Pathophysiology and therapy of irinotecan-induced delayed-onset diarrhea in patients with advanced colorectal cancer: a prospective assessment.
OBJECTIVE
Irinotecan (CPT-11), a camptothecin derivative, has shown efficacy against colorectal cancer. Delayed-onset diarrhea is its main limiting toxicity. The aim of this study was to determine the pathophysiology of CPT-11-induced delayed-onset diarrhea and assess the efficacy of combined antidiarrheal medication in a phase II, prospective, successive-cohorts, open study.


METHODS
Twenty-eight patients with advanced colorectal cancer refractory to fluorouracil (5-FU) therapy received CPT-11 350 mg/m2 every 3 weeks. The first cohort of 14 consecutive patients explored for the mechanism of diarrhea received acetorphan (a new enkephalinase inhibitor) 100 mg three times daily; the second 14-patient cohort received, in addition to acetorphan, loperamide 4 mg three times daily. Before treatment, and if late diarrhea occurred, patients underwent colon mucosal biopsies for CPT-11 and topoisomerase I levels; intestinal transit time; fecalogram; fat and protein excretion; alpha1-antitrypsin clearance; D-xylose test; blood levels for vasoactive intestinal polypeptide, glucagon, gastrin, somatostatin, prostaglandin E2, and carboxylesterase; CPT-11/SN-38 and SN-38 glucuronide pharmacokinetics; and stool cultures.


RESULTS
Delayed-onset diarrhea occurred during the first three treatment cycles in 23 patients (82%). Electrolyte fecal measurements showed a negative or small osmotic gap in nine of nine patients and an increased alpha1-antitrypsin clearance in six of six patients. There were no modifications in stool cultures or hormonal dysfunction. Four of 11 patients (36%) with delayed-onset diarrhea in the first cohort responded to acetorphan, whereas nine of 10 patients (90%) responded to the combination of acetorphan and loperamide (P < .02).


CONCLUSIONS
CPT-11-induced delayed-onset diarrhea is caused by a secretory mechanism with an exudative component. Early combined treatment with loperamide and acetorphan seems effective in controlling the diarrheal episodes.
Saliba
F
F
Paul Brousse Hospital, Villejuif, France.
Hagipantelli
R
R
Misset
J L
JL
Bastian
G
G
Vassal
G
G
Bonnay
M
M
Herait
P
P
Cote
C
C
Mahjoubi
M
M
Mignard
D
D
Cvitkovic
E
E
D000328:Adult; D000368:Aged; D000930:Antidiarrheals / Q000627:therapeutic use*; D000972:Antineoplastic Agents, Phytogenic / Q000009:adverse effects* / Q000627:therapeutic use; D002166:Camptothecin / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D015179:Colorectal Neoplasms / Q000188:drug therapy*; D003967:Diarrhea / Q000139:chemically induced* / Q000188:drug therapy / Q000503:physiopathology; D005260:Female; D006801:Humans; D000077146:Irinotecan; D008139:Loperamide / Q000009:adverse effects / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015244:Thiorphan / Q000009:adverse effects / Q000031:analogs & derivatives / Q000493:pharmacokinetics / Q000627:therapeutic use
D000930:Antidiarrheals; D000972:Antineoplastic Agents, Phytogenic; D008139:Loperamide; D000077146:Irinotecan; C049331:racecadotril; D015244:Thiorphan; D002166:Camptothecin