Sixteen patients (55.2%) received all four cycles of JK1201I treatment, while 13 patients (44.8%) discontinued their treatment cycles: Six showed progressive disease (PD), two withdrew voluntarily, one developed rapid‐onset anaphylaxis, one died of pulmonary mucormycosis, one experienced treatment delay for over 2 weeks due to anemia, one developed diarrhea and grade 4 neutropenia with UGT1A1*6 (A/A) homozygosity mutations, and one refused to receive follow‐up examinations. Here, UGT1A1 is linked to neutropenia.