De Jong, F.A., Kehrer, D.F., Mathijssen, R.H., Creemers, G.J., de Bruijn, P., van Schaik, R.H., … De Jong, M.J. (2006). Prophylaxis of irinotecan-induced diarrhea with neomycin and potential role for UGT1A1*28 genotype screening: A double-blind, randomized, placebo-controlled study. Oncologist, 11, 944–954.

Patients were treated with 350 mg/m² irinotecan during their first cycle of chemotherapy combined with 660 mg neomycin (n = 28; 45%) administered three times daily for three consecutive days starting two days before irinotecan or combined with placebo (n = 34; 55%). 

The two groups were balanced for demographic parameters, hematologic function, bilirubin, and liver enzyme values. The administered dose of irinotecan did not differ significantly between groups (mean dose of 640 mg versus 679 mg, p = 0.9).

This was a double-blind, randomized, placebo-controlled study.

• The National Cancer Institute (NCI) Common Toxicity Criteria (CTC), version 2, was used for diarrhea, nausea, and vomiting up to three weeks following administration of irinotecan. 
• Duration of diarrhea (in days) was scored.

• Overall incidence and severity of delayed-type diarrhea did not differ significantly between study groups (p = 0.33).
• The neomycin group experienced a 45% lower incidence of grade 3 diarrhea compared to the placebo group (17.9% versus 32.4%; p = 0.19). However, no difference was found between study groups when combining grade 2 and 3 incidence (46.4% versus 50.0%; p = 0.78).
• Treatment with neomycin did not result in significantly shorter duration of diarrhea (4.0 versus 4.9 days; p = 0.32).

• Patients receiving neomycin had a 4.5 times higher risk for grade 2 nausea than those receiving placebo (39.9% versus 8.8%; p < 0.01). 
• A larger trial is warranted.