UGT1A1 and neutropenia: Though many of the patients with UGT1A1*1/*28 or *1/*6 had received a reduced starting dose of nal-IRI, their PFS and OS were comparable to those in patients with UGT1A1*1/*1. Several reports from Asian countries have suggested that the initial dose reduction of nal-IRI results in less frequent neutropenia but no change in efficacy [32,33].