Dose levels for phase I/II protocol of iodine 131–anti-CD20 (tositumomab), etoposide, and cyclophosphamide
| Dose level . | No. of patients . | 131I–anti-CD20 dose* (Gy) . | Etoposide dose (mg/kg) . | CTX dose (mg/kg) . |
|---|---|---|---|---|
| 0 (starting) | 5† | 20 | 0 | 100 |
| 1 | 12 | 20 | 60 | 100 |
| 2 | 4 | 23 | 60 | 100 |
| 3 | 23 | 25 | 60 | 100 |
| 4 | 8 | 27 | 60 | 100 |
| Dose level . | No. of patients . | 131I–anti-CD20 dose* (Gy) . | Etoposide dose (mg/kg) . | CTX dose (mg/kg) . |
|---|---|---|---|---|
| 0 (starting) | 5† | 20 | 0 | 100 |
| 1 | 12 | 20 | 60 | 100 |
| 2 | 4 | 23 | 60 | 100 |
| 3 | 23 | 25 | 60 | 100 |
| 4 | 8 | 27 | 60 | 100 |
131I indicates iodine-131; CTX, cyclophosphamide.
The 131I–anti-CD20 dose is expressed as the radiation-absorbed dose delivered to the normal organ receiving the greatest dose of radiation (usually the lungs). The actual dose of131I administered varied from patient to patient within a cohort according to antibody biodistribution and time-activity curves.
One patient in group 0 could not be evaluated for late nonhematologic toxic effects, so 5 patients were treated in the first cohort before the escalation to dose level 1.