Preliminary experience with a new chemotherapy regimen for adults with acute lymphoblastic leukemia.

We treated 11 consecutive adult patients who presented with acute lymphoblastic leukemia to the University of Chicago with a novel, intensified chemotherapy regimen to evaluate the feasibility and toxicity of this program. Following a 5-drug induction therapy (course A), patients received sequential courses (B and C) of high-dose antimetabolite therapies, in part to replace cranial irradiation for CNS prophylaxis. All patients achieved a complete remission. The regimen was designed with a goal of administering all post-remission therapy in the outpatient setting. With the exception of the initial induction course (A), 3(1/3)8 total patient courses were administered in the outpatient clinic. As expected, the induction and consolidation courses (A and B) of this regimen were associated with grade 4 hematologic toxicity and significant but manageable infectious toxicity. Another novel aspect of the regimen included a combined intravenous and oral dosing schedule designed to sustain methotrexate levels > or = 1.0 microM for 30 hours (course C). There was minimal toxicity with the CNS prophylaxis/high-dose methotrexate course (C). Methotrexate levels at 30 hours ranged from 0.31-4.0 microM, with a median of 1.0 microM (n=37). This study demonstrates that this novel post-remission regimen is feasible in adults and that high concentrations of methotrexate can be sustained in the outpatient setting. The Cancer and Leukemia Group B is presently evaluating the efficacy of this regimen in a large phase II trial (CALGB study 19802).