Randomized double-blind phase 2 trial of 3 doses of TAS-108 in patients with advanced or metastatic postmenopausal breast cancer.

BACKGROUND: The objective of this study was to evaluate 3 different doses of (7α)-21-(4-[(diethylamino)methyl]-2 methoxyphenoxy)-7 methyl-19 norpregna-1,3,5(10)-trien-3-ol 2-hydroxy-1,2,3-propanetricarboxylate (TAS-108) in patients with recurrent, hormone-responsive breast cancer. METHODS: In this randomized, double-blind, multicenter study, TAS-108 was administered daily at a dose of 40 mg, 80 mg, or 120 mg to postmenopausal patients with locally advanced, or inoperable, or metastatic hormone-receptor positive breast cancer. The primary efficacy outcome was clinical benefit (CB), defined as the total number of patients who achieved a complete response, a partial response, or stable disease for ≥24 weeks. The study was a 2-stage design in which 19 patients per dose group were planned in the first stage. If at least 3 patients in any dose group achieved a CB, then that dose group was to be allowed to continue enrolling for the second stage, and the group could include up to a total of 60 patients. RESULTS: The 40-mg and 80-mg groups met the criterion and enrolled patients into the second stage. In the 40-mg group, there were 13 CB events in 60 patients (21.7%); and, in the 80-mg group, there were 12 CB events in 60 patients (20%). The 120-mg daily dose was stopped early, because it failed to achieve the criterion. For the 40-mg and 80-mg groups, the median time to progression was 15.0 weeks and 15.9 weeks, respectively. Only 1 drug-related serious adverse event (grade 3 hyperglycemia) was reported. CONCLUSIONS: TAS-108 at 40 mg and 80 mg daily demonstrated clinical activity with an encouraging duration of benefit. Because of its superior safety profile, TAS-108 40 mg daily is recommended for further development.

Comparison of the pharmacokinetics and pharmacodynamics of S-1 between Caucasian and East Asian patients.

S-1 is an oral fluoropyrimidine anti-neoplastic agent that is converted by CYP2A6 to 5-fluorouracil (5FU). We prospectively studied the pharmacokinetics and pharmacodynamics of S-1 in two groups of East Asian and Caucasian patients with solid malignancy refractory to standard chemotherapy, or for which 5FU was indicated, to elucidate differences in relation to CYP2A6 genotype and phenotype. S-1 was given orally at 30 mg/m(2) b.i.d. for 14 days every 21 days. Dose normalized AUC(0-48 h) for tegafur (P = 0.05) and gimeracil (P = 0.036) were higher in East Asians; conversely, AUC(0-48 h) of fluoro-ß-alanine was higher in Caucasians (P = 0.044). Exposure to 5FU was similar in both groups (P = 0.967). Mean cotinine:nicotine ratio was 54% higher in the Caucasian group (P = 0.03), and correlated with oral clearance of tegafur (r = 0.59; P = 0.002). Grade 3/4 gastrointestinal toxicities were more common in Caucasians than Asians (21%vs 0%). Treatment with S-1 yields no significant difference in 5FU exposure between Caucasians and East Asians.

Phase I study of two schedules of oral S-1 in combination with fixed doses of oxaliplatin and bevacizumab in patients with advanced solid tumors.

BACKGROUND: S-1 is a novel oral agent combining the 5-fluorouracil (FU) prodrug tegafur with gimeracil and oteracil, which inhibit 5-FU degradation by dihydropyrimidine dehydrogenase and phosphorylation within the gastrointestinal tract, respectively. The study was designed to identify the maximum tolerable dose and the dose-limiting toxicities of two schedules of S-1 combined with oxaliplatin and bevacizumab, in advanced solid tumor patients. METHODS: Schedule A: S-1 was administered orally at 20 mg/m(2) twice daily for 14 consecutive days, escalated by 5 mg/m(2), with fixed-dose intravenous bevacizumab 7.5 mg/kg and oxaliplatin 130 mg/m(2) on day 1 of each 3-week cycle. Schedule B: S-1 was administered at 25 mg/m(2) twice daily for 7 consecutive days, escalated by 5 mg/m(2), with fixed-dose intravenous bevacizumab 5 mg/kg and oxaliplatin 85 mg/m(2) on day 1 of each 2-week cycle. RESULTS: The maximum tolerated dose and recommended phase II dose of S-1 was 25 mg/m(2) twice daily for 14 days for schedule A and 35 mg/m(2) twice daily for 7 days for schedule B. The most common dose-limiting toxicities were grade 3 diarrhea. Both regimens were well tolerated. No pharmacokinetic interactions between oxaliplatin and S-1 components were observed. CONCLUSIONS: S-1, oxaliplatin and bevacizumab can be administered with acceptable safety and tolerability and without evidence of pharmacokinetic interactions.

Phase 1 study of oral TAS-102 in patients with refractory metastatic colorectal cancer.

PURPOSE: To evaluate safety of TAS-102 administered twice daily (bid) on days 1-5 and 8-12 of a 4-week cycle, confirm feasibility of the Japanese recommended dose (RD), 35 mg/m(2), in Western patients with metastatic colorectal cancer (mCRC) refractory to standard chemotherapies, and describe preliminary antitumor activity. METHODS: This open-label, dose-escalation phase 1 study was conducted at four US centers. Patients were enrolled into two sequential cohorts [30 (cohort 1) or 35 mg/m(2)/dose bid (cohort 2)]; dose-limiting toxicities (DLT) were evaluated during cycle 1 in dose-escalation cohorts. At RD, 15 additional patients were enrolled in an expansion cohort. RESULTS: Patients (N = 27) with refractory mCRC received TAS-102; 74 % had received ≥4 prior regimens. DLT was not observed in three patients in cohort 1, and was in one out of nine patients in cohort 2 (grade 3 febrile neutropenia). Therefore, RD was identified as 35 mg/m(2) bid. At RD, fatigue (63 %), gastrointestinal disturbances and nausea (46 %), vomiting (46 %), and diarrhea (42 %) were common but rarely grade 3/4. Grade 3/4 nausea, vomiting, and diarrhea occurred at 4 % each. Grade 3/4 toxicity was predominantly hematologic [neutropenia (71 %), anemia (25 %)]; febrile neutropenia was observed in two patients. Stable disease lasting ≥6 weeks was achieved by 16 evaluable patients (70 %); median progression-free survival and overall survival were 5.3 and 7.5 months, respectively. CONCLUSIONS: TAS-102 has an acceptable safety profile and preliminary evidence of disease stabilization in Western patients with refractory mCRC. Results from a randomized phase 3 study have shown survival benefit with disease stabilization evidence in this population.

Effect of food and a proton pump inhibitor on the pharmacokinetics of S-1 following oral administration of S-1 in patients with advanced solid tumors.

PURPOSE: S-1 is a novel oral fluoropyrimidine comprised of FT and two modulators, gimeracil (CDHP) and oteracil potassium (Oxo). This study investigated the food effects on the pharmacokinetics (PK) of Oxo, other components of S-1, and their metabolites at different gastric pH adjusted by proton pump inhibitor (PPI). METHODS: Patients with and without PPI were treated with S-1 at 30 mg/m(2) twice daily orally on days 1-7 under either fed or fasting condition, and then were crossed over to fasting/fed conditions on days 15-21 with washout on days 8-14 and 22-28. RESULTS: The study enrolled 55 patients including 27 PK-evaluable patients. For the single-dose and multiple-dose pharmacokinetics, the administration of S-1 under fed conditions resulted in decreased exposure to Oxo relative to fasting administration. There was a marginal decrease in exposure to CDHP and 5-FU under fed versus fasting conditions, although FT exposure was not altered by food, which demonstrated lack of food effect. PPI administration together with S-1 did not significantly change its bioavailability. CONCLUSIONS: Oxo exposure was reduced under fed compared to fasting condition. To increase the bioavailability of S-1, the administration of S-1 under fasting condition was more effective in the western countries.

An open-label, multicenter, three-stage, phase II study of s-1 in combination with cisplatin as first-line therapy for patients with advanced non-small cell lung cancer.

INTRODUCTION: S-1 is a rationally designed oral agent that combines the 5-fluorouracil prodrug tegafur with gimeracil and oteracil, which inhibit 5-fluorouracil degradation by dihydropyrimidine dehydronase and phosphorylation within the gastrointestinal tract, respectively, to increase antineoplastic activity while reducing gastrointestinal toxicity. We investigated the activity and toxicity of S-1 in combination with cisplatin in patients with unresectable non-small cell lung cancer (NSCLC). METHODS: Cisplatin, 75 mg/m, was administered intravenously on day 1, with S-1, 25 mg/m PO two times a day, days 1 to 14, every 21 days for a maximum of six cycles. Primary end point was overall response. RESULTS: A total of 58 patients received at least one cycle of protocol-specified therapy. The best overall response rate was 23.2% (95% confidence interval: 13.0-36.4), and the disease control rate was 67.9%. The median progression-free survival was 4.0 months (95% confidence interval: 3.3-5.5). There did not appear to be any relationship between response to therapy and tumor histology. The most frequently reported adverse events of G3 or more (≥10%) were neutropenia (28%), hyponatremia (19%), diarrhea (17%), hypokalemia (12%), fatigue (10%), dehydration (10%), and deep vein thrombosis (10%). CONCLUSIONS: Although the S-1 + cisplatin regimen used in this study appeared to have a similar level of antitumor activity and toxicity to that of established cisplatin-based doublets in NSCLC, the protocol-specified criteria of sufficient efficacy to warrant further study with an objective response rate ≥30% was not achieved. Therefore, while S-1 appears to be a promising agent in NSCLC, further evaluation should be conducted to determine the optimal S-1-based regimen to take forward for additional study.

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.