Table 1.
Conditioning regimens for case (CY/TBU) and control (TBU/CY) patients.a
| CY/TBU Cases (n=51) | TBU/CY Controls (n=271) | |
|---|---|---|
| Conditioning agents, by transplant day | ||
| -7 | CY IV 60 mg/kgb | BUc |
| -6 | CY IV 60 mg/kg | TBU |
| -5 | BUc | TBU |
| -4 | TBU | TBU |
| -3 | TBU | CY IV 60 mg/kgb |
| -2 | TBU | CY IV 60 mg/kg |
| -1 | Rest | Rest |
| 0 | Allograft infusion | Allograft infusion |
| Busulfan administration route & dosing frequency | ||
| Oral every 6 hours | 0 | 252 (93%) |
| IV every 6 hours | 0 | 15 (6%) |
| IV once daily | 51 (100%) | 4 (1%) |
| Cumulative busulfan dose (mg) | ||
| Oral | Not applicable | 1048 (572–1916) |
| IV | 1098 (580–1510) | 976 (608–1668) |
| Target busulfan Css (ng/ml) | ||
| ≤900d | 0 | 2 (0.7%) |
| 600–900 | 0 | 3 (1.1%) |
| 800–900 | 51 (100%) | 262 (96.7%) |
| >900d | 0 | 4 (1.5%) |
| Busulfan pharmacokinetics | ||
| Dose #1 Css >900 ng/mL | 23 (45%) | 128 (47%) |
| Average daily Csse >900 ng/mL | 1 (2%) | 18 (7%) |
| Average daily Csse (ng/mL) | 856 (811–1191) | 861 (627–968) |
Data presented as median (range) or number (%). Abbreviations: TBU, targeted busulfan; CY, cyclophosphamide; IV, intravenous; Css, busulfan steady-state concentration.
Mesna given concurrently with IV cyclophosphamide to prevent hemorrhagic cystitis.
Phenytoin started one day before busulfan and continued throughout busulfan administration (i.e., day -6 through day -1 for CY/TBU, and day -8 through day -3 for TBU/CY).
Specific target Css detailed in the busulfan dosing and pharmacokinetics section of text.
Cumulative over all 4 days of busulfan administration. For Css, each patient’s busulfan Css over all 4 days was calculated, and then divided by 4 to provide the average daily Css.