Table 1.
Impact of CYP2B6 and CYP2A6 polymorphisms on mid-dose efavirenz concentrations* in 65 human immunodeficiency virus-infected patients
| Variable | n (%) | Median (IQR) efavirenz mid-dose concentration* | P-value |
|---|---|---|---|
| CYP2B6 c.516G→T | <0.001 | ||
| GG | 22 (30%) | 1 282 (1089–1901)† | |
| GT | 38 (51%) | 1 560 (1379–2205)† | |
| TT | 14 (19%) | 8 320 (6085–10 673)† | |
| CYP2B6 c.983T→C | 0.88 | ||
| TT | 59 (91%) | 1 567 (1274–2649) | |
| TC | 6 (9%) | 1 832 (1334–3102) | |
| CYP2A6*9B (g.1836G→T) | 0.07 | ||
| TT | 59 (91%) | 1 562 (1265–2356) | |
| TG | 5 (8%) | 3 102 (1568–4712) | |
| GG | 1 (1%) | 10 726 | |
| CYP2A6*17 (c.1093G→A) | 0.15 | ||
| GG | 51 (78%) | 1 557 (1274–2334) | |
| GA | 12 (19%) | 1 994 (1325–4063) | |
| AA | 2 (3%) | 6 374 (4220–8529) | |
| CYP2A6*9B or *17 | 0.017 | ||
| Reference | 47 (72%) | 1 516 (1242–2084) | |
| Variant carrier | 18 (28%) | 2 694 (1597–5943) |
*
Values are the average of efavirenz concentrations determined at 4 and 8 weeks in each patient; note that four patients had missing efavirenz concentration data at week 4, and seven patients had missing concentration data at week 8.
†
P < 0.001 for 516TT vs. GT, P < 0.001 for 516TT vs. GG, P= 0.027 for 516GG vs. GT groups determined by Student–Newman–Keuls test.