Phase I/II study of a 3-week cycle of irinotecan and S-1 in patients with advanced colorectal cancer

REDOMA: Bayesian random-effects dose-optimization meta-analysis using spike-and-slab priors

The rise of cutting-edge precision cancer treatments has led to a growing significance of the optimal biological dose (OBD) in modern oncology trials. These trials now prioritize the consideration of both toxicity and efficacy simultaneously when determining the most desirable dosage for treatment. Traditional approaches in early-phase oncology trials have conventionally relied on the assumption of a monotone relationship between treatment efficacy and dosage. However, this assumption may not hold valid for novel oncology therapies. In reality, the dose-efficacy curve of such treatments may reach a plateau at a specific dose, posing challenges for conventional methods in accurately identifying the OBD. Furthermore, achieving reliable identification of the OBD is typically not possible based on a single small-sample trial. With data from multiple phase I and phase I/II trials, we propose a novel Bayesian random-effects dose-optimization meta-analysis (REDOMA) approach to identify the OBD by synthesizing toxicity and efficacy data from each trial. The REDOMA method can address trials with heterogeneous characteristics. We adopt a curve-free approach based on a Gamma process prior to model the average dose-toxicity relationship. In addition, we utilize a Bayesian model selection framework that uses the spike-and-slab prior as an automatic variable selection technique to eliminate monotonic constraints on the dose-efficacy curve. The good performance of the REDOMA method is confirmed by extensive simulation studies.

A straightforward meta-analysis approach for oncology phase I dose-finding studies

Phase I early-phase clinical studies aim at investigating the safety and the underlying dose-toxicity relationship of a drug or combination. While little may still be known about the compound's properties, it is crucial to consider quantitative information available from any studies that may have been conducted previously on the same drug. A meta-analytic approach has the advantages of being able to properly account for between-study heterogeneity, and it may be readily extended to prediction or shrinkage applications. Here we propose a simple and robust two-stage approach for the estimation of maximum tolerated dose(s) utilizing penalized logistic regression and Bayesian random-effects meta-analysis methodology. Implementation is facilitated using standard R packages. The properties of the proposed methods are investigated in Monte Carlo simulations. The investigations are motivated and illustrated by two examples from oncology.

Comparison of short-term efficacy and safety of TIROX and DCF regimens for advanced gastric cancer

OBJECTIVE

To compare the short-term efficacy and safety profile of the S-1 + irinotecan + oxaliplatin (TIROX) and docetaxel + cisplatin + flurouracil (DCF) anticancer regimens in patients with advanced gastric cancer.

METHODS

Patients with recurrent or metastatic gastric cancer diagnosed by pathology were randomly divided into two groups to receive six cycles of either the TIROX regimen (21-day cycle) or the DCF regimen (21-day cycle). After six chemotherapy cycles, the short-term efficacy was evaluated according to the Response Evaluation Criteria in Solid Tumors guidelines and adverse reactions were recorded according to National Cancer Institute Common Toxicity Criteria 2.0 standards.

RESULTS

A total of 60 patients were enrolled in the study. The response rate (complete response + partial response) was significantly higher in the TIROX group (18/30 patients; 60.0%) compared with the DCF group (10/30 patients; 33.3%). The rates of grade III-IV leucopenia and neurotoxicity were significantly higher in the TIROX group than the DCF group.

CONCLUSION

The TIROX regimen was effective for the treatment of advanced gastric cancer, but it was associated with leucopenia and neurotoxicity.

A phase II study evaluating the feasibility of a 5-week cycle of S-1 plus irinotecan (IRIS) in patients with advanced and recurrent colorectal cancer

PURPOSE

A number of clinical trials, including the FIRIS study, have shown that S-1 plus irinotecan (IRIS) is safe and effective in patients with colorectal cancer. Several different treatment protocols for IRIS are commonly used in Japan, besides the one used in the FIRIS study. This study was designed to evaluate the feasibility of a 5-week cycle of IRIS.

METHODS

Between January 2005 and February 2008, a total of 55 patients with metastatic colorectal cancer were enrolled at nine centers in Japan. All patients received irinotecan intravenously (80 mg/m(2)) on days 1 and 15 and S-1 orally (40-60 mg twice daily, according to body surface area) on days 1-21 of a 5-week repeated cycle.

RESULTS

The overall response rate was 29.1 %. The response rate was 43.8 % in patients who received IRIS as first-line therapy and 23.1 % in those who received IRIS as second-line or subsequent therapy. The median survival time was 678 days (22.6 months). Adverse events of Grade 3 or higher that occurred at an incidence of ≥10 % were neutropenia (12.7 %) and diarrhea (10.9 %).

CONCLUSION

Our efficacy and safety data suggest that a 5-week cycle of IRIS is an effective alternative to used currently regimens.

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.