Table 2.

Summary therapeutic recommendations based on UGT1A1 predicted phenotype for irinotecan.

UGT1A1 predicted phenotype	Therapeutic recommendation
PM (*28/*28)	Start with 70% of the normal dosea. If the patient tolerates this initial dose, the dose can be increased, guided by the neutrophil count.
PM other	Start with 70% of the normal dosea. If the patient tolerates this initial dose, the dose can be increased, guided by the neutrophil count.
IM (*1/*28)	No action required.
IM other	No action required.

IM intermediate metaboliser, PM poor metaboliser.

^aThe normal dose is defined as the dose the patient would receive if he/she would not have a gene variant.