Background: Patients with acute lymphocytic leukemia (ALL) and those with lymphoblastic lymphoma (LBL) have overlapping clinical and immunophenotypic features and they have been treated with the same or very similar chemotherapy regimens. The goal of this multi-institutional phase II trial was to evaluate the therapeutic efficacy of a short-term, six-drug chemotherapy regimen for adult patients with untreated ALL or LBL.
Methods: Forty-six eligible patients, 41 with ALL and five with LBL, were treated with a short-term (planned total therapy duration; 36-38 weeks), simplified chemotherapy program; two courses of VEPA-L (vincristine, cyclophosphamide, prednisolone, doxorubicin, I-asparaginase plus intrathecal methotrexate and prednisolone) followed by four courses of M-VEPA (methotrexate plus VEPA), without the traditional maintenance therapy using daily 6-mercaptopurine and weekly methotrexate.
Results: Thirty-six (78%; 95% confidence interval 64-89%) of the 46 eligible patients achieved complete remission (CR). Among the 36 patients who achieved CR, four (11%) died of treatment complications, 26 (72%) relapsed and six (17%) remain alive in continuous CR. The median survival for all 46 eligible patients is 14 months and the median disease-free survival (DFS) for the 36 patients who achieved CR is 11 months. The estimate of the proportion of survival at 7 years of all 46 eligible patients is 15% at a median follow-up time of 96 months and that of DFS of the 36 patients achieving CR is 17% at a median follow-up time of 93 months. Subgroup analysis showed that an elevated serum C-reactive protein (CRP) level, age of 30 years or older, the presence of B-symptom and T-cell phenotype were likely to be associated with shortened survival. Although the observed CR rate (78%) is within the range of satisfaction, the long-term survival rate (15%) is inferior to those of published programs incorporating maintenance therapy.
Conclusions: A fraction of adult patients with ALL or LBL are curable with a short-term, six-drug chemotherapy regimen. However, this simplified therapy of shorter duration cannot be recommended.