Phase I clinical and pharmacokinetic study of oral S-1 in patients with advanced solid tumors

Tislelizumab plus concurrent chemoradiotherapy versus concurrent chemoradiotherapy for elderly patients with inoperable locally advanced esophageal squamous cell carcinoma: a multicenter, randomized, parallel-controlled, phase II clinical trial

BACKGROUND

The standard treatment for elderly patients with unresectable locally advanced esophageal squamous cell carcinoma (ESCC) is definitive chemoradiotherapy with S-1. However, the 3-year overall survival (OS) is limited to approximately 40%. Tislelizumab is the first- and second-line standard treatment for advanced ESCC with tolerable toxicity. In this study, we aimed to explore a new curative strategy for locally advanced unresectable ESCC in the elderly by combining tislelizumab with chemoradiotherapy.

METHODS

This study is an open-label, multicenter, investigator-initiated phase II clinical trial in older patients with inoperable locally advanced ESCC evaluating tislelizumab plus concurrent chemoradiotherapy compared with concurrent chemoradiotherapy. The main inclusion criteria were pathological confirmation of locally advanced inoperable ESCC at clinical cT1N2-3M0 or cT2-4bN0-3M0 (stage II-IVA), age ≥ 70 years, absence of previous systemic anti-tumor therapy, and adequate organ function. A total of 136 patients will be recruited from approximately seven centers (in Tianjin, Chengdu, Taiyuan, Zhengzhou, Shijiazhuang, Changsha, Nanjing) over a period of 18 months and randomized in a 1:1 ratio to receive tislelizumab in combination with concurrent chemoradiotherapy (tislelizumab + S-1 + radiotherapy) or concurrent chemoradiotherapy (S-1 + radiotherapy). The efficacy and safety of the treatment will be evaluated during the therapy and follow-up period until disease progression, death, or the end of the trial. The primary study endpoint was investigator-assessed progression-free survival (PFS), and secondary study endpoints were OS, objective response rate (ORR), duration of remission (DOR), and safety. Fresh or archival tumor tissues and peripheral blood samples will be used in exploratory studies.

DISCUSSION

This study is the first "programmed death-1 (PD-1) inhibitor combined with concurrent chemoradiotherapy" for elderly patients with inoperable locally advanced ESCC (NCT06061146). The synergistic efficacy of combined definitive concurrent chemoradiotherapy with tislelizumab is expected to result in survival benefits for elderly patients with inoperable locally advanced ESCC. Because S-1 plus concurrent radiotherapy is the standard treatment option for locally advanced ESCC in older patients, the combination of definitive concurrent chemoradiotherapy and tislelizumab has the potential to change the standard ESCC therapeutic strategy with comparable safety.

TRIAL REGISTRATION

ClinicalTrials.gov NCT06061146.Registered 9/10/2023.

Consensus, debate, and prospective on pancreatic cancer treatments

Pancreatic cancer remains one of the most aggressive solid tumors. As a systemic disease, despite the improvement of multi-modality treatment strategies, the prognosis of pancreatic cancer was not improved dramatically. For resectable or borderline resectable patients, the surgical strategy centered on improving R0 resection rate is consensus; however, the role of neoadjuvant therapy in resectable patients and the optimal neoadjuvant therapy of chemotherapy with or without radiotherapy in borderline resectable patients were debated. Postoperative adjuvant chemotherapy of gemcitabine/capecitabine or mFOLFIRINOX is recommended regardless of the margin status. Chemotherapy as the first-line treatment strategy for advanced or metastatic patients included FOLFIRINOX, gemcitabine/nab-paclitaxel, or NALIRIFOX regimens whereas 5-FU plus liposomal irinotecan was the only standard of care second-line therapy. Immunotherapy is an innovative therapy although anti-PD-1 antibody is currently the only agent approved by for MSI-H, dMMR, or TMB-high solid tumors, which represent a very small subset of pancreatic cancers. Combination strategies to increase the immunogenicity and to overcome the immunosuppressive tumor microenvironment may sensitize pancreatic cancer to immunotherapy. Targeted therapies represented by PARP and KRAS inhibitors are also under investigation, showing benefits in improving progression-free survival and objective response rate. This review discusses the current treatment modalities and highlights innovative therapies for pancreatic cancer.

Pathological response to neoadjuvant chemoradiotherapy for oesophageal squamous cell carcinoma in Eastern versus Western countries: meta-analysis

OBJECTIVE

Locally advanced oesophageal squamous cell carcinoma can be treated with neoadjuvant chemoradiotherapy or chemotherapy followed by oesophagectomy. Discrepancies in pathological response rates have been reported between studies from Eastern versus Western countries. The aim of this study was to compare the pathological response to neoadjuvant chemoradiotherapy in Eastern versus Western countries.

METHODS

Databases were searched until November 2022 for studies reporting pCR rates after neoadjuvant chemoradiotherapy for oesophageal squamous cell carcinoma. Multi-level meta-analyses were performed to pool pCR rates separately for cohorts from studies performed in centres in the Sinosphere (East) or in Europe and the Anglosphere (West).

RESULTS

For neoadjuvant chemoradiotherapy, 51 Eastern cohorts (5636 patients) and 20 Western cohorts (3039 patients) were included. Studies from Eastern countries included more men, younger patients, more proximal tumours, and more cT4 and cN+ disease. Patients in the West were more often treated with high-dose radiotherapy, whereas patients in the East were more often treated with a platinum + fluoropyrimidine regimen. The pooled pCR rate after neoadjuvant chemoradiotherapy was 31.7% (95% c.i. 29.5% to 34.1%) in Eastern cohorts versus 40.4% (95% c.i. 35.0% to 45.9%) in Western cohorts (fixed-effect P = 0.003). For cohorts with similar cTNM stages, pooled pCR rates for the East and the West were 32.5% and 41.9% respectively (fixed-effect P = 0.003).

CONCLUSION

The pathological response to neoadjuvant chemoradiotherapy is less favourable in patients treated in Eastern countries compared with Western countries. Despite efforts to investigate accounting factors, the discrepancy in pCR rate cannot be entirely explained by differences in patient, tumour, or treatment characteristics.

Adjuvant Treatment with S-1 in Patients after R0-Resection of Adenocarcinoma of the Stomach and Esophagogastric Junction: A Multicenter Phase I/II Feasibility Study (GMBH-STO-0114)

INTRODUCTION

S-1 has been shown to be an effective adjuvant treatment option for East Asian patients who underwent gastrectomy for stage II/III gastric cancer. We conducted a phase I/II study to evaluate the feasibility, tolerability, and efficacy of administering S-1 in the adjuvant setting after R0-resection of adenocarcinoma of the stomach and esophagogastric junction (EGJ) in Caucasian patients.

METHODS

In this single-cohort, open-label, phase I/II trial, we enrolled patients with locally advanced adenocarcinoma of the stomach or EGJ having undergone R0-resection with or without neoadjuvant treatment. One treatment cycle consisted of oral S-1 (30 mg/m2 bid) for 14 days. Cycles were repeated every 3 weeks for 18 cycles (54 weeks). Primary endpoint was feasibility and tolerability. Safety was evaluated according to the Common Toxicity Criteria Adverse Events (CTCAE) version 4.0. Secondary endpoints were 1-year relapse-free survival (RFS) rate, RFS, and overall survival (OS).

RESULTS

Between October 2015 and February 2018, 32 patients were enrolled in 12 German centers, and 30 started adjuvant study treatment. Seventeen patients completed all 18 cycles. Two patients terminated study treatment early due to adverse events (AEs), 7 due to patient's or investigator's decision, and 4 due to recurrence or distant metastasis during adjuvant therapy. Dose levels were reduced to 25 mg/m2 in 9 patients and to 20 mg/m2 in 1 patient. Of patients completing all 18 cycles, 5 did so with reduced dosage of S-1. Documented grade ≥3 AEs were neutropenia, diarrhea, vomiting, polyneuropathy, palmar-plantar erythrodysaesthesia, and rash. Serious AEs were observed in 7 patients. Median RFS was 32.2 months. One-year RFS rate was 77%. Data on OS were still premature at the end of the study.

CONCLUSION

Adjuvant treatment with S-1 for 1 year is a feasible and safe treatment option for Caucasian patients diagnosed with gastric adenocarcinoma or cancer of the EGJ after R0-resection.

Neoadjuvant and Adjuvant Treatments for Resectable and Borderline Resectable Pancreatic Ductal Adenocarcinoma: The Current Status of Pancreatic Ductal Adenocarcinoma Treatment in Japan

Resection is the only curative treatment for pancreatic ductal adenocarcinoma (PDAC). Although the outcome of technically resectable PDAC has improved with advances in surgery and adjuvant therapy, the 5-year survival rate remains low at 20% to 40%. More effective therapy is needed. Almost 15 years ago, the National Comprehensive Cancer Network guidelines proposed a resectability classification of PDAC based on preoperative imaging. Since then, treatment strategies for PDAC have been devised based on resectability. The standard of care for resectable PDAC is adjuvant chemotherapy after R0 resection, as shown by the results of pivotal clinical trials. With regard to neoadjuvant treatment, several recent clinical trials comparing neoadjuvant treatment with upfront resection have been conducted on resectable PDAC and borderline resectable PDAC, and the benefits and efficacy of neoadjuvant treatment for pancreatic cancer has become clearer. The significance of neoadjuvant treatment for resectable PDAC remains controversial, but in borderline resectable PDAC the efficacy of neoadjuvant treatment has been further recognised, although the standard of care has not yet been established. Several promising clinical trials for PDAC are ongoing. This review presents previous and ongoing trials of perioperative treatment for resectable and borderline resectable PDAC, focusing on the difference between Asian and Western countries.

S-1 maintenance therapy in Caucasian patients with metastatic esophagogastric adenocarcinoma-final results of the randomized AIO MATEO phase II trial

PURPOSE

Platinum-fluoropyrimidine combinations are standard of care for treatment of metastatic esophagogastric adenocarcinoma. The optimal duration of first-line chemotherapy is unknown, however, and maintenance strategies have not yet been established.

DESIGN

MATEO is an international randomized phase II trial exploring efficacy and safety of S-1 maintenance therapy in human epidermal growth factor receptor 2 (HER2)-negative advanced esophagogastric adenocarcinoma. After 3 months of first-line platinum-fluoropyrimidine-based induction therapy, patients without progression were randomized in a 2 : 1 allocation to receive S-1 monotherapy (arm A) or to continue combination chemotherapy (arm B). The primary objective was to show non-inferiority of overall survival in the S-1 maintenance group. Progression-free survival, adverse events, and quality of life were secondary endpoints.

RESULTS

From 2014 to 2019, 110 and 55 patients were randomized in arm A and arm B, respectively (recruitment closed prematurely). Median overall survival from randomization was 13.4 months for arm A and 11.4 months for arm B [hazard ratio 0.97 (80% confidence interval 0.76-1.23), P = 0.86]. Median progression-free survival from randomization was 4.3 and 6.1 months for arm A versus arm B, respectively [hazard ratio 1.10 (80% confidence interval 0.86-1.39), P = 0.62]. Patients in arm A had numerically fewer treatment-related adverse events (84.9% versus 93.9%) and significantly less peripheral sensory polyneuropathy ≥grade 2 (9.4% versus 36.7%).

CONCLUSIONS

S-1 maintenance following platinum-based induction therapy leads to non-inferior survival outcomes compared with the continuation of platinum-based combination. Toxicity patterns favor a fluoropyrimidine maintenance strategy. These data challenge the continued use of platinum combination chemotherapy after response to 3 months induction therapy in patients with advanced human epidermal growth factor receptor 2-negative esophagogastric adenocarcinoma.

Moderately hypo-fractionated radiotherapy combined with S-1 in inoperable locally advanced esophageal squamous cell carcinoma: A prospective, single-arm phase II study (GASTO-1045)

Purpose

We launched this prospective phase II single-arm trial on the combination of moderately hypo-fractionated radiotherapy and S-1, to explore the safety and efficacy of the new potent regimen in inoperable locally advanced esophageal squamous carcinoma (LA-ESCC) patients.

Methods

Patients with unresectable stage II-IVB LA-ESCC (UICC 2002, IVB only with metastatic celiac or supraclavicular lymph nodes) were included. Moderately hypofractionated radiotherapy (60Gy in 24 fractions) concurrent with S-1 was delivered. Meanwhile, gastrostomy tube placement by percutaneous endoscopic gastrostomy (PEG) was performed to provide nutritional support. Nutritional supplements were prescribed to meet requirements. The study outcomes included objective response rate (ORR), progression-free survival (PFS), overall survival (OS), locoregional progression-free survival (LRPFS), distant metastasis-free survival (DMFS), failure pattern, toxicities, nutritional status and treatment compliance. Endoscopy was routinely performed during post-treatment follow-up.

Results

Fifty-eight patients were included with a median follow-up of 24.4 months. The median age was 63 years (range 49-83 years) and 42 patients (72.4%) had stage III or IV diseases. The ORR was 91.3% and the CR rate was 60.3%. The estimated 2-year PFS rate and 2-year OS rate was 44.2% (95% confidence interval (CI), 31.3-57.1%) and 71.4% (95% CI, 59.4-83.4%), respectively. Radiation-induced esophagitis was the most common non-hematologic toxicity and 5 patients (8.6%) developed grade≥3 esophagitis. While, with PEG nutrition support, the nutrition-related indicators presented a clear trend toward a gradual improvement. Treatment-related death was not observed.

Conclusions

The moderately hypo-fractionated radiotherapy combined with S-1 showed promising loco-regional disease control and survival benefit in inoperable LA-ESCC patients. Meanwhile, favorable nutritional status and low incidence of severe radiation-induced esophagitis were observed with PEG nutritional support. Moreover, endoscopy examination contributed to the early detection of recurrent esophageal lesions and timely salvage treatment. The efficacy and toxicity of the combined regimen deserved further evaluation.

Trial registration

Clinicaltrials.gov, identifier NCT03660449.

Evaluation of clinical validity of an S-1 dosage formula based on renal function using data of the SPIRITS and the G-SOX trials

BACKGROUND

The aim of this study was to evaluate clinical validity of the S-1 dosage formula based on body surface area (BSA) and creatinine clearance (CLcr) to achieve the target area under the concentration-time curve of 5-FU, which we had developed and refined in each prospective pharmacokinetic study.

METHODS

The recommended dose determined by the refined formula was assessed using data of the SPIRITS (S-1 vs. S-1 plus cisplatin [SP]) and the G-SOX (SP vs. S-1 plus oxaliplatin [SOX]) trials. Nine hundred and thirty-eight patients in these trials were classified into three groups according to their actual S-1 starting doses compared with the recommended doses (under-dosed, <recommended dose; equal-dosed, =recommended dose; over-dosed, >recommended dose).

RESULTS

The patients in the under-dosed group in both trials showed similar tendencies: male, younger, higher BSA, and higher CLcr. The incidence of any grade neutropenia was significantly greater in the over-dosed group compared with the equal-dosed group in the S-1 and the SOX arms. The hazard ratios (HR) of overall survival (OS) (under-dosed vs. equal-dosed) were 1.361 (S-1 arm), 1.259 (SP arm) in the SPIRITS trial, and 1.381 (SOX arm), 0.999 (SP arm) in the G-SOX trial. Multivariate analysis in all the patients demonstrated that OS of the over-dosed group was equivalent (HR 1.002, 95% confidence interval [CI] 0.850-1.182, p = 0.980) and that of the under-dosed group was inferior (HR 1.267, 95% CI 1.005-1.597, p = 0.045) to the equal-dosed group.

CONCLUSIONS

It is suggested that the refined S-1 dosage formula can recommend optimal dose in terms of safety and efficacy.

Camrelizumab combined with apatinib and S-1 as second-line treatment for patients with advanced gastric or gastroesophageal junction adenocarcinoma: a phase 2, single-arm, prospective study

BACKGROUND

The current second-line treatment of advanced gastric or gastroesophageal junction adenocarcinoma remains unsatisfactory. Anti-PD-1 monoclonal antibody combined with anti-angiogenic therapy shows anti-tumor activity and synergistic effect. We aimed to assess the efficacy and safety of the combination therapy of camrelizumab, apatinib, and S-1 in patients with gastric or gastroesophageal junction adenocarcinoma.

METHODS

In this open-label, single-arm, phase 2 trial, in each 21-day cycle, eligible patients received 200 mg intravenous camrelizumab in the first day, 500 mg oral apatinib once daily continuously, and specific dose oral S-1 in the first 14 days until the trial was discontinued disease progression, development of intolerable toxicity, or withdrawal of consent. The primary endpoint was objective response rate. The secondary endpoints were disease control rate, progression-free survival and overall survival, and safety. This study was registered at ClinicalTrials.gov, NCT04345783.

RESULTS

Between May 2019 and August 2020, we enrolled a total of 24 patients in this trial. At the data cutoff (December 1, 2020), the median follow-up duration was 8.13 months. Seven of 24 (29.2%, 95%CI 14.9-49.2%) patients reached objective response. The median-progression-free survival was 6.5 months (95%CI 6.01-6.99) and the median overall survival was not reached. Grade 3 or 4 adverse events occurred in 6 (25.0%) patients, including elevated transaminase, thrombocytopenia, fatigue, proteinuria, and intestinal obstruction. No serious treatment-related adverse events or treatment-related deaths occurred.

CONCLUSIONS

In this trial, the combination of camrelizumab, apatinib, and S-1 showed promising anti-tumor activity and manageable toxicity as a second-line therapy in patients with advanced gastric or gastroesophageal junction adenocarcinoma, regardless of PD-L1 expression.

CLINICAL TRIAL REGISTRATION

NCT04345783.

Apatinib plus S-1 for previously treated, advanced gastric or gastro-oesophageal junction adenocarcinoma: a phase 2, single-arm, prospective study

Background

The current management of advanced gastric or gastro-oesophageal junction adenocarcinoma remains unsatisfactory. We investigated the efficacy and safety of the combination therapy of apatinib and S-1, considering the potential advantage of home-based treatment without hospital admission, in patients with platinum-refractory gastric or gastro-oesophageal junction adenocarcinoma.

Methods

In this open-label, single-arm, phase 2 trial, in each 21-day cycle, eligible patients received apatinib at an initial dose of 500 mg once daily continuously and S-1 at a dose of 40-60 mg twice daily on days 1-14 until the trail was discontinued disease progression, development of intolerable toxicity, or withdrawal of consent. The primary endpoints were progression-free survival. The secondary endpoints were objective response rates, disease control rates, and safety, and overall survival. This study was registered at ClinicalTrials.gov, NCT04338438.

Results

Between April 2015 and May 2019, we included 37 patients with advanced gastric or gastro-oesophageal junction adenocarcinoma refractory to first-line platinum-containing therapy. At the data cutoff, the 6-month progression-free survival was 31.5%, the median progression-free survival and overall survival were 4.2 (95% CI: 3.50-4.90) months and 8.2 (95% CI: 4.69-11.71) months, respectively. Of 37 eligible patients, 8 (21.6%) patients reached objective responses, 31 (83.8%) patients reached disease control. Grade 3 or 4 adverse events occurred in 8 (21.6%) patients, including hand-foot syndrome, hypertension, and diarrhea, etc.

Conclusions

The combination of Apatinib and S-1 showed promising efficacy and manageable toxicity as a home-based, second-line therapy in patients with advanced gastric or gastro-oesophageal junction adenocarcinoma, especially for the elder patients with poor performance status.

Trial Registration

NCT04338438.

Efficacy of Concurrent Chemoradiotherapy With S-1 vs Radiotherapy Alone for Older Patients With Esophageal Cancer: A Multicenter Randomized Phase 3 Clinical Trial

Importance

Most older patients with esophageal cancer cannot complete the standard concurrent chemoradiotherapy (CCRT). An effective and tolerable chemoradiotherapy regimen for older patients is needed.

Objective

To evaluate the efficacy and toxic effects of CCRT with S-1 vs radiotherapy (RT) alone in older patients with esophageal cancer.

Design, Setting, and Participants

A randomized, open-label, phase 3 clinical trial was conducted at 23 Chinese centers between June 1, 2016, and August 31, 2018. The study enrolled 298 patients aged 70 to 85 years. Eligible participants had histologically confirmed esophageal cancer, stage IB to IVB disease based on the 6th edition of the American Joint Committee on Cancer (stage IVB: only metastasis to the supraclavicular/celiac lymph nodes) and an Eastern Cooperative Oncology Group performance status of 0 to 1. Data analysis was performed from August 1, 2020, to March 10, 2021.

Interventions

Patients were stratified according to age (<80 vs ≥80 years) and tumor length (<5 vs ≥5 cm) and randomly assigned (1:1) to receive either CCRT with S-1 or RT alone.

Main Outcomes and Measures

The primary end point was the 2-year overall survival rate using intention-to-treat analysis.

Results

Of the 298 patients enrolled, 180 (60.4%) were men. The median age was 77 (interquartile range, 74-79) years in the CCRT group and 77 (interquartile range, 74-80) years in the RT alone group. A total of 151 patients (50.7%) had stage III or IV disease. The CCRT group had a significantly higher complete response rate than the RT group (41.6% vs 26.8%; P = .007). Surviving patients had a median follow-up of 33.9 months (interquartile range: 28.5-38.2 months), and the CCRT group had a significantly higher 2-year overall survival rate (53.2% vs 35.8%; hazard ratio, 0.63; 95% CI, 0.47-0.85; P = .002). There were no significant differences in the incidence of grade 3 or higher toxic effects between the CCRT and RT groups except that grade 3 or higher leukopenia occurred in more patients in the CCRT group (9.5% vs 2.7%; P = .01). Treatment-related deaths were observed in 3 patients (2.0%) in the CCRT group and 4 patients (2.7%) in the RT group.

Conclusions and Relevance

In this phase 3 randomized clinical trial, CCRT with S-1 was tolerable and provided significant benefits over RT alone in older patients with esophageal cancer.

Trial Registration

ClinicalTrials.gov Identifier: NCT02813967.

A Phase II Study Demonstrates No Feasibility of Adjuvant Treatment with Six Cycles of S-1 and Oxaliplatin in Resectable Esophageal Adenocarcinoma, with ERCC1 as Biomarker for Response to SOX

Simple Summary

Neoadjuvant chemoradiotherapy followed by surgery is currently standard of care in esophageal adenocarcinoma. However, prognosis remains dismal. The aim of our study was to assess the feasibility of administering six cycles of adjuvant S-1 and oxaliplatin following neoadjuvant chemoradiotherapy and esophagectomy. Although six cycles of adjuvant S-1 and oxaliplatin were not feasible in pretreated patients, mainly due to toxicity, efficacy results were promising compared to a propensity-score matched cohort. Exploratory biomarker analyses demonstrated potential benefit for patients with Excision repair cross-complementation group 1 (ERCC1) negative tumor expression. A proteomics biomarker model provided valuable information for prediction of survival and pharmacokinetics of 5-FU showed a correlation with treatment-related toxicity. Although it remains unclear if additional chemotherapy should be provided in the adjuvant setting, subgroups such as patients with ERCC1 negativity, could potentially benefit from this treatment option based on our exploratory biomarker research.

Abstract

We assessed the feasibility of adjuvant S-1 and oxaliplatin following neoadjuvant chemoradiotherapy (nCRT) and esophagectomy. Patients treated with nCRT (paclitaxel, carboplatin) and esophagectomy received six 21-day cycles with oxaliplatin (130 mg/m²) on day 1 and S-1 (25 mg/m² twice daily) on days 1–14. The primary endpoint was feasibility, defined as ≥50% completing treatment. We performed exploratory propensity-score matching to compare survival, ERCC1 and Thymidylate Synthase (TS) immunohistochemistry analyses, proteomics biomarker discovery and 5-FU pharmacokinetic analyses. Forty patients were enrolled and 48% completed all adjuvant cycles. Median dose intensity was 98% for S-1 and 62% for oxaliplatin. The main reason for early discontinuation was toxicity (67%). The median recurrence-free and overall survival were 28.3 months and 40.8 months, respectively (median follow-up 29.1 months). Survival was not significantly prolonged compared to a matched cohort (p = 0.09). Patients with ERCC1 negative tumor expression had significantly better survival compared to ERCC1 positivity (p = 0.01). Our protein signature model was predictive of survival [p = 0.04; Area under the curve (AUC) 0.80]. Moreover, 5-FU pharmacokinetics significantly correlated with treatment-related toxicity. To conclude, six cycles adjuvant S-1 and oxaliplatin were not feasible in pretreated esophageal adenocarcinoma. Although the question remains whether additional treatment with chemotherapy should be provided in the adjuvant setting, subgroups such as patients with ERCC1 negativity could potentially benefit from adjuvant SOX based on our exploratory biomarker research.

Prospective evaluation and refinement of an S-1 dosage formula based on renal function for clinical application

In patients with impaired renal function, S-1-related toxicities increase due to higher exposure of 5-fluorouracil (5-FU). Our previous pharmacokinetic study in 16 cancer patients with various renal functions developed an S-1 dosage formula based on individual creatinine clearance (CLcr) and body surface area (BSA). To evaluate and refine the formula, this prospective study was conducted. Thirty-three patients with various renal functions received S-1 for 4 weeks at doses determined by the nomogram derived from the previously developed formula. A series of blood samples were collected after the first dose to calculate the area under the concentration-time curve (AUC) of 5-FU. Thirty patients with BSA of 1.14-1.84 m² and CLcr of 23.8-96.4 mL/min were assessable for pharmacokinetics. The observed daily AUC ranged from 712.6 to 2868.7 ng·h/mL, and 18 patients achieved the target AUC (1447.8 ± 545.4 ng·h/mL). Three patients experienced S-1-related grade 3 adverse events during the first course. In the population pharmacokinetic analysis from the combined data of 46 patients in this study and the previous study, sex was identified as a statistically significant covariate for 5-FU clearance. Hence, the refined formula includes sex as an additional factor: Recommended daily dose = target AUC × (14.5 + 8.23 × SEX [0 for female and 1 for male] + 0.301 × CLcr) × BSA. Revised nomograms for recommended daily doses derived from the refined formula can be used in clinical practice to achieve the target AUC ensuring efficacy and safety of S-1.

Phase I study of DFP-11207, a novel oral fluoropyrimidine with reasonable AUC and low Cmax and improved tolerability, in patients with solid tumors

5-fluorouracil (5-FU) and 5-FU derivatives, such as capecitabine, UFT, and S-1, are the mainstay of chemotherapy treatment for gastrointestinal cancers, and other solid tumors. Compared with other cytotoxic chemotherapies, these drugs generally have a favorable safety profile, but hematologic and gastrointestinal toxicities remain common. DFP-11207 is a novel oral cytotoxic agent that combines a 5-FU pro-drug with a reversible DPD inhibitor and a potent inhibitor of OPRT, resulting in enhanced pharmacological activity of 5-FU with decreased gastrointestinal and myelosuppressive toxicities. In this Phase I study (NCT02171221), DFP-11207 was administered orally daily, in doses escalating from 40 mg/m2/day to 400 mg/m2/day in patients with esophageal, colorectal, gastric, pancreatic or gallbladder cancer (n = 23). It was determined that DFP-11207 at the dose of 330 mg/m2/day administered every 12 hours was well-tolerated with mild myelosuppressive and gastrointestinal toxicities. The pharmacokinetic analysis determined that the 5-FU levels were in the therapeutic range at this dose. In addition, fasted or fed states had no influence on the 5-FU levels (patients serving as their own controls). Among 21 efficacy evaluable patients, 7 patients had stable disease (33.3%), of which two had prolonged stable disease of >6 months duration. DFP-11207 can be explored as monotherapy or easily substitute 5-FU, capecitabine, or S-1 in combination regimens.

Pharmacokinetic and bioequivalence study of new S-1 capsule in Chinese cancer patients

S-1 is a multicomponent capsule containing tegafur, gimeracil, and oteracil potassium that has shown anticancer activity against numerous tumor types. However, S-1 capsules from different manufacturing companies have shown variations in pharmacokinetics and safety. Therefore, this multicenter, single-dose, randomized-sequence, open-label, two-way, self-crossover study was conducted to evaluate the bioequivalence of a newly developed generic S-1 (New Times Pharmaceutical Co., Ltd., Shandong, China) and the original brand-name S-1 capsule (Taiho Pharmaceutical Co., Ltd., Japan). Furthermore, the safety profiles of both products were compared. A total of 70 patients with 18 types cancer including breast, lung, gastric, and colorectal recruited at 5 hospitals who were randomly and alternatively administered 50 mg of the reference and test S-1 with a 7-day interval. Plasma concentrations of tegafur, 5-chloro-2,4-dihydroxypyridine (CDHP), oteracil potassium, and 5-fluorouracil were detected using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Pharmacokinetic parameters, including maximum drug concentration (C_max), time to achieve C_max (T_max), half-life (t_1/2, area under the concentration-time curve from 0-time t (AUC_0-t), and AUC from 0-infinity (AUC_0-∞) were determined using non-compartmental analysis with DAS2.0 software. Bioequivalence of the reference and test S-1 was evaluated according to 90% confidence intervals (CIs) for ratios of AUC and C_max of S-1. Adverse events were evaluated by monitoring symptoms, physical and laboratory examinations, electrocardiogram, and subject interviews. No significant difference was observed in plasma concentrations and pharmacokinetic profiles of tegafur, CDHP, oteracil potassium, or 5-fluorouracil (p > 0.05) among cancer patients treated with the reference or test S-1 formulation. The 90% CIs of C_max, AUC_0-t, and AUC_0-∞ ratios were within the 80%-125% limit. The generic S-1 caused eight mild adverse events including liver dysfunction, diarrhea, nausea, fatigue, abnormal blood electrolytes, hyperglycemia, and dermal toxicity. Similarly, 18 mild adverse events were observed including dysarteriotony, diarrhea, nausea, fatigue, fever, hematotoxicity, abnormal blood electrolytes, hyperglycemia, dermal toxicity, and joint pain. There were no differences in the adverse event incidence between the two formulations. In conclusion, the newly developed generic S-1 showed similar pharmacokinetics to those of an original brand-name S-1 in cancer patients, thereby indicating bioequivalence. Furthermore, both treatments were well tolerated, suggesting that the cost-effective generic S-1 should be considered as a feasible option when treating patients.

A multicenter, phase I/II trial of biweekly S-1, leucovorin, oxaliplatin and gemcitabine in metastatic pancreatic adenocarcinoma-TCOG T1211 study

BACKGROUND

This phase I/II study evaluated the feasibility and efficacy of S-1, leucovorin, oxaliplatin and gemcitabine (SLOG), a triplet regimen, for treating patients with metastatic pancreatic ductal adenocarcinoma (PDAC).

METHODS

Patients with chemo-naive, metastatic PDAC were eligible to receive fixed-rate infusion (10 mg/m²/min) of gemcitabine of 800 mg/m² followed by oxaliplatin of 85 mg/m² on day 1 plus oral S-1 and leucovorin (20 mg/m²) twice daily from days 1 to 7 in a 2-week cycle. The dose of S-1 would be escalated from 20, 30, 35 to 40 mg/m2 in a 3 + 3 designed phase I part to determine the maximum tolerated dose (MTD) for phase II study, in which the primary end-point was objective response rate (ORR). The recommended dose of S-1 was from phase I. This trial is registered at ClinicalTrials.gov: NCT01415713.

RESULTS

Seventy-three patients were enrolled. In the phase I study (n = 19), the MTD of S-1 was 35 mg/m² twice daily. Of 54 patients in phase II, the ORR was 40.7% (95% confidence interval [CI], 28%-55%). The median progression-free survival and overall survival were 7.6 (95% CI, 5.6-11.0) and 11.4 (95% CI, 8.1-16.3) months, respectively. The most common grade III/IV adverse event was neutropenia (40.7%). Twenty-four percent of patients had SLOG treatment for more than 1 year. The mean relative dose intensities of gemcitabine, oxaliplatin, and S-1 were 92%, 92% and 89%, respectively.

CONCLUSION

Biweekly SLOG is a feasible regimen with promising activity and safety profiles. A randomised study comparing SLOG versus modified folinic acid, fluorouracil, irinotecan, and oxaliplatin (FOLFIRINOX) in advanced PDAC is ongoing (ClinicalTrials.gov: NCT03443492).

Should S-1 be better than capecitabine for patients with advanced gastric cancer in Asia? A systematic review and meta-analysis

Background

S-1 or capecitabine (Cap) containing treatment is an increasingly used strategy in patients with advanced gastric cancer in Asia. It is unclear whether there is sufficient evidence to support which regimen is better.

Methods

A systematic review of retrospective studies and randomized controlled trials (RCTs) comparing S-1 with Cap containing treatment in advanced gastric cancer patients was performed. Embase, PubMed, ClinicalTrials.gov, Cochrane Library, and reference lists were searched from inception until August 2018 for relevant studies. Outcomes of interest included 1-year overall survival (OS), 1-year progression-free survival (PFS), objective response rate (ORR), and adverse events. Meta-analyses of the random events were performed. We also performed sensitivity analysis to examine whether the results of the meta-analyses were robust.

Results

A total of 770 subjects from six RCTs and two retrospective studies in Asia were analyzed. Compared with S-1, Cap containing treatment had better ORR (overall risk ratio =0.85, 95% CI: 0.72, 0.99, I ²=0%, P=0.043) and higher incidence of all-grade hand-foot syndrome (HFS) (overall risk ratio =0.29, 95% CI: 0.20, 0.40, I ²=0%, P<0.001) and neutropenia (overall risk ratio =0.85, 95% CI: 0.73, 0.99, I ²=0%, P=0.039). But there was no statistical difference in 1-year PFS, 1-year OS, incidence of other all-grade or grade 3-4 adverse events between S-1 and Cap containing arms (P>0.05). We found no publication bias in this review.

Conclusion

This systematic review showed that for Asian patients, Cap shows superiority in ORR but not 1-year OS or PFS, and it will increase the risk of all-grade HFS and neutropenia. Until now, S-1 containing treatment might be a better choice for advanced gastric cancer patients. But more high-quality RCTs are needed to confirm these results.

Gemcitabine plus S-1 for metastatic pancreatic cancer

To investigate the treatment effects of gemcitabine plus S-1 (GS) for metastatic pancreatic cancer in our institution.Data from 41 patients with metastatic pancreatic cancer treated with GS regimen in West China Hospital, Sichuan University were reviewed. The therapeutic efficacy and toxicity were evaluated. The influencing factors of progression-free survival (PFS) and overall survival (OS) were also explored.At the last follow-up, all patients had died. The objective response rate was 22.0% (9/41) and the disease control rate was 65.9% (27/41). The median PFS and OS times were 5.1 (range, 1.5-21) and 10.6 months (range, 1.5-40), respectively. The 0.5-, 1-, and 2-year OS rates were 65.9%, 41.5%, and 9.8%, respectively. In multivariate analysis, body mass index and carbohydrate antigen 19-9 change were the significant influencing factors of PFS, compared to tumor site and chemotherapy cycles for OS. The adverse effects were moderate and tolerable.The effects of GS for metastatic pancreatic cancer in our institution were good. The adverse effects were moderate and tolerable. However, further investigation in future prospective clinical studies is warranted.

Radiotherapy and Oral Capecitabine in the Preoperative Treatment of Patients with Rectal Cancer: Rationale, Preliminary Results and Perspectives

Preoperative radiotherapy alone or combined with chemotherapy increases the chances of tumor downstaging and down-sizing and facilitates sphincter-sparing surgical procedures, thereby improving survival and quality of life. Though several innovative agents are being investigated in combination with radiotherapy, 5-fluorouracil in continuous infusion remains the common schedule used in the preoperative chemoradiation setting. However, the protracted venous infusion of 5-fluorouracil requires specialized pumps and long-term venous access, which makes patients susceptible to infections or thrombosis. To overcome the 5-fluorouracil infusion-related problems, oral 5-fluorouracil precursors and inhibitors of 5-fluorouracil degradation have been developed and explored. These include oral fluoropyrimidines such as tegafur (ftora-fur), uracil plus tegafur (UFT), S-1, eniluracil and the oral carbamate capecitabine. Phase I trials have demonstrated the feasibility of the capecitabine-radiotherapy combination with respect to the bolus or infusion 5-fluorouracil-radiation approach and have defined the optimal dose of capecitabine during radiotherapy (825 mg/m2/day through a bid administration). Severe hand-foot syndrome occurred in 7-15% of patients, representing the most commonly observed toxicity. It is noteworthy that severe diarrhea with capecitabine during radiotherapy was not common. Leukopenia frequently occurred but was mild and reversible. Phase II trials, although limited in number, have evidenced a high probability of pathological complete response (up to 31%) with capecitabine and radiation, with an increased probability of sphincter-sparing surgical procedures. Although it is too early to assess whether oral capecitabine will be able to replace iv 5-fluorouracil in combination with preoperative radiotherapy, the NSABP will address this question in a large randomized trial. Finally, phase I-II trials evaluating escalating doses of capecitabine associated with oxaliplatin or irinotecan with radiotherapy are being carried out to assess the maximum-dose tolerance and efficacy in the preoperative setting. It is likely that these new chemoradiation associations might increase rectal cancer clearance, hopefully without increasing toxicity.

A phase II study of S-1 with concurrent radiotherapy in elderly patients with esophageal cancer

Background

Concurrent chemoradiotherapy (CCRT) using conventional platinum-based doublets are often associated with significant incidence of toxic effects in elderly patients with esophageal cancer. We previously reported a phase I trial of CCRT using S-1, an oral 5-fluorouracil derivative, which yielded well safe and active outcomes.

Methods

Patients with histologically confirmed esophageal cancer, who were age of 70 years or older with performance status (PS) score of 0-2 or age of 66 to 69 with PS score of 2, were eligible for this Phase II trial. Radiotherapy was delivered in 1.8 Gy per fraction to a total dose of 54 Gy. Concurrently, S-1 was administered at 70 mg/m² on days 1–14 and 29–42. The primary end point was 2-year overall survival rate.

Results

Thirty patients were enrolled, and 28 patients completed the full course of radiotherapy. No grade 4 toxicity or treatment-related death occurred. The grade 3 toxicities included esophagitis (16.7%), leucopoenia (13.3%), neutropenia (10%), anaemia (3.3%), pneumonitis (3.3%) and fatigue (3.3%). The median progression-free survival time and median survival time was 19 and 24 months, respectively. The 2-year overall survival rate was 45.1%, which exceeded the predefined threshold of 2-year OS 35% and met the primary end point of the study.

Conclusions

The results suggest that CCRT using S-1 is effective with mild toxicity in elderly patients with esophageal cancer. A phase III trial is needed to further evaluate this regimen.

Comparative study of cisplatin-based definitive concurrent chemoradiotherapy with S-1 versus paclitaxel for unresectable locally advanced esophageal squamous cell carcinoma

This study compared the efficiency and safety of definitive concurrent chemoradiotherapy (CCRT) using Paclitaxel plus Cisplatin (TP) versus S-1 plus Cisplatin (CS) in unresectable locally advanced esophageal squamous cell carcinoma (LAESCC). Between January 2009 and December 2013, 203 LAESCC patients were retrospectively reviewed. We performed a propensity score matching analysis; 41 patients treated with the CS regimen were matched 1:1 to patients who received the TP regimen. Patient- and disease-related characteristics were well-balanced between the two groups. The CS group showed significantly better treatment compliance (90.2% vs. 70.7%, P = 0.026) and less hospital stay (48 days vs 49 days, P = 0.025) over the TP group during the CCRT course. The complete response rate was comparable between the two groups (51.2% vs. 48.8%, P = 0.825). The 1- and 3-year overall survival (OS) rates in the TP group were 63.4% and 32.4% compared to 62.8% and 32.1% in the CS group, respectively (P = 0.796). The 1- and 3-year progression-free survival (PFS) rates in the TP group were 51.2% and 24.9%, compared to 53.6% and 18.9% in the CS group, respectively (P = 0.630). The incidence of severe and total neutropenia in the TP group was significantly higher compared to the CS group (P = 0.011 and 0.046, respectively). Multivariate analysis revealed that T stage and the complete response rate were strong prognostic factors associated with OS and PFS. In conclusion, both treatment regimens yielded satisfactory survival outcomes, but the CS regimen could significantly improve treatment compliance, reduce hematological toxicities and lengths of hospital stay. Future prospective studies in large cohorts are highly warranted to confirm the findings in our report.

Multicenter, randomized, open-label Phase II study comparing S-1 alternate-day oral therapy with the standard daily regimen as a first-line treatment in patients with unresectable advanced pancreatic cancer

PURPOSE

Non-inferiority for overall survival (OS) following alternate-day treatment with the oral anticancer drug S-1 compared with standard daily treatment was assessed in Japanese patients with unresectable advanced pancreatic cancer in a multicenter, randomized, phase II study. This trial was registered at the UMIN Clinical Trials Registry (no. 000008604).

METHODS

Chemotherapy-naïve patients with locally advanced or metastatic pancreatic cancer were randomly assigned 2:1 to treatment with alternate-day (twice daily on alternate days from days 1 through 42 of a 42-day cycle) or daily (twice daily on days 1 through 28 of a 42-day cycle) treatment with S-1. The primary endpoint was OS. Secondary endpoints were progression-free survival (PFS), time to treatment failure, response rate, quality of life assessments, and safety.

RESULTS

A total of 190 patients were enrolled, of which 185 were included in the final analysis (alternate-day: 121; daily: 64). Median OS was 9.4 for the alternate-day group and 10.4 months for the daily group [hazard ratio (HR), 1.19; 95% credible interval, 0.86 to 1.64], indicating that non-inferiority of alternate-day treatment to daily treatment was not demonstrated. Median PFS was 3.0 for the alternate-day group and 4.2 months for the daily group (HR, 1.65; 95% credible interval, 1.20-2.29). The incidence of anorexia, fatigue, neutrophils, pigmentation, and pneumonitis was lower in alternate-day treatment compared with daily treatment.

CONCLUSION

S-1 for advanced pancreatic cancer should be taken daily as recommended, based on the decreased OS and PFS and marginal improvement in safety observed in the alternate-day group.

Current Development of Anti-Cancer Drug S-1

S-1 is a novel oral fluoropyrimidine derivative, widely used for treating gastric, pancreatic, lung, head, neck and breast carcinomas. It is designed to enhance the clinical utility of an oral fluoropyrimidine and is associated with low gastrointestinal toxicity. S-1 consists of three pharmacological agents (at a molar ratio of 1:0.4:1)-Tegafur (FT), a prodrug of 5-Fluorouracil (5-FU), 5-Chloro-2-4-Dihydroxypyridine (CDHP), which inhibits the activity of Dihydropyrimidine Dehydrogenase (DPD) and Oxonic Acid (Oxo), which reduces Gastrointestinal (GI) toxicity of 5-FU. The present article reviews the current development of clinical study of S-1.

Long-term results of definitive concurrent chemoradiotherapy using S-1 in the treatment of geriatric patients with esophageal cancer

Objective

The aim of this study was to investigate the efficiency and safety of using S-1 as monotherapy and maintenance therapy combined with definitive concurrent radiotherapy for elderly patients with esophageal cancer.

Patients and methods

From January 2009 to December 2010, 68 elderly patients were included. Radiotherapy was delivered with a daily fraction of 1.8–2.0 Gy to a total radiation dose of 54.0–60.0 Gy. Preplanned concurrent S-1 (80 mg/m²/d) was given on days 1–14, every 3 weeks. After concurrent chemoradiotherapy, maintenance S-1 was repeated up to four cycles.

Results

The median age of the enrolled patients was 76 years (range: 70–88 years), and the clinical stages were stage I (two patients), stage II (24 patients), stage III (28 patients), and stage IV (14 patients). A total of 51 (75.0%) patients finished treatment on schedule, with a median of five cycles of S-1, in which 35 (51.5%) patients achieved complete response. The median follow-up time was 42.7 months, and the median overall survival (OS) and progression-free survival (PFS) times were 25.7 months and 21.5 months, respectively. The 1-year, 3-year, and 5-year OS and PFS rates were 70.6%, 41.8%, and 25.9% and 68.1%, 32.9%, and 15.9%, respectively. Grade ≥3 neutropenia and leukopenia were found in 14 patients and 13 patients, respectively. The most common nonhematologic toxicity was esophagitis including six patients and one patient with grades 3 and 4, respectively. Multivariate analysis revealed that cycles of S-1 and complete response were strong factors for OS and PFS.

Conclusion

For geriatric patients with esophageal cancer, S-1 as monotherapy and maintenance chemotherapy in combination with definitive concurrent radiation therapy yielded satisfactory survival outcomes with tolerable toxicities. More studies are highly warranted to further clarify this issue.

Development of an S-1 dosage formula based on renal function by a prospective pharmacokinetic study

BACKGROUND

S-1 is an oral anticancer drug, containing tegafur (a prodrug of 5-fluorouracil, 5-FU), 5-chloro-2,4-dihydroxypyridine, and potassium oxonate. As renal dysfunction is known to increase exposure of 5-FU following S-1 administration, the incidence of severe adverse reactions is increased in patients with impaired renal function. However, no reliable information on its dose modification for patients with renal dysfunction has been provided.

METHODS

We conducted a prospective pharmacokinetic study to develop an S-1 dosage formula based on renal function. Sixteen cancer patients with various degrees of renal function received a single dose of S-1 at 40 mg/m(2). A series of blood samples were collected at predefined times within 24 h to assess the plasma concentration profiles of 5-FU, 5-chloro-2,4-dihydroxypyridine, and tegafur. A mathematical model for the relationship between renal function and exposure of 5-FU was constructed by a population pharmacokinetic analysis.

RESULTS

The clearance of 5-FU following S-1 administration was related to body surface area and creatinine clearance in the range 15.9-108.8 mL/min as estimated by the Cockcroft-Gault equation. The S-1 dosage formula was derived as follows:[Formula: see text]where AUC is the area under the concentration-time curve, CLcr is creatinine clearance, and BSA is body surface area. The recommended daily doses of S-1 in Asia and Europe were also proposed as nomograms according to exposure matching to the previously reported area under the concentration-time curve of 5-FU, which confirmed the efficacy and toxicity in pivotal registration studies.

CONCLUSIONS

We have developed a novel formula for determining the S-1 dosage on the basis of renal function. Further validation is needed to confirm the formula for practical application.

The evaluation of surgical treatment for gastric cancer patients with noncurative resection

PURPOSE

This study aims to analyze the results of treatment in a series of 233 gastric cancer patients who underwent a noncurative resection.

METHODS

We performed a retrospective study of patients with noncurative treatment for advanced gastric cancer who were divided into three treatment groups: total gastrectomy (TG, n=150), distal gastrectomy (DG, n=44), and nonresection (NR, bypass procedure or chemotherapy only, n=39).

RESULTS

In multivariate analysis, surgical treatment (TG) and an absence of chemotherapy were significant independent prognostic factors for a poor survival. In the late period, the overall survival rate was significantly lower in the TG group than in the DG group (p=0.005) and was marginally lower than in the NR group (p=0.054). The resection group had a poorer compliance for chemotherapy than the NR group, and the TG group had a poorer compliance than the DG group (p<0.01). The morbidity rate was higher in the TG group than in the DG group (p<0.05).

CONCLUSIONS

TG is considered to be inappropriate for the treatment of noncurative gastric cancer because of the poor prognosis, high morbidity rates, and poor compliance for chemotherapy associated with the procedure. However, noncurative DG was acceptable and postoperative chemotherapy should be used in selected patients.

A phase I dose escalation study of S-1 with concurrent radiotherapy in elderly patients with esophageal cancer

BACKGROUND

Concurrent chemoradiotherapy (CRT) with 5-fluorouracil (5-FU) and cisplatin (CDDP) are often associated with significant incidence of toxic effects in elderly patients with esophageal cancer. This phase I trial was designed to determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of S-1, an oral 5-FU derivative, when given with radiotherapy in elderly patients.

METHODS

Patients who were age of 70 years or older with histologically confirmed esophageal cancer, and had an Eastern Cooperative Oncology Group (ECOG) score of 0-2 were eligible for this study. Radiotherapy was administered in 1.8 Gy fractions 5 times weekly to a total dose of 54 Gy. S-1 was administered on days 1-14 and 29-42 at the following dosages: 60, 70, and 80 mg/m(2)/day.

TRIAL REGISTRATION

NCT01175447 (ClinicalTrials.gov).

RESULTS

Twelve previously untreated patients were enrolled in this study. No grade 3 or 4 toxicity was observed in six patients treated at the 60 and 70 mg/m(2) dose levels. DLT was observed in four of six patients treated at the 80 mg/m(2) dose level. Two patients developed grade 3 esophagitis, one patient developed grade 3 esophagitis and pneumonitis, and one patient developed grade 3 thrombocytopaenia. Endoscopic complete response (CR) was observed in eight patients (66.7%). The median progression free survival (PFS) was 20 months and median overall survival was 29 months.

CONCLUSIONS

The MTD of S-1 was 80 mg/m(2), and the recommended dose (RD) for phase II studies was 70 mg/m(2). This regimen was well tolerated and active in elderly patients with esophageal cancer, meriting further investigation in phase II studies.

Emerging role of S-1 in gastric cancer

Gastric cancer remains one of the most important malignancies worldwide in terms of incidence and mortality. The treatment is based on the combination of local surgery and radiation therapy as well as systemic chemotherapy and targeted molecules. Fluoropyrimidines and particularly 5-fluorouracil (FU) represent still the backbone for gastric cancer chemotherapy and new molecular versions of this molecule have been brought to clinical practice in order to improve benefits and reduce adverse effects. S-1 is an oral prodrug of 5-FU, which has demonstrated high effectiveness for gastric cancer treatment and a favorable safety profile. Currently, there are geographic differences in the treatment of gastric cancer and in the use of S-1, which is a mainstay of gastric cancer management in Eastern countries, but is not part of the standard care in the rest of the world. In this review, we gathered data from phase I, II, and III trials of S-1 in gastric cancer, in order to define its real benefit-risk ratio and assess whether geographic differences in S-1 use are justified by unchangeable factors.

Corneal limbal stem cell deficiency associated with the anticancer drug S-1

Purpose

An oral antineoplastic drug, S-1, is known to be more effective with less toxicity and fewer gastrointestinal side effects than the conventional intravenous 5-fluorouracil. We report a case of limbal stem cell deficiency that occurred in a patient receiving chemotherapy using S-1 alone for gastric cancer.

Case Report

A 65-year-old woman with symptoms of grittiness and epiphora in both eyes for several months was referred to the ophthalmology clinic. She had been receiving S-1 orally after total gastrectomy for advanced gastric cancer. Slit lamp examination revealed an irregular hazy corneal epithelium in both eyes that extended to the center of the cornea overlying the pupil and showed late staining with fluorescein dye. Palisades of Vogt at the superior limbus were absent in both eyes. Best-corrected distance vision was 20/50 in both eyes with all other structures of the anterior and posterior segment unremarkable including a patent lacrimal drainage system. There was no change in the corneal lesions of either eye despite 3 months of topical therapy. The lesions did resolve in 4 months after discontinuation of S-1 therapy owing to acute renal failure.

Conclusions

Early detection of this adverse reaction before significant visual loss through regular follow-up appears to be important in patients receiving S-1 therapy.

The addition of S-1 to gemcitabine-based chemotherapy improves survival with increased toxicity for patients with advanced pancreatic cancer: combined meta-analysis of efficacy and safety profile

PURPOSE

To investigate the efficiency and safety profile of the addition of S-1 to gemcitabine (GEM)-based chemotherapy for advanced pancreatic cancer (APC).

METHODS

Computerized search was undertaken to identify randomized controlled trials of S-1 plus GEM versus GEM monotherapy in APC patients. The outcomes included overall survival (OS), progression-free survival (PFS), response rate, and toxicities.

RESULTS

Five studies with 917 patients were included. Overall, there was a significant difference between the two regimens in terms of OS (HR=0.83, 95%CI=0.72-0.96, P=0.01), PFS (HR=0.64, 95%CI=0.56-0.74, P<0.0001), and overall response rate (ORR; RR=2.36, 95%CI=1.73-3.22, P<0.00001). Occurrence of grade 3/4 hematological toxicities (neutropenia, thrombocytopenia) and non-hematological toxicities (diarrhea, nausea/vomit, rush, stomatitis/mucositis) were significantly higher with GEM/S-1 treatment.

CONCLUSIONS

This meta-analysis indicated a significant survival benefit with increased toxicity when S-1 was combined with GEM. GEM/S-1 might be an option of first-line chemotherapy for APC patients, at least in Asia.

Phase II clinical trial of S-1 plus oral leucovorin in previously treated patients with non-small-cell lung cancer

BACKGROUND

S-1, a novel oral fluoropyrimidine, has potent antitumor activity against non-small-cell lung cancer (NSCLC). Meanwhile, leucovorin enhances the efficacy of 5-fluorouracil by inhibiting thymidylate synthase. Therefore, this phase II clinical trial evaluated the safety and efficacy of S-1 plus leucovorin combination therapy for previously treated patients with NSCLC.

PATIENTS AND METHODS

Patients with stage IIIB or IV NSCLC were prospectively enrolled if they received 1 or 2 prior chemotherapy regimens. S-1 (40-60 mg) and leucovorin (25mg) were administered together orally twice per day for 7 consecutive days followed by 7 days of rest. This 2-week cycle was repeated for a maximum of 25 cycles until the onset of disease progression or unacceptable adverse events. Endpoints included objective tumor response, progression-free survival, overall survival, and safety.

RESULTS

Among 33 patients, 6 (18.2%), 14 (42.4%), and 11 (33.3%) had partial response, stable disease, and progressive disease, respectively. Median progression-free and overall survival times were 3.5 and 11.7 months, respectively. The common grade 3 toxicities included stomatitis (18.2%), anorexia (12.1%), and neutropenia (9.1%). One patient had pneumatosis cystoides intestinalis, and another experienced paralytic ileus. There were no treatment-related deaths.

CONCLUSIONS

S-1 plus leucovorin combination therapy demonstrated promising efficacy and an acceptable toxicity profile in previously treated patients with NSCLC.

A systemic analysis of S-1 regimens for treatment of patients with colon cancer

BACKGROUND

Fluorouracil-based regimens have been widely accepted and recommended in the guidelines for treating patients with early or advanced staged colon cancer, although results are controversial. Here we performed a systemic analysis to evaluate the impact of S-1 based regimens on response and survival of patients with colon cancer.

METHODS

Clinical studies evaluating the impact of S-1 based regimens on response and survival of patients with colon cancer were identified using a predefined search strategy. Summary response rates (RRs) to treatment were calculated.

RESULTS

Six clinical studies which including 227 patients with advanced colorectal cancer were considered eligible for inclusion. Two studies were conducted using combination of S-1 and Oxaliplatin, and four studies featured S-1 and irinotecan. Systemic analysis showed that, in all patients, pooled RRs was 43.17%. Major adverse effects were hematological toxicities, gastrointestinal disturbance, neurosensory toxicity. No treatment related death occurred.

CONCLUSION

This systemic analysis suggests that S-1 based regimens, both with oxaliplatin or irinotean are associated with acceptable response and toxicity in patients with colon cancer.

Optimization of cancer chemotherapy on the basis of pharmacokinetics and pharmacodynamics: from patients enrolled in clinical trials to those in the 'real world'

  Cytotoxic anticancer drugs are the most challenging therapeutic agents among all medicines with relatively narrow efficacy profiles. Therefore, medical oncologists have to practically manage the risk of severe toxic effects to optimize treatment outcomes. Dose and treatment-schedule recommendations for cytotoxic anticancer agents are determined on the basis of clinical trials. Patients enrolled in clinical trials are those likely to receive the drug in clinical practice, excluding those with conditions such as organ dysfunction, obesity, advanced age, or comorbidity. On the other hand, the 'real world' includes large numbers of such patients who do not meet the eligibility criteria of clinical trials. However, there is a paucity of data from sufficiently powered pharmacokinetic and pharmacodynamic studies to support dosage recommendations in such patients. Consequently, dose levels and treatment schedules for chemotherapy in these subjects are somewhat arbitrary and not evidence-based. Pharmacokinetic and pharmacodynamic studies of patients in the 'real world' are needed to address this issue. In this review article, we describe general aspects of clinical pharmacology in cancer patients enrolled in clinical trials and those in the 'real world,' and introduce recent findings regarding the pharmacokinetic and pharmacodynamic properties of irinotecan and S-1 in 'real world' cancer patients.

Total gastrectomy increases the incidence of grade III and IV toxicities in patients with gastric cancer receiving adjuvant TS-1 treatment

BACKGROUND

We aimed to evaluate the safety and efficacy of TS-1 adjuvant chemotherapy in Taiwanese patients with gastric cancer.

METHODS

We included in this study patients with locally advanced gastric cancer who received adjuvant TS-1 or 5-fluorouracil chemotherapy after curative surgery and extended lymph node dissection between 1 June 2008 and 31 December 2012 at Chang Gung Memorial Hospital. Patient characteristics, tumor features, safety profiles and compliance with TS-1 treatment were retrospectively analyzed from medical charts.

RESULTS

Forty patients received adjuvant chemotherapy with TS-1 and 193 with 5-fluorouracil within the study period. The 1- and 2-year overall survival rates were 90.6% and 87% in the TS-1 group and 95.4% and 86.8% in the 5-fluorouracil group (P = 0.34). The 1- and 2-year disease-free survival rates were 90.6% and 74.7% in the TS-1 group and 88% and 75.7% in the 5-fluorouracil group (P = 0.66). In the TS-1 group, tumor recurrence was more frequent in those with >15 metastatic lymph nodes than ≤15. Overall, 78.9%, 74.3%, 62.1% and 56% of patients underwent TS-1 treatment for at least 3, 6, 9 and 12 months, respectively. The most common adverse events of TS-1 were skin hyperpigmentation (55%), diarrhea (27.5%), dizziness (27.5%) and leucopenia (20%). Severe adverse events (SAEs; grade III or IV toxicity) were diarrhea (7.5%), stomatitis (7.5%), leukopenia (5%), vomiting (2.5%), anorexia (2.5%) and dizziness (2.5%). Patients who underwent total gastrectomy had a significantly greater risk of TS-1-related SAEs than patients who underwent subtotal gastrectomy (40% versus 8%, P = 0.014).

CONCLUSIONS

The incidence of SAEs during TS-1 therapy was more common in Taiwanese patients with gastric cancer who underwent total gastrectomy compared with those who underwent subtotal gastrectomy. Clinicians must be aware of and able to manage these SAEs to maximize patient compliance with adjuvant TS-1.

Clinical development of S-1 for non-small cell lung cancer: a Japanese perspective

For more than a decade, S-1 has been investigated aggressively against non-small cell lung cancer (NSCLC) in Japan. Recently, two randomized phase III trials of S-1 combined with cisplatin (CDDP) or carboplatin (CBDCA) compared with the standard platinum doublet chemotherapy were reported. S-1 and CDDP was noninferior to CDDP and DTX in terms of overall survival (OS) (median survival time [MST] 16.1 versus 17.1 months, respectively; hazard ratio [HR] 1.013; 96.4% confidence interval [CI] 0.837-1.227). Noninferiority of S-1 and CBDCA compared with CBDCA and paclitaxel was also confirmed for OS (MST 15.2 versus 13.3 months, respectively; HR 0.928; 99.2% CI 0.671-1.283). The noninferiority design employed an upper CI limit of HR<1.322 in the former trial and HR<1.33 in the latter. S-1 combined with CDDP or CBDCA was thought to be one of the standard platinum doublet regimens in the first-line setting for patients with advanced NSCLC in Japan. Some additional interesting phase I and II studies have been published in Japan. They include studies of S-1 as first-line chemotherapy when combined with nonplatinum agents; as second-line chemotherapy; within chemoradiotherapy for locally advanced disease; and in the postoperative adjuvant setting. This review will also describe the use of S-1 for the treatment of NSCLC in these settings.

Pharmacokinetic evaluation of novel oral fluorouracil antitumor drug S-1 in Chinese cancer patients

AIM

S-1 is an oral anticancer fluoropyrimidine formulation consisting of tegafur, 5-chloro-2,4-dihydroxypyridine and potassium oxonate. The aim of this study was to evaluate the pharmacokinetics and bioequivalence of a newly developed generic formulation of S-1 in Chinese cancer patients in comparison with the branded reference formulation of S-1.

METHODS

A single-dose, randomized-sequence, open-label, two-way self-crossover study was conducted in 30 Chinese cancer patients. The subjects alternatively received the two formulations (40 mg/m(2), po) with a 7-d interval. Plasma concentrations of FT, CDHP, Oxo, and 5-Fu were determined using LC-MS/MS. Pharmacokinetic parameters, including Cmax, Tmax, t1/2, AUC0-t, and AUC0-∞ were determined using non-compartmental models with DAS2.0 software. Bioequivalence of the two formulations were to be evaluated according to 90% CIs for the log-transformed ratios of AUC and Cmax of S-1. Adverse events were evaluated through monitoring the symptom, physical and laboratory examinations, ECGs and subject interviews.

RESULTS

The mean values of Cmax, AUC0-t, and AUC0-∞ of FT, 5-Fu, CDHP, and Oxo for the two formulations had no significant differences. The 90% CIs for natural log-transformed ratios of Cmax, AUC0-t, and AUC0-∞ were within the predetermined bioequivalence acceptance limits. A total of 11 mild adverse events, including fatigue, nausea and vomiting, anorexia, diarrhea and myelosuppression, were observed, and no serious and special adverse events were found.

CONCLUSION

The newly developed generic formulation and reference formulation of S-1 have similar pharmacokinetics with one dose (40 mg/m(2)) in Chinese cancer patients. Both the formulations of S-1 are well tolerated.

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.

5-Fluorouracil derivatives: a patent review

INTRODUCTION

The fluorinated analog of uracil 5-FU is an antimetabolite, active against a wide range of solid tumors. The main mechanism of action consists in interfering with DNA synthesis and mRNA translation. However, patients treated with 5-FU display several side effects, a result of its nonspecific cytotoxicity for tumor cells. Numerous modifications of the 5-FU structure have been performed in order to overcome these disadvantages.

AREAS COVERED

In this review, the metabolic pathways, pharmacokinetics and clinical pharmacology of 5-FU are briefly introduced. Moreover, several derivatives developed and patented, including oral 5-FU prodrugs and combinations with other active compounds, are presented. Finally, new innovative methods for administration and vehiculization of 5-FU and its derivatives are described.

EXPERT OPINION

The search for less toxic 5-FU derivatives, which diminish or circumvent some of its disadvantages, has allowed the development of selective antitumor prodrugs and novel methods for tissue-specific drug delivery. Although some of these oral prodrugs are being used clinically, either alone or in combination therapy with other anticancer agents, it seems that the potential of personalized medicine, including pharmacogenomics and targeted therapy with novel 5-FU derivatives, will improve the management and clinical responses of patients treated with 5-FU-based therapy.

S-1 as a core anticancer fluoropyrimidine agent

INTRODUCTION

5-FU is a core anticancer agent for GI and other malignancies, and infusional 5-FU regimens have been widely utilized. Orally administrable fluoropyrimidine prodrugs have been developed to enhance the anticancer efficacy of 5-FU and to reduce its adverse reactions.

AREAS COVERED

S-1 is an FT-based oral 5-FU prodrug in combination with a DPD inhibitor (CDHP) and an OPRT inhibitor (Oxo), which exerts the following effects: i) maintaining normal gut immunity, Oxo can decrease GI toxicities of 5-FU; ii) sustaining high plasma 5-FU concentrations, Cmax of FBAL after S-1 administration is extremely low, which dramatically decreases adverse reactions such as HFS, neurotoxicities and cardiotoxicities; iii) plasma 5-FU concentrations vary less extensively after S-1 administration and iv) S-1 can be safely administered to patients with DPD deficiency. Furthermore, the alternate-day S-1 administration can reduce the GI toxicities and myelotoxicities of 5-FU without reducing its anticancer efficacy, enabling patients to continue the oral administration for 6 - 12 months.

EXPERT OPINION

Replacement of regimens with infusional 5-FU and other fluoropyrimidines by the alternate-day S-1 administration may be recommended because the latter procedure is efficient for patients while sustaining the enhanced anticancer efficacy of 5-FU and without reducing its dose intensity.

A comprehensive review of S-1 in the treatment of advanced gastric adenocarcinoma

Gastric cancer is the fourth most common malignancy worldwide with Japan, Korea, Taiwan, China, Mongolia and many countries in South America and eastern Europe, as well as parts of the Middle East, contributing to the majority of cases. In the USA, it was estimated that approximately 10,620 deaths would be caused by gastric cancer in 2010. Gastric cancer is often diagnosed in its advanced stages. Current first-line treatment for advanced gastric cancer (AGC) using triplet combination chemotherapy containing a platinum-based compound, a fluoropyrimidine with an anthracycline (frequently added in Europe) or a taxane (more often used in the USA and elsewhere) has resulted in higher response rates and modest improvement in overall survival compared with doublet combinations. However, triplet combinations can be associated with increased toxicity compared with the doublets and patient selection becomes important. A desirable research strategy is to improve outcomes of patients with AGC by identifying treatments that are effective, convenient and safe. The interest in oral agents compared with intravenous agents is mounting. One oral fluoropyrimidine, S-1, is novel as it combines tegafur, 5-chloro-2,4-dihydroxypyridine and potassium oxonate. S-1 is approved in Japan, China, Taiwan, Korea and Singapore for the treatment of patients with gastric cancer, and more recently has been approved in 27 European countries to treat AGC. Initial clinical trials in the USA and Europe observed diarrhea as the dose-limiting toxicity; however, initial Japanese studies reported myelosuppression as the dose-limiting toxicity. The differing dose tolerance in these two populations is likely due to polymorphisms in the CYP2A6 gene. Based on our review of Phase II and III studies, we conclude that S-1 is a convenient oral fluoropyrimidine that provides safety advantage over intravenous fluorouracil without compromising efficacy against AGC.

Phase II trial of S-1 as second-line therapy in patients with advanced non-small cell lung cancer

PURPOSE

Currently available agents for the treatment of advanced stage non-small cell lung cancer (NSCLC) have limited efficacy. S-1 is a novel formulation of oral fluoropyrimidine shown to be tolerable and active in patients with NSCLC in Japan. We conducted a multicenter phase II study in previously treated patients with NSCLC to evaluate the efficacy of single-agent S-1 in a predominantly non-Asian population.

PATIENTS AND METHODS

Patients with advanced NSCLC and previously treated with only one line of chemotherapy received oral S-1 at 30 mg/m every 12 hours for 14 consecutive days followed by a 7-day rest until meeting discontinuation criteria. The primary end point was to evaluate the overall response rate.

RESULTS

Fifty-seven patients were accrued from 21 centers across the United States. Overall response rates and stable disease according to independent review were 7.1% and 48.2%, respectively, with a disease control rate of 55.3%. Progression-free survival was 2.9 months, median overall survival 7.3 months, and 1-year survival 31.6%. There were no significant differences in survival according to histologic subtype. The treatment was well tolerated, with the most common treatment-related side effects being nausea (54%) and diarrhea (49%).

CONCLUSION

Single-agent S-1 is well tolerated and has activity comparable with the other agents approved for use in recurrent/relapsed NSCLC.