Results of a European Organization for Research and Treatment of Cancer/Early Clinical Studies Group phase II trial of first-line irinotecan in patients with advanced or recurrent squamous cell carcinoma of the cervix.
(57/2758)
PURPOSE: To determine the efficacy and tolerability of irinotecan (CPT-11) in advanced or recurrent cervical carcinoma. PATIENTS AND METHODS: Eligible patients had histologically confirmed, inoperable, progressive, metastatic or recurrent squamous cell cervical carcinoma and had received no radiotherapy in the preceding 3 months and had never received chemotherapy. The initial irinotecan dosage of 350 mg/m(2) every 3 weeks was modifiable according to toxicity. Treatment continued for six cycles after complete response, or until disease progression or excessive toxicity after partial response, or for three additional cycles in the case of stable disease. Patients were stratified into group A (>/= one measurable lesion in a previously unirradiated area, with or without progressive disease in irradiated fields) or group B (measurable new lesion[s] in an irradiated field). RESULTS: Fifty-one of 55 enrolled patients were eligible for inclusion (median age, 47 years; range, 30 to 71 years). The response rate was 15.7% (95% confidence interval [CI], 7.0% to 28.6%) overall, 23.5% (95% CI, 10.7% to 41.2%) for group A (complete response, 2.9%), and zero for group B. The median time to progression and median survival were 4.0 and 8.2 months for group A and 2.5 and 4.2 months for group B, respectively. The major grade 3/4 toxicities for groups A and B were diarrhea (24.3% and 55.5%, respectively) and neutropenia (24.3% and 33.3%, respectively). There were four toxicity-related deaths, three in group B. Patients with no prior external pelvic irradiation experienced fewer grade 3 and 4 adverse events. CONCLUSION: Irinotecan is effective in treating cervical squamous cell carcinoma if disease is located in an unirradiated area. Because of toxicity, a reduced dose is advised for patients previously treated with external pelvic irradiation. (+info)
Phase II trial of weekly irinotecan plus cisplatin in advanced esophageal cancer.
(58/2758)
PURPOSE: To evaluate the response, toxicity, survival, and quality of life in patients with unresectable or metastatic esophageal cancer treated with weekly irinotecan and cisplatin. PATIENTS AND METHODS: Thirty-five patients with metastatic or unresectable esophageal adenocarcinoma (23 patients) or squamous cell carcinoma (12 patients) were treated. No prior chemotherapy was allowed. The majority of patients had metastatic and bidimensionally measurable disease (34 patients each [97%]). Patients were treated with cisplatin 30 mg/m(2) and irinotecan 65 mg/m(2), repeated weekly for 4 weeks, followed by a 2-week rest period. Treatment was recycled every 6 weeks. Degree of dysphagia relief was monitored, and quality of life was measured prospectively using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C-30 and Functional Assessment of Cancer Therapy-General instruments. RESULTS: Thirty-five patients were assessable for response and toxicity. Major objective responses were observed in 20 patients (57%; 95% confidence interval, 41% to 73%), including two complete responses (6%). Similar response rates were observed for adenocarcinoma (12 of 23 patients; 52%) and squamous carcinoma (eight of 12 patients; 66%). The median duration of response was 4.2 months (range, 1 to 8.8+ months). Median actuarial survival was 14.6 months (range, 1 to 15.2+ months). In 20 patients with dysphagia assessable at baseline, 18 (90%) noted either improvement or resolution of dysphagia on chemotherapy. Global quality of life improved in responding patients, primarily because of improvements in pain, emotional state, and relationships with family and friends. Toxicity was relatively mild and included only three patients (9%) with grade 4 neutropenia and four (11%) with grade 3 diarrhea. There were no treatment-related deaths. CONCLUSION: The combination of weekly cisplatin plus irinotecan had significant activity in metastatic esophageal carcinoma and resulted in significant relief of dysphagia. The regimen was well tolerated, with acceptable myelosuppression and rare treatment-related diarrhea. Further evaluation of the combination of weekly irinotecan and cisplatin, including the addition of other agents to this regimen, is indicated. (+info)
Fish oil supplementation enhanced CPT-11 (irinotecan) efficacy against MCF7 breast carcinoma xenografts and ameliorated intestinal side-effects.
(59/2758)
The cancer chemotherapeutic efficacy of the topoisomerase I inhibitor, CPT-11 (irinotecan) is often limited by the induction of severe delayed diarrhoea. In animal studies, CPT-11 use is associated with histopathological damage to the mucosa of the small and large intestines. Results from the present study demonstrate that 60 mg CPT-11 per kg body weight (i.v. q4d x 6) halted the growth, but did not cause significant regression, of MCF7 human breast carcinoma xenografts in mice fed a diet containing 7% corn oil. However, when the diet of the MCF7-bearing mice was supplemented with 3% or 6% fish oil, the same CPT-11 treatment caused significant regression of the MCF7 xenograft. Histomorphometric analyses of intestinal mucosa of mice treated with CPT-11 and fed the diet containing 7% com oil indicated that treatment with CPT-11 induced structural changes in the intestinal mucosa which persisted at least 5 days after the last dose of CPT-11. The intestinal mucosal architecture of mice that were treated with CPT-11 and fed the diets containing fish oil was largely unchanged from the architecture of the group of mice which did not receive CPT-11. These findings indicate that fish oil supplements may be a useful adjunct to CPT-11 treatment. (+info)
Concurrent irinotecan and 5-fluorouracil plus levo-folinic acid given every other week in the first-line management of advanced colorectal carcinoma: a phase I study of the Southern Italy Cooperative Oncology Group.
(60/2758)
OBJECTIVES: To determine the maximum tolerable doses (MTDs) of irinotecan (CPT-11) and 5-fluorouracil (5-FU) plus levofolinic acid (LFA) administered together every two weeks, to define the toxicity profile of this regimen, and to have a preliminary evidence of its activity in the first-line management of advanced colorectal cancer patients. PATIENTS AND METHODS: Patients with histologically proven colorectal carcinoma, no prior chemotherapy for their advanced disease, and with at least one measurable or evaluable indicator lesion, were admitted to this study. The starting dose of CPT-11 was 150 mg/m2 given i.v. (90 min infusion) on day 1, followed on day 2 by a fixed dose of LFA (250 mg/m2) as a two-hour i.v. infusion plus a starting dose of 5-FU 600 mg/m2 as i.v. bolus. No intra-patient dose escalation was allowed. If no dose limiting toxicity (DLT) was observed among three patients of each cohort, CPT-11 and 5-FU were alternately escalated in the subsequent cohort. Otherwise, three more patients were enrolled at the same dose level. DLT was defined as: WHO grade 3 non-haematological toxicity (except for vomiting or alopecia), grade 3 febrile neutropenia, grade 4 neutro- or thombocytopenia, or a > 2-week delay in recycling. The MTDs were defined as the doses at which two of three, or four of six, patients showed the same DLT. RESULTS: Thirty-one patients (five pretreated in adjuvant setting) were enrolled in this study, and a total number of 293 cycles (median 6/patient) were administered. Dose escalation safely proceeded to 210/950/250 mg/m2 of CPT-11/5-FU/LFA. These dosages were considered as MTDs, since four of six patients showed grade 4 neutropenia, in one case associated with grade 3 stomatitis. A mild decrease of both the CPT-11 and 5-FU doses to 200 and 850 mg/m2, respectively, caused different DLTs (neutropenia and diarrhoea) in two out of seven patients. At these dosages, transient grades 3 or 4 neutropenia affected two patients each during their treatment, while only one patient suffered from a severe delayed diarrhoea. Other non-haematological toxicities were mild and manageable. Therefore, we recommend this latter dose level for further study. Major responses (3 complete and 11 partial) were reported in 14 patients, for an overall response rate of 45% (95% CI: 27%-64%) according to an intent-to-treat analysis. Responses were observed from first dose level, and in four of five previously treated patients. Median failure-free and overall survivals, after a median follow-up of 39 weeks, were 42 and 55 weeks, respectively. CONCLUSIONS: The concurrent administration of CPT-11 and modulated 5-FU every two weeks is feasible at the recommended dosages. This regimen demonstrated interesting activity in the management of advanced colorectal cancer patients, and it probably better exploits the synergism between CPT-11 and 5-FU than recently tested alternating schedules. A phase II study is ongoing to more precisely define its activity and toxicity. (+info)
Potent topoisomerase I inhibition by novel silatecans eliminates glioma proliferation in vitro and in vivo.
(61/2758)
Although topoisomerase inhibitors, such as camptothecin and topotecan, have been widely used in the treatment of nonglial tumors, their application for gliomas has been limited by poor efficacy relative to toxicity that may in part reflect limited bioavailability and blood stability of these agents. However, the potential promise of this class of agents has fostered efforts to develop new, more potent, and less toxic inhibitors that may be clinically relevant. Using a cascade radical annulation route to the camptothecin family, we developed a series of novel camptothecin analogues, 7-silylcamptothecins ("silatecans"), that exhibited potent inhibition of topoisomerase I, dramatically improved blood stability, and sufficient lipophilicity to favor blood-brain barrier transit. We explored the efficacy of a series of these agents against a panel of five high-grade glioma cell lines to identify a promising compound for further preclinical testing. One of the most active agents in our systems (DB67) inhibited tumor growth in vitro with an ED50 ranging between 2 and 40 ng/ml, at least 10-fold more potent than the effects observed with topotecan, and at least comparable with those of SN-38, the active metabolite of CPT-11. Because DB67 also exhibited the highest human blood stability of any of the agents examined, this agent was then selected for in vivo studies. A dose-escalation study of this agent in a nude mouse U87 glioma model system demonstrated a concentration-dependent effect, with tumor growth inhibition at day 28 postimplantation (the day control animals began to require sacrifice because of large tumor size) of 61 +/- 7% and 73 +/- 3% after administration of DB67 doses of 3 and 10 mg/kg/day, respectively, for 5 days beginning on postimplantation day 7. Animals that continued treatment with 10 mg/kg/day in three additional 21-day cycles all remained progression free after >90 days of follow-up but later developed enlarging tumors after treatment was stopped. However, a slightly higher dose (30 mg/kg/day) induced complete tumor regression after only two cycles in all study animals and was effective even if treatment was delayed until large, bulky tumors had developed. Application of the 30 mg/kg/day dose to treat established intracranial glioma xenografts led to long-term (>90 day) survival in six of six animals, whereas all controls died of progressive disease (P < 0.00001). No apparent toxicity was encountered in any of the treated animals. In summary, the present studies indicate that silatecans may hold significant promise for the treatment of high-grade gliomas and provide a rationale for proceeding with further preclinical evaluation of their efficacy and safety versus commercially available camptothecin derivatives. (+info)
Yeast gene for a Tyr-DNA phosphodiesterase that repairs topoisomerase I complexes.
(62/2758)
Covalent intermediates between topoisomerase I and DNA can become dead-end complexes that lead to cell death. Here, the isolation of the gene for an enzyme that can hydrolyze the bond between this protein and DNA is described. Enzyme-defective mutants of yeast are hypersensitive to treatments that increase the amount of covalent complexes, indicative of enzyme involvement in repair. The gene is conserved in eukaryotes and identifies a family of enzymes that has not been previously recognized. The presence of this gene in humans may have implications for the effectiveness of topoisomerase I poisons, such as the camptothecins, in chemotherapy. (+info)
Ref-1 regulates the transactivation and pro-apoptotic functions of p53 in vivo.
(63/2758)
Ref-1 is a multifunctional protein that stimulates DNA binding by a number of transcription factors and serves as the abasic (A/P) endonuclease in base excision repair. Ref-1 was discovered to be a potent activator of p53 DNA binding in vitro. To address the physiological significance of the effects of Ref-1 on p53, we have analyzed its role in regulating p53 function in vivo. We found that Ref-1 over-expression enhances the ability of p53 to transactivate a number of p53 target promoters and increases the ability of p53 to stimulate endogenous p21 and cyclin G expression. Additionally, it was observed that Ref-1 associates with p53 in vivo and in vitro. Importantly, downregulation of Ref-1 (by antisense) causes a marked reduction in p53 induction of p21 mRNA and protein, as well as diminished ability of p53 to transactivate the p21 and Bax promoters. Moreover, Ref-1 levels are correlated with the extent of apoptosis induced by p53. Finally, we observed that Ref-1 cooperates with a DNA-damaging compound, camptothecin, to stimulate the transcriptional activity of p53. Together these data indicate that Ref-1 is a key cellular regulator of p53. (+info)
A functional linker in human topoisomerase I is required for maximum sensitivity to camptothecin in a DNA relaxation assay.
(64/2758)
Human topoisomerase I is composed of four major domains: the highly charged NH(2)-terminal region, the conserved core domain, the positively charged linker domain, and the highly conserved COOH-terminal domain. Near complete enzyme activity can be reconstituted by combining recombinant polypeptides that approximate the core and COOH-terminal domains, although DNA binding is reduced somewhat for the reconstituted enzyme (Stewart, L., Ireton, G. C., and Champoux, J. J. (1997) J. Mol. Biol. 269, 355-372). A reconstituted enzyme comprising the core domain plus a COOH-terminal fragment containing the complete linker region exhibits the same biochemical properties as a reconstituted enzyme lacking the linker altogether, and thus detachment of the linker from the core domain renders the linker non-functional. The rate of religation by the reconstituted enzyme is increased relative to the forms of the enzyme containing the linker indicating that in the intact enzyme the linker slows religation. Relaxation of plasmid DNA by full-length human topoisomerase I or a 70-kDa form of the enzyme that is missing only the non-essential NH(2)-terminal domain (topo70) is inhibited approximately 16-fold by the anticancer compound, camptothecin, whereas the reconstituted enzyme is nearly resistant to the inhibitory effects of the drug despite similar affinities for the drug by the two forms of the enzyme. Based on these results and in light of the crystal structure of human topoisomerase I, we propose that the linker plays a role in hindering supercoil relaxation during the normal relaxation reaction and that camptothecin inhibition of DNA relaxation depends on a direct effect of the drug on DNA rotation that is also dependent on the linker. (+info)