Gastrointestinal toxicities of 5-fluorouracil increase the proportion of regulatory T cells in intestinal tract: advantages of alternate-day S-1 administration

Characterization of a novel dual murine model of chemotherapy-induced oral and intestinal mucositis

Oral and intestinal mucositis are debilitating inflammatory diseases observed in cancer patients undergoing chemo-radiotherapy. These are devastating clinical conditions which often lead to treatment disruption affecting underlying malignancy management. Although alimentary tract mucositis involves the entire gastrointestinal tract, oral and intestinal mucositis are often studied independently utilizing distinct organ-specific pre-clinical models. This approach has however hindered the development of potentially effective whole-patient treatment strategies. We now characterize a murine model of alimentary tract mucositis using 5-Fluorouracil (5-FU). Mice were given 5-FU intravenously (50 mg/kg) or saline every 48 h for 2 weeks. Post initial injection, mice were monitored clinically for weight loss and diarrhea. The incidence and extent of oral mucositis was assessed macroscopically. Microscopical and histomorphometric analyses of the tongue and intestinal tissues were conducted at 3 interim time points during the experimental period. Repeated 5-FU treatment caused severe oral and intestinal atrophy, including morphological damage, accompanied by body weight loss and mild to moderate diarrhea in up to 77.8% of mice. Oral mucositis was clinically evident throughout the observation period in 88.98% of mice. Toluidine blue staining of the tongue revealed that the ulcer size peaked at day-14. In summary, we have developed a model reproducing the clinical and histologic features of both oral and intestinal mucositis, which may represent a useful in vivo pre-clinical model for the study of chemotherapy-induced alimentary tract mucositis and the development of preventative therapies.

Clinical study of XiangShaLiuJunZi decoction combined with S-1 as maintenance therapy for stage III or IV gastric carcinoma and colorectal carcinoma

INTRODUCTION

S-1, a new oral fluorouracil chemotherapeutical drug, has been increasingly used in clinical maintenance after first-line chemotherapy for stage III or IV gastric carcinoma (GC) and colorectal carcinoma (CRC) for its own advantages. XiangshaLiujunzi Decoction (XSLJZD), a classic traditional Chinese medicine (TCM) formula with effects of alleviating the adverse reactions of chemotherapy and improving the quality of life of cancer patients has been gradually confirmed, with no more reports about the maintenance therapy mode of combination of chemotherapeutic drugs and TCM. We designed the study of XSLJZD combined with S-1 in the maintenance therapy of Stage III or IV GC and CRC, and hoped that this research program will go further and comprehensively evaluate its efficacy and safety.

OBJECTIVES

The aim of this study was to determine the efficacy and safety of XSLJZD combined with S-1 in the maintenance therapy of stage III or IV GC and CRC.

METHODS

This study is an open, single-center, randomized study. Patients with stage III or stage IV GC and CRC will be randomized (1:1) into S-1group, S-1 combined with XSLJZD group for 5 years of maintenance therapy. The primary endpoint was progression-free survival, and secondary end point was overall survival and Quality of Life Assessment (QOLA), which include an improvement in symptoms before and after treatment, Karnofsky Performance Status, and adverse events assessment.

DISCUSSION

This study will provide meaningful clinical information about the combination of chemotherapeutic drugs S-1 with TCM in the maintenance therapy of stage III or IV GC and CRC.

TRIAL REGISTRATION

Chinese Clinical Trial Registry: ChiCTR-INR-16008575.

A phase II study of bevacizumab and irinotecan plus alternate-day S-1 as a second-line therapy in patients with metastatic colorectal cancer: the AIRS study

BACKGROUND

The aim of this single-arm phase II clinical trial was to evaluate whether the alternate-day administration of S-1 plus irinotecan would reduce the incidence of severe diarrhea in comparison to consecutive-day S-1 administration (standard IRIS regimen) in second-line treatment for patients with metastatic colorectal cancer.

METHODS

Patients with metastatic colorectal cancer after failure with first-line treatment of oxaliplatin and fluoropyrimidine were enrolled. Irinotecan (150 mg/m²) and bevacizumab (5 mg/kg) were given intravenously on day 1. Oral S-1 was administered on alternate days at a dose of 40-60 mg twice a day. Cycles were repeated every 2 weeks. The primary endpoint was the incidence of grade ≥ 3 diarrhea. Our hypothesis set 21% as a threshold incidence and 10% as an expected incidence from previous studies with one-sided alpha 0.05. The secondary endpoints included the relative dose intensity, progression-free survival, overall survival and other adverse events.

RESULTS

A total of 51 patients were enrolled. The incidence of grade ≥ 3 diarrhea was 15.7% (8/51). Other common grade ≥ 3 adverse events were neutropenia, anemia, thrombocytopenia and fatigue were 13.7% (7/51), 5.9% (3/51), 2.0% (1/51) and 5.9% (3/51), respectively. The relative dose intensities of irinotecan, bevacizumab, and S-1 were 80.0, 86.8, and 77.7%, respectively. The median progression-free survival and overall survival were 8.4 months (5.8-9.8) and 17.1 months (11.8-22.3).

CONCLUSIONS

The alternate-day S-1 administration does not have significant effectiveness to reduce diarrhea in patients who received second-line treatment for metastatic colorectal cancer.

Chemotherapy Induces Oral Mucositis in Mice Without Additional Noxious Stimuli

Oral mucositis (OM) is a serious side effect of cancer chemotherapy. The pathobiology of oral mucositis remains incompletely understood due to lack of appropriate models which recapitulate the human condition. Existing rodent models are intraperitoneal and require radiation, chemical or mechanical injury to the chemotherapy protocol to induce oral lesions. We aimed to develop an OM mouse model that is induced solely by chemotherapy and reproduces macroscopic, histopathologic and inflammatory characteristics of the human condition. Female C57BL/6 mice were given intravenous 5-Fluorouracil (5-FU) injections every 48 hours, for 2 weeks. A high daily dose of intraperitoneal administration was tested for comparison. Mice were monitored daily for weight loss. Epithelial histomorphometric analyses in tongue, esophageal and intestinal tissues were conducted coupled with assessment of apoptosis, cell proliferation, neutrophilic infiltration and the integrity of adherens junctions by immunohistochemistry. Neutropenia was assessed in peripheral blood and bone marrow. Tissues were analyzed for pro-inflammatory cytokines at the protein and mRNA levels. Daily intraperitoneal administration of 5-FU led to rapid weight loss and intestinal mucositis, but no oral inflammatory changes. Intravenous administration triggered atrophy of the oral and esophageal epithelium accompanied by reduction in cell proliferation and increased apoptosis. Coincidental with these changes were up-regulation of NF-κB, TNFα, IL-1β, GM-CSF, IL-6 and KC. Despite neutropenia, increased oral neutrophilic infiltration and reduced E-cadherin was observed in oroesophageal mucosae. We developed a novel experimental tool for future mechanistic studies on the pathogenesis of chemotherapy-induced OM.

Drug delivery of oral anti-cancer fluoropyrimidine agents

INTRODUCTION

Sixty years since its introduction, 5-FU still forms the core of chemotherapy regimens for many types of malignancies. 5-FU is a time-dependent drug but is rapidly degraded in plasma by dihydropyrimidine dehydrogenase (DPD). Although originally developed in an intravenous form, 5-FU oral prodrugs were developed with the goal of improving efficacy and minimizing toxicity as well as to capitalize on the advantages of oral drug administration. The inactive 5-FU prodrug is gradually converted into the active form in the systemic circulation. UFT, S-1, and capecitabine are oral 5-FU prodrugs currently in clinical use. However, the efficacy of 5-FU can be further improved by its combination with DPD inhibitors and biochemical modulators, such as uracil and leucovorin, in addition to modifying administration schedules. Areas covered: We focused on the drug delivery of oral 5-FU prodrugs, their pharmacokinetics, and the development of DPD inhibitors. Since oral 5-FU prodrugs have been formulated into combination drugs, we also discussed the regulatory approval of combination drugs. Expert opinion: Many regimens that include intravenously administered 5-FU can be replaced by oral 5-FU prodrugs. Patients would benefit from development of combination 5-FU oral prodrug formulations and its associated path through the combination drug regulatory approval process.