Enhanced antitumor efficacy of a combination of CPT-11, a new derivative of camptothecin, and cisplatin against human lung tumor xenografts

Establishment of preclinical chemotherapy models for gastroenteropancreatic neuroendocrine carcinoma

Gastroenteropancreatic neuroendocrine carcinoma (GEP-NEC) is a rare and devastating malignancy, and preclinical studies are needed to evaluate potential therapeutic regimens. Here, we examined the antitumor effects of cisplatin (CDDP), etoposide (ETP) and irinotecan (CPT-11) and their combinations on GEP-NEC using three small-cell GEP-NEC cell lines (pancreatic NEC, A99; esophageal NEC, TYUC-1; duodenum NEC, TCC-NECT-2). In vitro studies were conducted using cell viability assays. In vivo experiments were conducted in mice inoculated with A99 or TCC-NECT-2 and treated with no agent, CDDP, CDDP+ETP (EP) or CDDP+CPT-11 (IP). TYUC-1 was the most susceptible to all agents, whereas A99 was refractory. Classical isobolograms showed synergism in both the EP and IP combinations for the three cell lines. In the TCC-NECT-2 mouse model, the IP regimen showed a significant antitumor effect, and CDDP alone showed a marginal effect compared to the control. In contrast, no effect was detected in the A99 model, probably because A99 was established from a metastatic tumor after chemotherapy with EP. Gene expression analysis of the ATP-binding cassette transporters revealed that ATP binding cassette subfamily B member1 (ABCB1) was conspicuously expressed in A99, and ABCB1 and ATP binding cassette subfamily C member2 (ABCC2) were deficient in TYUC-1, which might explain a part of different CDDP susceptibilities between cell lines. These preclinical models indicate that CDDP is a key agent, and IP regimen might be a reasonable option, although its efficacy is moderate. Our data on the platinum-based regimen will be useful as reference information in developing new agents for GEP-NEC.

Phase II study of nedaplatin and irinotecan as adjuvant chemotherapy for completely resected non-small cell lung cancer

INTRODUCTION

Cisplatin-based chemotherapy is the standard adjuvant therapy for patients with completely resected stage II or III non-small cell lung cancer (NSCLC). However, the completion rate of four cycles of cisplatin-based chemotherapy is about 50%. This phase II study was conducted to evaluate the tolerability and efficacy of nedaplatin and irinotecan as adjuvant chemotherapy.

METHODS

Patients with pathological stage II or III NSCLC who underwent complete resection were enrolled. Treatment consisted of four cycles of nedaplatin (50 mg/m²) and irinotecan (50 mg/m²) on days 1 and 8 every 4 weeks. The primary end-point was the completion rate of four cycles of nedaplatin and irinotecan.

RESULTS

Between January 2009 and March 2012, 39 patients (23 males and 16 females; median age 68 years) were registered. Overall, 36/39 (92.3%) patients completed four cycles. The median clinical follow-up time was 56 months (range 11-88 months). There were no differences in adverse events between patients with UGT1A1 polymorphisms and patients with wild-type UGT1A1. The median disease-free survival (DFS) was 49.4 months (95% confidence interval 14.2-84.5 months). Median overall survival (OS) was not reached. There were no treatment-related deaths, and adverse events were acceptable. The 5-year DFS and OS rates were 43.1 and 69.8%, respectively.

CONCLUSION

Nedaplatin and irinotecan is a tolerable regimen for adjuvant chemotherapy, and was associated with adequate 5-year DFS and OS rates.

Drug ratio-dependent antitumor activity of irinotecan and cisplatin combinations in vitro and in vivo

Irinotecan and cisplatin are two established anticancer drugs, which together constitute an effective combination for treating small-cell lung cancer. We investigated whether the efficacy of this combination could be improved by controlling drug ratios following in vivo administration. Irinotecan and cisplatin combinations were evaluated systematically for drug ratio-dependent synergy in vitro using a panel of 20 tumor cell lines. In vitro screening informatics on drug ratio-dependent cytotoxicity identified a consistently antagonistic region between irinotecan/cisplatin molar ratios of 1:2 to 4:1, which was bordered by two synergistic regions. Liposomal co-formulations of these two agents were developed that exhibited plasma drug half-lives of approximately 6 hours and maintained a fixed drug ratio for more than 24 hours. Drug ratio-dependent antitumor activity was shown in vivo for these liposome formulations, and irinotecan/cisplatin ratios between 5:1 and 10:1 were identified as therapeutically optimal. The relationship between irinotecan/cisplatin ratio and in vivo efficacy was consistent with in vitro drug ratio dependency results. Superior antitumor activity was observed for the liposome-encapsulated 7:1 molar ratio of irinotecan/cisplatin (designated CPX-571) compared with the free-drug cocktail in all models tested. Further efficacy studies in a range of human tumor xenografts, including an irinotecan-resistant model, showed that both liposomal agents contributed to the overall efficacy in a manner consistent with in vivo synergy. These results show the ability of drug delivery technology to enhance the therapeutic activity of irinotecan/cisplatin combination treatment by maintaining synergistic ratios in vivo. CPX-571, a fixed-ratio formulation of irinotecan and cisplatin, is a promising candidate for clinical development.

Phase II trial of irinotecan plus cisplatin in patients with recurrent or metastatic squamous carcinoma of the head and neck

BACKGROUND

Patients with recurrent or metastatic HNC have a poor response and survival with currently available chemotherapy agents. Thus, new agents are needed. The authors report the results of a phase II trial of irinotecan and cisplatin in patients with metastatic or recurrent HNC.

METHODS

Patients were treated with irinotecan 65 mg/m2 IV over 90 minutes and cisplatin 30 mg/m2 were administered intravenously weekly for four weeks, followed by a two week rest. However, after 17 patients were treated with weekly irinotecan at a dose of 65 mg/m2, toxicity analysis demonstrated the poor tolerance of that dose in this patient population. Thus, the protocol was amended, and irinotecan was dose reduced to a starting dose of 50 mg/m2. Twenty-three additional patients were treated with this dose.

RESULTS

Forty patients were enrolled on study between February 2002 and April 2006, 17 patients at the first dose level and 23 patients at the amended dose level. Overall, 12 of 17 patients (71%) treated with irinotecan 65 mg/m2 experienced clinically significant grade 3 or 4 toxicity. Twelve patients required dose reductions. Toxicity was reduced but 17% of patients still experienced grade 3 or 4 toxicity on the lower irinotecan dose. The response rate was 35% for patients treated at irinotecan 65 mg/m2 and 22% for patients treated at 50 mg/m2. No complete responses were noted.

CONCLUSIONS

The combination of irinotecan and cisplatin is efficacious in a poor prognosis group of patients but toxicity is substantial.

Phase I Study of Radical Thoracic Radiation, Weekly Irinotecan, and Cisplatin in Locally Advanced Non-small Cell Lung Carcinoma

BACKGROUND

Irinotecan and cisplatin individually are active in non-small cell lung carcinoma (NSCLC). Each is synergistic with radiation. Dosages of 65 mg/m2 of irinotecan and 30 mg/m2 of cisplatin Q weekly times four every 6 weeks yielded a 36% response rate and median survival of 11.6 months in advanced NSCLC (Jagasia et al.; Clinical Cancer Research 7: 68, 2001). A weekly schedule for each agent (versus less frequent doses) limits toxicity and increases the opportunity for radiosensitization.

MATERIALS AND METHODS

We initiated a phase I study of weekly irinotecan and cisplatin during radical thoracic radiation (TRT). Cisplatin was fixed at 25 mg/m2 Q weekly times seven. Irinotecan was dosed initially at 30 mg/m2 per week for 7 weeks and was increased by 10 mg/m2 per week in three- to six-patient cohorts. TRT was administered in 34 single daily fractions to 63 Gy. Eligibility stipulated locally advanced NSCLC; Eastern Cooperative Oncology Group performance status 0 to 1; < or = 10% unintended weight loss; and adequate physiologic indices.

RESULTS

Fifteen patients were accrued: nine were stage IIIB, five were stage IIIA, and one had isolated mediastinal node recurrence after prior surgery. Median age was 65 years (range, 47-77). Seven patients received irinotecan at a dose of 30 mg/m2 per week; (dose level 1). Seven other patients received irinotecan at a dose of 40 mg/m2 per week; (dose level 2). The one other patient received irinotecan in doses of 50 mg/m2 per week; (dose level 3). Neutropenic fever occurred in one patient each at dose levels 1 and 2. Grade 4 neutropenia occurred in three patients at each dose level. Transient grade 3 diarrhea occurred in one patient at dose level 1. Esophagitis of grade 3 or higher occurred in one patient each at dose levels 2 and 3. There was one late grade 3 pneumonitis at dose level 2. Delivered irinotecan dose intensity for dose level 1 was 27 mg/m2 per week; for dose level 2, it was 31.4 mg/m2 per week. Nine of 13 evaluable patients (69%) responded. At median potential follow-up of 5 years, 14 have progressed, and 11 have died. Projected median survival is 28 months; one patient who was treated for mediastinal node recurrence remains free from progression at 6 years.

CONCLUSION

Weekly irinotecan and cisplatin combined with radical TRT (63 Gy) is active and fairly well tolerated in locally advanced NSCLC. In combination with fixed-dose cisplatin (25 mg/m2 per week), the maximum-tolerated dose of irinotecan is 30 mg/m2 per week.

Liposomalization of SN-38 as active metabolite of CPT-11

Although many drugs have been developed for the treatment of disease, some drugs have complications such as adverse effects, and antitumor agents should target tumors or cells more selectively. It is therefore necessary to develop drug delivery systems, and liposomes are reportedly useful as an effective drug carrier. An antitumor agent, CPT-11, inhibits DNA synthesis by the inhibition of topoisomerase1 and has a strong antitumor activity. SN-38 is converted from CPT-11 as an active metabolite by carboxylesterase in the liver. As SN-38 is insoluble, it has not been applied at the clinical stage as an injection. It is expected that SN-38 liposomalization may increase its usefulness in cancer chemotherapy. Our purpose is to have a clinical application of SN-38 by a novel method of liposomalization to expand the application for the other insolubility drugs. As SN-38 is hydrophobic, SN-38-trapped liposome preparation was attempted using the Bangham method, which is effective for general preparation. However, a high ratio of SN-38 trapped in liposome was not achieved, and this was not improved by the freezing-thawing method or the freeze-drying method. On the other hand, the ratio of SN-38 trapped in liposome by the modified remote loading method was about 4 times that by the Bangham method, and the ratio by the film loading method, novel method of liposomal preparation, reached 2 times and 8 times that by the modified remote loading method and Bangham method, respectively, showing a remarkable increase. In conclusion, it was suggested that the preparation of SN-38 liposome using the film loading method effectively entraps SN-38. Thus, it is expected that SN-38 liposome can be applied as an injection. This preparation method is useful if application is possible in the other insolubility drugs.

Second-line treatment with irinotecan plus cisplatin vs cisplatin of patients with advanced non-small-cell lung cancer pretreated with taxanes and gemcitabine: a multicenter randomised phase II study

The aim of this study was to compare the irinotecan/cisplatin regimen with cisplatin as second-line chemotherapy in patients with advanced non-small-cell lung cancer (NSCLC) pretreated with a taxane/gemcitabine regimen. Patients (n = 147) with stage IV NSCLC pretreated with a taxane/gemcitabine regimen were randomly assigned to receive either irinotecan (110 mg m(-2), day 1 and 100 mg m(-2), day 8) and cisplatin (80 mg m(-2), day 8) (IC; n = 74) or CDDP (80 mg m(-2), day 1) (C; n = 73) every 3 weeks. Patients treated with IC and C had a median survival of 7.8 and 8.8 months, respectively (P = 0.933). The 1-year survival rate was 34.3% for IC-treated patients and 31.7% for C-treated patients. Cox's regression analysis revealed that response to treatment (hazard ratio (HR) = 2.787; 95% confidence interval (CI): 1.1578-4.922) and performance status (HR = 1.865; 95% CI: 1.199-2.872) was independent prognostic factors for survival. Overall response rate was 22.5% (95% CI: 12.8-32.2%) for IC-treated patients and 7.0% (95% CI: 1.15-13.6%) for C-treated patients (P = 0.012); tumour growth control (partial remission (PR) + stable disease (SD)) was observed in 26 (38%) IC and 25 (36%) C patients (P = 0.878). There was no difference in terms of quality of life between the two chemotherapy arms. The incidence of febrile neutropenia, grade 3 and 4 neutropenia and grade 3 and 4 diarrhoea was significantly higher in the IC- than the C-treated patients. Other toxicities were mild. There were no treatment-related deaths in either arm. The IC regimen did not confer a survival benefit compared with C as second-line treatment of patients with advanced NSCLC pretreated with a taxane/gemcitabine regimen, despite its better efficacy in terms of response rate.

Irinotecan in small-cell lung cancer: current data

Irinotecan, a new topoisomerase I inhibitor, has significant activity in the treatment of untreated and previously treated patients with small-cell lung cancer (SCLC). In combination with cisplatin, a Japanese randomized trial showed a statistically significant survival advantage over cisplatin/etoposide in chemotherapy- naive patients with extensive-stage disease. This represents the first major advance in the treatment of extensive-stage SCLC in 20 years. Randomized trials in the United States are underway to confirm these impressive results. Meanwhile, trials incorporating irinotecan and cisplatin into treatment regimens for limited-stage disease are being conducted. Furthermore, irinotecan-containing regimens with other agents such as carboplatin, etoposide, and paclitaxel in first- or second-line therapies for SCLC are being evaluated. Preliminary results are encouraging. This article will highlight the exciting results achieved with irinotecan in SCLC and discuss its promising future in this disease.

Results of recent Japanese clinical trials in lung cancer

Lung cancer is one of the most common cancers and its associated mortality continues to rise in Japan. The lung cancer cure rate is still very low. To improve the survival of patients with lung cancer, well-designed and well-conducted clinical trials are essential. Several Japanese study groups have been conducting clinical trials for lung cancer. However, most randomized phase III studies were conducted by the Japan Clinical Oncology Group (JCOG), the West Japan Thoracic Oncology Group, and pharmaceutical companies supporting temporarily organized groups. In the past decade, the quality of Japanese clinical studies has improved tremendously. The results of JCOG9511 have recently been reported; and demonstrated that treatment with irinotecan/cisplatin significantly improved patient survival in extensive-stage small-cell lung cancer over standard etoposide/cisplatin, with less myelosuppression. A randomized phase II study using gefitinib (ZD1839; Iressa) for non-small-cell lung cancer was also recently reported and showed a high response rate against platinum-refractory lung cancer, especially in adenocarcinoma and in females. A 4-arm multicenter, randomized cooperative phase III study for advanced non-small-cell lung cancer is currently underway.

Phase II study of exatecan mesylate (DX-8951f) as first line therapy for advanced non-small cell lung cancer

BACKGROUND

Exatecan mesylate (DX-8951f) is a water soluble analogue of camptothecin that inhibits topoisomerase I. This multi-centre phase II study evaluated the activity of single agent exatecan in previously untreated patients with advanced non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

Patients with histologically or cytologically proven stage IIIb or IV NSCLC were treated with exatecan 0.5 mg/m(2) per day by 30 min intra-venous (i.v.) infusion for 5 days every 3 weeks to a maximum of six cycles. Measurable disease was documented prior to study entry and patients were re-staged every two cycles. Pharmacokinetic (PK) sampling was performed during cycle one.

RESULTS

39 patients (32 patients ECOG performance status 0 or 1; 29 male and ten female; mean age 63 years) were entered into the study. Thirty-three completed at least two cycles of exatecan and 11 completed six cycles. Two patients (5.1%, 95% C.I. 0.3-21.3%) had a partial response, 7 (18.0%) minor response and 8 (20.5%) stable disease. Median time to tumour progression (TTP) was 88 days and median overall survival 262 days. The main toxicity was reversible neutropenia. PK analysis of exatecan demonstrated a mean clearance of 2.28 l/h per m(2), volume of distribution 18.2 l/m(2) and mean elimination half-life of 7.9 h.

CONCLUSIONS

Exatecan mesylate has limited activity in advanced NSCLC and is not recommended for further evaluation as a single agent in this tumour type. PK data from this trial supports results established in phase I studies.

Phase I Study of Weekly Alternating Therapy with Irinotecan/Cisplatin and Etoposide/Cisplatin for Patients with Small-Cell Lung Cancer

The combination of IP (irinotecan/cisplatin) has been shown to confer a survival benefit compared with EP (etoposide/cisplatin) in patients with extensive-stage small-cell lung cancer (SCLC). Based on this and potential synergy from sequential inhibition of topoisomerases I and II, we conducted a phase I study to assess the feasibility of weekly therapy alternating IP and EP. The doses of EP were fixed (etoposide 60 mg/m2 on days 1-3 and cisplatin 20 mg/m2 on day 1). The dose of irinotecan was escalated in serial cohorts at 3 dose levels: 80, 90, and 100 mg/m2 on day 1. Granulocyte colony-stimulating factor was given on days 2-5 and days 4-7 after IP and EP, respectively. Patients with limited-stage SCLC received chemoradiation during weeks 4-6 with etoposide 120 mg/m2 on days 1-3, cisplatin 60 mg/m2 on day 1, and thoracic radiation 1.5 Gy twice daily in 30 fractions. Patients received 12 weeks of therapy. To evaluate dose escalation in subsequent cohorts, dose-limiting toxicity (DLT) was initially assessed during weeks 1-3 of treatment. Characteristics of the 18 patients accrued are as follows: performance status 0/1, n = 9; female sex, n = 9; extended-stage SCLC, n = 16; and median age, 53 years. Four patients treated at irinotecan dose level 1 (80 mg/m2), 6 patients at dose level 2 (90 mg/m2), and 6 patients at dose level 3 (100 mg/m2) did not experience DLT in weeks 1-4 and completed therapy without major incident. The only 2 patients to experience DLT during weeks 1-4 were treated at dose level 2. Both were hospitalized during week 4 and subsequently died. However, patients had already been accrued at dose level 3 and tolerated therapy well. Therefore, the trial design was modified to assess DLT during weeks 1-4, and additional patients were cautiously added to the dose level 2 and 3 cohorts. Analysis of summary toxicity data resulted in a recommendation that dose level 3 be used in phase II based on the probability of DLT of 16% (95% CI, 3%-29%). Responses in 16 evaluable patients include complete response in 1 patient, partial response in 14 patients, and minor response in 1 patient. With the exception of the 2 deaths, the therapy was well tolerated and active. Phase II evaluation of the regimen in patients with extensive-stage SCLC is ongoing.

Randomised phase III trial of irinotecan combined with cisplatin for advanced non-small-cell lung cancer

To determine a standard combination chemotherapy for patients with advanced non-small-cell lung cancer (NSCLC), we conducted a phase III trial of irinotecan (CPT-11) to test the hypotheses that CPT-11+cisplatin is superior to cisplatin+vindesine and that CPT-11 monotherapy is not inferior to cisplatin+vindesine. A total of 398 patients with previously untreated NSCLC were randomised to receive cisplatin+CPT-11 (CPT-P), cisplatin+vindesine (VDS-P) or CPT-11 alone (CPT). In the CPT-P arm, CPT-11 60 mg m(-2) was administered on days 1, 8 and 15, and cisplatin 80 mg m(-2) was administered on day 1. In the VDS-P arm, cisplatin 80 mg m(-2) was administered on day 1, and vindesine 3 mg m(-2) was administered on days 1, 8 and 15. In the CPT arm, CPT-11 100 mg m(-2) was administered on days 1, 8 and 15. The median survival time was 50.0 weeks for patients on CPT-P, 45.6 weeks for those on VDS-P and 46.0 weeks for those on CPT (P=0.115, CPT-P vs VDS-P; P=0.089, CPT vs VDS-P), and the hazard ratio was 0.85 (95% confidence interval (CI): 0.65-1.11) for CPT-P vs VDS-P and 0.83 (0.64-1.09) for CPT vs VDS-P. The response rate was 43.7% for patients on CPT-P, 31.7% for those on VDS-P and 20.5% for those on CPT. Major adverse reactions were grade 4 neutropenia observed in 37, 54 and 8% of the patients on CPT-P, VDS-P and CPT, respectively; and grades 3 and 4 diarrhoea observed in 12, 3 and 15% of the patients, respectively. CPT-P therapy produces comparable survival to VDS-P in patients with advanced NSCLC. CPT-11 monotherapy is not inferior to VDS-P in terms of survival. The CPT-11-containing regimen is one of the most efficacious and well tolerated in the treatment of advanced NSCLC.

Chemotherapy for small cell lung cancer

There were approximately 42,000 new cases of small cell lung cancer (SCLC) in 2002. Despite its initial sensitivity to chemotherapy, only 10% of all SCLC patients will have significant long-term survival. Studies have yet to show significant survival advantages for maintenance chemotherapy, and it appears that four to six cycles of chemotherapy is as effective as longer durations. As yet, there is no defined role for dose escalation in the treatment of SCLC. No one chemotherapy combination has exhibited a definitive survival advantage in extensive disease, although it appears that single-agent oral etoposide may be inferior to combination intravenous chemotherapy. In limited disease, however, cisplatin plus etoposide alone or in alternation with cyclophosphamide/doxorubicin/vincristine is superior to other approaches. There are several new agents with significant activity in SCLC awaiting further study.

Irinotecan plus cisplatin has substantial antitumor effect as salvage chemotherapy against germ cell tumors

BACKGROUND

Only 20-30% of patients with refractory or recurrent germ cell tumors (GCT) are cured by salvage chemotherapy. Irinotecan, a new derivative of camptothecin, is a potent anticancer agent against a variety of solid cancers. The current pilot study investigated the efficacy of salvage chemotherapy with irinotecan in combination with cisplatin (CDDP) or nedaplatin (NDP), a derivative of cisplatin, for GCT.

METHODS

The combination chemotherapy consisted of 100-150 mg/m(2) irinotecan on Days 1 and 15 or 200-300 mg/m(2) on Day 1 in combination with 20 mg/m(2) CDDP on Days 1-5 or 100 mg/m(2) NDP on Day 1 every 4 weeks. Patients with refractory GCT, ranging in age from 17 to 43 years, received 2-11 cycles of the combination chemotherapy. The median duration of follow-up is 28 months (8-140 months).

RESULTS

Twenty patients entered this study, 18 of whom were assessed for response and toxicity. The response rate was 50 % (two complete responses and seven partial responses). Nine patients remain alive without disease. However, six patients died of the disease and one patient died of a brain glioma. The 5-year survival rate was approximately 53%. Myelosuppression was the major toxicity, but was manageable.

CONCLUSIONS

This pilot study demonstrates that the chemotherapy with irinotecan in combination with CDDP or NDP showed significant anticancer activity for patients with refractory GCT, without serious side effects. Although this study comprised only a few patients, these findings suggest that the combination chemotherapy may be one of the options of salvage chemotherapy for patients with refractory GCT.

Intermittent, repetitive administrations of irinotecan (CPT-11) reduces its side-effects

To reduce the side-effects of irinotecan (CPT-11) while maintaining its anti-cancer effects against recurrent ovarian carcinomas, we devised a novel administration schedule for CPT-11 single chemotherapy. It consisted of an initial dose of 70 mg/m2, followed by increasing the dose to 100 mg/m2 every 10 days (three times per month) for 9 cycles. Nineteen patients with refractory or recurrent ovarian carcinomas were treated. In comparison with a late phase II study of single CPT-11 chemotherapy in Japan (100 mg/m2 every 7 days; four times per month), the number of patients who suffered from leukocytopenia and diarrhea higher than grade 3 was significantly lower with our new method (36.8 versus 57.1%; P < 0.01 and 0 versus 19.2%; P < 0.001, respectively). The total response rate was 26% (5/19). This rate was almost equal to a late phase II study. We suggest that our new protocol of single CPT-11 administration should be available clinically to all patients for reducing the side-effects while maintaining its anti-cancer effects. CPT-11 is useful in patients with refractory ovarian carcinomas as a second- or third-line chemotherapy.

Weekly chemotherapy with carboplatin, docetaxel and irinotecan in advanced non-small-cell-lung cancer: a phase II study

The aim of this study was to evaluate the efficacy and tolerability of carboplatin, docetaxel plus irinotecan given weekly to patients with locally advanced or metastatic non-small cell lung cancer (NSCLC). 50 patients with previously untreated NSCLC (stage IIIB 10; stage IV 40; 44% squamous cell carcinoma; median Eastern Cooperative Oncology Group (ECOG) status 1) received intravenous (i.v.) carboplatin area under the curve (AUC) 2, docetaxel 20 mg/m(2) and irinotecan 60 mg/m(2) on days 1, 8 and 15, repeated every 5 weeks. Prophylactic granulocyte colony-stimulating factor (G-CSF) 150 ug/m(2) was given from days 3 to 6 and 10 to 13. Response was evaluated every two cycles. Four complete responses (8%) and 24 (48%) partial responses were observed, giving an overall intent-to-treat response rate of 56%. 8 patients (16%) achieved stable disease and 14 (28%) progressed. The median time to progression (TTP) was 9.6 months (range 2.5-21.8 months), median survival was 14.8 months (range 0.3-27+ months) and actuarial 1-year survival time was 55%. Grade 3/4 anaemia and thrombocytopenia occurred in 18 and 22% of patients, respectively; 13 patients (26%) developed grade 3/4 neutropenia and 7 (14%) had neutropenic fever that required hospitalisation, but was successfully treated with antibiotics and G-CSF support. One patient developed a severe allergy during docetaxel administration and was withdrawn. Other grade 3/4 adverse events included diarrhoea (n=14; 3 required hospitalisation), nausea/vomiting (n=9), neurotoxicity (n=5) and fatigue (n=5). 6 patients required a dose reduction. This combination of i.v. carboplatin AUC 2, docetaxel 20 mg/m(2) and irinotecan 60 mg/m(2) given weekly is highly effective in the treatment of chemotherapy-naïve advanced NSCLC. Toxicity was moderate, but manageable.

Cisplatin and irinotecan (CPT-11) as second-line treatment in patients with advanced non-small cell lung cancer

Irinotecan (CPT-11) and cisplatin (P) are both active agents against non-small cell lung cancer (NSCLC), and their combination has shown in vitro an additive or synergistic effect. We conducted a phase II study to determine the toxicity and efficacy of their combination as salvage treatment in patients with advanced NSCLC progressing after a docetaxel-based front line regimen. Forty-four patients with histologically confirmed NSCLC were enrolled. The patients' median age was 60.5 years; 39 patients (87%) were male; 38 (86%) had stage IV disease; and 32 (73%) had a performance status (WHO) 0-1. CPT-11 was administered as a 60 min i.v. infusion at a dose of 100 mg/m(2) on day 1 and 110 mg/m(2) on day 8; P was administered at a dose of 80 mg/m(2) on day 8 after CPT-11 administration. Treatment was repeated every 3 weeks. A total of 159 chemotherapy cycles was administered. In an intention-to-treat analysis, nine patients (22; 95% CI: 9.28-34.62%) achieved a partial response (PR), 8 (20%) had stable disease (SD), and 24 (58%) progressive disease (PD). The median duration of response was 4 months, the median time-to-progression (TTP) 8 months, and the median survival for the entire group 8 months. Grade 3-4 neutropenia was observed in 20 (46%) patients and in four cases this was febrile, requiring patient's hospitalisation. Grade 3-4 thrombocytopenia occurred in four (9%) patients. Grade 3-4 diarrhoea was seen in 12 (27%) patients and three of them required hospitalisation. Grade 2-3 neurotoxicity was observed in two (4%) patients and grade 2-3 fatigue in 14 (32%). Other toxicity was mild and no treatment-related death was reported. The combination of CPT-11 and P is a safe, well-tolerated, and active regimen for the treatment of patients with advanced NSCLC previously treated with a docetaxel-based front-line regimen.

Fractionated administration of irinotecan and cisplatin for treatment of non-small-cell lung cancer: a phase II study of Okayama Lung Cancer Study Group

A phase II study of fractionated administration of irinotecan (CPT-11) and cisplatin (CDDP) in patients with non-small-cell lung cancer (NSCLC) was conducted. Between January 1996 and January 1998, 44 previously untreated patients with stage IIIB or IV NSCLC were enrolled. CDDP at a dose of 60 mg x m(-2) was given first and followed by CPT-11 at a dose of 50 mg x m(-2). Both drugs were given by 1-hour infusion on days 1 and 8, and repeated every 4 weeks up to 4 cycles. 42 patients were evaluated for response and 44 for survival and toxicity. 20 patients (48%: 95% confidence interval 32-63%) achieved an objective response. The median duration of responses was 8 months, and the median survival time and the 1-year survival rate were 12.5 months and 56.8%, respectively. Major toxicities were neutropenia and diarrhoea. Grade 3 or 4 neutropenia occurred in 70.5% of the patients and one patient died of sepsis. Grade 3 or 4 diarrhoea was experienced in 25.0%, but manageable by conventional therapy. In conclusion, fractionated administration of CPT-11 and CDDP was highly effective for advanced NSCLC with manageable toxicities.

Topoisomerase I Inhibitors in the Combined Modality Therapy of Lung Cancer

Locally advanced non small-cell lung cancer (NSCLC) represents 30%-40% of all pulmonary malignancies. Despite the fact that the disease is confined to the chest, most patients will eventually succumb to their dis-ease. Therefore, the management of NSCLC is undergoing rapid evolution with hope of improving overall survival. The arrival of a new generation of chemotherapeutic agents, including the taxanes, gemcitabine, and topoisomerase inhibitors such as irinotecan and topotecan, offers the hope of real advances against this malignancy. Irinotecan and topotecan are camptothecin derivatives that are felt to exert their cytotoxic effects by targeting topoisomerase I. It is believed that topoisomerase I inhibitors stabilize a DNA-topoisomerase I cleavable complex, and interactions between this complex and the replication machinery may lead to cell death. There is a significant volume of in vitro and in vivo data demonstrating that these topoisomerase I inhibitors also act as radiosensitizers. Early clinical data with topotecan suggests that it is a more active agent in small-cell lung cancer than it is in NSCLC despite a common mechanism of action with irinotecan. With the increasing data that exist on the improved outcome with concurrent chemoradiation treatment for malignancies including lung cancer and head and neck cancers, there is an impetus to pursue the addition of other drugs that can radiosensitize tumors and further improve local control. Irinotecan is undergoing early clinical trials in the combined modality setting in several different disease sites. This paper will review the in vitro and in vivo data on the ability of irinotecan and topotecan to render tumors more susceptible to ionizing radiation. It will then focus on the experience with both drugs and thoracic radiation in the treatment of NSCLC, in which irinotecan has yielded acceptable toxicity results and response rates in excess of 60% in early trials. It is hoped that newer treatment strategies, such as the combination of radiation and topoisomerase I inhibitors in lung cancer, will have a significant impact on cure rates in the future.

Topoisomerase I targeting agents in small-cell lung cancer

The topoisomerase I inhibitors such as irinotecan and topotecan are active agents against small-cell lung cancer that are effective in treating not only chemotherapy-naïve tumors but also progressed-stage tumors after treatment with cisplatin-based regimens, because their mechanism of antitumor activity differs from that of the agents included in standard chemotherapy for small-cell lung cancer. Etoposide plus cisplatin or etoposide plus cisplatin alternating with cyclophosphamide, doxorubicin, and vincristine is considered the standard regimen for small-cell lung cancer. No new standard combination chemotherapy for small-cell lung cancer has been developed over the past decade. Irinotecan with cisplatin is now established as a new standard chemotherapy for extensive-stage small-cell lung cancer based on the results of the Japan Clinical Oncology Group trial. Of course, confirmation through phase III studies will be extremely important. The Japan Clinical Oncology Group is intensively investigating other irinotecan-containing regimens and the incorporation of irinotecan into treatment of patients with limited-stage small-cell lung cancer.

A dose-escalation study of irinotecan (CPT-11) in combination with cisplatin in patients with advanced non-small cell lung cancer previously treated with a docetaxel-based front line chemotherapy

PURPOSE

A phase I study was conducted to determine the maximum-tolerated dose (MTD) and the dose-limiting toxicities (DLTs) of a CPT-11 plus cisplatin combination as salvage treatment in patients with advanced non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

Twenty-two patients with histologically confirmed NSCLC, who had failed taxotere-based front-line chemotherapy, were enrolled. The patients' median age was 61 years, 19 (86%) were male, and 17 (77%) had a performance status (World Health Organization (WHO)) 0-1. CPT-11 was administered as a 60-min i.v. infusion at a fixed dose of 100 mg/m2 on day 1 and at escalating doses on day 8, starting from 100 mg/m2 with increments of 10 mg/m2; cisplatin was administered at a fixed dose of 80 mg/m2 on day 8, 2 h after CPT-11 administration. Treatment was repeated every 3 weeks.

RESULTS

At the dose of CPT-11 120 mg/m2, three out of four enrolled patients presented DLTs (grade 4 neutropenia, febrile neutropenia and delayed diarrhea); the addition of G-CSF at this level did not permit further dose-escalation. Grade 3/4 neutropenia was observed in 12 (18%) cycles, febrile neutropenia in four (6%), and grade 3/4 thrombocytopenia in four (6%). Grade 3/4 diarrhea was seen in six (29%) patients, and grade 2/3 nausea and vomiting in 12 (57%). Neurotoxicity grade 2 was observed in six (29%) patients and grade 3 in one (5%). Other toxicities were mild. The MTD was CPT-11 100 mg/m2 on day 1 and 110 mg/m2 on day 8 in combination with CDDP 80 mg/m2 on day 8. Among 12 patients evaluable for response, partial response was achieved in two (16.7%) patients and stable disease in five (41.7%).

CONCLUSION

The combination of CPT-11 and cisplatin has substantial but manageable toxicity and marginal activity as salvage treatment of patients with NSCLC who have failed taxotere-based front-line chemotherapy: further investigation is warranted to define its precise role in the second-line setting.

Novel combination chemotherapy in the treatment of non-small cell lung cancer

Treatment of patients with advanced non-small cell lung cancer (NSCLC) remains a vexing problem and long-term survival beyond 5 years is extremely rare. Five new agents, paclitaxel, docetaxel, vinorelbine, gemcitabine and irinotecan, have been introduced for the treatment of NSCLC and investigated extensively both preclinically and clinically. Monotherapy with one of these agents has produced survival benefits over the best supportive care in Phase III studies. Combination chemotherapy with a new agent and platinum produced a higher response rate than conventional cisplatin-based chemotherapy and improved survival was observed in some randomised trials. There was little difference in efficacy and toxicity between the chemotherapeutic regimens with a new agent and a platinum in Phase III trials, suggesting the clinical utility of these regimens is similar. Many trials have focused on regimens containing two new agents, with or without platinum. Preliminary results of Phase III trials of three drug combinations versus two drug combinations suggested the former to be more promising, in terms of response rates and survival. Whether the era of platinum-based chemotherapy in the treatment of NSCLC should continue or not must be determined by Phase III trials, evaluating the use of a platinum agent with one of the new agent combinations. These aggressive chemotherapeutic combinations will hopefully improve survival and quality of life for patients with advanced NSCLC.

Salvage treatment of advanced non-small-cell lung cancer previously treated with docetaxel-based front-line chemotherapy with irinotecan (CPT-11) in combination with cisplatin

BACKGROUND

A phase II study was conducted in order to determine the toxicity and efficacy of the combination of CPT-11 and cisplatin, as salvage treatment in patients with advanced non-small-cell lung cancer (NSCLC), progressing after a docetaxel-based front-line regimen.

PATIENTS AND METHODS

Thirty-one patients (median age 61 years) with NSCLC, were enrolled. Twenty-six (84%) patients were male, twenty-five (81%) had disease stage IV, and twenty-eight (90%) had a performance status (WHO) 0-1. CPT-11 was administered as a 60-minute i.v. infusion at the dose of 100 mg/m2 on day 1 and 110 mg/m2 on day 8; cisplatin was administered at the dose of 80 mg/m2 on day 8, after CPT-11 administration. Treatment was repeated every three weeks.

RESULTS

A total of 110 chemotherapy cycles were administered. In an intention-to-treat analysis 7 patients (23%; 95%) Introduction confidence interval (95% CI): 8%-37%) achieved a partial response, 6 (19%) had stable disease, and 18 (58%) progressive disease. Three of responders had failed a previous docetaxel-carboplatin combination. The median duration of response was 3 months, the median TTP 8 months and the median survival for the entire group 8 months. Grade 3-4 neutropenia was observed in 16 (52%) patients and in two cases this was febrile. Grade 3 and 4 thrombocytopenia occurred in two (7%) patients, respectively. Grade 3 and 4 diarrhea was seen in 10 (33%) patients, grade 2-3 neurotoxicity in 2 (6%), and fatigue grade 2-3 in 12 (39%). Other toxicities were mild.

CONCLUSIONS

The combination of CPT-11 and cisplatin has manageable toxicity and interesting activity as salvage treatment of patients with advanced NSCLC, previously treated with a docetaxel-based front-line regimen.

The role of new agents in advanced non-small-cell lung carcinoma

Over the past 5 to 7 years, new and promising systemic agents have entered the therapeutic armamentarium in the treatment of advanced non-small-cell lung cancer. In particular, the taxanes, irinotecan, vinorelbine, and gemcitabine, have each been shown to perturb the natural history of this disease. In combination with cisplatin, these agents have yielded improvements in response rates and in survival, compared with either cisplatin alone or with older platinum combinations, with consistent 1-year survival rates of 30% to 40% or more and response rates exceeding 25%. Other factors may also be responsible for improved survival rates, including patient selection, improved supportive care, and more extensive screening procedures, such as CT and positron emission tomography, which have resulted in stage migration. Future directions will focus on the role of nonplatinum combinations, particularly in the elderly and in patients with compromised performance status; salvage therapy in patients with intact performance status; quality of life and quality adjusted survival; and the role of new biologic agents, which alter the tumor milieu and may be readily integrated into standard cytotoxic regimens. Except for unfit or unwilling patients, there is no room for therapeutic nihilism.

Phase II study of irinotecan plus cisplatin in patients with advanced non-small-cell lung cancer

PURPOSE

To evaluate the antitumor efficacy and safety of a combination of irinotecan (CPT-11) and cisplatin in patients with inoperable non-small-cell lung cancer (NSCLC). A secondary objective was to characterize the pharmacokinetics and pharmacodynamics of CPT-11 and its active metabolite, SN-38.

PATIENTS AND METHODS

Patients with stage IIIB or IV NSCLC were treated with repeated 4-week courses comprising CPT-11 (60 mg/m(2)) administered on days 1, 8, and 15, and a single dose of cisplatin (80 mg/m(2)) after CPT-11 administration on day 1.

RESULTS

Fifty-two patients were enrolled, including 33 men and 19 women. The median age was 61 years (range, 29 to 79 years). Southwest Oncology Group performance status was 0 in 12 patients, 1 in 32 patients, and 2 in eight patients. Eleven and 41 patients had stage IIIB and IV disease, respectively. Objective responses occurred in 28.8% of patients (15 of 52; 95% confidence interval, 16.5% to 41.2%). The median survival duration was 9.9 months (range, 1.6 to 30.8 months). The 1-year survival rate was 37%. Grade 3/4 adverse events consisted primarily of nausea (32. 7% ) or vomiting (13.5%), late-onset diarrhea (17.3%), and neutropenia (46.1%). The study design led to preferential modification of CPT-11 doses, resulting in CPT-11 dose attenuations to < or = 40 mg/m(2) in the majority of patients (31 of 52; 60%), whereas dose reductions of cisplatin were uncommon. CPT-11 pharmacokinetic parameters were comparable to those reported previously in single-agent studies.

CONCLUSION

CPT-11/cisplatin is an active combination regimen with manageable toxicity in the therapy of stage IIIB/IV NSCLC. Future studies should be designed with schedules and dose modification provisions that avoid unnecessary CPT-11 dose reductions to exploit more directly the therapeutic synergy of these agents.

Fractionated administration of irinotecan and cisplatin for treatment of lung cancer: a phase I study

A combination chemotherapy of irinotecan (CPT-11) and cisplatin (CDDP) has been reported to be active for lung cancer. In the previous trial, however, diarrhoea and leucopenia became the major obstacle for sufficient dose escalation of CPT-11 to improve the treatment outcome. We conducted a phase I study to investigate whether the fractionated administration of CDDP and CPT-11 at escalated dose was feasible and could improve the treatment outcome. Twenty-four previously untreated patients with unresectable non-small-cell lung cancer (NSCLC) or extensive disease of small-cell lung cancer (SCLC) were eligible. Both CDDP and CPT-11 were given on days 1 and 8, and repeated every 4 weeks. The dose of CDDP was fixed at 60 mg m(-2) and given by 1-h infusion before CPT-11 administration. The starting dose of CPT-11 was 40 mg m(-2), and the dose was escalated by an increase of 10 mg m(-2). The maximally tolerated dose of CPT-11 was determined as 60 mg m(-2) because grade 4 haematological or grade 3 or 4 non-haematological toxicities developed in six patients out of 11 patients evaluated. Diarrhoea became a dose-limiting toxicity. The objective response rates were 76% for NSCLC and 100% for SCLC. The recommended dose of CPT-11 and CDDP in a phase II study will be 50 mg m(-2) and 60 mg m(-2) respectively.

Potentiation of paclitaxel cytotoxicity by inostamycin in human small cell lung carcinoma, Ms-1 cells

In the present study, we found that inostamycin increased the ability of paclitaxel to induce apoptosis in Ms-1 cells. A considerably higher concentration of paclitaxel was required for the induction of apoptosis in Ms-1 cells than in other cell lines tested. Treatment of Ms-1 cells with inostamycin, an inhibitor of phoshatidylinositol (PI) synthesis, reduced the dosage of paclitaxel required to induce cell death by apoptosis. This effect of inostamycin is specific to Ms-1 cells, and inostamycin did not increase the cytotoxicity of other antitumor drugs such as adriamycin, vinblastine, methotrexate, cisplatin, etoposide, or camptothecin in Ms-1 cells. Addition of inostamycin to paclitaxel-treated cells caused a significant increase in the sub G1 peak, representing apoptosis, which was accompanied by a decrease in the G2/M peak seen in paclitaxel-treated Ms-1 cells, without affecting paclitaxel-inhibited tubulin depolymerization. Moreover, paclitaxel did not enhance inostamycin-inhibited PI synthesis. The expression levels of Bcl-2, Bax, and Bcl-XL were not changed following the co-treatment with inostamycin plus paclitaxel, whereas the activated form of caspase-3 was markedly increased. Thus, inostamycin is a chemosensitizer of paclitaxel in small cell lung carcinoma Ms-1 cells.

A phase II trial of CPT-11 in recurrent squamous carcinoma of the cervix: a gynecologic oncology group study

OBJECTIVE

To determine the response rate and associated toxicity of weekly CPT-11 in squamous carcinoma of the cervix.

METHODS

From October 1994 to May 1996, the Gynecologic Oncology Group (GOG) conducted a Phase II trial in patients with recurrent squamous cervix carcinoma. The schedule employed weekly x4 intravenous CPT-11 at 125 mg/m2 followed with a 2-week rest, to be repeated until disease progression or unacceptable toxicity. Eligibility criteria were a GOG performance status of 0-2, adequate bone marrow reserve, adequate liver function, and serum creatinine <2 mg%. None of the patients had received prior chemotherapy other than radiation sensitizers. Standard GOG toxicity and response criteria were used.

RESULTS

Fifty-four patients were entered into the trial. Three patients were ineligible because of wrong cell type (N = 2) or inadequate pathology material (N = 1). Two were inevaluable because of inadequate trial of drug. An additional 4 patients were inevaluable for response. Thus, 49 were evaluable for toxicity and 45 were evaluable for response. The median age of patients was 45 years (range, 29-71 years). The median number of weekly doses delivered was 7 (range, 1-46). The incidence of grade 4 neutropenia and anemia was 6.1 and 4.1%, respectively. Nineteen patients (38.8%) developed gastrointestinal (GI) toxicity including 8 with grade 3 and 11 with grade 4 severity. The overall response rate was 13.3% (6/45). There was 1 patient death from GI toxicity. There was one complete response of 8.8 months duration and 5 partial responses.

CONCLUSION

OFFis schedule of CPT-11 exhibits modest activity with moderate toxicity in patients with recurrent squamous carcinoma of the cervix.

A phase II trial of combination of CPT-11 and cisplatin for advanced non-small-cell lung cancer. CPT-11 Lung Cancer Study Group

A phase I trial of the combination of irinotecan (CPT-11) with cisplatin in advanced non-small cell lung cancer (NSCLC) showed a very promising response rate of 54% in previously untreated NSCLC patients. This study was conducted to confirm the activity and toxicities of CPT-11 and cisplatin combination for previously untreated NSCLC in a multi-institutional phase II study. Seventy patients with stage IIIB or IV NSCLC received CPT-11 60 mg m(-2) intravenously (i.v.) on days 1, 8 and 15, and cisplatin 80 mg m(-2) (i.v.) on day 1 every 4 weeks. Assessments were made of response, survival and toxicities. Sixty-nine were eligible, and evaluable for toxicities and survival, and 64 patients evaluable for response. Thirty-three patients (52%; 95% confidence interval 39-64%) achieved an objective response, with one complete response (2%) and 32 partial responses (50%). The median duration of response was 19 weeks and the overall median survival time was 44 weeks. The 1-year survival rate was 33%. The major toxic effects were leucopenia and diarrhoea. Grade 3 or 4 leucopenia, neutropenia, and diarrhoea occurred in 32 patients (46%), 53 patients (80%), and 13 patients (19%) respectively. A combination of CPT-11 and cisplatin is very effective against non-small-cell lung cancer with acceptable toxicities.

Irinotecan (CPT-11) combined with cisplatin in patients with refractory or recurrent ovarian cancer

Irinotecan hydrochloride (CPT-11) is reportedly effective for the treatment of refractory or recurrent ovarian cancer. We investigated the antitumor efficacy and toxicity of combination therapy with CPT-11 and cisplatin in 25 patients (mean age 55 years, range 35-73 years) with refractory or recurrent ovarian cancer who had previously undergone platinum-based combination chemotherapy. Patients received two or more courses of treatment consisting of 50 or 60 mg/m2 of CPT-11 on days 1, 8 and 15 and 50 or 60 mg/m2 of cisplatin on day 1 administered intravenously. All patients were evaluable for the response and the toxicity profile. Complete responses were obtained in two (8.0%) patients and partial responses were obtained in eight (32.0%) patients, giving an overall response rate of 40% (10 of 25 patients) (95% CI 23.0-59.0%). The median duration of response was 5.5 months (range 2-27 months), the median time to tumor progression was 6 months (range 3-28 months) and the median overall survival was 12 months (range 3-39+ months). Grade 3 or 4 neutropenia, which was the most frequent and severe toxic effect, occurred in 36 (54.5%) of the 66 treatment courses and in 16 (64.0%) of 25 patients. The nadir of the leukocyte count occurred on days 18-19. Neutropenia was reversed by short-term administration of granulocyte colony-stimulating factor for 2-10 days. Less serious hematologic effects and non-hematologic effects, such as diarrhea, were also observed. This preliminary study showed that this regimen of CPT-11 and cisplatin was effective in patients with recurrent ovarian cancer.

A risk-benefit assessment of irinotecan in solid tumours

Irinotecan is a water-soluble camptothecin analogue. Its cytotoxicity effects are exerted through interaction with the topoisomerase I-DNA complex, eventually leading to cell death. In preclinical studies, irinotecan has demonstrated a broad spectrum of activity in vitro and in vivo, and synergistic effects have been observed when it is administered in combination with other antineoplastic agents. Phase I studies of irinotecan conducted in Europe, Japan and the US have provided useful information on optimal dosage and scheduling, as well as thorough evaluation of the toxicity profile of the drug. Phase II and III trials utilising either irinotecan alone or in innovative combinations with other drugs are currently in progress. Available data indicate that irinotecan alone or in combination with other cytotoxic agents has therapeutic potential in several types of malignancy, including colorectal, lung, ovarian, cervical and gastric cancers and non-Hodgkin's lymphoma. It is the first drug since fluorouracil to possess consistent antitumour activity against metastatic colorectal cancer. The principal toxicities associated with irinotecan are diarrhoea and leucopenia. Effective strategies have been developed to circumvent both the early- and delayed-onset diarrhoea induced by irinotecan, thus allowing safer delivery of this promising agent in the clinical setting.

Effect of liposomalization on the antitumor activity, side-effects and tissue distribution of CPT-11

We have examined the efficacy of liposomalization and polyethyleneglycol (PEG) modification of liposomes on the antitumor activity, side-effects and tissue distribution of irinotecan hydrochloride (CPT-11). PEG-liposome was confirmed to elevate the plasma circulation of CPT-11 and SN-38 (active metabolite) concentrations. The tumor accumulation of CPT-11 and SN-38 was increased by the PEG-modified liposomes. The antitumor activity of CPT-11 increased due to the elevated tumor distribution of CPT-11 and SN-38 levels by the PEG-modified liposomes. In the tumor, CPT-11 was converted to SN-38. Thus, it is considered that passive targeting to the tumor by liposomalization elevated the SN-38 level in the tumor especially and increased the antitumor activity of CPT-11. Furthermore, intestinal disorder, a side toxicity of CPT-11, decreased dependent on the CPT-11 and SN-38 concentrations in the bile by liposomalization. Although the liposomes induce improved tissue distribution of the prodrug, the tissue distribution of active metabolites does not always improve. However, CPT-11-entrapped liposome was useful, as CPT-11 is converted to SN-38 in the tumor. These results suggested that the usefulness of CPT-11 could be extended.

Induction of hydrogen peroxide production and Bax expression by caspase-3(-like) proteases in tyrosine kinase inhibitor-induced apoptosis in human small cell lung carcinoma cells

In our previous studies (S. Simizu, et al., 1996, Cancer Res. 56, 4978-4982), we reported that apoptosis of human small cell lung carcinoma (SCLC) cells induced by protein tyrosine kinase inhibitors, such as erbstatin and herbimycin A, was mediated by H2O2 via a newly synthesized protein(s). In the present study, we demonstrated that induction of apoptosis by erbstatin resulted in activation of caspase-3(-like) proteases, which are interleukin-1 beta-converting enzyme family proteases (caspases) and that inhibition of these protease activities reduced the extent of cell death and H2O2 generation. We also demonstrated that expression of apoptotic protein Bax was induced by erbstatin. Erbstatin-induced Bax expression was inhibited by the inhibitor of caspase-3(-like) proteases. These results indicate that generation of intracellular H2O2 and Bax expression in tyrosine kinase inhibitor-induced apoptosis were modulated by the activation of caspase-3(-like) proteases in SCLC cells.

New Agents in the Management of Non-Small Cell Lung Cancer

BACKGROUND: Non-small-cell carcinoma of the lung has long been considered a chemotherapeutically resistant neoplasm. Newer agents and combinations are being tested. METHODS: The authors have reviewed data on recent and active phase I and phase II trials of several new agents and combinations. RESULTS: New drugs that affect both response rates and survival include vinorelbine, paclitaxel, docetaxel, gemcitabine, topotecan, and irinotecan. CONCLUSIONS: The advent of several relatively well-tolerated agents that alone have beneficial effects in advanced non-small-cell lung cancer provides reasonable hope that more effective drug combinations will soon be available for this disease.

Enhancement of tumor radio-response by irinotecan in human lung tumor xenografts

We investigated the ability of 7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxycamptothecin (CPT-11) to increase tumor radio-response in vivo using human lung tumor xenografts. The xenografts were treated with (1) CPT-11 (10 mg/kg) intraperitoneally on days 1, 5 and 9, (2) single dose radiation (10 Gy/leg) on day 1, or (3) a combination regimen of both treatments in which radiation was given 1 h after the first dose of CPT-11. DNA flow cytometry studies were performed to define the cell cycle changes following treatment for 1 to 12 h with 0, 0.5, 2.0 or 8.0 ng/ml SN-38, the major active metabolite of CPT-11. In both small cell lung cancer (MS-1) and small cell/large cell carcinoma (LX-1) xenografts, combination treatment resulted in significant tumor regression compared with the use of CPT-11 (P = 0.0005, 0.0053) or radiation treatment (P = 0.00221, 0.0035) alone. Neither severe body weight loss nor enhanced skin reaction was observed following the combined treatment. In flow cytometry studies, the proportion of cells in G2/M-phase, the most radio-sensitive phase, increased after 1 h exposure to the lowest dose of SN-38 (0.5 ng/ml). These findings suggest that CPT-11 is a potent radiosensitizing agent, and that its activity is related to the cell cycle. This is the first report to indicate that CPT-11 serves as a radiosensitizer in vivo.

Camptothecin and its analogs. An overview of their potential in cancer therapeutics

From the outset of their clinical testing the camptothecins have shown antitumor activity against gastrointestinal cancer. With the definition of mechanism of action and introduction of several analogs their antitumor activity spectrum has expanded to include ovarian, cervical, small-cell and non-small cell lung cancers and malignant lymphomas, among others. The wide range of trials in these disease areas have been reviewed for CPT-11, topotecan, and 9-aminocamptothecin. A therapeutic role is anticipated for these and other camptothecins in these disease sites. Issues in guiding treatment indications and clinical development include: 1) pharmacokinetics and scheduling relevant to each of the drugs, with the oral route emerging as a practical way for testing prolonged exposure; 2) dose-intensification with cytokines, and its relevance in maintaining effective doses particularly in combination with other myelosuppressive drugs; and 3) pharmacodynamic determinants of response-an area of research that is particularly attractive because topoisomerase I is the target for camptothecins.

Relationship between the pharmacokinetics of irinotecan and diarrhea during combination chemotherapy with cisplatin

Two phase I trials of irinotecan (CPT-11) in combination with cisplatin were conducted. In both cases, the dose-limiting toxicities were leukopenia and/or diarrhea. During these trials the pharmacokinetics of CPT-11 and its active metabolite, 7-ethyl-10-hydroxycamptothecin (SN-38), were investigated to evaluate the relationship between pharmacokinetic parameters and diarrhea, since this is an unpredictable and severe toxicity of combination chemotherapy using CPT-11 and cisplatin. Twenty-three previously untreated patients with advanced lung cancer were evaluated in the pharmacokinetic study. Ten patients received CPT-11 at 80 or 90 mg/m2 plus cisplatin at 60 mg/m2. The other 13 patients received CPT-11 at 80 or 90 mg/m2 plus cisplatin at 80 mg/m2 with the granulocyte colony-stimulating factor support (2 micrograms/kg x 16 days). CPT-11 was given as a 90-min intravenous infusion on days 1, 8, and 15. Cisplatin was given on day 1. The pharmacokinetics of CPT-11 and SN-38 were analyzed on day 8 during the first course of treatment. The maximum tolerated dose of CPT-11 was 90 mg/m2 in both phase I trials. The severity of diarrhea was best correlated with the peak plasma concentration of SN-38 among the pharmacokinetic parameters tested. In addition, patients with a plasma SN-38 level > 12.4 ng/ml at 1.75 h after the start of CPT-11 infusion had a higher incidence of Eastern Cooperative Oncology Group grade 3-4 diarrhea than those with a lower SN-38 level (P = 0.0003). Stepwise logistic regression analysis identified the SN-38 concentration as a significant contributor to the development of diarrhea (P = 0.0021). We conclude that there is a clear relationship between the SN-38 concentration and diarrhea during chemotherapy with CPT-11 plus cisplatin.

Clinical studies of irinotecan alone and in combination with cisplatin

Irinotecan (CPT-11), a new derivative of camptothecin, showed schedule-dependent antitumor activity and toxicity in preclinical animal studies. We carried out a phase I study of weekly CPT-11 infusion, which indicated that the recommended dose for phase II studies was 100 mg/m2. In a phase II trial, CPT-11 achieved a response rate of 32% for non-small cell lung cancer (NSCLC). In two phase II trials, CPT-11 achieved objective response rates of 37% and 47% for small cell lung cancer (SCLC). The high activity of CPT-11 in these phase II studies suggested that the next rational step was to investigate combination chemotherapy. The first phase I trial of CPT-11 combined with cisplatin achieved an encouraging response rate of 54% in 27 patients with previously untreated NSCLC, and the recommended schedule for phase II studies was 60 mg/m2 of CPT-11 (days 1, 8, and 15) plus 80 mg/m2 of cisplatin (day 1) given at 4-week intervals. Given the high single-agent activity of CPT-11 against SCLC and NSCLC, a regimen with a higher dose of this agent and a lower dose of cisplatin seemed likely to be more effective. In the second trial, the cisplatin dose was accordingly reduced from 80 to 60 mg/m2, and the recommended dose of CPT-11 was concluded to be 80 mg/m2. Thus, reduction of the cisplatin dose to 60 mg/m2 allowed the safe administration of CPT-11 at 80 mg/m2 (33.3% dose intensification compared with the original regimen). The most recent trial of this combination with recombinant human granulocyte colony-stimulating factor (rhG-CSF) support demonstrated that the recommended dose is 80 mg/m2 of CPT-11 and 80 mg/m2 of cisplatin. Thus, we could raise the CPT-11 dose 33% above that given in the original regimen while maintaining the original cisplatin dose by the use of rhG-CSF support. Further trials are needed to evaluate the effect of CPT-11 given in combination with other active agents for the treatment of lung cancer.