Oral Methotrexate/6-mercaptopurine may be Superior to a Multidrug LSA2L2 Maintenance Therapy for Higher Risk Childhood Acute Lymphoblastic Leukemia Results From the NOPHO ALL-92 Study

The importance of maintenance therapy for higher risk childhood acute lymphoblastic leukemia (ALL) is uncertain, Between 1992 and 2001 the Nordic Society for Pediatric Haematology/Oncology compared in a nonrandomized study conventional oral methotrexate (MTX)/6-mercaptopurine (6MP) maintenance therapy with a multidrug cyclic LSA(2)L(2) regimen. 135 children with B-lineage ALL and a white blood count >= 50 x 10(9)/L and 98 children with T-lineage ALL were included. Of the 234 patients, the 135 patients who received MTX/6MP maintenance therapy had a lower relapse risk than the 98 patients who received LSA(2)L(2) maintenance therapy, which wits the case for both B-lineage (27% +/- 5% vs. 45% +/- 9%; P = 0.02) and T-lineage ALL (8% +/- 5% vs. 21% +/- 5% P = 0.12). In multivariate Cox regression analysis stratified for immune phenotype, a higher white blood count (P = 0.01) and administration of LSA(2)L(2) maintenance therapy (P = 0.04) were both related to an increased risk of in event (overall P Value of the Cox model: 0.003), whereas neither sex, age at diagnosis, administration of central nervous system irradiation, nor presence of 1 day 15 bone marrow with >= 25% versus < 25% lymphoblasts were of statistical significance. These results indicate that oral MTX/6MP maintenance therapy administered after the first year of remission can improve the cure rates of Children with T-lineage or with higher risk B-lineage ALL.