Michael, M., Brittain, M., Nagai, J., Feld, R., Hedley, D., Oza, A., … Moore, M.J. (2004). Phase II study of activated charcoal to prevent irinotecan-induced diarrhea. Journal of Clinical Oncology, 22(21), 4410–4417.

In cycle 1, 28 patients received irinotecan plus 1,000 mg oral-activated charcoal (AC) plus 25 ml water the evening before irinotecan and then three times per day for 48 hours after, on an empty stomach. In cycle 2, 24 patients received irinotecan without AC.

This study reported on 52 patients with advanced colorectal cancer receiving 125 mg/m² irinotecan weekly for four weeks with two weeks of rest.

This was a prospective, nonrandomized trial; patients served as their own controls.

• Patient diaries were used to record diarrhea frequency and grading using the National Cancer Institute (NCI) Common Toxicity Criteria (CTC) and daily loperamide use.
• Research nurses closely monitored compliance with the loperamide regimen (4 mg at first onset of delayed diarrhea and then 2 mg every 2 hours, 4 mg every 4 hours at night, until patient was diarrhea free for 12 hours) by inspection of provided diaries.

• Administration of AC with irinotecan in cycle 1 was associated with
  • Decreased grade 3 and 4 diarrhea
  • Decreased loperamide use
  • Increased irinotecan dose intensity.
• In cycle 1, 7.1% of patients recorded grade 3-4 diarrhea. In cycle 2, 25% of patients recorded grade 3-4 diarrhea.
• In cycle 1, 46.1% of patients recorded grade 0 diarrhea. In cycle 2, 20.8% of patients recorded grade 0 diarrhea.
• In cycle 1, 98% of patients received their planned doses. In cycle 2, 70% of patients received their planned doses.
• In cycle 1, 25% of patients received more than 10 loperamide cycles. In cycle 2, 54% of patients received more than 10 loperamide cycles.

Any statistical comparison in the efficacy parameters defined in the trial would be associated with large confidence intervals.

• The sample size was small.
• Patients acted as their own controls.
• Irinotecan dose reductions and supportive care are complex.

This was an exploratory trial with small patient numbers; results are hypothesis-generating and require additional confirmation in a larger study.