Dosage escalation study of S-1 and irinotecan in metronomic chemotherapy against 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.

Phase II clinical trial of metronomic chemotherapy with combined irinotecan and tegafur-gimeracil-oteracil potassium in metastatic and recurrent breast cancer

BACKGROUND

We investigated the efficacy and safety of metronomic chemotherapy with combined irinotecan and tegafur-gimeracil-oteracil potassium (TS-1) in patients with metastatic and recurrent breast cancer (MRBC), and the association between irinotecan metabolizing enzyme UDP-glucuronosyltransferase 1A1 (UGT1A1) gene polymorphisms and adverse events.

METHODS

The study group comprised 40 patients aged 35-79 years. Irinotecan (60 mg/m(2) in 5 % dextrose) was administered by 120-min infusion on days 1, 8, and 15 every 4 weeks. TS-1 (prescribed in a standard quantity) was administered at 80 mg/m(2)/day orally on days 3-7, 10-14, and 17-21 every 4 weeks.

RESULTS

Tumor response data were available for 34 patients. Median follow-up was 12 months (range 1-45 months). Response rate was 47 % (one complete and 15 partial responses). Stable disease was observed in 17 patients (50 %). One patient had disease progression (3 %). Median progression-free survival was 14 months [95 % confidence interval (CI), 10-26]. Median overall survival was 26 months (95 % CI not calculable owing to sample size), and 79.3 % of patients survived for 1 year. The most common grade 3 or 4 adverse events were neutropenia (15 %), leukopenia (12.5 %), diarrhea (7.5 %), and anemia (2.5 %). All other adverse events were grade 1 or 2. Treatment-related toxicity was generally modest and manageable. No significant correlation was observed between UGT1A1 polymorphisms and hematological or non-hematological toxicities.

CONCLUSIONS

Metronomic chemotherapy with combined irinotecan and TS-1 was effective in MRBC patients. Adverse effects were mild and the regimen was safely administered without identifying UGT1A1 polymorphisms.

Efficacy of schedule-dependent metronomic S-1 chemotherapy in human oral squamous cell carcinoma cells

Metronomic chemotherapy is based on administration of anticancer agents at low-doses at close regular intervals with no prolonged breaks, and aims to inhibit vascular endothelial cells as well as tumor cells. Recently, it was suggested that metronomic chemotherapy exerts anti-angiogenic effects by inducing thrombospondin-1 (TSP-1) and early growth response-1 (EGR-1), and antitumor effects by suppressing cancer stem cells. S-1 is a novel orally administered anticancer drug that is a combination of tegafur, 5-chloro-2, 4-dihydroxypyridine and oteracil potassium for maintaining efficacious concentrations of 5-FU and reducing the serious gastrointestinal toxicity associated with 5-FU. In the present study, we tried to determine the suitable administration method of S-1 against oral squamous cell carcinoma as a metronomic chemotherapy. We performed in vivo experiments in which tumor-bearing nude mice were used to examine the antitumor activity of S-1 (6.9 mg/kg). HSC2 tumors were treated with three different regimens, given as 4-week treatment and 2-week rest (4W-2W, 1 cycle); 2-week treatment and 1-week rest (2W-1W, 2 cycles); or alternate days treatment (1D-1D, 6 weeks). A fourth group served as control. Antitumor effects and body weight changes were compared in each group. Expression of TSP-1, EGR-1, CD31 and CD44 in HSC2 tumors was examined by immunohistochemistry. The treated groups showed higher tumor growth inhibition compared to the control group, and the relative tumor growth inhibition was not different between the treated groups. Briefly, each relative tumor growth inhibition was 32.4% (4W-2W), 39.6% (2W-1W) and 37.0% (1D-1D). During treatment periods, body weights were lower in the mice with 4W-2W or 2W-1W than 1D-1D or control. Moreover, reduction of microvessel density and CD44 expression, and induction of TSP-1 and EGR-1 expression was markedly seen in 1D-1D-treated tumors compared to 4W-2W-, 2W-1W-treated tumors or untreated control tumors by immunohistochemistry. These findings suggest that the 1D-1D regimen is more useful than the 4W-2W or 2W-1W regimen as a metronomic chemotherapy.

Multicenter Phase II Study of a New Effective S-1 and Irinotecan Combination Schedule in Patients with Unresectable Metastatic or Recurrent Colorectal Cancer

INTRODUCTION

This multicenter phase II study determined the efficacy and safety of new daily oral S-1 and weekly irinotecan (CPT-11) combination schedule in patients with previously untreated advanced or recurrent colorectal cancer.

PATIENTS AND METHODS

Patients received first-line chemotherapy comprising S-1 80 mg/m(2)/day given on days 3 to 7, 10 to 14, and 17 to 21 and 60 mg/m(2) CPT-11 administered intravenously on days 1, 8, and 15 of a 28-day cycle.

RESULTS

A total of 45 eligible patients were enrolled in this study. The overall response rate was 48.9%. Median progression-free survival and median overall survival was 8.1 months and 20.9 months, respectively. The rates of grade 3 or 4 toxicity were as follows: neutropenia, 8.9%; anemia, 4.4%; anorexia, 6.7%; and diarrhea, 6.7%.

CONCLUSIONS

This new S-1 and irinotecan combination schedule appeared to be an effective, well-tolerated, and convenient regimen in patients with advanced colorectal cancer as compared with conventional regimens such as FOLFIRI and IRIS.