A phase II study of combination therapy with irinotecan and S-1 (IRIS) in patients with advanced colorectal cancer

Efficacy of S-1 in colorectal cancer

INTRODUCTION

S-1 is an oral fluoropyrimidine that consists of tegafur, 5-chloro-2, 4-dihydroxypyridine and potassium oxonate. It has been developed as a prodrug of 5-fluorouracil with the goal of improving therapeutic efficacy and tolerability.

AREAS COVERED

This review aims to provide an evidence-based update of clinical trials that have investigated the clinical efficacy, adverse-event profile, dosage and administration of S-1, given alone or in combination with conventional chemotherapeutics and new target-oriented drugs, in the management of colorectal cancer (CRC). Additionally, differences in the tolerability and pharmacokinetics of S-1 between Caucasians and Asians have been described. Finally, the therapeutic efficacy of S-1 regarding metastatic CRC or postoperative CRC has been discussed. Available data have stimulated further research, including Phase III trials for the treatment of advanced CRC.

EXPERT OPINION

Treatment using S-1 combined with oxaliplatin (± bevacizumab) and irinotecan has achieved promising results in terms of feasibility, safety and effectiveness. Furthermore, S-1 is an acceptable treatment as adjuvant chemotherapy for colon cancer.

A phase 3 non-inferiority study of 5-FU/l-leucovorin/irinotecan (FOLFIRI) versus irinotecan/S-1 (IRIS) as second-line chemotherapy for metastatic colorectal cancer: updated results of the FIRIS study

PURPOSE

The FIRIS study previously demonstrated non-inferiority of IRIS (irinotecan plus S-1) to FOLFIRI (5-fluorouracil/leucovorin with irinotecan) for progression-free survival as the second-line chemotherapy for metastatic colorectal cancer (mCRC) as the primary endpoint. The overall survival (OS) data were immature at the time of the primary analysis.

METHODS

Between 30 January 2006 and 29 January 2008, 426 patients with mCRC who failed in first-line chemotherapy were randomly assigned to receive either FOLFIRI or IRIS. After the primary analysis, the follow-up survey was cut off on 29 July 2010, and the final OS data were analysed.

RESULTS

With a median follow-up of 39.2 months, the median OS was 17.4 months in the FOLFIRI group and 17.8 months in the IRIS group [hazard ratio (HR) 0.900; 95% confidence interval (CI) 0.728-1.112]. In the pre-planned subgroup of patients who received prior chemotherapy containing oxaliplatin, the median OS was 12.7 months in the FOLFIRI group and 15.3 months in the IRIS group (HR 0.755; 95% CI 0.580-0.983).

CONCLUSIONS

IRIS is non-inferior to FOLFIRI for OS as second-line chemotherapy for mCRC. IRIS can be an option for second-line chemotherapy of mCRC. (ClinicalTrials.gov Number: NCT00284258).

Gimeracil and oteracil porassium capsules as a single drug in adjuvant treatment of patients with advanced colorectal cancer: A randomized clinical study

AIM: To evaluate the efficacy and safety of gimeracil and oteracil porassium capsules (S-1) as a single drug in the adjuvant treatment of patients with advanced colorectal cancer.

METHODS: Eligible patients with advanced colorectal cancer were randomly assigned to either a control group or an experimental group. The patients of the control group received routine symptomatic treatment, while the experimental group was additionally given S-1 [60 mg/(m²•d), bid, P.O. on days 1-14, then drug withdrawal for 1 wk, repeated every 3 wk, stopped until disease progression or unacceptable toxicity occurred] beside the routine symptomatic treatment.

RESULTS: A total of 83 eligible patients were enrolled, including 4 in the control group and 41 in the experimental arm. Median follow-up period was 54 wk. The baseline characteristics were comparable between the two groups. S-1 treatment improved the progression-free survival (PFS), though there was no statistical difference (HR = 0.52, 95%CI: 0.22-1.23, P = 0.1384). For all patients with advanced colorectal cancer, the 1-year PFS for the control arm and experimental arm was 78.6% and 97.6%, respectively, favoring the S-1 regimen. For patients with advanced colon cancer, the improvement of PFS did not differ significantly between the two arms (HR = 0.62, 95%CI: 0.20-1.95, P = 0.4156). The 1-year PFS for the control arm and experimental arm was 76.2% and 95.0%, favoring the S-1 regimen. For patients with advanced rectal cancer, the improvement of PFS did not differ significantly between the two arms (HR = 0.42, 95%CI: 0.11-1.58, P = 0.2005). The 1-year PFS for the control arm and experimental arm was 76.2% and 95.2%, respectively. Three cases developed S-1-induced adverse reactions, including one case of grade Ⅱ and two cases of grade Ⅰ, which, however, did not cause treatment discontinuation.

CONCLUSION: S-1 can improve the PFS in patients with advanced colorectal cancer, indicating that such patients may benefit from S-1 regimen in the adjuvant setting.

Phase II study of combined chemotherapy with irinotecan and S-1 (IRIS) plus bevacizumab in patients with inoperable recurrent or advanced colorectal cancer

BACKGROUND

In Japan, a study comparing the effectiveness and safety of irinotecan plus S-1 (IRIS) with those of a combination of 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI) as second-line treatment in patients with advanced or recurrent colorectal cancer demonstrated that IRIS was non-inferior to FOLFIRI. We previously reported that IRIS is also effective as first-line treatment.

PATIENTS AND METHODS

Eligibility criteria included inoperable recurrent colorectal cancer with a confirmed diagnosis of adenocarcinoma, age ≥20 years, and no history of prior chemotherapy. S-1 (40-60 mg twice daily) was given orally on Days 1 to 14, and irinotecan (100 mg/m(2)) and bevacizumab (5 mg/kg) were given intravenously on Days 1 and 15 of a 28-day cycle. The primary endpoint was safety. The secondary endpoints included overall response (OR), progression-free survival (PFS), and overall survival (OS).

RESULTS

A total of 52 eligible patients were enrolled from October 2007 through March 2009. In safety analysis, the incidences of grade 3 or 4 adverse reactions were as follows: neutropenia, 27%; hypertension, 21%; and diarrhea, 17%. The overall response rate was 57.7%. Median progression-free survival was 16.7 months.

CONCLUSION

IRIS plus bevacizumab is a well-tolerated, highly effective chemotherapeutic regimen that is easy to administer.

S-1 for the treatment of gastrointestinal cancer

INTRODUCTION

5-Fluorouracil (5-FU)-based regimens are used worldwide as the standard treatment in chemotherapy for gastric cancer. S-1 , a fourth-generation oral fluoropyrimidine that combines tegafur and two biochemical modulators: gimeracil and oteracil potassium, is now attracting considerable interest.

AREAS COVERED

This review addresses the clinical evidence of S-1 in gastrointestinal malignancies, such as gastric, colorectal, pancreatic and biliary tract cancers. S-1 has demonstrated advantages over standard therapies, in both advanced and postoperative settings, in large Phase III studies. S-1 alone or S-1 plus cisplatin is recommended in the 2010 Gastric Cancer Treatment Guidelines, by the Japanese Gastric Cancer Association. Results from Phase III studies have demonstrated that S-1 in combination with chemotherapies, such as cisplatin in gastric cancer, and irinotecan and oxaliplatin in colorectal cancers, is non-inferior to conventional 5-FU-based standard regimens, with the benefit of convenience and reduced toxicity.

EXPERT OPINION

The excellent design of S-1 aimed to reduce toxicity by avoiding certain routes of degradation, and to enhance activity by reducing catabolism. This has provided not only a suitable alternative to 5-FU, but also higher efficacy.

A Phase II study of clinical outcomes of 3-week cycles of irinotecan and S-1 in patients with previously untreated metastatic colorectal cancer: influence of the UGT1A1 and CYP2A6 polymorphisms on clinical activity

OBJECTIVES

We investigated the efficacy and safety of the combination of irinotecan (CPT-11) and S-1 (IRIS regimen) as a first-line treatment in patients with metastatic colorectal cancer. We also evaluated the association between UGT1A1 and CYP2A6 polymorphisms and clinical phenotypes.

METHODS

The patients received CPT-11 (225 mg/m(2)) on day 1 and S-1 (80 mg/m(2)) on days 1-14 every 3 weeks. The association of the UGT1A1 (*6 and *28) and CYP2A6(*4, *7, *9, and *10) polymorphisms with toxicities and efficacy were analyzed.

RESULTS

Thirty patients were treated. The overall response rate was 66.7% (95% CI 48.7-84.6). The median time to progression was 7.6 months (95% CI 5.8-9.5). The most common grade 3/4 hematologic and non-hematologic toxicity were neutropenia (53.4%) and diarrhea (16.7%), respectively. The allele frequencies of UGT1A1*6 and *28 were 15.5 and 10.3%, respectively. The frequencies of CYP2A6*4, *7, *9, and *10 were 15.5, 8.6, 29.3, and 3.5%, respectively. Stratification of patients according to the number of UGT1A1*28 and *6 alleles showed a significant correlation between the number of defective alleles and the incidence of grade 3/4 neutropenia.

CONCLUSIONS

Our results indicate that IRIS is a promising first-line regimen in patients with metastatic colorectal cancer. Severe neutropenia may be associated with interindividual variations in UGT1A1 polymorphisms.

Phase II study of oral S-1 with irinotecan and bevacizumab (SIRB) as first-line therapy for patients with metastatic colorectal cancer

Fluorouracil (5-FU) plus irinotecan combined with bevacizumab has significant activity in metastatic colorectal cancer (mCRC), but S-1 has become a substitute for continuous infusion of 5-FU and has a very low incidence of hand-foot syndrome. With the S-1 plus irinotecan regimen (SIR), the response rate was 62.5%, and the progression-free survival was 8.0 months. We report here on an update of efficacy and safety of the SIR plus bevacizumab (SIRB) regimen as first line treatment for mCRC patients. Fifty-one eligible patients with histologically confirmed advanced or recurrent colorectal cancer received this treatment. S-1 was administered orally on days 1-14 of a 21-day cycle. Patients were assigned on the basis of body surface area (BSA) to receive one of the following oral doses twice daily: 40 mg, 50 mg, or 60 mg. Irinotecan (150 mg/m(2)) plus bevacizumab (7.5 mg/kg) were administered by intravenous infusion on day 1. Safety analysis identified a grade 3/4 neutropenia rate of 26%. Other grade 3/4 toxicities were diarrhea (8%), nausea (6%), vomiting (2%), and hypertension (8%). The response rate was 67% and the median progression-free survival time was 373 days. The SIRB regimen appears to be highly active and well tolerated as first-line treatment for mCRC.

Phase II study of combined treatment with irinotecan and S-1 (IRIS) in patients with inoperable or recurrent advanced colorectal cancer (HGCSG0302)

OBJECTIVES

This phase II study was designed to evaluate the efficacy and safety of oral fluoropyrimidine S-1 plus irinotecan (IRIS regimen) in patients with previously untreated metastatic colorectal cancer.

METHODS

The response rate was the primary endpoint. Safety, progression-free survival time, and median survival time were secondary endpoints. The subjects were untreated patients with inoperable advanced colorectal cancer. Irinotecan was administered at a dose of 100 mg/m² (on days 1 and 15). S-1 (40 mg/m²) was administered for 2 weeks (on days 1 to 14) and followed by a 2-week rest.

RESULTS

Forty patients were enrolled. Four patients had grade 4 neutropenia, and six patients had grade 3 diarrhea. No other serious hematologic or nonhematologic adverse reactions occurred, and all patients received IRIS safely on an outpatient basis. The response rate was 52.5% (95% confidence interval [CI], 36.1-68.5%). Median progression-free survival was 8.6 months (95% CI, 5.3-11.9), and median survival time was 23.4 months (95% CI, 15.9-30.8).

CONCLUSIONS

IRIS produced a high response rate and could be given safely. IRIS may become a first-line treatment for inoperable or recurrent advanced colorectal cancer.

Irinotecan plus S-1 (IRIS) versus fluorouracil and folinic acid plus irinotecan (FOLFIRI) as second-line chemotherapy for metastatic colorectal cancer: a randomised phase 2/3 non-inferiority study (FIRIS study)

BACKGROUND

Fluorouracil and folinic acid with either oxaliplatin (FOLFOX) or irinotecan (FOLFIRI) are widely used as first-line or second-line chemotherapy for metastatic colorectal cancer. However, infusional fluorouracil-based regimens, requiring continuous infusion and implantation of an intravenous port system, are inconvenient. We therefore planned an open-label randomised controlled trial to verify the non-inferiority of irinotecan plus oral S-1 (a combination of tegafur, 5-chloro-2,4-dihydroxypyridine, and potassium oxonate; IRIS) to FOLFIRI as second-line chemotherapy for metastatic colorectal cancer.

METHODS

Between Jan 30, 2006, and Jan 29, 2008, 426 patients with metastatic colorectal cancer needing second-line chemotherapy from 40 institutions in Japan were randomly assigned by a computer-based minimisation method to receive either FOLFIRI (n=213) or IRIS (n=213). In the FOLFIRI group, patients received folinic acid (200 mg/m(2)) and irinotecan (150 mg/m(2)) and then a bolus injection of fluorouracil (400 mg/m(2)) on day 1 and a continuous infusion of fluorouracil (2400 mg/m(2)) over 46 h, repeated every 2 weeks. In the IRIS group, patients received irinotecan (125 mg/m(2)) on days 1 and 15 and S-1 (40-60 mg according to body surface area) twice daily for 2 weeks, repeated every 4 weeks. The primary endpoint was progression-free survival, with a non-inferiority margin of 1.333. Statistical analysis was on the basis of initially randomised participants. This study is registered with ClinicalTrials.gov, number NCT00284258.

FINDINGS

All randomised patients were included in the primary analysis. After a median follow-up of 12.9 months (IQR 11.5-18.2), median progression-free survival was 5.1 months in the FOLFIRI group and 5.8 months in the IRIS group (hazard ratio 1.077, 95% CI 0.879-1.319, non-inferiority test p=0.039). The most common grade three or four adverse drug reactions were neutropenia (110 [52.1%] of 211 patients in the FOLFIRI group and 76 [36.2%] of 210 patients in the IRIS group; p=0.0012), leucopenia (33 [15.6%] in the FOLFIRI group and 38 [18.1%] in the IRIS group; p=0.5178), and diarrhoea (ten [4.7%] in the FOLFIRI group and 43 [20.5%] in the IRIS group; p<0.0001). One treatment-related death from hypotension due to shock was reported in the FOLFIRI group within 28 days after the end of treatment; no treatment-related deaths were reported in the IRIS group.

INTERPRETATION

Progression-free survival with IRIS is not inferior to that with FOLFIRI in patients receiving second-line chemotherapy for metastatic colorectal cancer. Treatment with IRIS could be an additional therapeutic option for second-line chemotherapy in metastatic colorectal cancer.

FUNDING

Taiho Pharmaceutical Co Ltd and Daiichi Sankyo Co Ltd.