A phase I trial of CPT-11 and S-1 combination chemotherapy in patients with metastatic colorectal cancer.
OBJECTIVE
To establish a safe and practical chemotherapeutic regimen using CPT-11 in combination with an oral 5FU derivative S-1 for patients with metastatic colorectal cancer, a phase I clinical trial was conducted in an outpatient setting.


METHODS
Nine patients with metastatic colorectal cancer were enrolled. S-1 was administered at approved doses of 80 mg/body/day to eligible patients with a body surface area (BSA) of less than 1.25m2, 100 mg/body/day to those with a BSA of 1.25-1.5m2, and 120 mg/body/day to those with a BSA of more than 1.5m2, for 2 weeks followed by 1 week rest, comprising one treatment cycle of 3 weeks. CPT-11 was administered on day 8 of the S-1 cycle. The dose of CPT-11 was escalated from 60-120 mg/m2 by every 20 mg/m2 for every cohort consisting of at least 3 patients in order to define dose-limiting toxicity (DLT), maximal tolerated dose (MTD), and recommended dose (RD) in preparation for a phase II trial.


RESULTS
In regard to the hematologic toxicity, a decrease of WBC to less than grade 2 was observed in 2 patients until the dose was escalated to 100 mg/m2 of CPT-11, which delayed the treatment for 1 week in 1 patient. Regarding non-hematologic toxicity, fatigue and gastrointestinal toxicity, including anorexia and nausea/vomiting, at grades 1 and 2 were commonly observed throughout the dose levels. Diarrhea at grade 3 was observed at the 4th cycle of 100 mg/m2 CPT-11 in 2 of 3 patients, both of whom required hospitalization. All patients were able to complete more than 3 treatment cycles, and 1 patient at 80 mg/m2 of CPT-11 was able to receive 31 treatment cycles. Observed tumor responses included 1 partial response (PR), 2 moderate responses, 4 stable diseases, and 2 progressive diseases. Serum CEA level decreased in 7 of the 9 patients enrolled.


CONCLUSIONS
These results suggest that this treatment regimen using CPT-11 in combination with oral S-1 therapy is a safe regimen in an outpatient setting and effective for patients with metastatic colorectal cancer. The DLT is diarrhea at a MTD of 100 mg/m2 of CPT-11, and 80 mg/m2 CPT-11 is recommended for the next phase II trial.
Yamaguchi
Yoshiyuki
Y
Department of Surgical Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan. shogo@hiroshima-u.ac.jp
Minami
Kazuhito
K
Kawabuchi
Yoshiharu
Y
Ohshita
Akiho
A
Hironaka
Katsuji
K
D000328:Adult; D000368:Aged; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage*; D002166:Camptothecin / Q000008:administration & dosage / Q000031:analogs & derivatives*; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000473:pathology; D004338:Drug Combinations; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D000077146:Irinotecan; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D010094:Oxonic Acid / Q000008:administration & dosage*; D005641:Tegafur / Q000008:administration & dosage*
D000964:Antimetabolites, Antineoplastic; D004338:Drug Combinations; C079198:S 1 (combination); D005641:Tegafur; D010094:Oxonic Acid; D000077146:Irinotecan; D002166:Camptothecin