Randomized phase III trial of S-1 versus capecitabine in the first-line treatment of metastatic colorectal cancer: SALTO study by the Dutch Colorectal Cancer Group.

BACKGROUND: Hand-foot syndrome (HFS) is a common side-effect of capecitabine. S-1 is an oral fluoropyrimidine with comparable efficacy to capecitabine in gastrointestinal cancers but associated with a lower incidence of HFS in Asian patients. This study compares the incidence of HFS between S-1 and capecitabine as first-line treatment in Western metastatic colorectal cancer (mCRC) patients. PATIENTS AND METHODS: Patients with previously untreated mCRC and planned treatment with fluoropyrimidine monochemotherapy were randomized 1 : 1 to receive either capecitabine (1250 mg/m2 orally for patients <70 years; 1000 mg/m2 for patients ≥70 years, twice daily on days 1-14) or S-1 (30 mg/m2 orally twice daily on days 1-14) in 3-weekly cycles, with bevacizumab optional in both groups. The primary endpoint was the incidence of any grade HFS, as assessed by both physicians and patients (diaries). Secondary endpoints included grade 3 HFS, other toxicities, relative dose intensity, progression-free survival, response rate and overall survival. RESULTS: A total of 161 patients were randomized in 27 centres. The incidence of any grade HFS as assessed by physicians was 73% in the capecitabine group (n = 80) and 45% in the S-1 group (n = 80) [odds ratio (95% confidence interval) 0.31 (0.16-0.60), P = 0.0005]. The incidence of grade 3 HFS was 21% and 4% (P = 0.003), respectively. Patient-assessed any grade HFS was 84% and 58%, respectively (P = 0.004). Grade 3 anorexia was more common in the S-1 group (3% versus 13%, P = 0.03). Median relative dose intensity was 88% in the capecitabine group and 95% in the S-1 group (P = 0.026). There were no statistically significant differences in median progression-free survival, response rate and overall survival rates. CONCLUSION: Treatment with S-1 in Western mCRC patients is associated with a significantly lower incidence of HFS compared with capecitabine, with comparable efficacy. CLINICALTRIALS.GOV REGISTRATION NUMBER: NCT01918852.

Continuation of fluoropyrimidine treatment with S-1 after cardiotoxicity on capecitabine- or 5-fluorouracil-based therapy in patients with solid tumours: a multicentre retrospective observational cohort study.

BACKGROUND: Capecitabine- or 5-fluorouracil (5-FU)-based chemotherapy is widely used in many solid tumours, but is associated with cardiotoxicity. S-1 is a fluoropyrimidine with low rates of cardiotoxicity, but evidence regarding the safety of switching to S-1 after 5-FU- or capecitabine-associated cardiotoxicity is scarce. PATIENTS AND METHODS: This retrospective study (NCT04260269) was conducted at 13 centres in 6 countries. The primary endpoint was recurrence of cardiotoxicity after switch to S-1-based treatment due to 5-FU- or capecitabine-related cardiotoxicity: clinically meaningful if the upper boundary of the 95% confidence interval (CI; by competing risk) is not including 15%. Secondary endpoints included cardiac risk factors, diagnostic work-up, treatments, outcomes, and timelines of cardiotoxicity. RESULTS: Per protocol, 200 patients, treated between 2011 and 2020 [median age 66 years (range 19-86); 118 (59%) males], were included. Treatment intent was curative in 145 (73%). Initial cardiotoxicity was due to capecitabine (n = 170), continuous infusion 5-FU (n = 22), or bolus 5-FU (n = 8), which was administered in combination with other chemotherapy, targeted agents, or radiotherapy in 133 patients. Previous cardiovascular comorbidities were present in 99 (50%) patients. Cardiotoxic events (n = 228/200) included chest pain (n = 125), coronary syndrome/infarction (n = 69), arrhythmia (n = 22), heart failure/cardiomyopathy (n = 7), cardiac arrest (n = 4), and malignant hypertension (n = 1). Cardiotoxicity was severe or life-threatening in 112 (56%) patients and led to permanent capecitabine/5-FU discontinuation in 192 (96%). After switch to S-1, recurrent cardiotoxicity was observed in eight (4%) patients (95% CI 2.02-7.89, primary endpoint met). Events were limited to grade 1-2 and occurred at a median of 16 days (interquartile range 7-67) from therapy switch. Baseline ischemic heart disease was a risk factor for recurrent cardiotoxicity (odds ratio 6.18, 95% CI 1.36-28.11). CONCLUSION: Switching to S-1-based therapy is safe and feasible after development of cardiotoxicity on 5-FU- or capecitabine-based therapy and allows patients to continue their pivotal fluoropyrimidine-based treatment.

Oral drugs in the treatment of metastatic colorectal cancer.

INTRODUCTION: Intravenous administration of fluoropyrimidine-based chemotherapy has been the cornerstone of treatment in metastatic colorectal cancer (mCRC) for decades. The availability of oral capecitabine has improved the tolerability in monotherapy schedules, and has simplified combination schedules. Since then, other oral drugs have proven efficacy in this setting. AREAS COVERED: We review the available evidence and most recent data concerning oral drugs with proven efficacy in mCRC, including capecitabine, S-1, trifluridine-tipiracil (TAS-102) and regorafenib. EXPERT OPINION: The use of capecitabine is widely implemented in the care of mCRC. However, with recent data supporting its prolonged use, the relatively high incidence of hand-foot syndrome (HFS) may impair quality of life. In Asian populations, S-1 is associated with equivalent efficacy but lower incidence of HFS compared to capecitabine. Further studies evaluating the effects of S-1 in Western populations are needed. Both regorafenib and TAS-102 improve the overall survival of patients in whom all other treatment options have failed. Since only a subset of patients appears to benefit, future studies to identify predictive biomarkers are needed.