Phase II trial of irinotecan in patients with metastatic colorectal carcinoma

Improving the evaluation of new cancer treatments: challenges and opportunities

There are, at present, ten times more anticancer drugs being tested in clinical trials than there were 15 years ago. Many of the new classes of agents, however, are predicted to work in only small subpopulations of patients, target unconventional aspects of tumour development and interact with other agents in an unpredictable manner. How can clinical trials be re-designed to accommodate the new features of targeted anticancer drugs?

An open phase I study assessing the feasibility of the triple combination: oxaliplatin plus irinotecan plus leucovorin/ 5-fluorouracil every 2 weeks in patients with advanced solid tumors

BACKGROUND

The aim of this study was to determine the maximum-tolerated dose (MTD) and the recommended dose of irinotecan and oxaliplatin with a fixed 5-fluorouracil (5-FU)/leucovorin (LV) regimen in patients with metastatic solid tumors.

PATIENTS AND METHODS

The trial was designed to evaluate escalating doses of oxaliplatin and irinotecan, starting at 60 mg/m2 and 90 mg/m2, respectively, given at day 1 with the full-dose LV5FU2 regimen, given on days 1 and 2 as follows: folinic acid 200 mg/m2 followed by 5-FU 400 mg/m2 bolus and 600 mg/m2 22 h continuous infusion, every 2 weeks. The second cohort of patients was treated at the recommended dose for oxaliplatin and irinotecan with the simplified LV5FU regimen: on day 1, a 2-h infusion of folinic acid (400 mg/m2), followed by a 10-min intravenous bolus of 5-FU (400 mg/m2), followed by a continuous infusion of 5-FU (2400 mg/m2) over 46 h.

RESULTS

Thirty-four patients were treated at the following dose levels (oxaliplatin/irinotecan mg/m2): 60/90, 60/120, 85/120, 85/150, 85/180, 85/200 and 85/220 and seven patients were treated at the recommended dose with the simplified LV5FU scheme. The MTD was reached at dose level 85/220 mg/m2 but the recommended dose chosen for the second step was 85/180 mg/m2 to keep a better compliance with the biweekly schedule. Main grade 3/4 toxicities per patient included the following: neutropenia in 78% (febrile episodes in 12%), diarrhea in 27%, nausea/vomiting in 24% and peripheral neuropathy in 37% (Lévi's scale). Antitumor activity was observed at almost all dose levels. Most objective responses were observed in digestive malignancies, since 10 out of 11 were obtained in five colorectal cancers, two pancreatic cancers, two cholangiocarcinoma and one gastric cancer.

CONCLUSION

The recommended dose for the triple association is 85/180 mg/m2 of oxaliplatin and irinotecan, respectively, with LV5FU2 or simplified LV5FU. The antitumor activity in gastrointestinal malignancies should be evaluated in phase II studies in different tumor types.

Phase III comparison of two irinotecan dosing regimens in second-line therapy of metastatic colorectal cancer

PURPOSE

Randomized trials in fluorouracil (FU)-refractory colorectal cancer demonstrate significant survival advantages for patients receiving irinotecan. We prospectively compared the efficacy and tolerability of two irinotecan regimens (once a week for 4 weeks followed by a 2-week rest period [weekly] v once every 3 weeks) in such patients.

PATIENTS AND METHODS

This multicenter, open-label, phase III study randomly assigned patients in a 1:2 ratio to irinotecan given either weekly (125 mg/m(2)) or once every 3 weeks (350 mg/m(2), or 300 mg/m(2) in patients who were >/= 70 years of age, who had Eastern Cooperative Oncology Group performance status equal to 2, or who had prior pelvic irradiation).

RESULTS

With median follow-up of 15.8 months, there was no significant difference in 1-year survival (46% v 41%, respectively; P =.42), median survival (9.9 v 9.9 months, respectively; P =.43), or median time to progression (4.0 v 3.0 months, respectively; P =.54) between the two regimens. Grade 3/4 diarrhea occurred in 36% of patients treated weekly and in 19% of those treated once every 3 weeks (P =.002). Grade 3/4 neutropenia occurred in 29% of patients treated weekly and 34% of those treated once every 3 weeks (P =.35). Treatment-related mortality occurred in five patients (5.3%) receiving irinotecan weekly and three patients (1.6%) given therapy once every 3 weeks (P =.12). Global quality of life was not statistically different between treatment groups.

CONCLUSION

Irinotecan schedules of weekly and of once every 3 weeks demonstrated similar efficacy and quality of life in patients with FU-refractory, metastatic colorectal cancer. The regimen of once every 3 weeks was associated with a significantly lower incidence of severe diarrhea.

Combined irinotecan, oxaliplatin and 5-fluorouracil in patients with advanced colorectal cancer. a feasibility pilot study

OBJECTIVES

To evaluate the feasibility and a possible activity range of combination irinotecan (CPT-11), oxaliplatin, and 5-FU in advanced colorectal cancer (ACC).

PATIENTS AND METHODS

A total of 53 patients (51% chemoresistant) were treated. Twenty-eight received monthly intravenous oxaliplatin (120 mg/m2) and CPT-11 (250 mg/m2) on day 1 and a course of 5-FU; these constituted the IRI250 group. Twenty-five received monthly intravenous oxaliplatin (120 mg/m2), CPT-11 (300 mg/m2) on day 1, and a course of 5-FU (IRI300 group). 5-FU administration was carried out as follows. Those with predominant hepatic disease (n = 32) received an intra-arterial infusion of 5-FU (2,500 mg/day on days 1-4); these were the IA-FU group. The remaining 21 patients received intravenous 5-FU (2,600 mg/m2 plus leucovorin 500 mg/m2 on days 1 and 15); these constituted the IV-FUFOL group.

RESULTS

Intention-to-treat response rate was 54.7% (4 CR, 7.5%). Twelve patients (22.5%) had stable disease; only 4 (7.5%) progressed. Median progression-free and overall survivals were 10 and 18 months, respectively. One-year progression-free and overall survival rates were 44.3 and 67.4%, respectively. Grade 3-4 toxicities included diarrhea (45.3% of patients), neutropenia (52.8%), mucositis (13.2%), and emesis (11.3%). There were 3 treatment-related deaths (5.7%), all in the IA-FU/IRI300 subgroup. Severe adverse effects requiring chemotherapy dose adjustment were observed in 67.9% of the patients, with odds ratios 9.04-fold higher in the IA-FU/IRI300 group (95% CI: 1.07-76.20) and 0.23-fold lower in the IV-FUFOL/IRI250 group (95% CI: 0.05-0.97).

CONCLUSION

This combination seems to have substantial activity in ACC. Overall toxicity was unacceptable in the IA-FU and IRI300 groups, with diarrhea and cytopenia constituting the dose-limiting side effects. Tolerance and efficacy profiles achieved with IV oxaliplatin (120 mg/m2 day 1), IV CPT-11 (250 mg/m2 day 1) and IV 5-FU 2.6 g/m2 with IV leucovorin (500 mg/m2 days 1 and 15) was favorable and deserves further investigation.

Isolated liver perfusion for non-resectable liver tumours: a review

Many treatments have been proposed for non-resectable primary or secondary hepatic cancer but the results have generally been disappointing. Isolated Hepatic Perfusion (IHP) was first attempted four decades ago but it gained acceptance only recently, after spectacular tumour responses were obtained by isolated limb perfusion with melphalan and tumour necrosis factor (TNF) for melanomas and sarcomas. Surgical isolation of the liver is a technically demanding operation that allows the safe administration of high doses of chemotherapeutics and TNF. Percutaneous techniques using balloon occlusion catheters are simpler but result in higher leakage rates from the perfusion circuit into the systemic circulation. Several phase I-II trials indicate that IHP can yield high tumour response rates, even when there is resistance to systemic chemotherapy. However, no significant advantage in overall survival has been demonstrated so far. IHP offers unique pharmacokinetic advantages for locoregional chemotherapy and biotherapy. It might also allow gene therapy with limited systemic exposure and toxicity. At present, IHP nevertheless remains an experimental treatment modality which should therefore be used in controlled trials only.

Antitumour activity of three second-line treatment combinations in patients with metastatic colorectal cancer after optimal 5-FU regimen failure: a randomised, multicentre phase II study

BACKGROUND

We have investigated the efficacy, safety and quality of life profiles of three therapeutic combinations [irinotecan + leucovorin (LV)/5-fluorouracil (5-FU), oxaliplatin + LV/5-FU and irinotecan +oxaliplatin] in patients with metastatic colorectal cancer after failure of a 5-FU-based regimen, or whose disease had progressed within 6 months of the end of treatment.

PATIENTS AND METHODS

One hundred and one patients were randomised to receive either: (i) irinotecan 180 mg/m(2) on day 1 followed by an LV 200 mg/m(2) infusion, before a 5-FU 400 mg/m(2) bolus followed by a 5-FU 600 mg/m(2) infusion (LV5FU2 regimen), on days 1 and 2 every 2 weeks; (ii) oxaliplatin 85 mg/m(2) on day 1 followed by the LV5FU2 regimen on days 1 and 2 every 2 weeks; or (iii) oxaliplatin 85 mg/m(2) followed by irinotecan 200 mg/m(2), both on day 1 every 3 weeks. The primary end point was overall response rate (ORR).

RESULTS

The intention-to-treat ORRs were 11.4% [95% confidence interval (CI) 3.2-26.7), 21.2% (95% CI 9.0-38.9) and 15.2% (95% CI 5.1-31.9), respectively, in the three arms. Tumour growth control was >or=60% for all three combinations and overall survivals were 12.2 months (95% CI 9.2-16.0), 11.5 months (95% CI 9.0-14.1) and 11.0 months (95% CI 8.1-12.2), respectively. All patients were evaluable for safety. Main grade 3-4 toxicity was neutropenia (33 to 39% of patients).

CONCLUSIONS

Thus, second-line treatment with irinotecan/LV5FU2, oxaliplatin/LV5FU2 or irinotecan/oxaliplatin, provides good tumour growth control and survival coupled with an acceptable safety profile.

A phase I study of sequential irinotecan and 5-fluorouracil/leucovorin

BACKGROUND

Irinotecan (CPT-11) and 5-fluorouracil (5-FU)/leucovorin are active agents in colorectal cancer. A sequence-dependent synergism of SN-38 followed by 5-FU/leucovorin in vitro led us to conduct a phase I trial of CPT-11 followed by 5-FU/leucovorin to determine the maximum tolerated dose (MTD) and toxicities of this regimen and to obtain preliminary indications of its activity in patients with advanced solid tumors.

PATIENTS AND METHODS

Fifty-six patients were enrolled in sequential cohorts to receive escalating doses of CPT-11 (90 min infusion) on day 1, followed by leucovorin 20 mg/m(2) (intravenous push) and 5-FU (90 min infusion) on days 2-5 of each 21-day cycle.

RESULTS

A total of 347 treatment cycles (median 4, range 1-25) were administered. Dose-limiting toxicities were diarrhea, neutropenia and fatigue. Nine patients with colorectal cancer and one with gastric cancer had partial or minor responses. Eight of the 10 had prior chemotherapy.

CONCLUSIONS

CPT-11 and 5-FU/leucovorin, as constituents of this novel mechanism-based schedule, have promising activity in patients who have received prior chemotherapy. The recommended phase II/III starting doses are CPT-11 275 mg/m(2) over 90 min on day 1, and 5-FU 400 mg/m(2) plus leucovorin 20 mg/m(2) on days 2-5 every 21 days. This combination can be administered safely to this schedule if there is strict adherence to the 90 min infusion time for both CPT-11 and 5-FU.

Irinotecan, oxaliplatin, and 5-fluorouracil/leucovorin combination chemotherapy in advanced colorectal carcinoma: a phase II study

The purpose of this study was to evaluate the efficacy and tolerance of a combination of irinotecan, oxaliplatin, and 5-fluorouracil (5-FU)/leucovorin in advanced colorectal cancer (ACC). Twenty-six consecutive patients with ACC and an Eastern Cooperative Oncology Group performance status of 0-2 were treated with a combination of oxaliplatin (120 mg/m2 intravenously [i.v.] for 2 hours) on day 1, irinotecan (250 mg/m2 i.v. for 90 minutes) on day 1, and 5-FU (2600 mg/m2 plus leucovorin 500 mg/m2 i.v. in a 24-hour infusion) on day 1 and 15, every 4 weeks. Five of the patients (19.2%) had shown previous chemoresistance. One hundred sixty-two cycles were administered (median, 6; range, 3-13 cycles). All patients were evaluated for toxicity; 23 were evaluable for response. According to intention-to-treat, the overall response rate was 69.2% (18 patients; 95% CI: 48.2%-85.7%), including 3 complete remissions (11.5%). Four additional patients (15.3%) had stable disease, and only 1 (3.8%) progressed. Major toxicities were neutropenia and diarrhea. Grade 3 neutropenia occurred in 9 patients (34.6%), and grade 4 occurred in 1 patient (3.8%). Grade 3 diarrhea occurred in 8 patients (30.7%) and grade 4 in 1 patient (3.8%). Other toxicities were mild. After a median follow-up of 15.5 months, the median progression-free survival was 14 months. Seventeen patients (65.4%) are still alive, and the median overall survival has not been reached yet. This combination of irinotecan, oxaliplatin, and 5-FU/leucovorin is fairly well tolerated and shows promising activity in ACC. This treatment merits further comparison with other combination regimens.

Phase II trial of irinotecan in combination with amifostine in patients with advanced colorectal carcinoma

BACKGROUND

Irinotecan is effective in patients with advanced colorectal carcinoma in both first-line and salvage settings but its use can be limited by serious side effects. Amifostine has been shown to reduce the incidence of cisplatin-induced cumulative renal toxicity in patients with advanced ovarian carcinoma and nonsmall cell lung carcinoma. In the current pilot Phase II trial, the authors examined the potential role of amifostine as a protective agent against irinotecan-induced diarrhea and myelosuppression and evaluated an every-2-weeks regimen as an alternative schedule for the administration of irinotecan in patients with previously treated metastatic colorectal carcinoma.

METHODS

All patients received amifostine, 740 mg/m2, followed by irinotecan, 250 mg/m2, every 2 weeks. A 6-week cycle of chemotherapy (every 2 weeks for 3 treatments) was chosen to assess toxicity and response. The main objective of the current study was to evaluate the impact of amifostine on gastrointestinal and hematologic toxicity.

RESULTS

A total of 22 patients entered the current study. Six of these 22 patients (27%) had WHO Common Toxicity Criteria Grade 3 or 4 diarrhea, including 2 patients (9%) with Grade 4 diarrhea. Eight of 22 patients (36.3%) developed Grade 3 or 4 neutropenia (Grade 4 in 4 of the 22 patients [18%]). Dose reduction was required in 25% of the treatment cycles. Five of the 22 patients (23%) withdrew from the trial due to amifostine toxicity. Of the 15 patients who were evaluable for response, 4 patients (26.6%) had achieved a partial response and 9 (60%) had stable disease as their best response.

CONCLUSIONS

The combination of irinotecan with amifostine in patients with previously treated metastatic colorectal carcinoma did not appear to reduce irinotecan toxicity. Amifostine did not appear to interfere with the cytotoxic effect of irinotecan. The results of the current study did demonstrate efficacy and safety of the every-2-weeks irinotecan schedule that was comparable to other established regimens and these results support its feasibility as a reasonable alternative in this disease setting.

Downstaging of hepatocellular carcinoma and liver metastases from colorectal cancer by selective intra-arterial chemotherapy

BACKGROUND

Although resection is the sole chance of cure in patients with hepatocellular carcinoma (HCC) or metastatic colorectal cancer to the liver, most patients are not candidates for surgery at the time of diagnosis. Strategies aiming at downstaging large or multifocal tumors to enable curative resection are appealing. The aim of this study was to evaluate the effects of neoadjuvant selective intra-arterial chemotherapy in noncirrhotic patients with unresectable HCC or metastatic colorectal cancer to the liver in the absence of extrahepatic disease.

METHODS

Selective chemotherapy was provided by using a subcutaneous pump device via a catheter placed in the gastroduodenal artery. Chemotherapy regimen included floxuridine (0.2 mg/kg/day for 14 days) in each patient with additional boluses of cisplatin and doxorubicin on day 1 of each cycle in the presence of HCC. Patients were evaluated at 3, 6, 9, and 12 months for possible curative resection. Complete follow-up was available for each patient.

RESULTS

Twenty-eight patients with unresectable liver tumors (5 HCC and 23 metastatic colorectal cancer) were included in this study. There were no surgical complications related to pump insertion, and local chemotherapy was started within 1 week of surgery in each patient. The median follow-up in survivors was 31 months (range, 30 months to 5 years). Chemotherapy was well tolerated in 18 (64%) patients. Chemotherapy was discontinued in 4 patients because of abnormal liver function test results, and 2 of them required a biliary stent to relieve a biliary stricture. In 9 patients downstaging enabled curative resection (3 HCC, 6 colorectal metastasis). Seven of these patients were alive and tumor free at the completion of the study, with at least 2 years of follow-up. The actuarial survival rates at 3 years for HCC and colorectal metastases were 60% and 50%, respectively.

CONCLUSIONS

About one third of patients with unresectable liver tumors can be successfully treated by neoadjuvant intra-arterial chemotherapy followed by curative resection. This strategy appears particularly promising in patients with large HCC. This approach should be investigated further.

Retrospective comparison of single-agent chemotherapy with weekly 5-fluorouracil or weekly irinotecan in previously treated patients with metastatic colorectal cancer

This study is a retrospective analysis of response, toxicity and freedom from progression of two single-agent chemotherapy regimens in patients with previously treated metastatic colorectal cancer. Thirty-five patients with histologically confirmed measurable metastatic colorectal cancer received chemotherapy after failure of first-line 5-fluorouracil (5-FU) and leucovorin treatment. The median age was 61 years. Twenty-seven patients had liver metastases, 6 had local recurrence, 1 had retroperitoneal lymph node metastases and 1 had lung metastases. Eighteen patients received weekly 2600 mg/m2 5-FU and 17 patients received weekly 125 mg/m2 irinotecan (CPT-11). Treatment was given until disease progression. Total number of cycles was 202 for 5-FU and 248 for CPT-11. The relative dose intensity was 1.0 for 5-FU and 0.84 for CPT-11. No grade 3-4 toxicity was registered in patients who received 5-FU. Grade 3-4 toxicity rates were as follows in those who received CPT-11: vomiting 1 (5.9%) patient in 1 cycle, diarrhea 3 (17.7%) patients in 3 cycles and neutropenia in 3 (17.7%) patients in 3 cycles. No patients manifested febrile neutropenia. Two patients (11.8%) needed hospital admission because of toxicity: 1 for vomiting and 1 for diarrhea. No objective responses were observed in the 5-FU group of patients. Three patients (17.6%) who received CPT-11, achieved partial response with a median duration of 8 months. Stable disease was registered in 3 (17.6%) and 9 (52.9%) patients in 5-FU and CPT-11 groups respectively (p=0.05). Median time to progression was 3.3 months for patients who received 5-FU and 4.2 months for those treated with CPT-11 (not significant). One-year survival was 22.2% and 54.3% respectively (p=0.05).

CONCLUSION

Weekly chemotherapy with CPT-11 is tolerated with acceptable toxicity and leads to a better response rate than weekly high dose 5-FU. It also significantly improves survival but does not prolong freedom from progression.

Optimizing the use of irinotecan in colorectal cancer

The introduction of new agents with novel mechanisms of action has led to considerable changes in the management of colorectal cancer in recent years. One of these novel agents, irinotecan, has been shown to offer survival benefits in both the first- and second-line treatment of advanced/metastatic colorectal cancer. Irinotecan monotherapy improves survival compared with both best supportive care and infused 5-fluorouracil (5-FU) in patients with 5-FU-pretreated disease, without impacting negatively on patients' quality of life. As a result, irinotecan monotherapy is now considered to be the standard treatment in this setting. Irinotecan in combination with 5-FU/leucovorin (LV) was subsequently evaluated as first-line therapy for metastatic colorectal cancer in two randomized, phase III studies. Both trials confirmed that irinotecan plus infused or bolus 5-FU/leucovorin LV provide a modest survival benefit without compromising patients' quality of life. Combined irinotecan/5-FU/LV represents a new standard in the first-line treatment of metastatic colorectal cancer. In an attempt to further improve efficacy and tolerability, recent studies have investigated irinotecan in combination with capecitabine as first-line treatment for colorectal cancer. The replacement of infused 5-FU with oral capecitabine provides a more convenient treatment option. A phase I study was conducted to establish the maximum tolerated dose, and demonstrated encouraging antitumor activity and a manageable safety profile with the combination. This article provides a brief overview of the pivotal clinical trial data for irinotecan and discusses how irinotecan-based therapy may be improved in the future. It also discusses potential optimization of irinotecan use through identification of patient subpopulations most likely to benefit from combination or sequential strategies, and the potential of new, oral agents such as capecitabine to replace i.v. 5-FU as a combination partner for irinotecan.

Integrating oxaliplatin into the management of colorectal cancer

Oxaliplatin, a third-generation platinum analogue, is a novel compound with proven anti-tumor activity in colorectal cancer that has demonstrated synergy with 5-fluorouracil (5-FU) in human tumor xenograft models. A series of phase II trials demonstrated that, as second-line therapy, oxaliplatin in combination with 5-FU/leucovorin (LV) is active and can overcome clinical resistance to 5-FU. Subsequently, two large, randomized, phase III trials demonstrated that the addition of oxaliplatin to 5-FU/LV significantly improved response rates and time to disease progression in the first-line setting, but had no statistically significant impact on survival. Oxaliplatin in combination with 5-FU/LV represents an important treatment option for patients in whom 5-FU-based therapy has failed and as first-line therapy. Oxaliplatin has also been investigated in combination with the oral fluoropyrimidine, capecitabine. As an oral agent that exploits the high intratumoral activity of thymidine phosphorylase to generate 5-FU preferentially within tumor tissue, capecitabine may improve the efficacy and tolerability of fluoropyrimidine/oxaliplatin combination therapy. A phase I dose-escalation study has been performed in patients with advanced/metastatic solid tumors to establish the most appropriate regimen. The study indicated that the combination is feasible and has substantial antitumor activity in patients with colorectal cancer. This article provides an overview of the clinical trial data for oxaliplatin and discusses how oxaliplatin may best be used in the future.

Randomised trial of SIR-Spheres plus chemotherapy vs. chemotherapy alone for treating patients with liver metastases from primary large bowel cancer

PURPOSE

SIR-Spheres are radioactive yttrium90 microspheres (SIR-Spheres, Sirtex Medical Limited, Australia) used to selectively target high levels of ionising radiation to tumors within the liver. This trial was designed to measure any increased patient benefit by adding a single administration of SIR-Spheres to a regimen of regional hepatic artery chemotherapy (HAC) administered as a 12 day infusion of floxuridine and repeated at monthly intervals, vs. the same chemotherapy alone.

PATIENTS AND METHODS

A phase III randomised clinical trial entering 74 patients was undertaken on patients with bi-lobar non-resectable liver metastases from primary adenocarcinoma of the large bowel. Patient benefit criteria assessed in the trial were tumor response, time to disease progression in the liver, overall survival, quality of life, and treatment related toxicity. Tumor response was measured by serial changes in both cross-sectional tumor areas and total tumor volumes, provided any response lasted not less than three months as well as changes in serum carcino-embryonic antigen (CEA).

RESULTS

The partial and complete response rate (PR + CR) was significantly greater for patients receiving SIR-Spheres when measured by tumor areas (44%) vs. 17.6%, P = 0.01) tumor volumes (50% vs. 24%, P = 0.03) and CEA (72% vs. 47%, P = 0.004). The median time to disease progression in the liver was significantly longer for patients receiving SIR-Spheres in comparison to patients receiving HAC alone when measured by either tumor areas (9.7 vs. 15.9 months, P = 0.001), tumor volumes (7.6 vs. 12.0 months, P = 0.04) or CEA (5.7 vs. 6.7 months, P = 0.06). The one, two, three and five-year survival for patients receiving SIR-Spheres was 72%, 39%, 17% and 3.5%, compared to 68%, 29%, 6.5% and 0% for HAC alone. Cox regression analysis suggests an improvement in survival for patients treated with SIR-Spheres who survive more than 15 months (P = 0.06). There was no increase in grade 3-4 treatment related toxicity and no loss of quality of life for patients receiving SIR-Spheres in comparison to patients receiving HAC alone.

CONCLUSION

The combination of a single injection of SIR-Spheres plus HAC is substantially more effective in increasing tumor responses and progression free survival than the same regimen of HAC alone.

Phase I-II study of irinotecan combined with mitomycin-C in patients with advanced gastric cancer

BACKGROUND

Irinotecan (CPT-11) shows synergism with mitomycin-C (MMC) in a preclinical setting. The goals of this study were to determine the maximum tolerated dose (MTD), the dose limiting toxicity, the recommended dose (RD), and preliminary anti-tumor activity in a combined CPT-11 and MMC treatment of advanced gastric cancer.

PATIENTS AND METHODS

The study was designed to evaluate escalated doses of CPT-11 and MMC administered every two weeks. Five escalating dose levels were studied (CPT-11/ MMC: 100/5; 125/5; 150/5; 150/7; 150/10 mg/m2).

RESULTS

Thirty-one patients were enrolled. Thirty patients were assessable for toxicity and tumor response for 89 treatment cycles. The median age was 60 years (32-73 years), and most patients (90%) had a performance status of 0 to 1. Fourteen patients were previously treated and 17 were chemotherapynaive. The MTD was CPT-11 150 mg/m2 plus MMC 10 mg/m2, in which all three patients experienced grade 4 neutropenia. including one episode of prolonged and one of febrile neutropenia, and one patient experienced grade 3 diarrhea during the first cycle. Fifteen partial responses were observed.

CONCLUSIONS

The RD based on this phase I-II study was CPT-11 150 mg/m2 plus MMC 5 mg/m2 administered every two weeks. This combination demonstrates promising activity against advanced gastric cancer and warrants further investigation in another phase II study.

Phase I trial of weekly irinotecan combined with UFT as second-line treatment for advanced colorectal cancer

The aim of this study was to determine the maximum-tolerated dose (MTD) and dose-limiting toxicity (DLT) of weekly Irinotecan (CPT-11) plus UFT, and to assess the antitumour activity of this combination as second-line chemotherapy in patients with advanced colorectal carcinoma, 31 patients with measurable advanced colorectal carcinoma were treated. Cohorts of 3 patients received increasing dose levels of the combination. Levels 1 to 4 included a fixed dose of oral (p.o.) UFT (250 mg/m(2)/day) for 21 days of a 28-day cycle combined with increasing intravenous (i.v.) doses of CPT-11 (80, 100, 110 and 120 mg/m(2)) on days 1, 8 and 15. Levels 5 and 6 included a higher fixed dose of oral UFT (300 mg/m(2)) combined with increasing i.v. doses of CPT-11 (100 and 110 mg/m(2)) on days 1, 8 and 15. 147 courses were administered. MTD were reached at level 4 (2 cases of grade 4 diarrhoea and 1 grade 3 asthenia), and level 6 (1 grade 4 diarrhoea, 1 grade 3 diarrhoea and 1 grade 3 febrile neutropenia). Responses in 30 evaluable patients were: 3 partial responses (10%), 15 stable disease (50%) and progressive disease in 12 patients (40%). Median time to progression was 4.5 months (95% Confidence Interval (CI): 3.4-6.6 months) and median survival was 11 months (95% CI: 7.9-14.1 months). The recommended doses for phase II trials are: (a) CPT-11 110 mg/m(2) i.v. on days 1, 8 and 15 every 28 days plus UFT 250 mg/m(2) p.o. on days 1 through to 21 or (b) CPT-11 100 mg/m(2) and UFT 300 mg/m(2).

Metastatic colorectal cancer

Despite advances in screening procedures and the use of adjuvant therapy, approximately 50% of patients with colorectal cancer eventually will develop metastatic disease. Long-term disease-free survival can be achieved in 25% to 40% of selected patients who undergo resection of liver or lung metastases. For all other patients, treatment is palliative. For decades, 5-fluorouracil was the only available drug for colorectal cancer; hence, numerous trials were performed that used various administration schedules and modulating agents to improve therapeutic efficacy. The addition of leucovorin to 5-FU improves response but not survival. Infusion schedules alter the toxicity profile but have a negligible impact on survival. Irinotecan was the first new drug to demonstrate activity in colorectal cancer. It was used initially in the second-line setting, where it was shown to improve quality of life and survival over best supportive care or infusional 5-FU. Recently, irinotecan has been incorporated into the front-line treatment of metastatic colorectal cancer in combination with 5-FU and leucovorin; this combination improves survival by approximately 3 months. Careful patient selection and adherence to strict dose adjustments are essential to prevent significant toxicity when patients are treated on this regimen. The oral fluoropyrimidine capecitabine recently has been approved for the front-line treatment of patients with colorectal cancer who are not appropriate candidates for combination therapy. Oxaliplatin, a novel DACH (diaminocyclohexane) platinum with definite activity in colorectal cancer, is approved for this disease in Europe and is undergoing phase III clinical trials in the United States. Other drugs with potential activity in colorectal cancer include raltitrexed, pemetrexed disodium, and the epothilone analog BMS-247550 (Bristol-Myers Squibb, New York, NY). Novel cytostatics with promising activity in colorectal cancer are being evaluated in clinical trials, including epidermal growth factor receptor inhibitors, such as IMC-C225 (Imclone Systems, New York, NY) and ZD1839 (AstraZeneca, London, UK), angiogenesis inhibitors such as bevacizumab and SU5416 (Sugen, San Francisco, CA), and vaccines such as CEAVac (Titan Pharmaceuticals, San Francisco, CA). For those patients whose disease is localized to the liver, there also is an emerging role for local therapies, including cryosurgery, radiofrequency ablation, and hepatic artery infusional chemotherapy, and resection. The emergence of these new drugs and new interventional modalities has allowed physicians who treat colorectal cancer to move beyond 5-FU.

Phase I dose-finding and pharmacokinetic trial of irinotecan (CPT-11) administered every two weeks

OBJECTIVES

This trial was performed to determine the maximum tolerated dose (MTD), dose-limiting toxicity (DLT), and pharmacokinetic profile of irinotecan (CPT-11) when administered on a once-every-2-week schedule.

PATIENTS AND METHODS

CPT-11 was administered to successive cohorts of patients at progressively increasing starting doses ranging from 125 to 350 mg/m2. The MTD and DLTs were determined both for CPT-11 alone and for CPT-11 followed by filgrastim (G-CSF). Plasma samples were obtained during the first 24 hours after initial dosing to determine the total concentrations (lactone + carboxylate forms) of CPT-11; of the active metabolite SN-38; and of SN-38 glucuronide (SN-38G).

RESULTS

Neutropenic fever was the DLT for CPT-11 at the 300 mg/m2 dose level. When G-CSF was added, dose escalation beyond 350 mg/m2 could not be achieved due to grade 2-3 toxicities that prevented on-time retreatment with CPT-11. Severe, late diarrhea was uncommon on this schedule. Peak plasma concentrations of SN-38 and SN-38G were approximately 2.5% and 4.2% of the corresponding peak plasma concentration for CPT-II, respectively The harmonic mean terminal half-lives for CPT-11, SN-38, and SN-38G were 7.1 hours, 13.4 hours, and 12.7 hours, respectively. No predictive correlation was observed between CPT-11 or SN-38 peak concentration or AUC and first-cycle diarrhea, neutropenia, nausea, or vomiting. Across the range of doses studied, mean CPT-11 clearance was 14.0 +/- 4.0 l/h/m2 and volume of distribution was 146 +/- 45.9 l/m2.

CONCLUSIONS

When administered every two weeks, the recommended phase II starting dose of CPT-11 is 250 mg/m2 when given alone and 300 mg/m2 when supported by G-CSF. This every-two-week regimen offers a tolerable and active alternative to weekly or every-three-week single-agent CPT-11 therapy.

Toxicity of irinotecan (CPT-11) and hepato-renal dysfunction

Various clinical and laboratory parameters have been investigated for their ability to predict toxicity arising from the use of the anticancer drug, irinotecan (CPT-11). In particular, patients deficient in the conjugation of SN-38, a metabolite of CPT-11, are known to be at greater risk. We describe one case of a patient with metastatic colorectal cancer treated with a single dose of CPT-11 at 125 mg/m(2). Although this patient lacked any known predictive factors for toxicity, he experienced severe side-effects several days later. We hypothesized that the toxicity in this patient was due to compromised SN-38 conjugation. Plasma samples were analyzed by reversed-phase high-performance liquid chromatography assay for CPT-11 and its metabolites at 96, 144, 168, 192 and 288 h post-administration. We observed that the concentrations of both the parent drug and its metabolites were markedly raised (11- to 60-fold expected). Additionally the estimated terminal half-lives were 1.5-7 times those expected (29.5, 101, 39.6 and 41.8 h for CPT-11, APC, SN-38G and SN-38, respectively). We conclude that the toxicity in this patient was not caused by deficient SN-38 conjugation, but by decreased drug excretion through both hepatic and renal routes.

Liver metastases from colorectal cancer: regional intra-arterial treatment following failure of systemic chemotherapy

This study was designed to determine response rate, survival and toxicity associated with combination chemotherapy delivered intra-arterially to liver in patients with hepatic metastases of colorectal origin refractory to standard systemic treatment. A total of 28 patients who failed prior systemic treatment with fluoropyrimidines received a median of 5 cycles of intra-arterial treatment consisting of 5-fluorouracil 700 mg/m(2)/d, leucovorin 120 mg/m(2)/d, and cisplatin 20 mg/m(2)/d for 5 consecutive days. Cycles were repeated at intervals of 5-6 weeks. A major response was achieved in 48% of patients: complete response in 8% and partial response in 40%. The median duration of response was 11.5 months. Median survival was 12 months at a median follow up of 12 months. On multivariate analysis, the only variables with a significant impact on survival were response to treatment and performance status. Toxicity was moderate: grades III-IV neutropenia occurred in 29% of patients. Most of the patients complained of fatigue lasting for a few days following each cycle. There were no cases of hepatobiliary toxicity. These findings indicate that regional intra-arterial treatment should be considered in selected patients with predominantly liver disease following failure of standard treatment.

Review of the role of CPT-11 in the treatment of colorectal cancer

Colorectal cancer (CRC) is the second leading cause of cancer death in Western countries, and although the treatment of advanced CRC has progressed substantially, the improvements in response rates have not always been translated into a significant survival benefit. Until recently, the standard therapy for advanced CRC was a variety of biomodulated 5-fluorouracil (5-FU) regimens. 5-FU was used as first- or second-line therapy, and a different 5-FU regimen was used second line if first-line 5-FU therapy failed. Typically, the survival times for these patients were short and their quality of life poor. In recent years, a variety of new agents have emerged that have demonstrated activity in the treatment of advanced CRC. Of these, irinotecan (CPT-11) and oxaliplatin in combination with 5-FU and folinic acid (FA) have yielded the most promising results. However, only CPT-11 combined with either bolus or high-dose infusional 5-FU/FA, in randomized phase III studies, has demonstrated an increased response rate and median time to progression, producing a significant and clinically relevant survival advantage. In 2 randomized phase III studies, oxaliplatin/5-FU/FA demonstrated a clear increase in response rate over 5-FU/FA alone but failed to demonstrate a survival advantage. CPT-11 was approved by the Food and Drug Administration in April 2000 for the first-line treatment of advanced CRC in combination with 5-FU/FA.

Hepatic-arterial chemotherapy

The liver is a common site of metastases from cancers from most sites, but particularly from the gastrointestinal tract, since the portal vein drains into the liver. About half of all patients with colorectal cancer develop liver metastases. The response of liver metastases to systemic combination chemotherapy has improved, but the 2-year survival is only 25-30%. Hepatic-arterial infusion of chemotherapy produces higher response rates, with a 2-year survival of 50-60%. In patients who can undergo liver resection followed by hepatic-arterial infusion, the 2-year survival is 85%. This review summarises the anatomical basis, pharmacokinetic background, and cost-effectiveness of this procedure. We discuss the phase II and phase III studies of hepatic-arterial infusion therapy, with a focus on liver metastases from colorectal cancer.

Advances in the treatment of metastatic colorectal cancer

Colorectal cancer represents the third leading cause of cancer mortality in the United States. During the past four decades, 5-fluorouracil (5-FU) has served as the cornerstone of therapy for individuals with advanced colorectal cancer (ACRC). Despite numerous attempts at maximizing efficacy of 5-FU through biochemical modulation, a significant benefit in terms of survival has never been realized. The recent emergence of novel chemotherapeutic drugs employing different mechanisms of action than 5-FU has led to the incorporation of irinotecan (CPT-11) with 5-FU/leucovorin as the new standard first-line regimen for future trials. This review outlines emerging data utilizing oral fluoropyrimidines and other new agents including oxaliplatin, raltitrexed, and eniluracil. Randomized clinical trials are currently underway in an effort to define optimal combination chemotherapy regimens, scheduling of agents, duration of therapy, and choice of therapy using a variety of prognostic molecular markers.

Irinotecan plus fluorouracil/leucovorin for metastatic colorectal cancer: a new survival standard

BACKGROUND

Irinotecan is a topoisomerase I inhibitor that prolongs survival in patients with colorectal cancer refractory to fluorouracil (5-FU) and leucovorin (LV). This demonstrated activity of irinotecan as effective second-line therapy for colorectal cancer led to evaluation of combination irinotecan/5-FU/LV as first-line therapy for patients with metastatic disease. The results of two prospective phase III randomized, controlled, multicenter, multinational clinical trials in patients with previously untreated metastatic colorectal cancer served as the basis for U.S. and European approval of irinotecan/5-FU/LV for this indication. An overview of the findings of these two pivotal studies provides insights regarding the application of this new combination in clinical practice.

METHODS

Patients were randomly assigned to receive 5-FU/LV, either alone, or with concurrent irinotecan. The study conducted primarily in North America (study 1), employed bolus 5-FU/LV schedules, while the study performed primarily in Europe (study 2), employed infusional 5-FU/LV regimens. Major endpoints included tumor response rate, time to tumor progression (TTP), overall survival, quality of life, and safety.

RESULTS

In study 1, the respective confirmed response rates for irinotecan/5-FU/LV versus 5-FU/LV were 39% and 21% (p <.001); median TTPs were 7.0 months and 4.3 months, respectively (p =.004). In study 2, response rates for irinotecan/5-FU/LV versus 5-FU/LV alone were 35% and 22% (p =.005); median TTPs were 6.7 months and 4.4 months, respectively (p <.001). Survival time increased significantly with irinotecan/5-FU/LV versus 5-FU/LV alone in both studies (study 1: median 14.8 months versus 12.6 months, p =.042; study 2: median 17.4 months versus 14.1 months, p =.032). The combined analysis of the data from the two studies showed median survivals of 15.9 months versus 13.3 months, favoring the irinotecan-containing combinations (stratified-by-study p =.003). Patients in study 1 had a 36% lower risk of tumor progression and a 20% lower risk of death with the irinotecan combination than with 5-FU/LV alone; comparable risk reduction values in study 2 were 42% and 23%. While grade 3 diarrhea and vomiting were more common with irinotecan/5-FU/LV, grade 4 neutropenia, neutropenic fever, and mucositis were less common with irinotecan/5-FU/LV than with the Mayo Clinic 5-FU/LV regimen.

CONCLUSION

The combination of irinotecan/5-FU/LV is superior to 5-FU/LV alone as first-line therapy for patients with metastatic colorectal cancer, offering consistently improved tumor control and prolonged survival. Irinotecan-based combination therapy sets a new survival standard for the treatment of this life-threatening disease.

Irinotecan in the treatment of colorectal cancer: clinical overview

PURPOSE AND METHODS

For more than three decades, the therapeutic options for patients with advanced colorectal cancer have almost exclusively been based on fluoropyrimidines. With the recognition that topoisomerase-I (TOP-I) is an important therapeutic target in cancer therapy, irinotecan, a semisynthetic TOP-I-interactive camptothecin derivative, has been clinically established in the treatment of colorectal cancer.

RESULTS

Irinotecan was investigated as second-line chemotherapy after prior treatment with fluorouracil (FU)-based regimens in two large randomized phase III trials comparing irinotecan with either best supportive care or an infusional FU/leucovorin (LV) regimen. The outcomes of these trials established irinotecan as the standard therapy in the second-line treatment of colorectal cancer. The therapeutic value of irinotecan in the first-line treatment of metastatic colorectal cancer was investigated in two large randomized phase III trials comparing the combination of irinotecan and FU/LV with FU/LV alone. Both trials demonstrated significant superior efficacy for the combination of irinotecan and FU/LV in terms of response rate, median time to disease progression, and median survival time. Consequently, the combination of irinotecan and FU/LV has been approved as first-line chemotherapy for patients with metastatic colorectal cancer and constitutes the reference therapy against which other treatment options must be tested in the future.

CONCLUSION

In this review, the clinical rationale and update of the present clinical status of irinotecan in the treatment of colorectal cancer and future prospects of irinotecan-based combinations are discussed.

Irinotecan-associated pulmonary toxicity

We present the circumstances surrounding a 57-year-old Caucasian man with advanced colorectal cancer who developed relapsing interstitial lung disease following a single exposure to irinotecan (CPT-11). Progressive pulmonary insufficiency and death were reported in the initial Japanese studies, despite institution of empiric steroid therapy for a syndrome similar to that which our patient experienced. As a result, patients with compromised pulmonary function were generally excluded from US clinical trials. Notwithstanding this, cough and dyspnea were reported in approximately 20% of patients in the US studies. As the clinical indications for the use of this agent expand, we describe irinotecan-associated interstitial pneumonitis as a serious potential adverse effect. Patients with pre-existing pulmonary disease may be at higher risk for this complication and clinicians should be alert to this possibility.

Clinical use of topoisomerase I inhibitors in anticancer treatment

The camptothecin analogs topotecan and irinotecan have shown to be among the most effective anticancer agents and, as S-phase specific agents, their antitumor effect is maximized when they are administered in protracted schedules. The documented activity as single agents in many adult and pediatric malignancies has been followed by their use in combination with other anticancer agents. These studies have shown promising results, and have placed topotecan and irinotecan in the first line treatment for some malignancies. However, studies to better determine the optimal schedules and sequence of combinations are needed.

Irinotecan plus fluorouracil and leucovorin for metastatic colorectal cancer. Irinotecan Study Group

BACKGROUND

The combination of fluorouracil and leucovorin has until recently been standard therapy for metastatic colorectal cancer. Irinotecan prolongs survival in patients with colorectal cancer that is refractory to treatment with fluorouracil and leucovorin. In a multicenter trial, we compared a combination of irinotecan, fluorouracil and leucovorin with bolus doses of fluorouracil and leucovorin as first-line therapy for metastatic colorectal cancer. A third group of patients received irinotecan alone.

METHODS

Patients were randomly assigned to receive irinotecan (125 mg per square meter of body-surface area intravenously), fluorouracil (500 mg per square meter as an intravenous bolus), and leucovorin (20 mg per square meter as an intravenous bolus) weekly for four weeks every six weeks; fluorouracil (425 mg per square meter as an intravenous bolus) and leucovorin (20 mg per square meter as an intravenous bolus) daily for five consecutive days every four weeks; or irinotecan alone (125 mg per square meter intravenously) weekly for four weeks every six weeks. End points included progression-free survival and overall survival.

RESULTS

Of 683 patients, 231 were assigned to receive irinotecan, fluorouracil, and leucovorin; 226 to receive fluorouracil and leucovorin; and 226 to receive irinotecan alone. In an intention-to-treat analysis, as compared with treatment with fluorouracil and leucovorin, treatment with irinotecan, fluorouracil, and leucovorin resulted in significantly longer progression-free survival (median, 7.0 vs. 4.3 months; P=0.004), a higher rate of confirmed response (39 percent vs. 21 percent, P<0.001), and longer overall survival (median, 14.8 vs. 12.6 months; P=0.04). Results for irinotecan alone were similar to those for fluorouracil and leucovorin. Grade 3 (severe) diarrhea was more common during treatment with irinotecan, fluorouracil, and leucovorin than during treatment with fluorouracil and leucovorin, but the incidence of grade 4 (life-threatening) diarrhea was similar in the two groups (<8 percent). Grade 3 or 4 mucositis, grade 4 neutropenia, and neutropenic fever were less frequent during treatment with irinotecan, fluorouracil, and leucovorin. Adding irinotecan to the regimen of fluorouracil and leucovorin did not compromise the quality of life.

CONCLUSIONS

Weekly treatment with irinotecan plus fluorouracil and leucovorin is superior to a widely used regimen of fluorouracil and leucovorin for metastatic colorectal cancer in terms of progression-free survival and overall survival.

Progress in colorectal cancer chemotherapy: how far have we come, how far to go?

Fluorouracil has been the mainstay of treatment for colorectal cancer (CRC) for almost 40 years. Various schedules and biochemical modulators have been investigated in an attempt to improve the therapeutic efficacy of fluorouracil. To date, fluorouracil plus folinic acid represents the standard therapy in CRC for the adjuvant treatment of patients at high risk for relapse and for the first-line treatment of metastatic disease. To gain clinical acceptance, however, oral fluoropyrimidines must confer at least the same survival advantages associated with the optimal intravenous fluorouracil regimens. Irinotecan and oxaliplatin are 2 other novel agents that have mechanisms of action that are uniquely different from those of fluorouracil, with demonstrated activity in patients with fluorouracil-refractory disease. Recent randomised trials comparing fluorouracil plus folinic acid with combinations of either irinotecan or oxaliplatin and fluorouracil plus folinic acid have shown that response rates are improved and time to progression is increased in patients receiving the combination regimens. These regimens are being rapidly introduced in the adjuvant setting, and the role and acceptance of these combination regimens as first-line therapy needs to be defined. Other novel agents being evaluated in the treatment of patients with advanced CRC include oral edrecolomab (monoclonal antibody 17-1A) and tumour vaccines. Future research is focused on enabling clinicians to individualise treatment strategies in patients with CRC, so as to improve clinical outcomes and reduce drug toxicity.

Novel chemotherapeutic agents in colorectal cancer

Colorectal cancer remains the second most common cause of cancer death in Europe. A number of new agents, with varying mechanisms of action, have been developed and are being evaluated, both as single agents and in combination. Irinotecan, a topisomerase I inhibitor, and oxaliplatin, a new platinum compound, have proven efficacy in advanced colorectal cancer resistant to 5-fluorouracil. Capecitabine and other oral fluoro-pyrimidines are also emerging as potentially effective drugs. Raltitrexed and other inhibitors of thymidylate synthase (TS) are entering clinical practice although their role has yet to be determined. The new fluoro-pyrimidines and TS inhibitors are important classes of drug which have been designed to take advantage of the knowledge of folate metabolism gained from basic clinical research. Their design features could perhaps reduce the toxicity seen with the first generation cytotoxic agents. This review will focus on these new chemotherapeutic agents in colorectal cancer with respect to their mechanisms of action, current clinical activity and their potential use both in the adjuvant and palliative settings.

5-Fluorouracil and folinic acid with or without CPT-11 in advanced colorectal cancer patients: a multicenter randomised phase II study of the Southern Italy Oncology Group

PURPOSE

The combination regimen CPT-11 plus bolus and infusion 5-fluorouracil (5-FU) with high-dose leucovorin (hybrid regimen LV5FU2) has been tested for activity and toxicity against advanced colorectal carcinoma in a randomised, multicenter phase II trial.

PATIENTS AND METHODS

A total of 102 chemotherapy-naïve patients were randomised in a 1:2 fashion to receive: leucovorin 100 mg/m2 administered as a two-hour infusion before 5-FU 400 mg/m2 as an intravenous bolus, and FU 600 mg/m2 as a 22-hour infusion immediately after 5-FU bolus injection repeated on days 1 and 2 (LV5FU2 regimen, arm A, 34 patients) or CPT-11 at 180 mg/m2 (150 mg/m2 for patients of age > or = 70 and < 75 years) only on day 1 immediately before LV5FU2 therapy (LV5FU2 + CPT-11 regimen, arm B 68 patients). Both treatments were repeated every two weeks. The presence of a calibration arm assured consistency and more realistic evaluation of results achieved with the LV5FU2 + CTP-II regimen.

RESULTS

Thirty-three and sixty-four patients were evaluable in arm A and B, respectively. The overall response rate was 18% in arm A (95% CI: 7%-34%) and 40% in arm B (95% CI: 28%-52%). Median time to progression, median duration of response and survival were similar in both groups. Responders (CR + PR) survived statistically longer than non-responders only in arm B (20 vs. 10 months, P = 0.0016). All patients were evaluable for toxicity which was mild in both groups; gastrointestinal disturbances were the most common. There were no treatment-related deaths. Grade 3-4 toxicity was uncommon in both arms.

CONCLUSIONS

The addition of CPT-11 to the hybrid LV5FU2 regimen provided a significant overall response rate (40%) with relatively mild toxicity. The overall response rate was 18% in patients treated with LV5FU2 alone in the calibration arm. Thus, considering other encouraging data from the literature, the CPT-11 + FU-LV combination therapy can be regarded as a new, very effective treatment option for first-line treatment of advanced colorectal cancer patients.

Prognostic factors for tumour response, progression-free survival and toxicity in metastatic colorectal cancer patients given irinotecan (CPT-11) as second-line chemotherapy after 5FU failure. CPT-11 F205, F220, F221 and V222 study groups

Our purpose was to determine, in patients with metastatic colorectal carcinoma treated with irinotecan single-agent after 5-FU failure, the most significant predictive parameters for tumour response, progression-free survival and toxicity. Between October 1992 and April 1995, 455 patients with 5-FU resistant metastatic colorectal carcinoma entered four consecutive phase II trials. The first two studies assessed tumour response, the other two were randomized studies which assessed the efficacy of racecadotril to prevent irinotecan-induced diarrhoea. Due to homogeneous main eligibility criterias, data from those studies could be pooled for statistical analysis. Potential clinical and biological predictive factors (PF) for toxicity, tumour growth control, e.g. response or stabilization and progression-free survival (PFS), were studied in multivariate analysis. 363 patients were evaluable for response, 432 were evaluable for PFS, 368 for neutropenia and 416 for delayed diarrhoea, respectively. Normal baseline haemoglobin level (Hb), time since diagnosis of colorectal carcinoma, grade 3 or 4 neutropenia or diarrhoea at first cycle and a low number of organs involved were the most PF for tumour growth control (P<0.05). Significant prognostic variables for PFS were WHO Performance Status, liver and lymph-node involvement, time since diagnosis, age and CEA value (P < or =0.02). Six groups of patients based on the number of unfavourable prognostic factors are presented. Baseline bilirubin, haemoglobin level, number of organs involved and time from diagnosis were PF for neutropenia; PS, serum creatinine, leukocyte count, time from 5-FU progression and prior abdominopelvic irradiation were PF for delayed diarrhoea (P< or =0.05). These PF should help clinicians to anticipate for a given patient the probability to observe a response/stabilization or a toxicity. These results should also be prospectively confirmed in ongoing or future trials using irinotecan, both as a single agent and in combination with other drugs.

Expression of DNA topoisomerase I in neoplasms of the kidney: correlation with histological grade, proliferation, and patient survival

Renal cell carcinoma is an inherently chemotherapeutically resistant neoplasm. Because of this, new drugs targeting this tumor are needed. One class of new anticancer drug targets the enzyme DNA topoisomerase I. Laboratory data indicate that cells sensitive to topo I targeting drugs contain high topo I levels. To determine whether some renal cell carcinomas contain elevated topo I and might therefore be targets of topo I active antitumor agents, we used a new immunohistochemical stain for topo I to determine the expression of the enzyme in 51 tumors of the kidney. Increased topo I expression was found in 4 of 11 (36%) grade 3 renal cell carcinomas and in 8 of 8 (100%) grade 4 renal cell carcinomas. Normal topo I expression was observed in all adenomas, oncocytomas, and grade 1 and grade 2 renal cell carcinomas. Because topo I targeted anticancer drugs are S-phase specific, topo II-alpha and MIB-1 proliferation indices also were performed. Topo II-alpha correlates well with MIB-1 (correlation coefficient = 0.96). Of the 12 tumors with elevated topo I, only 3 had topo II-alpha proliferation indices greater than 40, indicating a tumor with elevated topo I expression and a large growth fraction. We hypothesize that these tumors might be susceptible to topo I anticancer drug therapy. In addition, we found that the average topo II-alpha proliferation index of tumors from patients who died of disease was 27.4 +/- 19.8, which was statistically different from the average topo II-alpha index of 5.8 +/- 6.5 observed in tumors from patients who remained alive during our follow-up.

Phase I and pharmacologic study of irinotecan administered as a 96-hour infusion weekly to adult cancer patients

PURPOSE

We conducted a phase I and pharmacologic study of a weekly 96-hour infusion of irinotecan to determine the maximum-tolerated dose, define the toxicity profile, and characterize the clinical pharmacology of irinotecan and its metabolites.

PATIENTS AND METHODS

In 26 adult patients with solid tumors, the duration and dose rate of infusion were escalated in new patients until toxicity was observed.

RESULTS

In 11 patients who were treated with irinotecan at 12.5 mg/m(2)/d for 4 days weekly for 2 of 3 weeks, dose-limiting grade 3 diarrhea occurred in three patients and grade 3 thrombocytopenia occurred in two patients. The recommended phase II dose is 10 mg/m(2)/d for 4 days given weekly for 2 of 3 weeks. At this dose, the steady-state plasma concentration (Css) of total SN-38 (the active metabolite of irinotecan) was 6.42 +/- 1.10 nmol/L, and the Css of total irinotecan was 28.60 +/- 17.78 nmol/L. No patient experienced grade 3 or 4 neutropenia during any cycle. All other toxicities were mild to moderate. The systemic exposure to SN-38 relative to irinotecan was greater than anticipated, with a molar ratio of the area under the concentration curve (AUC) of SN-38 to irinotecan of 0.24 +/- 0.08. One objective response lasting 12 months in duration was observed in a patient with metastatic colon cancer.

CONCLUSION

The recommended phase II dose of irinotecan of 10 mg/m(2)/d for 4 days weekly for 2 of 3 weeks was extremely well tolerated. Further efficacy testing of this pharmacologic strategy of administering intermittent low doses of irinotecan is warranted.

Sequence-dependent growth inhibition and DNA damage formation by the irinotecan-5-fluorouracil combination in human colon carcinoma cell lines

We evaluated irinotecan (CPT-11) together with 5-fluorouracil (5-FU) for improved cell growth inhibition with respect to that by either agent alone in the human colon carcinoma cell lines SW620, HT-29 and SNU-C4. Cells were exposed for 24 h to each drug, as well as to various combinations and sequences of low, fixed doses of one drug with higher varying doses of the other, cultured for two more days in drug-free medium and then assessed for growth response with the sulphorhodamine B assay. Multiple drug effect analysis was used to evaluate the data, which were then related to the amount of DNA damage occurring in the cells which was determined by a fluorescence-enhancement assay for DNA unwinding. Cellular responses were also related to thymidylate synthase topoisomerase I and carboxyl esterase activities, which were assessed by a ligand-binding and a 3H-release assay; a DNA decatenation assay; and a spectrophotometric method, respectively. IC50 values for 5-FU alone in the SW620, HT29 and SNU-C4 cells were 15.3 +/- 0.8, 8.2 +/- 1.3 and 2.2 +/- 0.7 microM, respectively, and for CPT-11 2.0 +/- 0.9, 2.5 +/- 0.5 and 3.8 +/- 0.3 microM, respectively. The differential responses to 5-FU alone were possibly determined by differences in substrate affinity and conversion rate of thymidylate synthase (K(m) of approximately 7.5, 5.0 and 2.5 microM and V0 of approximately 800, 200 and 2400 microM/h, respectively). The comparable cellular responses to CPT-11 alone might be accounted for by the counterbalancing effects of differences in topoisomerase I (1, 1, and 1.5 arbitrary units, respectively) and carboxyl esterase activities (5055 +/- 1789, 4080 +/- 752, 1713 +/- 522 mU/mg, respectively). IC20 CPT-11 prior to 5-FU was additive to synergistic in SW620, HT-29 and SNU-C4 cells (CIs of 0.7 +/- 0.1). By contrast, pre-treatment with IC20 5-FU antagonised the CPT-11-mediated growth inhibition (CIs of 1.9 +/- 0.4, 1.7 +/- 1.1, 2.5 +/- 0.9, respectively). Simultaneous drug treatment did not produce more cell growth inhibition than either drug alone in the SW620 and the HT-29 cells, but was additive or antagonistic in the SNU-C4 cells (CIs of 1.1 +/- 0.3 and 2.2 +/- 1.4), depending on the ratio of the drugs. Increased DNA damage in the SW620 and HT-29 cells was only seen when IC20 CPT-11 preceded IC50 5-FU, resulting in approximately 40 and 25%, respectively, more lesions than for IC50 5-FU alone. In the SNU-C4 cells, not only such a treatment, but also simultaneous drug treatment produced (30 to 60%) more DNA damage than either drug alone. Our results show clear sequence-dependent antiproliferative effects and DNA damage formation by CPT-11 and 5-FU at combinations of low, fixed doses with higher, varying doses in cultured human colon carcinoma cells, and may be of relevance to the design of improved chemotherapeutic regimens in this disease.

Multicenter phase II study of bimonthly high-dose leucovorin, fluorouracil infusion, and oxaliplatin for metastatic colorectal cancer resistant to the same leucovorin and fluorouracil regimen

PURPOSE

To evaluate the objective tumor response rates and toxicities of leucovorin (LV) plus fluorouracil (5-FU) cancer regimen combined with oxaliplatin (85 mg/m(2)) every 2 weeks on metastatic colorectal cancer patients with documented proof of progression while on bimonthly LV and 5-FU alone.

PATIENTS AND METHODS

One hundred patients were enrolled onto this study and 97 received the study drugs between October 1995 and December 1996. Eighty-nine patients were eligible for per-protocol efficacy analysis with documented proof of progression on one of the following two treatments: LV 500 mg/m(2) and continuous 5-FU infusion 1.5 to 2 g/m(2)/22 hours, days 1 through 2 every 2 weeks (FOLFUHD); or LV 200 mg/m(2), bolus 5-FU 400 mg/m(2), and continuous 5-FU infusion 600 mg/m(2)/22 hours, days 1 through 2 every 2 weeks (LV5FU2). In our study, 40 patients received FOLFUHD + 85 mg/m(2) of oxaliplatin day 1 (FOLFOX3) and 57 patients received LV5FU2 + 85 mg/m(2) of oxaliplatin day 1 (FOLFOX4).

RESULTS

Of the 97 patients treated, 20 partial responses were observed (FOLFOX3/4: response rate, 20.6%; 95% confidence interval, 13% to 31.1%; FOLFOX3: response rate,18.4%; FOLFOX4: response rate, 23.5%). For patients treated with FOLFOX3/4, the median response duration for was 7.5 months, and the major toxicities were peripheral neuropathy and neutropenia. The incidence of grade 3 (National Cancer Institute common toxicity criteria) peripheral neuropathy was 20.6%; whereas the overall incidence of grade 3 to 4 neutropenia was 27.8%, 15%, and 36.9% for FOLFOX3/4, FOLFOX3, and FOLFOX4, respectively (P =.02). From the start of treatment, median progression-free survival was 4. 7, 4.6, and 5.1 months for FOLFOX3/4, FOLFOX3, FOLFOX4, respectively, and median overall survival was 10.8, 10.6, and 11.1 months, respectively.

CONCLUSION

This phase II study of oxaliplatin at 85 mg/m(2) in combination with bimonthly LV plus 5-FU in patients with colorectal cancer resistant to LV plus 5-FU alone confirms the enhanced antitumor activity of oxaliplatin in combination with 5-FU.