8 months).

CONCLUSION

Capecitabine combined with nedaplatin offers a satisfactory clinical activity and an acceptable safety profile for recurrent and metastatic nasopharyngeal carcinoma patients after failure of cisplatin-based chemotherapy.

Prospective study of daily low-dose nedaplatin and continuous 5-fluorouracil infusion combined with radiation for the treatment of esophageal squamous cell carcinoma

Background

Protracted low-dose concurrent chemotherapy combined with radiation has been proposed for enhanced treatment results for esophageal cancer. We evaluated the efficacy and the toxicity of a novel regimen of daily low-dose nedaplatin (cis-diammine-glycolatoplatinum) and continuous infusion of 5-fluorouracil (5-FU) with radiation in patients with esophageal squamous cell carcinoma.

Methods

Between January 2003 and June 2008, 33 patients with clinical stage I to IVB esophageal squamous cell carcinoma were enrolled. Nedaplatin (10 mg/body/day) was administered daily and 5-FU (500 mg/body/day) was administered continuously for 20 days. Fractionated radiotherapy for a total dose of 50.4-66 Gy was administered together with chemotherapy. Additional chemotherapy with nedaplatin and 5-FU was optionally performed for a maximum of 5 courses after chemoradiotherapy. The primary end-point of this study was to evaluate the tumor response, and the secondary end-points were to evaluate the toxicity and the overall survival.

Results

Twenty-two patients (72.7%) completed the regimen of chemoradiotherapy. Twenty patients (60.6%) achieved a complete response, 10 patients (30.3%) a partial response. One patient (3.0%) had a stable disease, and 2 (6.1%) a progressive disease. The overall response rate was 90.9% (95% confidence interval: 75.7%-98.1%). For grade 3-4 toxicity, leukopenia was observed in 75.8% of the cases, thrombocytopenia in 24.2%, anemia in 9.1%, and esophagitis in 36.4%, while late grade 3-4 cardiac toxicity occurred in 6.1%. Additional chemotherapy was performed for 26 patients (78.8%) and the median number of courses was 3 (range, 1-5). The 1-, 2- and 3-year survival rates were 83.9%, 76.0% and 58.8%, respectively. The 1- and 2-year survival rates were 94.7% and 88.4% in patients with T1-3 M0 disease, and 66.2% and 55.2% in patients with T4/M1 disease.

Conclusion

The treatment used in our study may yield a high complete response rate and better survival for each stage of esophageal squamous cell carcinoma.

Trial registration

ClinicalTrials.gov Identifier: NCT00197444

Results of radiation therapy combined with nedaplatin (cis-diammine-glycoplatinum) and 5-fluorouracil for postoperative locoregional recurrent esophageal cancer

Background

Although the effectiveness of radiotherapy with concurrent administration of several anti-tumor drugs for postoperative recurrent esophageal cancer has been demonstrated, the results are not satisfactory. The purpose of the present study was to evaluate the effectiveness and safety of radiotherapy combined with nedaplatin and 5-FU for postoperative locoregional (excluding hematogenous metastasis) recurrent esophageal cancer.

Methods

In June 2000, we started a phase II study on treatment of postoperative locoregional recurrent esophageal cancer with radiotherapy (60 Gy/30 fr/6 weeks) combined with chemotherapy consisting of two cycles of nedaplatin (70 mg/m²/2 h) and 5-FU (500 mg/m²/24 h for 5 days).

The primary endpoint of the present study was overall survival rate, and the second endpoints were irradiated-field control rate, tumor response and toxicity.

Results

A total of 30 patients were included in this study. The 1-year and 3-year overall survival rates were 60.6% and 56.3%, respectively, with a median survival period of 39.0 months, and the 1-year and 3-year irradiated-field control rates were 86.4% and 72%, respectively. Complete response and partial response were observed in 13.3% and 60.0% of the patients, respectively. Grade 3 or higher leukocytopenia and thrombocytopenia were observed in 30% and 3.3% of the patients, respectively, but renal toxicity of grade 3 or higher was not observed. The regimen was completed in 76.7% of the patients.

In univariate analysis, the difference between survival rate in preradiotherapy performance status, recurrent pattern (worse for patients with anastomotic recurrence) and age (worse for younger patients) were statistically significant.

Conclusion

Radiotherapy combined with nedaplatin and 5-FU is a safe and effective salvage treatment for postoperative locoregional recurrent esophageal cancer.

A phase I/II study of nedaplatin and 5-fluorouracil with concurrent radiotherapy in patients with esophageal cancer

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Radiation therapy combined with cis-diammine-glycolatoplatinum (nedaplatin) and 5-fluorouracil for Japanese stage II-IV esophageal cancer compared with cisplatin plus 5-fluorouracil regimen: a retrospective study

To evaluate the treatment outcome of radiotherapy combined with cis-diammine-glycolatoplatinum (nedaplatin) plus 5-fluorouracil (5-FU) for esophageal cancer. From January 2000 to December 2004, a total of 12 esophageal cancer patients with locally advanced and metastatic esophageal cancer (stages II-IVB) were treated with radiation therapy (50.4 Gy) combined with nedaplatin (80 mg/m(2), bolus infusion) and 5-FU (800 mg/m(2)/24 h, continuous infusion for 4 days) (NDP group). We compared the data with those of patients during the same period receiving a different chemotherapy regimen consisting of cisplatin (75 mg/m(2), bolus infusion) and 5-FU (1000 mg/m(2)/24 h, continuous infusion for 4 days) (n = 29, CDDP group) combined with the same radiation therapy. The median survival period was 11.5 months in the NDP group and 13.1 months in the CDDP group. The overall survival rates at 1-, 2-, and 3-years were 40%, 13%, and 13% in the NDP group and 56%, 42%, and 8% in the CDDP group (P = 0.2472), respectively. Grade III and IV leukocytopenia was observed in six (50%) and none of the patients in the NDP group and 14 (48%) and seven (24%) in the CDDP group, respectively. Grade III thrombocytopenia was observed in three (25%) in the NDP group and four (14%) in the CDDP group. Radiation combined with nedaplatin and 5-FU is a safe and effective method for treating esophageal cancer. We recommend that NDP should be used rather than dose-reduction of CDDP combined with 5-FU in patients with impaired renal function as indicated by low creatinine clearance value (40-60 mL/min).

Relationship between cisplatin or nedaplatin-induced nephrotoxicity and renal accumulation

Nedaplatin is known to exhibit antitumor activity similar to that of cisplatin. However, concerning side effects, nedaplatin causes renal toxicity less frequently than cisplatin. In this study, we compared the incidence of renal toxicity between cisplatin and nedaplatin by investigating the difference in kidney tissue accumulation. Kidney tissue accumulation of cisplatin administered at 3.75 mg/kg was similar to that of nedaplatin administered at 24 mg/kg. At these doses, the plasma creatinine level and urinary excretion of glucose and N-acetyl-beta-D-glucosaminidase (NAG) similarly increased. There was a correlation between kidney accumulation of cisplatin and nedaplatin and the increases in plasma creatinine level and urinary excretion of NAG. Therefore, our results suggest that nedaplatin less frequently causes renal toxicity in comparison to cisplatin due to lower kidney accumulation.

Serum thymic factor, FTS, attenuates cisplatin nephrotoxicity by suppressing cisplatin-induced ERK activation

Serum thymic factor (FTS), a thymic peptide hormone, has been reported to attenuate the bleomycin-induced pulmonary injury and also experimental pancreatitis and diabetes. In the present study, we investigated the effect of FTS on cis-diamminedichloroplatinum II (cisplatin)-induced nephrotoxicity. We have already demonstrated that cephaloridine, a nephrotoxic antibiotic, leads to extracellular signal-regulated protein kinase (ERK) activation in the rat kidney, which probably contributes to cephaloridine-induced renal dysfunction. The aim of this study was to examine the effect of cisplatin on ERK activation in the rat kidney and also the effect of FTS on cisplatin-induced nephrotoxicity in rats. In vitro treatment of LLC-PK1 cells with FTS significantly ameliorated cisplatin-induced cell injury. Treatment of rats with intravenous cisplatin for 3 days markedly induced renal dysfunction and increased platinum contents in the kidney cortex. An increase in pERK was detected in the nuclear fraction prepared from the rat kidney cortex from days 1 to 3 after injection of cisplatin. FTS suppressed cisplatin-induced renal dysfunction and ERK activation in the kidney. FTS did not influence any Pt contents in the kidney after cisplatin administration. FTS has been shown to enhance the in vivo expression of heat shock protein (HSP) 70 in the kidney cortex. The beneficial role of FTS against cisplatin nephrotoxicity may be mediated in part by HSP70, as suggested by its up-regulation in the kidney cortex treated with FTS alone. Our results suggest that FTS participates in protection from cisplatin-induced nephrotoxicity by suppressing ERK activation caused by cisplatin.

Expression of p21(Waf1/Cip1) predicts response and survival of esophageal cancer patients treated by chemoradiotherapy

Chemoradiotherapy is a multimodal therapy routinely used as a primary treatment for advanced esophageal cancer. However, it is beneficial only to patients who respond. To identify pretreatment markers predicting response and survival, we examined the expression of cell cycle regulatory molecules, p53, p21(Waf1/Cip1) cyclin D1, and CDC25B, in biopsy specimens from 76 patients with stage III and stage IV squamous cell carcinoma. Overexpression of p53, p21, cyclin D1 and CDC25B was observed in 58%, 30%, 28%, and 32% of patients, respectively. The expression of p21 correlated significantly with response to chemoradiotherapy (P = 0.0001). Survival of patients with p21-expressing tumors was better than that of patients with p21-negative tumors (P = 0.013). Expression of other genes was not significantly correlated with treatment response and survival. In patients with p53-negative tumors, survival of those patients with p21-positive tumors was significantly higher than that of those with p21-negative tumors (P = 0.0452), but no significant difference was found in patients with p53-positive tumors. Multivariate analysis revealed that p21 expression was an independent variable among pretreatment parameters in predicting survival. These results suggest that p21 expression is potentially useful for predicting the response to chemoradiotherapy and survival of patients with advanced esophageal squamous cell cancer.

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.

Radiation therapy combined with cis-diammine-glycolatoplatinum (Nedaplatin) and 5-fluorouracil for untreated and recurrent esophageal cancer

From January 1999 to November 2000, a total of 24 esophageal cancer patients (17 untreated and 7 recurrent cases) were treated with radiation therapy (60-70 Gy) combined with cis-diammine-glycolatoplatinum (Nedaplatin) (80-120 mg/body) and 5-fluorouracil (5-FU) (500-1,000 mg/body/24 h, continuous infusion for 5 days). Grade III leukocytopenia was observed in 6 (25%) of the patients. Grade III and IV thrombocytopenia was observed in one patient each. The 1-year and 2-year survival rates for definitively irradiated patients were 59% and 39%, respectively, and for patients with postoperative recurrence 69% and 69%, respectively. High-dose radiation combined with Nedaplatin and 5-FU is a safe and effective method for treating esophageal cancer.

Phase I study of combination chemotherapy with 5-fluorouracil (5-FU) and nedaplatin (NDP): adverse effects and eecommended dose of NDP administered after 5-FU

When nedaplatin (NDP) was used as a single agent in the phase I study, the dose-limiting toxicity (DLT) was thrombocytopenia and the recommended dose (RD) was 100 mg/m2. However, the DLT, maximum tolerated dose (MTD) and RD of NDP used in combination with 5-fluorouracil remained unknown. Therefore, we performed this study to assess the DLT and RD of NDP administered after 5-fluorouracil (5-FU). In this study, 5-FU was administered to 38 patients at a fixed dose (700 mg/m2/d on days 1-5) and NDP administered on day 6 at an initial dose of 80 mg/m2, which was subsequently increased to 100, 120, 130, 140, 150, and 160 mg/m2. The DLT of NDP was leukopenia and its MTD and RD were 160 and 150 mg/m2, respectively. Concerning impairment of renal function, only two patients had a grade I increase in serum creatinine. There were 19 responders (50%, 19/38) achieving partial response or complete response in the evaluation of antitumor effect. The result of this study is notable in that administration of 5-FU before NDP allows the dose of NDP to be substantially increased.

A significant enhancement of therapeutic effect against hepatic metastases of M5076 in mice by a liposomal interleukin-2 (mixture)

Recombinant interleukin-2 (IL-2) was strongly and almost completely adsorbed onto small hydrophobic liposomes under optimal conditions (liposome: DSPC-DSPG; molar ratio, 10:1; 30-50 nm in size, ratio of IL-2 to liposome: 4.0 JRU/nmol lipid). This liposomal IL-2 improved the distribution of IL-2 after intravenous administration as reported, previously. Liposomal IL-2 (300-10000 JRU/mouse per day) was significantly more effective than free IL-2 alone for inhibiting against the experimental metastases of M5076 in mice. The inhibitory effect of liposomal IL-2 was greatest in the liver. The ED(50) of liposomal IL-2 and that of free IL-2 in the liver were 1640 and 12500 JRU/mouse per day, respectively. This simple preparation (mixture) using IL-2 and liposome suspension is expected to have potential for increasing therapeutic efficacy against hepatic metastases.

Preclinical combination chemotherapy of nedaplatin with gemcitabine against gemcitabine-refractory human lung cancer

The antitumor efficacy of the combination of nedaplatin (NDP) with gemcitabine (GEM) was evaluated against Ma44/GEM, a GEM-refractory subline of Ma44 human lung cancer, which was established by serial in vitro passage of Ma44 cells in the presence of GEM.Ma44/GEM showed less sensitivity to GEM and cytosine arabinoside with resistance factors of 7.7 and 8.3, respectively, but not to Taxol, Irinotecan, Mitomycin C and NDP. Flow cytometry analysis demonstrated that membrane transporter molecules such as multidrug-resistant, multidrug-resistant related protein or lung resistant protein were not induced in Ma44/GEM cells. In vivo experiments confirmed the less sensitivity of Ma44/GEM to GEM. The resistant factor of Ma44/GEM to GEM in vivo was estimated to be 6.7 in terms of ED(50).MA44/GEM-implanted athymic mice were treated with GEM i.v. once followed by i.v. injection of NDP at an interval of approximately 30 min. The mice were treated again with GEM after 3 or 4 days. The combined dosing of NDP with GEM resulted in synergistically enhanced inhibition of tumor growth against Ma44/GEM. The antitumor efficacy of the combination of NDP and GEM was superior to the best effect of either monotherapy. These results demonstrate the effectiveness of the combination of NDP with GEM against the GEM-refractory human lung cancer model.

Sequence-dependent antitumor efficacy of combination chemotherapy with nedaplatin, a newly developed platinum, and paclitaxel

We evaluated the sequence dependency of antitumor efficacy and toxicity in combination therapy of nedaplatin (NDP) with paclitaxel (TXL) against Lewis lung carcinoma. The sequential administration of NDP prior to TXL (NT therapy) resulted in severe body weight loss followed by frequent toxic death of mice. In contrast, the sequential dosing of TXL prior to NDP (TN therapy) resulted in synergistically enhanced inhibition of tumor growth with less toxicity compared with the NT therapy. Comparing the antitumor activity of NDP plus TXL with that of cisplatin (CDDP) plus TXL or carboplatin (CBDCA) plus TXL, the combination effect of NDP plus TXL was significantly higher than that of CDDP plus TXL or CBDCA plus TXL. These results indicate that the TN therapy may have significant potential in clinical use.

Improved in vivo antitumor efficacy and reduced systemic toxicity of carboxymethylpullulan-peptide-doxorubicin conjugates

The antitumor efficacy of the conjugate of doxorubicin (DXR) and carboxymethylpullulan (CMPul) with Phe-Gly spacer (CMPul-FG-DXR) was evaluated using murine tumor models and compared with that of DXR. The conjugate exhibited higher antitumor efficacy against Lewis lung carcinoma than DXR. Complete tumor regression followed by long-term tumor-free survival was frequently observed when CMPul-FG-DXR was administered i.v. three times at a dose equivalent to 10 mg / kg of DXR. The superior survival as well as anti-metastatic effect of CMPul-FG-DXR in comparison with DXR was also demonstrated with the M5076 murine reticulosarcoma model. Body weight loss in mice treated with the conjugate was less than that in the DXR-treated group, indicating lower systemic toxicity of CMPul-FG-DXR. Simply mixing CMPul with DXR did not enhance the antitumor activity of DXR, showing that the conjugation of DXR with CMPul is necessary for improved antitumor activity. However, no enhanced antitumor efficacy of the conjugates was observed against a non-solid tumor model such as P388 leukemia. In summary, improved antitumor efficacy with reduced systemic toxicity of CMPul-FG-DXR was demonstrated in the present study. CMPul-FG-DXR may be useful as a cancer chemotherapy agent against solid tumors and metastases.

Combination chemotherapy with nedaplatin and cyclophosphamide in human ovarian cancer model

The antitumor efficacy of the combination of nedaplatin (NDP) with cyclophosphamide (CPM) was evaluated using human ovarian cancer models. Since NDP has been found to have greater antitumor activity and lower nephrotoxicity than cisplatin (CDDP), we also compared the antitumor activity of NDP plus CPM with that of CDDP plus CPM. Increasing doses of NDP (16.5, 33 and 66 mg/kg as a total dose) and a fixed amount of CPM (174 or 348 mg/kg as a total dose) were injected three times at intervals of 7 days via the tail vein into mice implanted with RMUG-S, OC9-JCK or KF-28 human ovarian cancer. Simultaneous administration of NDP with CPM resulted in markedly enhanced inhibition of tumor growth for all cancers tested. The growth inhibition and survival effect of the combination therapy of NDP with CPM against KF-28 and OC9-JCK were as potent as those of CDDP plus CPM. Neither increased hematotoxicity nor a significant difference in maximum concentration, half time or area under the curve of platinum or CPM in plasma between the single and combined treatment was found. These results suggest that the combination of NDP with CPM may be clinically effective.