Clinical studies of irinotecan alone and in combination with cisplatin

Role of HGF/MET axis in resistance of lung cancer to contemporary management

Lung cancer is the number one cause of cancer related mortality with over 1 million cancer deaths worldwide. Numerous therapies have been developed for the treatment of lung cancer including radiation, cytotoxic chemotherapy and targeted therapies. Histology, stage of presentation and molecular aberrations are main determinants of prognosis and treatment strategy. Despite the advances that have been made, overall prognosis for lung cancer patients remains dismal. Chemotherapy and/or targeted therapy yield objective response rates of about 35% to 60% in advanced stage non-small cell lung cancer (NSCLC). Even with good initial responses, median overall survival of is limited to about 12 months. This reflects that current therapies are not universally effective and resistance develops quickly. Multiple mechanisms of resistance have been proposed and the MET/HGF axis is a potential key contributor. The proto-oncogene MET (mesenchymal-epithelial transition factor gene) and its ligand hepatocyte growth factor (HGF) interact and activate downstream signaling via the mitogen-activated protein kinase (ERK/MAPK) pathway and the phosphatidylinositol 3-kinase (PI3K/AKT) pathways that regulate gene expression that promotes carcinogenesis. Aberrant MET/HGF signaling promotes emergence of an oncogenic phenotype by promoting cellular proliferation, survival, migration, invasion and angiogenesis. The MET/HGF axis has been implicated in various tumor types including lung cancers and is associated with adverse clinicopathological profile and poor outcomes. The MET/HGF axis plays a major role in development of radioresistance and chemoresistance to platinums, taxanes, camtothecins and anthracyclines by inhibiting apoptosis via activation of PI3K-AKT pathway. DNA damage from these agents induces MET and/or HGF expression. Another resistance mechanism is inhibition of chemoradiation induced translocation of apoptosis-inducing factor (AIF) thereby preventing apoptosis. Furthermore, this MET/HGF axis interacts with other oncogenic signaling pathways such as the epidermal growth factor receptor (EGFR) pathway and the vascular endothelial growth factor receptor (VEGFR) pathway. This functional cross-talk forms the basis for the role of MET/HGF axis in resistance against anti-EGFR and anti-VEGF targeted therapies. MET and/or HGF overexpression from gene amplification and activation are mechanisms of resistance to cetuximab and EGFR-TKIs. VEGF inhibition promotes hypoxia induced transcriptional activation of MET proto-oncogene that promotes angiogenesis and confers resistance to anti-angiogenic therapy. An extensive understanding of these resistance mechanisms is essential to design combinations with enhanced cytotoxic effects. Lung cancer treatment is challenging. Current therapies have limited efficacy due to primary and acquired resistance. The MET/HGF axis plays a key role in development of this resistance. Combining MET/HGF inhibitors with chemotherapy, radiotherapy and targeted therapy holds promise for improving outcomes.

Phase 2 study of irinotecan and paclitaxel in patients with recurrent or refractory small cell lung cancer

BACKGROUND

Patients with extensive stage small cell lung cancer (SCLC) who develop disease progression with standard cisplatin-based therapy are reported to have a poor overall prognosis. Irinotecan and paclitaxel are active as single agents and exhibit preclinical synergy in SCLC cell lines. A phase 2 study was conducted to evaluate this combination in patients with recurrent or refractory SCLC.

METHODS

Patients with SCLC who progressed with 1 prior chemotherapy regimen and had measurable disease present; an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0 to 2; and adequate bone marrow, hepatic, and renal function were included in the study. Paclitaxel (at a dose of 75 mg/m(2)) and irinotecan (at a dose of 50 mg/m(2)) were administered intravenously on Days 1 and 8 of each 3-week treatment cycle. Therapy was continued until disease progression or unacceptable toxicity. The target response rate of interest was > or =30%.

RESULTS

A total of 55 patients were enrolled, 51 of whom received at least 1 dose of therapy. The majority of the patients had an ECOG PS of 0 or 1 (96%). A median of 3 cycles of treatment was administered, and 15 patients received > or =6 cycles. Seventeen patients experienced toxicity of grade 3 or higher (neutropenia in 8 patients and fatigue in 5 patients). The overall response rate was 21%. The median survival was 25.4 weeks, and the 1-year survival rate was 22%.

CONCLUSIONS

The regimen of irinotecan and paclitaxel was found to be tolerated well in patients with recurrent or refractory SCLC. Although modest anticancer activity was noted, the efficacy failed to meet the primary endpoint of interest.

A phase II study of biweekly irinotecan and cisplatin for patients with extensive stage disease small cell lung cancer

BACKGROUND

An irinotecan and cisplatin (IP) combination is one of active regimen used in treatment of extensive stage disease (ED) small cell lung cancer (SCLC). However, a 4-week cycle of irinotecan treatment can result in significant myelosuppression and diarrhea. Therefore, the present study was conducted to evaluate the efficacy and safety of biweekly IP in patients with ED SCLC.

METHODS

Patients with previously untreated ED SCLC received intravenous irinotecan at a dose of 60mg/m(2) and cisplatin at a dose of 30mg/m(2) on days 1 and 15 every 4 weeks.

RESULTS

Thirty-five patients were enrolled in this study. Three complete responses and 23 partial responses were confirmed, giving an overall response rate of 74.3%. After a median follow-up of 15.1 months, the median time to progression and overall survival were 7.7 months and 12.2 months, respectively. Grade 3/4 neutropenia occurred in seven patients and grade 3 febrile neutropenia was observed in one patient. Grade 3 diarrhea occurred in two patients.

CONCLUSIONS

The combination chemotherapy of biweekly IP was found to be well tolerated and effective in patients with ED SCLC. Further evaluation of the combination of IP at the dose and schedule in this study is warranted in ED SCLC patients.

Phase II study of weekly irinotecan and cisplatin for refractory or recurrent non-small cell lung cancer

Even with the standard first-line chemotherapy, advanced non-small cell lung cancer (NSCLC) recurs in most cases. The purpose of this study is to develop a new chemotherapeutic regimen for patients with NSCLC that has relapsed or was refractory to previous chemotherapy. Patients with proven NSCLC refractory or recurrent after previous single-regimen chemotherapy, PS of 0-2, age of 15 years or older, adequate organ functions and measurable lesions were treated with irinotecan at 60 mg/m(2) and cisplatin at 25 mg/m(2) with 1000 ml hydration on day 1. This administration, considered as one cycle, was repeated every week without rest unless encountering defined skip and dose-reduction criteria. The treatment was administered for six cycles over a 49-day period, both median values, to 48 patients, with a response rate of 26%, progression free and median survival times of 3 and 11 months, respectively, and a 1-year survival rate of 46%. The most frequent grade 3 or 4 toxicities were neutropenia, anaemia and nausea, which were manageable. Subset analyses suggested that the response rate was independent of response to the first-line chemotherapy. In conclusion, second-line chemotherapy of weekly irinotecan and cisplatin with minimum hydration seemed effective, with tolerable toxicity, and is potentially useful irrespective of the outcome of previous chemotherapy.

New and Emerging Intraperitoneal (IP) Drugs for Ovarian Cancer Treatment

Chemotherapy after surgical debulking represents an essential component of treatment for patients with advanced ovarian cancer. Three quarters of patients respond very well to initial treatment with platinum-containing drugs used either alone or in combination with a taxane, usually paclitaxel. With relapse rates exceeding 50% and median survival time of 2 years for patients after relapse, efforts are focused on treatment approaches to achieve and extend clinical complete remissions. These approaches include consolidation and maintenance therapy, intraperitoneal (IP) administration of cytotoxic agents, new combination chemotherapy regimens, development of new cytotoxic agents, and molecular-targeted therapies (beyond tumor DNA, the classical target of cytotoxic drugs). IP chemotherapy, which involves direct instillation of chemotherapy into the tumor site in the peritoneal cavity, is the focus of this review article. This article discusses studies involving new and emerging IP drugs for both first-line chemotherapy treatment of advanced ovarian cancer and recurrent platinum-sensitive ovarian cancer.

Phase II Study of Combination Chemotherapy with Gemcitabine and Irinotecan in Patients with Advanced Non-Small-Cell Lung Cancer Previously Treated with Platinum-Containing Chemotherapy Regimens

OBJECTIVE

The aim of this study was to evaluate the efficacy and toxicity of gemcitabine combined with irinotecan in patients with previously treated non-small-cell lung cancer (NSCLC).

METHODS

Patients who failed to respond to platinum-containing first-line chemotherapy were enrolled and treated with gemcitabine 1000 mg/m(2) and irinotecan 150 mg/m(2) on days 1 and 15. Cycles were repeated every 4 weeks.

RESULTS

Twenty-seven of 30 registered patients were evaluated. There were previous combination treatments of platinum and taxane regimens in 21 out of 27 patients, with 17 patients treated with carboplatin and paclitaxel and 4 patients treated with cisplatin or carboplatin and docetaxel. A total of 87 cycles was administered and the median number of cycles administered per patient was 3.5 cycles. Objective responses were observed in 5 out of 27 patients (18.5%). No severe hematologic and non-hematologic toxicities were observed (grade 3 leukopenia in 3 patients; grade 3 anemia in 3 patients; grade 3 thrombocytopenia in 2 patients; grade 3 diarrhea in 1 patient). The median survival time was 7.7 months and 1-year survival rate was 34.8%.

CONCLUSION

Bi-weekly gemcitabine and irinotecan was well tolerated and had an acceptable response rate and a reasonable median survival time for patients with NSCLC who had previously been treated with platinum-based chemotherapy.

Phase I study of cisplatin and irinotecan combined with concurrent hyperfractionated accelerated thoracic radiotherapy for locally advanced non-small cell lung carcinoma

BACKGROUND

Irinotecan, when combined with cisplatin, is an effective treatment for advanced non-small cell lung cancer (NSCLC). This constitutes a rationale for conducting a phase I study of chemoradiotherapy including this combination for locally advanced NSCLC.

PATIENTS AND METHODS

Patients with locally advanced NSCLC and a performance status of 0 or 1 were eligible. The protocol consisted of escalating doses of irinotecan on days 1 and 15, and daily low-dose cisplatin (6 mg/m(2) daily for a total dose of 120 mg/m(2)) combined with concurrent hyperfractionated accelerated thoracic irradiation (1.5 Gy twice daily for a total dose of 60 Gy).

RESULTS

The maximum tolerable dose was 50 mg/m(2) of irinotecan, and the dose-limiting toxicity was esophagitis. Tumor response was observed in 50% of cases, and the median survival time of the 12 patients enrolled was 10.1 months, including two patients with 5-year disease-free survival. A pharmacokinetics study demonstrated an accumulation of total platinum, but not of free platinum, during the 26-day treatment period.

CONCLUSION

The recommended dose for phase II studies was determined.

Irinotecan and taxane combinations for non small-cell lung cancer

Based on nonoverlapping toxicity profiles and at least additive cytotoxicity in preclinical models, chemo-therapy regimens have been developed that feature the combination of irinotecan and a taxane drug. In the first study, the optimal doses of paclitaxel and irinotecan were 75 mg/m2 and 50 mg/m2, respectively, when chemotherapy was administered weekly for 4 consecutive weeks, followed by a 2-week rest. The dose-limit-ing toxicity for this regimen was neutropenia, and the most prominent nonhematologic toxicities were mild diarrhea and fatigue. Pharmacokinetic studies failed to demonstrate any sequence-dependent interaction be-tween these agents on the metabolism of irinotecan or its major metabolite. This regimen has been modified, with chemotherapy given on day 1 and day 8 every 3 weeks, and is being tested further in previously un-treated advanced non small-cell lung cancer (NSCLC). In a second trial, irinotecan was combined with docetaxel on a weekly schedule. When chemotherapy was given weekly for 4 weeks, followed by a 2-week rest, the recommended doses of docetaxel and irinotecan were 35 mg/m2 and 50 mg/m2, respectively. Low-grade gastrointestinal toxicity and asthenia were the dose-limiting toxicities. The treatment schedule was modified, with chemotherapy given on days 1 and 8 of a 21-day cycle, and patients are currently being treated with docetaxel 35 mg/m2 and irinotecan 65 mg/m2. Among the 10 evaluable patients with NSCLC in this second study, there was one partial response lasting 24 weeks and four patients with stable disease, including one patient who had progressive disease on a prior paclitaxel-containing regimen. The combinations of irinotecan and a taxane on a weekly schedule are active and well tolerated and deserve further evaluation in the treatment of NSCLC.

Antitumoral effect of irinotecan (CPT-11) on an experimental model of malignant neuroectodermal tumor

Irinotecan (CPT-11) is a topoisomerase I inhibitor with antitumor activity on a wide variety of neoplasms in several preclinical studies, but it showed poor efficacy in patients with nervous system tumors. We have carried out an experimental study in order to evaluate the effect of CPT-11 on the growth of a subcutaneously implanted malignant neuroectodermal tumor, after administration by different routes. The results showed that CPT-11 administration by intraperitoneal injections (at dose 10 mg/kg, 5 days per week, for 2 weeks, followed by 7-days rest period--one course--to a total of two courses) had no significant antitumor effect. Nevertheless, continuous infusion by intraperitoneal osmotic minipump over 28 days (at an infusion rate of 4.4 microg/h) showed a significant delay in tumor growth in 4 weeks of the implantation. The best antitumor effects were observed after CPT-11 intratumoral administration (at dose of 5 mg/kg, 5 days per week, for 2 weeks, followed by 7-days rest period, to a total of three courses) reaching tumor regression in the treated animals. These results suggest the utility of CPT-11, by means of intralesional administration, on malignant tumors of the nervous system.

Schedule-dependent cytotoxicity of SN-38 in p53 wild-type and mutant colon adenocarcinoma cell lines

In this study the effects of SN-38 on colon adenocarcinoma cell lines expressing wild-type p53 (LS174T) or mutant non-functional p53 (HT29) have been investigated. On exposure to SN-38, HT29 cells rapidly progressed through G1 and S and arrested in G2/M. Release and concomitant increase in apoptosis after 48 h was concentration- and time-dependent (P < 0.001), being more rapid at higher concentrations, but reaching plateau at 10 ng ml(-1) with prolonged exposure. LS174T cells showed only a small increase in apoptosis, and only at high concentrations (50-100 ng ml(-1)). The main effect of SN-38 in LS174T cells was prolonged cell cycle arrest, which was independent of concentration. Arrest occurred in all phases of the cell cycle, with the distribution depending on concentration (P < 0.001) and not duration (P > 0.05). With increasing concentration, LS174T cells arrested in G2/M, S and G1. Cell cycle arrest was coincident with increased p53 expression in each phase of the cell cycle. Expression in G1 increased with time and concentration (P < 0.001, P = 0.01 respectively)whereas in S and G2/M p53 expression increased only with time (P< 0.001). Dose-dependent p53-associated G1 arrest, in the absence of DNA synthesis indicates an additional cytotoxic mechanism for SN-38, which requires higher concentrations than the S phase mechanism, and detection of which seems to involve p53. For incubations with the same ED (exposure x duration), apoptosis in HT29 cells was significantly higher for prolonged exposure to lower concentrations, whereas in LS174T cells there was a trend towards increased apoptosis with shorter exposures to higher concentrations, indicating a schedule effect of SN-38. Although expression of wild-type p53 leads to a more rapid induction of apoptosis, SN-38 cytotoxicity was generally greater in cells with mutant p53, as wild-type cells escaped apoptosis by p53 associated prolonged cell cycle arrest. Thus, pulsed schedules with higher doses may be more effective in cells expressing wild-type p53, whereas continued exposure with protracted schedules may be more active in cells expressing mutant p53.

A pilot study of CPT-11 and cisplatin for ovarian clear cell adenocarcinoma

BACKGROUND

Ovarian clear cell adenocarcinoma is known to have poorer prognosis than ovarian serous cystadenocarcinoma. Cyclophosphamide plus cisplatin has been the standard therapy for ovarian cancer, but ovarian clear cell adenocarcinoma dose not respond to this therapy. The treatment for ovarian clear cell adenocarcinoma has not been established. We planned a pilot study of CPT-11 and cisplatin for the treatment of ovarian clear cell adenocarcinoma.

METHODS

First, three patients were administered 70 mg/m2 of cisplatin intravenously on day 1 and 60 mg/m2 of CPT-11 intravenously on days 1, 8 and 15. Treatment was repeated every 4 weeks. Other patients were administered 75 mg/m2 of cisplatin intraperitoneally on day 1 and 60 mg/m2 of CPT-11 intravenously on days 1, 8 and 15. Treatment was repeated every 4 weeks.

RESULTS

A total of 10 patients were entered in this study and a total of 43 courses were administered. 1 CR, 1 PR and 1 PD were observed in patients with measurable lesion. Grade 3 leukopenia was experienced in seven patients, grade 3 thrombocytopenia in two and grade 3 anemia in five. Grade 3 liver toxicity was observed in one patient and grade 3 diarrhea in one patient. No grade 4 toxicity was experienced.

CONCLUSION

CPT-11 plus cisplatin is feasible and has efficacy for ovarian clear cell adenocarcinoma. This regimen should be explored in a phase II study.

Five days of oral topotecan (Hycamtin), a phase I and pharmacological study in adult patients with solid tumours

Topotecan is a specific inhibitor to topoisomerase I. An oral formulation of topotecan is available with a bioavailability of 32-44% in humans. A phase I and pharmacological study of the oral formulation of topotecan administered daily for 5 days every 21 days was performed in adult patients with solid tumours to determine the maximum tolerated dose (MTD). Adult patients with a WHO performance status < or = 2 adequate haematological, hepatic and renal functions, with malignant solid tumours refractory to standard forms were entered into the study. Pharmacokinetics were performed on days 1 and 4 of the first course using a validated high performance liquid chromatographic assay. 29 patients entered the study, all patients were evaluable for toxicity and response. The doses studied in the 29 patients were 1.2, 1.8, 2.3, 2.7 mg/m2/day and a fixed dose of 4 mg/day without surface area adjustment. A total of 109 courses were given. Dose limiting toxicity (DLT) was reached at a dose of 2.7 mg/m2/day and consisted of CTC (NCI-Common Toxicity Criteria) grade IV granulocytopenia. The regimen was well tolerated. Non-haematological toxicities were mild, including fatigue, anorexia, nausea, vomiting and diarrhoea. A significant correlation was observed between the percentage decrease in white blood cells versus the area under the curve (AUC(t)) of topotecan lactone (R = 0.76 P < 0.01) which was modelled by a sigmoidal Emax function. The correlation coefficient between the absolute topotecan dose administered and the AUC(t) was R = 0.52 (P = 0.04). Pharmacokinetics of the fixed dose of 4 mg/day were comparable to the 2.3 mg/m2/day dose. DLT in this phase I study of five daily doses of oral topotecan every 21 days was granulocytopenia. The recommended dose for phase II studies is 2.3 mg/m2/day or alternatively, a fixed dose of 4 mg/day.

New chemotherapeutic agents for the treatment of non-small cell lung cancer: the Japanese experience

Non-small cell lung cancer (NSCLC) is refractory to systemic chemotherapy, compared with small cell lung cancer. Until recently, only five drugs--cisplatin, vindesine, mitomycin, ifosfamide, and vinblastine--could produce overall response rates of 15% against NSCLC. However, recent efforts have contributed to the development of new drugs with activity against NSCLC, including irinotecan hydrochloride (CPT-11), paclitaxel, docetaxel, vinorelbine, and gemcitabine. Combination chemotherapy against NSCLC using these agents has demonstrated high response rates. In Japan, various combination chemotherapy and combined-modality regimens employing CPT-11 have been evaluated for their efficacy. Randomized controlled trials to establish new state-of-the-art treatments for NSCLC are ongoing.

Gene mutation analysis and quantitation of DNA topoisomerase I in previously untreated non-small cell lung carcinomas

To elucidate whether gene alterations of topoisomerase I (topo I) exist in untreated non-small cell lung carcinomas (NSCLC), polymerase chain reaction-single strand conformation polymorphism analysis was performed in forty-four NSCLC tissue samples. Gene alterations of topo I were sought in three regions, near codons 361 and 363, 533, and 722 and 729, where point mutations have been found in resistant tumor cell lines selected by chronic camptothecin exposure. In addition, nuclear topo I contents were determined by immunoblotting. No mobility shifts were observed compared to the pattern observed in a normal control at any of the three regions in any sample, whereas topo I levels showed an approximately 12-fold variation. The variation is remarkably large compared to those seen in previous in vitro and in vivo studies. The results suggest that mutations of topo I may not contribute to intrinsic resistance of NSCLC to camptothecins, but low topo I levels may account, at least in part, for the resistance.

Clinical trials of irinotecan hydrochloride (CPT, campto injection, topotecin injection) in Japan

CPT-11 was synthesized in 1984 at the laboratory of Yakult Honsha. Phase I study of CPT-11 was begun in 1986. The appropriate doses for phase II studies were decided to be 100 mg/m2 weekly or 150 mg/m2 every 2 weeks. Phase II study was conducted and this drug was approved for NSCLC, SCLC, uterine cancer and ovarian cancer by MHW in 1994. It obtained approval for stomach cancer, colorectal cancer, breast cancer, skin cancer and non-Hodgkin's lymphoma in 1995. The combination chemotherapies including CPT-11 have been conducted by using various regimens such as CPT-11 + CDDP, CPT-11 + VP-16, CPT-11 + 5-FU and CBDCA + CPT-11. In stage IV SCLC two prospective randomized controlled trials are on going comparing CPT-11 vs. CPT-11 + CDDP vs. VDS + CDDP and CPT-11 + CDDP vs. VDS + CDDP. In advanced SCLC Japanese Clinical Oncology Group (JCOG) started a randomized controlled trial comparing CPT-11 + CDDP vs. VP-16 + CDDP. In stage III NSCLC the dose escalation studies of CPT-11 (CPT-11) in the combination with TRT are ongoing by JCOG. The problem of CPT-11 in the combination chemotherapy and combined modality is that it is quite difficult to increase the dose of CPT-11 to full dose to obtain the maximum effect.