Table 5. Relationship between the number of defective alleles and toxicity (n=40).
| UGT1A1 | No. of defective alleles | No. of patients | Irinotecan dose escalation | Grade 3–4 neutropenia | Febrile neutropenia | Treatment delay |
|---|---|---|---|---|---|---|
| (n=11) | ||||||
| *1/*1 | 0 | 11 | 4/11 (36%) | 1/11 (9%) | 0/11 | 2/9 (22%) |
| (n=15) | ||||||
| *1/*60 | 1 | 9 | 3/9 (33%) | 3/9 (33%) | 0/9 | 4/9 (44%) |
| *1/*6 | 1 | 6 | 1/6 (17%) | 4/6 (67%) | 1/6 (17%) | 2/5 (40%) |
| (n=14) | ||||||
| *60/*60 | 2 | 3 | 0/3 | 3/3 (100%) | 0/3 | 0/3 |
| *6/*60 | 2 | 1 | 0/1 | 0/1 | 0/1 | 0/1 |
| *6/*6 | 2 | 4 | 1/4 (25%) | 2/4 (50%) | 0/4 | 1/3 (33%) |
| *28/*60 | 2 | 5 | 1/5 (20%) | 3/5 (60%) | 0/5 | 1/5 (20%) |
| *6/*28/*60 | 3 | 1 | 0/1 | 1/1 (100%) | 0/1 | 1/1 (100%) |