Purpose: To evaluate the efficacy and safety of a new induction regimen for adult acute lymphoblastic leukemia (ALL) that does not contain vincristine or corticosteroids.
Patients and methods: Thirty-seven adult patients with newly diagnosed ALL and lymphoblastic lymphoma were treated with a dose-intense induction regimen. This regimen was designed to increase the fraction of patients achieving an early complete remission (CR) in an attempt to increase long-term disease-free survival. The induction regimen was cytarabine (Ara-C) 3 g/m2/d for 5 days and mitoxantrone 80 mg/m2 as a single dose on day 3. Granulocyte colony-stimulating factor (G-CSF) 200 micrograms/ m2/d beginning on day 7 was used to promote early myeloid recovery.
Results: There were 31 CRs (84%). Median time to CR was 34 days, median hospital stay was 28 days, and the median number of days with a neutrophil count less than 500/microL was 18. There were three patients with resistant disease who experienced treatment failure and three early deaths from sepsis. Four patients with Philadelphia chromosome-positive (Ph+) ALL achieved hematologic and cytogenetic CRs.
Conclusion: This dose-intense induction regimen produced a high incidence of CRs with acceptable toxicity without the use of vincristine or corticosteroids. Comparisons with our prior vincristine/prednisone-based induction regimen (the L-20 protocol) suggest that patients treated on the current study were more likely to achieve a CR and that they achieved this remission earlier than patients treated with a traditional four-drug (vincristine, prednisone, doxorubicin, and cyclophosphamide) induction regimen.