Phase II study of S-1 plus leucovorin in patients with metastatic colorectal cancer: Regimen of 1 week on, 1 week off

Modified gemcitabine, S-1, and leucovorin combination for patients with newly diagnosed locally advanced or metastatic pancreatic adenocarcinoma: A multi-center retrospective study in Taiwan

BACKGROUND

In pancreatic cancer, toxicities associated with current chemotherapeutic regimens remain concerning. A modified combination of gemcitabine, S-1, and leucovorin (GSL) was used as the first-line treatment for newly diagnosed locally advanced or metastatic pancreatic adenocarcinoma patients.

METHODS

GSL was administered every 2 weeks-intravenous gemcitabine 800 mg/m2 at a fixed-dose rate of 10 mg/m2/min on day 1 and oral S-1 (80-120 mg/day) plus leucovorin 30 mg twice daily on days 1-7. We retrospectively analyzed the feasibility of GSL and patient outcomes in three medical centers in Taiwan.

RESULTS

Overall, 49 patients received GSL with a median follow-up of 24.9 months from May 2015 to March 2019. The median patient age was 68 years (range, 47-83 years), with a marginally higher number of females (57.1%). Among the 44 patients who underwent image evaluation, 13 demonstrated a partial response (29.5%) and 17 presented with stable disease (38.6%). The partial response rate and stable disease rate was 26.5% and 34.7%, respectively, in the intent-to-treat analysis. The median time-to-treatment failure was 5.79 months (95% C.I., 2.63-8.94), progression-free survival was 6.94 months (95% C.I., 5.55-8.33), and overall survival time was 11.53 months (95% C.I., 9.94-13.13). For GSL treatment, the most common grade 3 or worse toxicities were anemia (18.3%), neutropenia (6.1%), nausea (4.1%), and mucositis (4.1%). Treatment discontinuation was mostly due to disease progression (65.3%).

CONCLUSIONS

The modified GSL therapy can be a promising and affordable treatment for patients with advanced and metastatic pancreatic cancer in Taiwan. A prospective trial of modified GSL for elderly patients is currently ongoing in Taiwan.

Phase I Study of Alternate-Day Administration of S-1, Oral Leucovorin, and Bevacizumab for Refractory Metastatic Colorectal Cancer

Trial Information

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Lessons Learned

The recommended S-1 dose was 40 mg/m2, twice daily on Monday, Wednesday, Friday, and Sunday, with oral leucovorin and bevacizumab. Compared with daily administration, the alternate-day administration of S-1 with oral leucovorin may reduce mucositis with promising antitumor activity in refractory metastatic colorectal cancer.

Background

Daily S-1 plus oral leucovorin administration in a 1-week-on/1-week-off schedule has promising efficacy in gastrointestinal cancer but is associated with high risk of mucositis and diarrhea.

Methods

This phase Ib, 3+3 dose-escalation trial included patients with chemorefractory metastatic colorectal cancer (mCRC) receiving S-1 (40 mg/m2) and leucovorin (25 mg) orally twice daily (level 1, even-numbered days; level 2, Monday, Wednesday, Friday, and Sunday) and intravenous bevacizumab (5 mg/kg) every 2 weeks. Enrollment continued at the recommended dose level in the expansion cohort.

Results

We enrolled 21 patients (3 and 18 patients in levels 1 and 2, respectively). Briefly, 12 and 9 patients had Eastern Cooperative Oncology Group (ECOG) performance status of 0 and 1, respectively, and 8 and 13 patients had 1–3 and ≥4 prior treatment lines, respectively. Dose-limiting toxicity (DLT) was not observed, and level 2 was confirmed as the recommended dose. Common grade 3–4 adverse events at level 2 were anemia (22%), anorexia (6%), and diarrhea (6%). In the entire cohort, response rate, disease control rate, and median progression-free survival were 10%, 71%, and 4.2 months, respectively.

Conclusion

The recommended S-1 dose was 40 mg/m2, twice daily on Monday, Wednesday, Friday, and Sunday, with 25 mg oral leucovorin twice daily and 5 mg/kg bevacizumab every 2 weeks. Compared with the daily administration, alternate-day administration of S-1 plus leucovorin may reduce mucositis with promising antitumor activity in refractory mCRC.

Pharmacokinetic and bioequivalence study between two formulations of S-1 in Korean gastric cancer patients

PURPOSE

S-1 is an oral fluoropyrimidine anticancer drug consisting of the 5-fluorouracil prodrug tegafur combined with gimeracil and oteracil. The purpose of this study was to evaluate the pharmacokinetic (PK), bioequivalence, and safety of a newly developed generic formulation of S-1 compared with the branded reference formulation, in Korean gastric cancer patients.

METHODS

This was a single-center, randomized, open-label, single-dose, two-treatment, two-way crossover study. Eligible subjects were randomly assigned in a 1:1 ratio to receive the test formulation or reference formulation, followed by a one-week washout period and administration of the alternate formulation. Serial blood samples were collected at 0 hrs (predose), 0.25, 0.5, 1, 2, 3, 4, 5, 6, 8, 10, 12, 24, 36, and 48 hrs after dosing in each period. The plasma concentrations of tegafur, 5-FU, gimeracil, and oteracil were analyzed using a validated liquid chromatography-tandem mass spectrometry method. The PK parameters were calculated using a non-compartmental method.

RESULTS

In total, 29 subjects completed the study. All of the 90% confidence intervals (CIs) of the geometric mean ratios (GMRs) fell within the predetermined acceptance range. No serious adverse events were reported during the study.

CONCLUSION

The new S-1 formulation met the Korean regulatory requirement for bioequivalence. Both S-1 formulations were well tolerated in all subjects.Clinical trial registry: https://cris.nih.go.kr CRIS KCT0003855.

Colorectal cancer: pharmacogenetics support for the correct drug prescription

Pharmacogenetics (PGx) in clinical practice is a tool that the clinician can use to guide, in a personalized way, the most suitable treatment that will be administered to the patient. The objective of this review is to summarize in a practical and accessible rational way, the advances that currently exist for the application of PGx in colorectal cancer chemotherapy management through the study of the patients' germline polymorphisms. To define the polymorphisms that can be applied, we rely on three fundamental cornerstones: the recommendations of drug regulatory agencies; the implementation guidelines prepared by expert consortia in PGx and information from clinical annotations (the drug/polymorphism relation) according to the scientific level of evidence assigned by PharmGKB experts.

A Phase II study of S-1 plus oral leucovorin in heavily treated metastatic colorectal cancer patients

Purpose

Fewer treatment options are available for refractory metastatic colorectal cancer (mCRC). In early trials, S-1 monotherapy was effective for mCRC patients after chemotherapy failure and its combination with oral leucovorin therapy offers promising results in untreated mCRC. Hence, we conduct a Phase II trial to assess the efficacy of S-1 plus oral leucovorin (SL) in refractory mCRC that progressed after multiple prior standard therapies.

Methods

In this open-label, single-arm study, we enrolled the refractory mCRC patients who received fluoropyrimidine, oxaliplatin, and irinotecan treatment and at least one targeted therapy previously. The doses of SL were 40–60 and 30 mg twice daily separately. They were administered for 7 days in a 2-week cycle. Treatment was continued until disease progression.

Results

Of the 41 enrolled patients, 36 patients were evaluable with 61.1% disease control rate. The median progression-free survival and overall survival were 2.55 and 7.63 months, respectively. Regression change in tumor size stayed 10%–20% in five patients (13.9%) through 18 weeks after treatment, and two patients continued free from tumor progression at 30 and 42 weeks. Compared with moderate heavily pretreated mCRC patient subgroup (≤4 prior regimens), the severe heavily pretreated subgroup (≥5 prior regimens) showed similar disease control rate and survival benefit. Grade 3 or higher toxicities were documented only in 11 patients (26.8%).

Conclusion

SL shows potential as a salvage regimen in refractory mCRC patients especially in the severe heavily pretreated setting and is well tolerated in these patients.

TAS-118 (S-1 plus leucovorin) versus S-1 in patients with gemcitabine-refractory advanced pancreatic cancer: a randomised, open-label, phase 3 study (GRAPE trial)

BACKGROUND

In our previous randomised phase 2 study for patients with gemcitabine-refractory advanced pancreatic cancer, S-1 plus leucovorin improved progression-free survival compared with S-1 alone. Here, we evaluated the efficacy of TAS-118 (S-1 plus leucovorin) versus S-1 in overall survival (OS).

PATIENTS AND METHODS

This randomised, open-label, phase 3 study was conducted at 58 centres in Japan and Korea. Patients with metastatic pancreatic cancer that progressed during first-line gemcitabine-based chemotherapy or recurred during or after post-operative gemcitabine-based adjuvant treatment were randomly assigned (1:1) to receive either S-1 (40-60 mg, twice daily for 4 weeks in a 6-week cycle) or TAS-118 (S-1 40-60 mg plus leucovorin 25 mg, twice daily for 1 week in a 2-week cycle). The primary end-point was OS.

RESULTS

A total of 603 patients were randomised, and 300 and 301 patients received TAS-118 and S-1, respectively. There was no difference in OS between groups (median OS for TAS-118 versus S-1, 7.6 months versus 7.9 months; hazard ratio [HR], 0.98 [95% confidence interval (CI), 0.82-1.16]; P = 0.756). Progression-free survival was significantly longer with TAS-118 than S-1 (median, 3.9 months versus 2.8 months; HR, 0.80 [95% CI, 0.67-0.95]; P = 0.009). There were interactions between Japan and Korea (P = 0.004) and between unresectable and recurrent disease (P = 0.025) in OS. Incidence, profile and severity of adverse events were similar between groups.

CONCLUSION

TAS-118 did not improve OS in patients with gemcitabine-refractory advanced pancreatic cancer compared to S-1. Further studies are needed to find patients who have benefit from adding leucovorin to S-1.

Phase II study of S-1 plus leucovorin in patients with metastatic colorectal cancer: Regimen of 1 week on, 1 week off

A phase II study of S‐1 plus leucovorin (LV) given in a 4‐week schedule (2 weeks’ administration followed by 2 weeks’ rest) for patients with untreated metastatic colorectal cancer (mCRC) showed that the combination was effective, but grade 3 toxicities (diarrhea, stomatitis and anorexia) occurred at a relatively high rate. In this phase II study, we evaluated the efficacy and safety of a 2‐week schedule of S‐1 plus LV. Patients with mCRC received oral S‐1 (40–60 mg) and LV (25 mg) twice daily for 1 week, followed by 1 week's rest. Treatment was repeated until disease progression or unacceptable toxicity. The primary endpoint was response rate. The pharmacokinetics of S‐1 and LV in Chinese patients were evaluated on day 1 of the first cycle. Seventy‐three patients were enrolled in Japan and China. Of 71 eligible patients, the response rate was 53.5%, and the disease control rate was 83.1%. Median progression‐free survival and median overall survival were 6.5 and 24.3 months, respectively. The incidences of grade 3 toxicities were diarrhea 8.3%, stomatitis 8.3%, anorexia 2.8% and neutropenia 9.7%. There were no treatment‐related deaths. The pharmacokinetics profiles of S‐1 plus LV in Chinese patients were similar to those in Japanese patients. This 2‐week schedule of S‐1 plus LV showed good efficacy and better tolerability than the 4‐week schedule. This therapy will be the base regimen for mCRC to be added by other cytotoxic or molecular‐targeted drugs. The optimized treatment schedule for S‐1 plus LV was 1 week on and 1 week off.