Pharmacokinetics of 5-fluorouracil in elderly Japanese patients with cancer treated with S-1 (a combination of tegafur and dihydropyrimidine dehydrogenase inhibitor 5-chloro-2,4-dihydroxypyridine)

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 phase 2 study of adjuvant carboplatin plus S-1 followed by maintenance S-1 therapy for patients with completely resected stage II/IIIA non-small cell lung cancer-Japanese Northern East Area Thoracic Surgery Study Group JNETS1302 study

Background

The standard adjuvant chemotherapy regimen for completely resected pathological stage II/IIIA non-small cell lung cancer (NSCLC) is four courses of cisplatin plus vinorelbine. However, the continuity and toxicity of cisplatin-based regimens remain problematic. Conversely, carboplatin-based chemotherapy is a less toxic and more tolerable regimen for various stages of NSCLC. In particular, the efficacy and tolerability of carboplatin plus S-1 in advanced NSCLC were confirmed by previous pivotal studies such as the LETS trail. Therefore, this phase II study assessed the feasibility, safety, and usefulness of carboplatin plus S-1 followed by maintenance S-1 as an adjuvant treatment.

Methods

In this single-arm, multicenter phase II study, 40 patients who previously underwent complete resection of NSCLC were enrolled from November 2013 to January 2015. The chemotherapy protocol was four cycles of carboplatin (AUC 5 on day 1) and oral S-1 (80 mg/m² every other day from days 1 to 21) followed by oral S-1 (80 mg/m² every other day for 48 weeks). The primary endpoint was the treatment completion rate, and the secondary endpoints were adverse events and 2-year recurrence-free survival.

Results

The treatment completion rate of the planned schedule was as low as 30.0% (90% confidence interval: 40.3–63.0%). The reasons for adjuvant chemotherapy discontinuation were adverse events, refusal, tumor recurrence, and other reasons in 13, 6, 10, and 2 patients, respectively. The 2-year progression-free survival rate was 66.7% among patients who completed maintenance chemotherapy. There were no treatment-related deaths, and most adverse events were less than grade 3.

Conclusions

Carboplatin plus S-1 followed by S-1 maintenance for 1 year in the adjuvant treatment of NSCLC was not tolerable, although most adverse events were not severe. However, patients who can fully complete the regimen might experience clinical benefit.

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.

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.

Feasibility of adjuvant chemotherapy with S-1 consisting of a 4-week administration and a two-week rest period in patients with completely resected non-small cell lung cancer

The efficacy of adjuvant chemotherapy with S-1 in patients with completely resected non-small cell lung cancer (NSCLC) has yet to be clarified, and the appropriate schedule for the adjuvant chemotherapy with S-1 remains unknown. A phase II study was conducted to evaluate the feasibility and efficacy of adjuvant chemotherapy with S-1. Patients enrolled in this study were 20-75 years old, had pathological stage IB-IIIA NSCLC, and had received complete resection of NSCLC. S-1 (80 mg/m²) was administered orally to the patients for four weeks followed by a two-week rest period (conventional schedule), for a maximum of eight cycles. The primary endpoint was relative dose intensity (RDI), while the secondary endpoints were safety and 1 year of disease-free survival (1y-DFS). Between May 2007 and October 2009, 28 patients were enrolled. The RDI was 63.1% (95% CI, 48.6-77.7). No grade 3 or worse hematological toxicity was observed. Grade 3 non-hematological toxicities were observed in four patients. No grade 4 or worse hematological toxicity was detected. The probability of 1y-DFS was 85.7% (95% CI, 72.8-98.6). In the subgroup analysis, the median RDI of patients over 65 years old was lower compared to the other patients (44.8 vs. 100%; P=0.013; Mann-Whitney U test). Creatinine clearance (CCr) was lower in the older group, with more grade 2 or 3 non-hematological toxicities in the elderly patients. These results suggest that the conventional schedule of adjuvant chemotherapy with S-1 is not likely to be feasible in older patients with completely resected NSCLC.