Sequence effect of irinotecan and fluorouracil treatment on pharmacokinetics and toxicity in chemotherapy-naive metastatic colorectal cancer patients

A phase II trial of UGT1A1 genotype-guided FOLFIRI plus bevacizumab as first-line therapy for advanced, unresectable colorectal cancer

BACKGROUND

FOLFIRI is a standard regimen for metastatic colorectal cancer (mCRC). We hypothesized that a pharmacogenomic-directed strategy where more efficient irinotecan metabolizers (UGT1A1 *1/*1 homozygotes and *1/*28 heterozygotes) receive higher-than-standard irinotecan doses would improve progression-free survival (PFS) compared to non-genotype selected historical controls with acceptable toxicity.

METHODS

In this phase II multicenter study irinotecan dosing in first-line FOLFIRI and bevacizumab for mCRC was based on UGT1A1 genotype with *1/*1, *1/*28, and *28/*28 patients receiving 310 mg/m2, 260 mg/m2, and 180 mg/m2, respectively. Primary endpoint was PFS. Secondary endpoints were investigator and patient-reported adverse events, and estimation of overall survival (OS).

RESULTS

One-hundred patients were enrolled with 91 evaluable for PFS and 83 evaluable for best response. Median PFS was 12.5 months (90% CI 10.9, 15.4), shorter than the anticipated alternative hypothesis of 14 months. PFS by genotype was 12.5 months (90% CI 10.9, 17.4) for *1/*1, 14.6 months (90% CI 11.8, 17.5) for *1/*28, and 6 months (90% CI 2.3, 7.7) for *28/28, respectively. OS was 24.5 months (90% CI 19.1, 30.7) and by genotype was 26.5 (90% CI 19.1, 32.9), 25.9 (90% CI 17.6, 37.7), and 13.4 (90% CI 2.3, 20.5) months for *1/*1, *1/*28, and *28/*28, respectively. G3/4 toxicity was similar between all subgroups, including diarrhea and neutropenia.

CONCLUSIONS

A pharmacogenomic-directed irinotecan strategy improved PFS in the *1/*1 and *1/*28 genotypes with higher rates of neutropenia and similar rates of diarrhea compared to expected with standard FOLFIRI dosing. However, improvements in response rate and PFS were modest. This strategy should not change standard practice for mCRC patients in the first-line setting.

Design, Synthesis, and Evaluation of Glucose Transporter Inhibitor-SN38 Conjugates for Targeting Colorectal Cancer

Irinotecan (1), a prodrug of SN38 (2) approved by the US Food and Drug Administration for treating colorectal cancer, lacks specificity and causes many side effects. To increase the selectivity and therapeutic efficacy of this drug, we designed and synthesized conjugates of SN38 and glucose transporter inhibitors (phlorizin (5) or phloretin (6)), which could be hydrolyzed by glutathione or cathepsin to release SN38 in the tumor microenvironment, as a proof of concept. These conjugates (8, 9, and 10) displayed better antitumor efficacy with lower systemic exposure to SN38 in an orthotopic colorectal cancer mouse model compared with irinotecan at the same dosage. Further, no major adverse effects of the conjugates were observed during treatment. Biodistribution studies showed that conjugate 10 could induce higher concentrations of free SN38 in tumor tissues than irinotecan at the same dosage. Thus, the developed conjugates exhibit potential for treating colorectal cancer.

Phase I Dose-Escalation Trial of an Innovative Chemotherapy Regimen Combining a Fractionated Dose of Irinotecan Plus Bevacizumab, Oxaliplatin, 5-Fluorouracil, and Folinic Acid (bFOLFIRINOX-3) in Chemorefractory Metastatic Colorectal Cancer

Simple Summary

Treatment of non-resectable metastatic colorectal cancer (mCRC) involves chemotherapy based on 5-fluorouracil, oxaliplatin and irinotecan and monoclonal antibodies targeting VEGF or EGFR. After an initial progression, it is usual to change the chemotherapy regimen and targeted therapy, with rather moderate results. Several studies have focused on the interest of using again already used molecules and rechallenge with oxaliplatin and irinotecan bi fractionation (FOLFIRI3) have previously shown efficacy in chemorefractory patients, but desynchronized triplet chemotherapy was never tested. The aim of this study was to evaluate the safety and efficacy of a new regimen so-called: FOLFIRINOX-3 bevacizumab in chemorefractory metastatic colorectal cancer.

Abstract

The care of metastatic colorectal cancers is based on combination chemotherapies including 5-fluorouracil, oxaliplatin, irinotecan, and monoclonal antibodies targeting the epidermal growth factor receptor or vascular endothelial growth factor. The regimen is determined based on the patient’s molecular biology and general condition. Irinotecan bifractionation showed efficacy in chemorefractory patients in a previous study, FOLFIRI-3, but a desynchronized triplet has never been tested. The aim of bFOLFIRINOX-3 is to determine the safety, tolerance, and efficacy of a new regimen (FOLFIRINOX-3 bevacizumab) in chemorefractory patients. The aim of this study was to evaluate the safety and efficacy of FOLFIRINOX-3 bevacizumab in chemorefractory metastatic colorectal cancer (mCRC). A standard phase I, “3 + 3” design study was performed. The standard protocol comprised simplified FOLFOX 4 (folinic acid 400 mg/m²), 5-fluorouracil (a 400 mg/m² bolus followed by 2400 mg/m² for 46 h), oxaliplatin (85 mg/m²) and irinotecan (administered before and after 5-fluorouracil infusion), plus bevacizumab (5 mg/kg). In a “3 + 3” design, three different doses of irinotecan were tested: 60, 70 and 90 mg/m². The primary endpoint was the maximum tolerable dose (MTD) of irinotecan. The secondary endpoints included the objective response (at 8 and 16 weeks) according to the RECIST 1.1 criteria and progression free survival. Thirteen patients were enrolled, and twelve patients were finally evaluated for dose-limiting toxicity (DLT). The dose level defined was 70 mg/m² irinotecan. A total of three DLTs were observed (grade 3 diarrhea): two DLTs at the 90 mg/m² dose level and one at the 70 mg/m² dose level. The most frequently described adverse events were asthenia (93%), diarrhea (77%), nausea (62%) and peripheral sensory neuropathy (46%). The most frequent biological event was thrombopenia (54%). Regarding efficacy, among the 11 evaluable patients, no progression was observed at 8 weeks, and the partial response rate was 18.2%. At 16 weeks, a partial response rate of 27.3% was observed, and five patients had a stable disease. The new regimen of bFOLFIRINOX-3 with irinotecan at 70 mg/m² was well tolerated. In chemorefractory patients, this protocol shows a high response rate.

Evaluation of the Expression Profile of Irinotecan-Induced Diarrhea in Patients with Colorectal Cancer

Irinotecan (CPT-11) is widely used for the treatment of unresectable colorectal cancer in combination with fluoropyrimidines, such as 5-fluorouracil and S-1. Diarrhea is one of the adverse effects associated with CPT-11 and frequently reported by patients treated with CPT-11-containing regimens combined with oral fluoropyrimidines. However, the mechanisms involved in this process, as well as whether fluctuations in the frequency and differences in the onset time of diarrhea with each CPT-11-containing regimen are caused by drug interactions remain unclear. Therefore, we examined the incidence of diarrhea caused by each CPT-11-containing regimen in patients with colorectal cancer using data from the large voluntary reporting Japanese Adverse Drug Event Report (JADER) database. Firstly, we searched for suspected drugs related to the occurrence of diarrhea using reported odds ratio and calculated the signal score to assess drug–drug interactions. Subsequently, we conducted a time-to-onset analysis using Weibull distribution. The results showed that the combination of CPT-11 with S-1 increased the frequency of diarrhea due to a pharmacological interaction but delayed its onset. The present results may contribute to the appropriate management of drug-induced adverse effects by healthcare professionals.

Drug-Drug Interactions of Irinotecan, 5-Fluorouracil, Folinic Acid and Oxaliplatin and Its Activity in Colorectal Carcinoma Treatment

The combination of folinic acid, 5-fluorouracil, oxaliplatin and/or irinotecan (FOLFOXIRI) is the standard of care for metastatic colorectal cancer (CRC). This strategy inhibits tumor growth but provokes drug resistance and serious side effects. We aimed to improve FOLFOXIRI by optimization of the dosing and the sequence of drug administration. We employed an orthogonal array composite design and linear regression analysis to obtain cell line-specific drug combinations for four CRC cell lines (DLD1, SW620, HCT116, LS174T). Our results confirmed the synergy between folinic acid and 5-fluorouracil and additivity, or even antagonism, between the other drugs of the combination. The drug combination administered at clinical doses resulted in significantly higher antagonistic interactions compared to the low-dose optimized drug combination (ODC). We found that the concomitant administration of the optimized drug combination (ODC) was comparatively active to sequential administration. However, the administration of oxaliplatin or the active metabolite of irinotecan seemed to sensitize the cells to the combination of folinic acid and 5-fluorouracil. ODCs were similarly active in non-cancerous cells as compared to the clinically used doses, indicating a lack of reduction of side effects. Interestingly, ODCs were inactive in CRC cells chronically pretreated with FOLFOXIRI, suggesting the occurrence of resistance. We were unable to improve FOLFOXIRI in terms of efficacy or specificity. Improvement of CRC treatment should come from the optimization of targeted drugs and immunotherapy strategies.

Use of a multi-drug regimen gemcitabine, 5-fluorouracil, irinotecan, cisplatin, bevacizumab, docetaxel, and cyclophosphamide (GFIP/BDC) for heavily pretreated relapsed epithelial ovarian, fallopian tube and primary peritoneal cancer

Background

Epithelial ovarian cancer has the highest fatality rate of all gynecologic malignancies. Although the majority of patients achieve complete clinical response after initial cytoreductive surgery and platinum-based chemotherapy, most recur and almost all will eventually acquire platinum-resistance for which treatment options become limited. The objective of the study was to describe response and tolerability of metronomic chemotherapy regimen GFIP/BDC, a modification of the G-FLIP regimen, in patients with persistent or recurrent epithelial ovarian, fallopian tube, and primary peritoneal cancer.

Methods

A retrospective descriptive analysis of 20 patients from a single academic institution who received combination GFIP/BDC therapy from January 1, 2011 to August 31, 2016 for persistent or recurrent EOC/FT/PP. Treatment consisted of a 2-day combination of gemcitabine 300 mg, 5-fluorouracil 500 mg/m2, irinotecan 20-30 mg/m2, cisplatin 20 mg/m2, bevacizumab 4 mg/kg, docetaxel 20 mg/m2, and cyclophosphamide 200 mg/m2 administered every 14 days. Toxicities were retrospectively graded using CTCAE v4.0.

Results

Twenty patients were identified with a median age 57.5 years (range 32–71). A total of 85% of patients were non-Hispanic white, 90% had cancer of high-grade serous histology, and all had a GOG performance status of 0–1. Patients had received a median of 3 prior regimens and 95% were platinum-resistant. Median number of cycles of GFIP/BDC administered was 9 (range 3–48) and patients remained on treatment for a median of 5.1 months (range 1.5–24). Eleven patients (55%) experienced a partial clinical response with a median duration of 6 months (range 1.5–20). Six patients (30%) survived progression free for at least 6 months.

Ten patients (50%) experienced at least one grade 3/4 adverse event. Grade 3 adverse events were hematologic (n = 5), constitutional (n = 3), gastrointestinal (n = 3), neurologic (n = 2), and vascular (n = 1). There was only one grade 4 adverse event which was severe neutropenia. Patients discontinued treatment due to disease progression 65% (n = 13), toxicity 20% (n = 4), patient preference 10% (n = 2), and 5% (n = 1) is currently on treatment.

Conclusions

Selected patients with epithelial ovarian, fallopian tube or primary peritoneal cancer who have failed multiple lines of conventional cytotoxic treatment may benefit from GFIP/BDC. Toxicity might be a limiting factor for administration.

Standardization of the infusion sequence of antineoplastic drugs used in the treatment of breast and colorectal cancers

The definition of antineoplastic administration sequences can help planning of therapeutic regimens in a more rational way, and thus optimize chemotherapy effects on patients, increasing efficacy and reducing toxic effects. In this way, this study aimed to evaluate the infusion order of antineoplastic agents of the main therapeutic protocols used in the treatment of colorectal and breast cancer which are used in a tertiary hospital, identifying possible interactions dependent on the infusion sequence. For the definition of protocols adopted in the hospital, medical prescriptions were used in the period of January to March 2016 and a literature review was conducted to search for studies assessing the sequence of administering the selected regimens. The databases used were SciELO, LILACS and MEDLINE, in addition to Micromedex Solutions® and UpToDate®. A total of 19 protocols were identified for antineoplastic therapy, 11 for colorectal cancer and 8 for breast cancer. The selected articles provided evidence for administration order of 19 protocols, and three protocols did no report relevance of infusion sequence. Sequence-dependent interactions were mainly related to toxicity, pharmacokinetics and efficacy of the drug combination. The definition of the infusion sequence has a great impact on the optimization of therapy, increasing efficacy and safety of the protocols containing combined antineoplastic therapies.

Phase 1 Study of ABT-751 in Combination With CAPIRI (Capecitabine and Irinotecan) and Bevacizumab in Patients With Advanced Colorectal Cancer

ABT-751 is an orally bioavailable sulfonamide with antimitotic properties. A nonrandomized phase 1 dose-escalation study of ABT-751 in combination with CAPIRI (capecitabine and irinotecan) and bevacizumab was conducted to define the maximum tolerated dose, dose-limiting toxicity (DLT), and pharmacokinetics in patients with advanced colorectal cancer. Patients were treated with ABT-751 daily for 7 days (alone) and then began 21-day cycles of treatment with ABT-751 daily and capecitabine twice daily for 14 days plus irinotecan on day 1 intravenously. Bevacizumab was added as standard of care at 7.5 mg/kg on day 1 after the first 2 dose levels. Because of intolerance to the regimen, a reduced dose of ABT-751 was also explored with reduced-dose and full-dose CAPIRI with bevacizumab. ABT-751 and irinotecan pharmacokinetics, ABT-751 glucuronidation, and protein binding were explored. Twenty-four patients were treated over 5 dose levels. The maximum tolerated dose was ABT-751 125 mg combined with full-dose CAPIRI and bevacizumab 7.5 mg/kg on day 1. DLTs were hypokalemia, elevated liver tests, and febrile neutropenia. ABT-751 is metabolized by UGT1A8 and to a lesser extent UGT1A4 and UGT1A1. Irinotecan and APC exposure were increased, SN-38 exposure was similar, and SN-38 glucuronide exposure was decreased. Clinically relevant alterations in ABT-751 and irinotecan pharmacokinetics were not observed. Despite modest efficacy, the combination of ABT-751, CAPIRI, and bevacizumab will not be studied further in colorectal cancer.

Personalized treatment is better than one treatment fits all in the management of patients with mCRC: a consensus statement

The VEGF- (bevacizumab) and EGFR- (cetuximab and panitumumab) targeting monoclonal antibodies have become integral components of the first-line treatment strategies for patients with metastatic colorectal cancer (mCRC). Increasingly combination chemotherapy, with or without a targeted agent, is being used to facilitate curative liver resection and improve survival rates in patients with initially unresectable but potentially resectable mCRC. Currently, the only selective marker for the treatment of patients with mCRC is tumor RAS mutational status. BRAF status is a strong prognostic indicator. Medical and clinical oncologists from Central Asia, Russia, the Middle East, Africa and Turkey reviewed data for the use of targeted agents in the treatment of patients with mCRC and have formed recommendations for the biological of choice first-line for patients with mCRC.

Treatment of colorectal cancer using a combination of liposomal irinotecan (Irinophore C™) and 5-fluorouracil

Purpose

To investigate the use of liposomal irinotecan (Irinophore C™) plus or minus 5-fluorouracil (5-FU) for the treatment of colorectal cancer.

Experimental Design

The effect of irinotecan (IRI) and/or 5-FU exposure times on cytotoxicity was assessed in vitro against HT-29 or LS174T human colon carcinoma cells. The pharmacokinetics and biodistribution of Irinophore C™ (IrC™) and 5-FU, administered alone or in combination, were compared in vivo. A subcutaneous model of HT-29 human colorectal cancer in Rag2-M mice was utilized to assess the efficacy of IrC™ alone, and in combination with 5-FU.

Results

The cytotoxicity of IRI and 5-FU were strongly dependent on exposure time. Synergistic interactions were observed following prolonged exposure to IRI/5-FU combinations. Pharmacokinetics/biodistribution studies demonstrated that the 5-FU elimination rate was decreased significantly when 5-FU was co-administered intravenously with IrC™, versus alone. Significant decreases in 5-FU elimination were also observed in plasma, with an associated increase of 5-FU in some tissues when 5-FU was given by intraperitoneal injection and IrC™ was given intravenously. The elimination of IrC™ was not significantly different when administered alone or in combination with 5-FU. Therapeutic studies demonstrated that single agent IrC™ was significantly more effective than the combination of IRI/5-FU; surprisingly, IrC™/5-FU combinations were no more effective than IrC™ alone. The administration of combinations of 5-FU (16 mg/kg) and IrC™ (60 mg IRI/kg) showed increased toxicity when compared to IrC™ alone. Treatment with IrC™ alone (60 mg IRI/kg) delayed the time required for a 5-fold increase in initial tumor volume to day 49, compared to day 23 for controls. When IrC™ (40 mg IRI/kg) was used in combination with 5-FU (16 mg/kg), the time to increase tumor volume 5-fold was 43 days, which was comparable to that achieved when using IrC™ alone (40 mg IRI/kg).

Conclusions

Single agent IrC™ was well tolerated and has significant therapeutic potential. IrC™ may be a suitable replacement for IRI treatment, but its use with free 5-FU is complicated by IrC™-engendered changes in 5-FU pharmacokinetics/biodistribution which are associated with increased toxicity when using the combination.

A phase I study of continuous hepatic arterial infusion of Irinotecan in patients with locally advanced hepatocellular carcinoma

PURPOSE

Aim of this phase I study was to identify the maximum tolerated dose and dose limiting toxicity of continuous infusion of Irinotecan through a port-a-cath placed in the hepatic artery in patients with hepatocellular carcinoma and cirrhosis to explore new strategies in advanced hepatocellular carcinoma. Response rate and time-to-progression were analysed.

METHODS

Irinotecan was delivered as a five-day continuous infusion every 21 days, with increases of 2.5mg/m(2)/day every three patients, starting from 7.5mg/m(2)/day. Dose limiting toxicity corresponded to one patient in each triplet developing G4 haematological or G3 non-haematological toxicity, confirmed in two triplets. Twenty-eight patients (17 Child-Pugh A, 11 B) received treatment and tumour response was assessed after three courses completed by 22 patients.

RESULTS

Dose limiting toxicity was G3 diarrhoea in two patients, reached at 27.5mg/m(2)/day and the recommended dose was set at 25mg/m(2)/day. Nineteen of 30 patients experienced adverse events related to porth-a-cath placement and one died from liver ischemia and sepsis. Median time-to-progression was 11.3 months.

CONCLUSION

Intrarterial infusion of Irinotecan is feasible in patients with hepatocellular carcinoma on cirrhosis at a recommended dose of 25mg/m(2)/day, with no major adverse drug-related events, but with some concerns about the insertion and management of the intra-arterial device.

Phase I/II study of sequential therapy with irinotecan and S-1 for metastatic colorectal cancer

Background:

Both irinotecan (CPT-11) and S-1 are active against colorectal cancer; however, as S-1 is a prodrug of 5-fluorouracil (5-FU), 5-FU and its metabolites might inhibit the antitumour effect of CPT-11. Therefore, we designed a sequential combination, in which CPT-11 infusion was given on day 1 and S-1 was given orally at 80 mg m⁻² per day on days 3–16 every 3 weeks.

Methods:

Twelve patients entered the phase I study, and the recommended doses were determined as a CPT-11 dose of 150 mg m⁻² and an S-1 dose of 80 mg m⁻².

Results:

In all, 36 patients entered the phase II study, of whom 4 and 16 had complete and partial responses. The overall response rate was 55.6% (95% confidence interval, 38.1–72.1%), and median progression-free survival was 7.7 months (95% confidence interval, 4.8–12.6 months). Grade 3 neutropenia was the most common haematological toxicity and occurred in 6.5% of 215 treatment courses. Grade 3 non-haematological toxicities included anorexia (1.4%) and diarrhoea (0.9%). There was no grade 4 toxicity of any kind.

Conclusion:

Our results suggest that this regimen is convenient, safe and promising, compared with conventional regimens for patients with metastatic colorectal cancer.

Efficacy of FOLFIRI-3 (irinotecan D1,D3 combined with LV5-FU) or other irinotecan-based regimens in oxaliplatin-pretreated metastatic colorectal cancer in the GERCOR OPTIMOX1 study

BACKGROUND

Second-line irinotecan-based chemotherapy is commonly used in metastatic colorectal cancers after first-line oxaliplatin-based chemotherapy. No standard schedule of irinotecan has been established in this situation.

PATIENTS AND METHODS

Metastatic colorectal cancer patients included in the OPTIMOX1 phase III study received first-line oxaliplatin-based chemotherapy (FOLFOX). No second line was defined in the protocol, but data concerning second line were prospectively registered. Inclusion criterion was patients receiving an irinotecan-based second-line chemotherapy. Second-line progression-free survival (PFS) and tumor response were evaluated according to type of irinotecan-based regimen administered.

RESULTS

A total of 342 patients received irinotecan-based chemotherapy as second-line chemotherapy: FOLFIRI-3 [n = 109, irinotecan 100 mg/m(2) days 1 and 3 combined with leucovorin (LV) 400 mg/m(2) day 1 and 46-h continuous 5-fluorouracil (5-FU) 2000 mg/m(2)], FOLFIRI-1 (n = 112, irinotecan 180 mg/m(2) day 1 combined with LV 400 mg/m(2) day 1, 5-FU bolus 400 mg/m(2) and 46-h continuous 5-FU 2400 mg/m(2)) and other various irinotecan-based regimens (n = 121). Median second-line PFS was 3.0 months (FOLFIRI-3: 3.7 months; FOLFIRI-1: 3.0 months; other regimens: 2.3 months). In multivariate analysis, FOLFIRI-3 regimen (relative risk 0.43, 95% confidence interval 0.28-0.68, P = 0.0003) and lactate deshydrogenase level at inclusion (P = 0.0006) in OPTIMOX1 were associated with a longer second-line PFS.

CONCLUSION

In unselected patients pretreated with oxaliplatin, PFS in second line appeared to be improved by FOLFIRI-3 regimen.

Irinotecan toxicity

PURPOSE OF REVIEW

The toxicity of irinotecan is predictable, manageable and nonadditive in the majority of patients; however, with its increasing use alone and in combination with other agents and modalities, the recognition and control of these adverse effects remain a clinical challenge. Major efforts over the last several years have focused not only on adding fluoropyrimidines and epidermal growth factor receptor inhibitors to irinotecan, but also investigating factors that account for interindividual differences in toxicities.

RECENT FINDINGS

The association of uridine diphosphoglucuronosyl transferase 1A polymorphisms with increased irinotecan-induced diarrhea and neutropenia, the dose adjustment of irinotecan in the setting of hepatic dysfunction and the observation that 'chemo' liver can develop in the neoadjuvant colorectal cancer setting are recently reported. Also, data from the Sandostatin LAR Depot Trial for the Optimum Prevention of chemotherapy-induced diarrhea support the 30 mg dose of octreotide LAR to manage the condition.

SUMMARY

Recent evidence demonstrates that patients with hepatic insufficiency, uridine diphosphoglucuronosyl transferase 1A polymorphisms (e.g. 1A128 homozygotes and heterozygotes), are at greater risk for irinotecan-induced toxicity. Adjusting irinotecan's dose to the degree of hepatic insufficiency is now established. While 'chemo' liver is not specific to irinotecan, its occurrence influences strategies for treating advanced colorectal cancer. Finally, controlling chemotherapy-induced diarrhea with 30 mg of octreotide LAR is adequate for most patients.

Phase I/II study of 24-hour infusion of irinotecan combined with oral UFT for metastatic colorectal cancer

BACKGROUND

To evaluate the efficacy and safety of irinotecan combined with UFT for untreated and pretreated metastatic colorectal cancer.

METHODS

Escalating doses of irinotecan (80-110 mg/m(2)) were administered by 24-hour infusion on day 1. UFT was administered orally at 400 mg/m(2)/day on days 3-7 and 10-14. The treatment cycles were repeated every 2 weeks.

RESULTS

In the phase I study, the maximum tolerated dose of irinotecan was 110 mg/m(2) and the recommended dose for the phase II study was determined to be 100 mg/m(2). Thirty-five patients including 3 patients at the recommended dose in the phase I study were evaluated in the phase II study. The grade 3/4 toxicities observed were leukopenia, neutropenia, thrombocytopenia and anemia. No grade 3 or more severe nonhematological toxicities were noted. The response rate was 62.9% and the median overall survival 16.7 months.

CONCLUSIONS

A 24-hour infusion of irinotecan combined with UFT is feasible and active for metastatic colorectal cancer.

Pooled efficacy analysis from a phase I-II study of biweekly irinotecan in combination with gemcitabine, 5-fluorouracil, leucovorin and cisplatin in patients with metastatic pancreatic cancer

Development of treatments to improve the outcomes achieved with single-agent gemcitabine therapy for metastatic pancreatic cancer remains a research priority. G-FLIP (gemcitabine, 5-fluorouracil, leucovorin and cisplatin) is a four-drug regimen designed to maximize sequence-dependent synergy, while attempting to minimize toxicity among the four drugs. The dose-limiting toxicities and maximum tolerated dose of irinotecan as part of the G-FLIP regimen have been published. For phase II testing, G-FLIP consisted of sequential gemcitabine 500 mg/m2 at a fixed rate of 10 mg/m2/min, irinotecan 120 mg/m2, bolus 5-fluorouracil 400 mg/m2 and leucovorin 300 mg, followed by a 24-h 5-fluorouracil infusion of 1500 mg/m2 on day 1 and cisplatin 35 mg/m2 on day 2. Cycles were repeated every 14 days. Thirty-three patients with metastatic pancreatic cancer (22 men and 11 women) were treated and 31 were evaluable. Median patient age was 63 years (range 44-78 years) and median Karnofsky performance status score was 70-80. Estimated median time to disease progression was 171 days (6.1 months) and Kaplan-Meir-estimated median overall survival was 229 days (8.1 months). Twelve- and 18-month survivals were 33 and 21%, respectively. As per Response Evaluation Criteria in Solid Tumors criteria, 13 patients had stable disease, seven (22%) attained a partial response, and 10 (32%) had disease progression. One patient attained a complete response and two were not evaluable (one withdrew consent and one died suddenly, each after cycle 1). Treatment generally was well tolerated. Grade 3-4 toxicities/patient were thrombocytopenia (3.1%), leukopenia (15%), neutropenia (21%), neutropenic fever (3%), fatigue (18%) and thrombosis (12.5%). Common grade 1-2 toxicities per patient included nausea/vomiting (69%), diarrhea (45%), constipation (21%) and fatigue (39%). In conclusion, G-FLIP is a feasible outpatient regimen with acceptable toxicity for metastatic pancreatic cancer patients. Disease control rate (stable disease rate plus partial or complete responses) and 1-year survival outcomes are encouraging.

A systematic review on drug interactions in oncology

OBJECTIVES

To systematically review drug interactions in oncology.

METHODS

We searched PubMed for eligible articles and online databases abstracts of major oncology meetings from 2002 to 2005.

RESULTS

One study reported on the frequency of drug interactions. Interactions between chemotherapy and nonchemotherapy agents have been reported mostly in small clinical trials and case series. Interactions between chemotherapic agents have been reported mostly in Phase I studies. Few studies described fatal outcomes of drug interactions in cancer patients.

CONCLUSION

Drug interactions comprise an important issue in oncology, but very limited data exist on their frequency and clinical consequences.

FOLFIRI.3, a new regimen combining 5-fluorouracil, folinic acid and irinotecan, for advanced pancreatic cancer: results of an Association des Gastro-Enterologues Oncologues (Gastroenterologist Oncologist Association) multicenter phase II study

BACKGROUND

The purpose of the study was to prospectively evaluate the efficacy and tolerability of the FOLFIRI.3 regimen in patients with unresectable pancreatic adenocarcinoma.

PATIENTS AND METHODS

Chemotherapy-naive patients with histologically proven advanced pancreatic adenocarcinoma were treated with the FOLFIRI.3 regimen, consisting of irinotecan 90 mg/m(2) as a 60-min infusion on day 1, leucovorin 400 mg/m(2) as a 2-h infusion on day 1, followed by 5-fluorouracil (5-FU) 2000 mg/m(2) as a 46-h infusion and irinotecan 90 mg/m(2), repeated on day 3, at the end of the 5-FU infusion, every 2 weeks.

RESULTS

Forty patients were enrolled, of whom 29 (73%) had metastatic disease. A total of 441 cycles were delivered (1-53). Grade 3-4 neutropenia occurred in 35% of the patients, accompanied by fever in two cases. Other relevant grade 3-4 toxic effects were nausea-vomiting (27%) and diarrhea (25%). Grade 2 alopecia occurred in 48% of the patients. There were no treatment-related deaths. The confirmed response rate was 37.5%. Stable disease was observed in 27.5% of the patients. The median progression-free and overall survivals were 5.6 months and 12.1 months, respectively. The 1-year survival rate was 51%.

CONCLUSION

The FOLFIRI.3 regimen seems to be active on advanced pancreatic cancer and to have a manageable toxicity profile. The lack of cross-resistance between FOLFIRI.3 and gemcitabine-based regimens allows efficient second-line therapies.

Schedule-dependent cytotoxicity of 5-fluorouracil and irinotecan in a colon cancer cell line

BACKGROUND

Our aim was to clarify the significance of widely accepted irinotecan (CPT-11)/5-fluorouracil (5-FU) combinations in colon cancer by investigating their sequential effect.

METHODS

The sequential effect of CPT-11/5-FU in two colon cancer cell lines, LoVo and SW480, was evaluated by WST-8 colorimetric assay. The cell cycle distributions of each drug were analyzed by flow cytometry, and then the chemoresistant mechanisms and expression of a drug transporter (MDR1), the bcl-2 apoptotic pathway, metabolizing enzymes [carboxylesterase (CE), dihydropyrimidine dehydrogenase], and target enzymes (topoisomerase I, thymidine synthase) associated with sequence-dependent cytotoxicity were examined.

RESULTS

The cytotoxicity of 5-FU (10, 100, 1000 microM) followed by CPT-11 (1 microM) was significantly greater than that of CPT-11 (1 microM) followed by 5-FU (10, 100, 1000 microM) (P < 0.05). Reverse transcription-polymerase chain reaction analysis revealed that exposure to 5-FU downregulated both MDR1 and bcl-2 mRNA and simultaneously upregulated CE2 mRNA expression, suggesting enhancement of subsequent CPT-11 cytotoxicity.

CONCLUSIONS

The cytotoxic effects of the CPT-11/5-FU combinations were shown to be schedule-dependent in human colon cancer cells. The findings suggest that 5-FU followed by CPT-11 administration might be the optimal sequence for CPT-11/5-FU treatment of advanced colon cancer.

Phase I/II study of S-1 combined with irinotecan for metastatic advanced gastric cancer

A dose-escalation study of irinotecan (CPT-11) combined with S-1, an oral dihydropyrimidine dehydrogenase inhibitory fluoropyrimidine, was performed to determine the maximum-tolerated dose (MTD), recommended dose (RD), dose-limiting toxicities (DLTs), and objective response rate (RR) in advanced gastric cancer (AGC). S-1 was administered orally at 80 mg m⁻² day⁻¹ from day 1 to 14 of a 28-day cycle and CPT-11 was given intravenously on day 1 and 8 at an initial dose of 70 mg m⁻² day⁻¹, stepping up to 100 mg m⁻². The treatment was repeated every 4 weeks, unless disease progression was observed. In the phase I portion, the MTD of CPT-11 was presumed to be 100 mg m⁻², because 66.6% of patients (two of three) developed DLTs. All three patients at the initial RD of CPT-11 (90 mg m⁻²) experienced grade 4 haematological or grade 3 nonhaematological toxicities at second course, followed by the dose reduction of CPT-11 from the third course. Considering safety and the ability to continue treatment, the final RD was determined to be 80 mg m⁻². In the phase II portion, 42 patients including seven patients in the final RD phase I portion were evaluated. The median treatment course was five (range: 1–13). The incidences of severe (grade 3–4) haematological and nonhaematological toxicities were 19 and 10%, respectively, but all were manageable. The RR was 62% (26 of 42, 95% confidence interval: 47.2–76.6%), and the median survival time was 444 days. Our phase I/II trial showed S-1 combined with CPT-11 is effective for AGC and is well tolerated, with acceptable toxicity.

Phase II study of capecitabine and irinotecan combination chemotherapy in patients with advanced gastric cancer

The present study was conducted to evaluate the efficacy and safety of a combination regimen of capecitabine plus irinotecan in patients with advanced gastric cancer. Patients with previously untreated metastatic or recurrent, measurable gastric cancer received oral capecitabine 1000 mg m⁻² twice daily from day 1 to 14 and intravenous irinotecan 100 mg m⁻² on days 1 and 8, based on a 3-week cycle. Forty-one patients were enrolled in the current study, among whom 38 were assessable for efficacy and 40 assessable for toxicity. Three complete responses and 16 partial responses were confirmed, giving an overall response rate of 46.3%. At a median follow-up of 269 days, the median time to progression and overall survival were 5.1 and 8.6 months, respectively. Grade 3/4 neutropenia occurred in four patients and grade 3 febrile neutropenia was observed in two patients. Grade 3 diarrhoea and grade 2 hand–foot syndrome occurred in six patients and eight patients, respectively. The combination of capecitabine and irinotecan was found to be well tolerated and effective in patients with advanced gastric cancer. Accordingly, this regimen can be regarded as one of first-line treatment options for advanced gastric cancer.

A phase II study of FOLFIRI-3 (double infusion of irinotecan combined with LV5FU) after FOLFOX in advanced colorectal cancer patients

In advanced colorectal cancer previously treated with oxaliplatin, efficacy of irinotecan-based chemotherapy is poor and the best regimen is not defined. We designed FOLFIRI-3 and conducted a phase II study to establish its efficacy and safety in advanced colorectal cancer patients previously treated with FOLFOX. FOLFIRI-3 consisted of irinotecan 100 mg m⁻² as a 60-min infusion on day 1, running concurrently with leucovorin 200 mg m⁻² as a 2-h infusion on day 1, followed by 46-h continuous infusion of 5-fluorouracil (5FU) 2000 mg m⁻², and irinotecan 100 mg m⁻² repeated on day 3, at the end of the 5FU infusion, every 2 weeks. Sixty-five patients entered the study. The intent-to-treat objective response rate was 23% (95% CI 13–33%). Disease was stable in 37% of patients, progressed in 26% and was not assessable in 14%. From the start of FOLFIRI-3, median progression-free survival was 4.7 months and median survival 10.5 months. Main toxicities (% of patients) were grade 3–4 diarrhoea 23% and grade 4 neutropenia 11%. FOLFIRI-3 is a promising regimen achieving high response rate and progression-free survival in patients previously treated with FOLFOX with a moderate toxicity.

Benefit-risk assessment of irinotecan in advanced colorectal cancer

Irinotecan exerts its cytotoxic activity through inhibition of the nuclear enzyme topoisomerase I. It has been approved in most countries worldwide for treatment of patients with advanced colorectal cancer (CRC). Activity is seen in previously untreated patients and in patients refractory to fluorouracil treatment, whether it is given alone or in combination with other cytotoxic drugs. Irinotecan was first developed in patients refractory to fluorouracil. Activity in terms of tumour responses and patient benefit was seen in several phase II trials that used either a weekly or a three-weekly schedule. In two randomised trials (irinotecan vs best supportive care, and irinotecan vs an infused fluorouracil-based regimen), irinotecan prolonged median survival by approximately 2.5 months without any deterioration in quality-of-life. It was later studied in previously untreated patients with advanced CRC in combination with fluorouracil/folinic acid (leucovorin). In three large randomised trials, median time to tumour progression was prolonged by approximately 2.5 months and overall survival by about 2.5 months compared with fluorouracil/folinic acid alone. Tumour responses were also seen more frequently in the irinotecan arm (35-40% vs 20%). Again, quality-of-life scores were not deteriorated by the addition of irinotecan. Irinotecan has many acute adverse effects. The most prominent and dose limiting being diarrhoea and neutropenia. With irinotecan monotherapy, diarrhoea was seen in 80% of patients and severe grade 3 to 4 diarrhoea occurred in 30-40% of the patients. The severity of diarrhoea can be diminished by preventive actions. Less risk of diarrhoea is generally seen when irinotecan is combined with fluorouracil. Neutropenia is generally short-lived, but may be severe if diarrhoea is also present. This has been noticed particularly when irinotecan has been given in combination with a bolus fluorouracil/folinic acid regimen. Other toxicities include acute cholinergic-like symptoms, nausea and vomiting, and alopecia. In spite of these adverse effects, irinotecan has been accepted as an important first-line treatment for patients with advanced CRC, in combination with, preferably, an infused fluorouracil-based regimen, and has been approved for use as monotherapy in the second-line indication.

A phase I/II and pharmacokinetic study of irinotecan in combination with capecitabine as first-line therapy for advanced colorectal cancer

PURPOSE

The aim of this study was to determine in patients with previously untreated advanced colorectal cancer the maximum tolerated dose (MTD) and safety profile of irinotecan in combination with capecitabine, to identify a recommended dose and to determine the response rate and time to disease progression. In addition, we aimed to explore the pharmacokinetic parameters of irinotecan and capecitabine when used in different sequences of administration, with irinotecan infusion either prior to or after the first intake of capecitabine.

PATIENTS AND METHODS

One hundred patients were included: 43 patients were recruited into an extended phase I trial of alternating escalation in dose of both drugs where irinotecan was administered intravenously (i.v) on day 1 after first intake of capecitabine taken from days 1-14 twice daily, with cycles repeated every 3 weeks. After the determination of recommended dose a further 57 patients were treated in a phase II evaluation with the reverse sequence of drugs on day 1. Pharmacokinetic analysis was performed in patients treated at the recommended dose in two cohorts of patients in which the sequence of the first administration of each drug was reversed.

RESULTS

The MTD of the combination was determined as irinotecan 300 mg/m2, with capecitabine 2000 mg/m2/day. Dose limiting toxicities were neutropenia and diarrhoea. The recommended dose is irinotecan intravenous (i.v.) 250 mg/m2 day 1 and capecitabine 2000 mg/m2/day days 1-14, every 3 weeks. Treatment was well tolerated, with diarrhoea the most common serious toxicity. Response rate in the phase II cohort was 42% [95% confidence interval (CI) 29% to 56%]. Median duration of response was 7.7 months (95% CI 7.5-8.9). Median time to progression was 8.3 months (95% CI 5.8-10). No significant effect on irinotecan pharmacokinetics was observed whatever the intake of capecitabine before or after irinotecan infusion. An effect of irinotecan on capecitabine and some capecitabine metabolites was observed, but irinotecan did not effect 5-fluorouracil (5-FU) pharmacokinetics.

CONCLUSIONS

Irinotecan in combination with capecitabine is a well tolerated regimen with an activity comparable to, but more convenient than, irinotecan-5-FU i.v. combinations in patients with previously untreated advanced colorectal cancer. The pharmacokinetic data suggest that the sequence of administration does not impact significantly on the metabolism of the two drugs.

Chemotherapy of metastatic colorectal cancer

Over the past decade, metastatic colorectal cancer has evolved from a relatively resistant disease to one that is sensitive to a variety of chemotherapeutic drugs and combinations of drugs. During the same period, the median survival of patients with metastatic colorectal cancer increased from approximately 14 months to almost 20 months. First-line chemotherapy prolongs survival and delays the appearance of symptoms and should be considered in patients who are still asymptomatic. Patients with metastatic colorectal cancer and adequate performance status should be treated with a combination of fluorouracil (5-FU) and either oxaliplatin or irinotecan. Bevacizumab, the monoclonal antibody against the vascular endothelial growth factor, has been shown to prolong survival with acceptable toxicity and may be added when available. When the disease recurs, second-line chemotherapy may also prolong survival in appropriately selected patients. Typically, treatment includes 5-FU and one of the drugs not used in the first-line therapy (oxaliplatin or irinotecan). Several oral prodrugs of 5-FU are currently available. Capecitabine, approved in the United States, may be safely substituted for 5-FU in the majority of settings and combinations. Cetuximab is a monoclonal antibody against the epidermal growth factor receptor and is approved both as a single agent and in combination with irinotecan for patients with recurrent disease. This treatment may represent a second-line or third-line option in selected patients. Treatment of patients with isolated liver metastases may also include surgical or other ablative procedures. In carefully selected patients, these modalities add to the efficacy of chemotherapy and may be used with potentially curative intent. However, for the vast majority of patients with metastatic colorectal cancer treatment is palliative.

A phase I clinical and pharmacokinetic study of capecitabine (Xeloda) and irinotecan combination therapy (XELIRI) in patients with metastatic gastrointestinal tumours

Capecitabine is a highly active oral fluoropyrimidine that is an attractive alternative to 5-fluorouracil in colorectal cancer treatment. The current study, undertaken in 27 patients with gastrointestinal tumours, aimed to assess the toxicity and potential for significant pharmacokinetic interactions of a combination regimen incorporating capecitabine with 3-weekly irinotecan (XELIRI). Irinotecan (200 and 250 mg m(-2)) was administered as a 90-min infusion on day 1 in combination with escalating capecitabine doses (700-1250 mg m(-2) twice daily) administered on days 2-15 of a 3-week treatment cycle. Pharmacokinetics were characterised on days 1 and 2 of the first two cycles. A total of 103 treatment cycles were administered. The principal dose-limiting toxicities were diarrhoea and neutropenia. Capecitabine 1150 mg m(-2) twice daily with irinotecan 250 mg m(-2) was identified as the maximum-tolerated dose and capecitabine 1000 mg m(-2) with irinotecan 250 mg m(-2) was identified as the recommended dose for further study. Analyses confirmed that there were no significant pharmacokinetic interactions between the two agents. The combination was clinically active, with complete and partial responses achieved in heavily pretreated patients. This study indicates that XELIRI is a potentially feasible and clinically active regimen in patients with advanced gastrointestinal cancer.

Sequential Treatment with Irinotecan and Doxifluridine: Optimal Dosing Schedule in Murine Models and in a Phase I Study for Metastatic Colorectal Cancer

BACKGROUND

Irinotecan (CPT-11) and doxifluridine (5'-DFUR) are active agents against colorectal cancer. Each drug, however, has the possibility of causing diarrhea.

METHODS AND RESULTS

First, we determined the optimal dosing regimen in murine models. CPT-11 (i.v., q2d x 3) and 5'-DFUR (p.o., qd x 14) were administered to mice bearing a human colorectal cancer xenograft model. Diarrhea was stronger in the simultaneously administered schedule but not much stronger in the sequentially administered schedule compared with monotherapies. Both schedules yielded similar antitumor efficacies. Next, we conducted a phase I study combining CPT-11 on days 1 and 15, and 5'-DFUR on days 3-14 and 17-28 every 5 weeks in 19 patients with metastatic colorectal cancer. The doses of CPT-11 ranged from 80 to 150 mg/m2 and those of 5'-DFUR from 800 to 1,200 mg. Diarrhea of grade 3/4 developed in only 1 patient at 100 mg/m2/800-mg doses. Dose-limiting toxicities were hyperbilirubinemia and skipping doses due to fatigue at 150 mg/m2/1,200-mg doses.

CONCLUSION

For the phase II study, the recommended dose was set at CPT-11 150 mg/m2 and 5'-DFUR 800 mg.

A Phase I and Pharmacokinetic Study of Irinotecan Given as a 7-Day Continuous Infusion in Metastatic Colorectal Cancer Patients Pretreated with 5-Fluorouracil or Raltitrexed

PURPOSE

The purpose is to determine the plasma pharmacokinetics, the maximum-tolerable dose and to preliminary evaluate the antitumor activity of irinotecan administered as a 7-day continuous infusion every 21 days in metastatic colorectal cancer patients pretreated with 5-fluorouracil or raltitrexed.

EXPERIMENTAL DESIGN

A total of 13 patients entered the study. Three received irinotecan at 20 mg/m(2)/day (dose level I), 6 at 25 mg/m(2)/day (dose level II), and 4 at 22.5 mg/m(2)/day (dose level III). In 8 patients, plasma levels of irinotecan and its metabolites SN-38 and SN-38 glucuronide (SN-38glu) were measured by high-performance liquid chromatography and main pharmacokinetic parameters, including steady-state concentration, area under the time-concentration curve, and clearance, were calculated and normalized to the dose level of 22.5 mg/m(2)/day.

RESULTS

Dose-limiting toxicity was grade 3-4 diarrhea, which occurred in 4 of 6 patients at dose level II and in 2 of 4 patients at dose level III. Therefore, we defined 22.5 mg/m(2)/day the maximum-tolerable dose and 20.0 mg/m(2)/day the recommended dose for Phase II studies. Hematological toxicity was rare. The pharmacokinetic data provided evidence that continuous infusion increased the metabolism of irinotecan to SN-38 with respect to standard 30/90-min administration. Indeed, the steady-state concentration of irinotecan, SN-38, and SN-38glu were 42.7 +/- 25.2, 14.9 +/- 1.9, and 31.7 +/- 3.5 nmol/liter, respectively, and the area under the time-concentration curves of irinotecan, SN-38, and SN-38glu were 6.94 +/- 0.41, 1.92 +/- 0.30, and 4.23 +/- 0.52 hx micro mol/liter, respectively. Twelve patients were evaluable for activity, and we observed 3 (25%) partial responses, 2 (17%) minor responses, and 4 (33%) disease stabilizations.

CONCLUSIONS

The administration of irinotecan as a 7-day continuous infusion every 21 days is feasible with diarrhea being the dose-limiting toxicity; recommended dose for Phase II studies is 20.0 mg/m(2)/day. The comparison of the present data with those obtained after a standard 30-90 min. i.v. infusion of irinotecan demonstrates that continuous infusion improves the transformation of irinotecan to SN-38 and also results in increased glucuronidation of the active metabolite. Antitumor activity in pretreated metastatic colorectal cancer patients is encouraging.

A phase I/II study of oral uracil/tegafur (UFT), leucovorin and irinotecan in patients with advanced colorectal cancer

BACKGROUND

The aim of this study was to determine the maximum tolerated dose (MTD), toxicity profile and response rate of the oral 5-fluorouracil prodrug UFT (tegafur/uracil) and leucovorin (LV) in combination with irinotecan in patients with advanced or metastatic colorectal cancer.

PATIENTS AND METHODS

Patients with histologically proven advanced or metastatic colorectal adenocarcinoma received first-line chemotherapy comprising UFT 250 mg/m(2)/day and LV 90 mg/day given on days 1 to 14, with escalating doses of irinotecan (200-300 mg/m(2)) administered intravenously on day 1 of a three-weekly cycle. Eligibility criteria were standard. The MTD was defined as the dose at which >33% of six patients experienced a dose-limiting toxicity (DLT) during cycle 1.

RESULTS

A total of 32 patients were studied. Initially, six patients were treated at each of the irinotecan dose levels (200, 250 and 300 mg/m(2)) combined with UFT 250 mg/m(2)/day and LV 90 mg/day. DLTs consisting of grade 3 or 4 diarrhoea and febrile neutropenia were observed in one of 20 patients at 250 mg/m(2) and three of six patients at the 300 mg/m(2) irinotecan dose level. Having defined the MTD, the 250 mg/m(2) dose level was established as the recommended dose (RD) and expanded to 20 patients in whom treatment was generally well tolerated. The overall response rate was 19%, with five patients having a partial response (PR) and 18 stable disease (SD) out of 32 response-evaluable patients.

CONCLUSION

UFT and LV can be safely combined with irinotecan. The RDs for future studies are UFT 250 mg/m(2)/day and LV 90 mg/day given on days 1-14, with irinotecan 250 mg/m(2) administered on day 1, every 3 weeks. This combination is well tolerated and active. Further investigation of UFT and LV in combination with irinotecan is warranted in patients with colorectal cancer.

Topoisomerase I interactive agents

Increased insight into the mechanism of interaction of topoisomerase I interactive agents will maximize the therapeutic index and enhance the development of additional agents. Preclinical studies designed to elucidate mechanisms by which the topoisomerase I interactive agents induce cell death will be essential. The role of ABC transporters in resistance to topoisomerase I interactive agents has been recently appreciated and future studies should be directed at circumventing this resistance. The results of preclinical studies must be translated into the design of clinical trials so that these agents can be used rationally. In this regard results of preclinical studies have clearly pointed to the enhanced antitumor activity from protracted dosing of topoisomerase I interactive agents and results of clinical trials are now supporting these preclinical findings. Finally, investigators are trying to understand better the mechanism(s) of the dose-limiting toxicities observed with the currently available topoisomerase I interactive agents in an effort to enable the optimal dosing of these agents. Even though the first priority must be to determine the therapeutic potential of the currently available agents, it is reassuring to know that other topoisomerase I interactive agents are currently under development.

A Phase II study of irinotecan in combination with 120-h infusion of 5-fluorouracil in patients with metastatic colorectal carcinoma: Japan Clinical Oncology Group Study (JCOG9703)

PURPOSE

To evaluate the antitumor effect and feasibility of a combination of irinotecan (CPT-11) and 5-day infusional 5-fluorouracil (5-FU) in a sequential schedule based on our previous combination phase I studies in patients with metastatic colorectal cancer.

PATIENTS AND METHODS

Forty chemotherapy-naive patients with metastatic colorectal cancer received 90-min infusion of CPT-11 at a dose of 150 mg/m(2) on days 1 and 15 and 120-h protracted infusion of 5-FU at 600 mg/m(2)/day on days 3-7, which were repeated every 4 weeks.

RESULTS

The median number of actually administered courses was five, ranging from one to 14. There were 16 (40%) patients who developed grade 3 or 4 neutropenia. Grade 3 or 4 nausea/vomiting and diarrhea were seen in three (8%) and seven (18%) patients, respectively. Only one early death not related to treatment occurred during the study. There was one complete response and 17 partial responses with a response rate of 45% (95% confidence interval: 29.3-61.5%). With a median follow-up period of 22.5 months for survivors, the median survival and median progression-free survival times were 15.9 and 7.0 months, respectively.

CONCLUSIONS

Although the toxicities were modest, this sequentially combined regimen is active and feasible in patients with metastatic colorectal cancer.

Biweekly chemotherapy with oxaliplatin, irinotecan, infusional Fluorouracil, and leucovorin: a pilot study in patients with metastatic colorectal cancer

PURPOSE

To determine the feasibility, recommended doses, plasma pharmacokinetics, and antitumor activity of a biweekly chemotherapy regimen with oxaliplatin (L-OHP), irinotecan (CPT-11), infusional fluorouracil (5-FU), and leucovorin (LV) in metastatic colorectal cancer patients.

PATIENTS AND METHODS

Patients received CPT-11 followed by L-OHP and LV 200 mg/m(2) and followed by 5-FU 3,800 mg/m(2) as a 48-hour infusion, repeated every 2 weeks. In the first part of the study, an escalation of CPT-11 dose and/or a decrease of the L-OHP dose were planned. Once the recommended doses of CPT-11 and L-OHP were determined, all subsequent patients were treated at the recommended doses.

RESULTS

Forty-two patients entered the study. CPT-11 175 mg/m(2) and L-OHP 100 mg/m(2) in combination with LV 200 mg/m(2) and 5-FU 3,800 mg/m(2) could be administered with acceptable toxicities; 39 patients were treated at these dose levels. The pharmacokinetics parameters of the agents used and their metabolites did not seem to be influenced by the concomitant use of the other drugs. The most relevant toxicities were diarrhea and neutropenia, with 14% of patients experiencing one episode of febrile neutropenia. In five patients (11.9%) a complete and in 25 (59.5%) a partial response was demonstrated, for an objective response rate of 71.4% (95% confidence interval, 47% to 83%). In 11 patients (26%), a surgical resection of residual disease could be performed. Median progression-free and overall survival times were 10.4 and 26.5 months, respectively.

CONCLUSION

This biweekly regimen is feasible and has acceptable and manageable toxicities and no apparent relevant pharmacokinetics interactions. This combination is associated with a promising antitumor activity, time to progression, and survival. A phase III randomized trial in Italy planned by the Gruppo Oncologico Nord Ovest has just started.

Acetylcholinesterase blockade does not account for the adverse cardiovascular effects of the antitumor drug irinotecan: a preclinical study

This study investigates the mechanisms that account for the adverse cardiovascular effects of the antitumor drug irinotecan. The activities of irinotecan, its active metabolite 7-ethyl-10-hydroxycamptothecin (SN-38), and camptothecin were assayed in urethane-anesthetized rats to determine their effects on heart rate and blood pressure. In vitro experiments were performed to assess the effects of test drugs on acetylcholinesterase activity. Intravenous irinotecan (10 micromol/kg) decreased heart rate and blood pressure, but SN-38, camptothecin, or intracerebroventricular irinotecan had no effect. The bradycardic and hypotensive responses induced by irinotecan were abolished by bilateral vagotomy or atropine. Physostigmine caused a transient bradycardia, followed by a tachycardic response, and promoted a marked increment of blood pressure. Vagotomy or atropine prevented the bradycardic action of physostigmine, whereas the tachycardic and hypertensive responses were sensitive to atropine, but not to vagotomy. Five minutes after irinotecan administration (10 micromol/kg i.v.), its concentration in plasma and atrial tissue accounted for 2.29 +/- 0.19 micromol/L and 1.08 +/- 0.16 micromol/kg, respectively. The in vitro activity of human erythrocyte acetylcholinesterase was significantly inhibited by irinotecan (-21.5% at 100 microM) or physostigmine (-84.8% at 1 microM), whereas SN-38 or camptothecin had no effect. Rat atrial acetylcholinesterase was also significantly inhibited in vitro by irinotecan (-16.9% at 100 microM). The present results indicate that irinotecan exerts depressant effects on both heart rate and arterial blood pressure. A direct activation of cholinergic receptors or an interaction with central nervous sites does not appear to account for these inhibitory actions, whereas a blockade of acetylcholinesterase seems to occur at concentrations of irinotecan that may not be relevant in clinical settings.