Kee, B.K., Morris, J.S., Slack, R., Crocenzi, T., Wong, L., Esparaz, B., . . . Fisch, M.J. (2015). A phase II, randomized, double blind trial of calcium aluminosilicate clay versus placebo for the prevention of diarrhea in patients with metastatic colorectal cancer treated with irinotecan. Supportive Care in Cancer, 23, 661–670.

To determine whether the oral administration of calcium aluminosilicate clay (CASAD) reduces the rate of grade 3 diarrhea associated with irinotecan administration in patients with colorectal cancer

Patients were provided with CASAD or placebo capsules. The treatment arm received capsules containing 500 mg of the active compound taken as two tablets four times daily. Treatment lasted for six weeks or until treatment criteria were met. After six weeks, all patients were offered off-label CASAD for an additional six weeks. Patients who developed diarrhea were provided standard-of-care antidiarrheal medication. Patients completed baseline assessments of bowel statuses and additional assessments at three, five, and six weeks. Daily bowel logs were completed by patients and reviewed at the third, fifth, and sixth provider visits.

• N = 100
• AGE RANGE = 20–83 years
• MALES: 54%, FEMALES: 46%
• KEY DISEASE CHARACTERISTICS: Metastatic colorectal cancer
• OTHER KEY SAMPLE CHARACTERISTICS: Scheduled to receive irinotecan alone or with other agents: Eastern Cooperative Oncology Group status ≤ 2

• SITE: Multi-site
• SETTING TYPE: Outpatient
• LOCATION: MD Anderson and affiliates

• PHASE OF CARE: Active antitumor treatment
• APPLICATIONS: Elder care

This was a phase II, randomized, double-blinded, multicenter study. Patients were randomized on a 1:1 ratio to receive CASAD or a placebo. Patients were stratified according to irinotecan therapy, no concurrent therapy, or concurrent therapy in addition to irinotecan.

• MD Anderson Symptom Inventory (MDASI)
• Patient completed bowel/ostomy assessment
• Daily diary

There were no differences between groups. In the CASAD arm, seven out of 49 patients in the CASAD arm versus three out of 46 patients in the placebo arm developed grade 3 diarrhea during the first six weeks (PR = 0.10). The incidence of any grade of diarrhea was similar in both arms. There was no difference in gastrointestinal (GI) toxicities between the two groups.

CASAD was ineffective in preventing diarrhea in this patient population. There were no issues with GI toxicities, indicating that CASAD was clinically safe.

• Subject withdrawals ≥ 10%
• Other limitations/explanation: Weak science on which study it was based on

CASAD is not indicated as a preventive measure for diarrhea associated with irinotecan administration.