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Biomedical subjects

D Lonsdale

Publications and source records attributed to D Lonsdale.

At least 55 records · Page 3Linked to original sources
PubMed1977

Effects of continuous or discontinuous maintenance therapy on subsequent remission maintenance in childhood leukemia.

This study was designed to determine if resistance to a standard drug during the second remission of children with acute leukemia was reduced by discontinuation of therapy during the initial remission. The initial maintenance therapy was either 6-mercaptopurine (6-MP), methotrexate (MTX), or cyclophosphamide (CYC) given continuously to relapse or discontinued (at random) at 2 or 6 months. Following the initial relapse and after induction of a second complete remission, 72 evaluable patients received (continuously to relapse) either 6-MP (53 patients) or CYC (19 patients) for the second remission maintenance. Resistance of 6-MP occurred during the second maintenance, regardless of the drug used during the initial maintenance, in that the length of second remissions was significantly shorter than the length of first remissions. However, this resistance was most pronounced in patients who initially relapsed while on continuous 6-MP maintenance (medium duration of remission [MDR] of 9 weeks). Patients whose initial relapse occurred after the discontinuation of 6-MP had a MDR of 23 weeks and patients whose second remission was maintained with CYC (after relapse from initial continuous remission on 6-MP) had a MDR of 25 weeks.

Acute Disease↗
PubMed1975

Interrupted vs. continued maintenance therapy in childhood acute leukemia.

A total of 313 patients with childhood acute leukemia received a combination of vincristine (2 mg/m2/week) and prednisone (60 mg/m2/day); 86% of 276 evaluable patients achieved a complete bone marrow remission in a median of 35 days. When a complete bone marrow remission was achieved, patients were randomized to one of three oral maintenance therapies: 6-mercaptopurine (6MP) (75 mg/m2/day), methotrexate (MTX) (25 mg/m2/twice weekly), or cyclophosphamide (CYC) (100 mg/m2/day). Patients receiving maintenance therapy were further randomized at 2 and 6 months after the start of maintenance either to continue or discontinue therapy. tthe median lengths of subsequent bone marrow remission for patients randomized at 2 months to continue vs. discontinue therapy were: 37 vs. 19 weeks for 6-MP patients; 25 vs. 14 weeks for MTX patients; and 29 vs. 13 weeks for CYC patients. The median lengths of subsequent marrow remissions for patients receiving maintenance therapy for 6 months and randomized to continue vs. discontinue were: 57 vs. 17 weeks for 6-MP patients; 60 vs. 40 weeks for MTX patients; and 23 vs. 10 weeks for CYC patients. Results indicate a significant advantage for continuing maintenance therapy at 2 and 6 months after the start of complete bone marrow remission.

Acute Disease↗
PubMed1975

Long-term results of reinforcement therapy in children with acute leukemia.

A total of 180 children with acute leukemia was randomized to one of two induction regimens: vincristine plus prednisone, or 6-mercaptopurine plus prednisone. Of 170 patients evaluable for induction therapy, a hematologic remission was achieved in 83% (72/87) on vincristine plus prednisone, and in 93% (77/83) on 6-mercaptopurine plus prednisone. When hematologic remission was achieved, patients were randomized to one of three maintenance schedules: 6-mercaptopurine alone, 6-mercaptopurine plus prednisone for 4 weeks every 3 months, or 6-mercaptopurine plus prednisone plus vincristine for 4 weeks every 3 months. The durations of hematologic remission were compared from the achievement of hematologic remission to bone marrow relapse. The survival data were presented as an overview of the effect of this initial therapy on duration of survival. There was no statistical difference between the two induction regimens. The most important finding in the comparison of the three maintenance schedules was that reinforcement of 6-mercaptopurine maintenance therapy with either prednisone or prednisone plus vincristine resulted in significantly longer durations of remission. Vincristine added to prednisone for reinforcement after induction of remission by vincristine plus prednisone did not increase the duration of hematologic remission or survival over prednisone reinforcement alone.

Acute Disease↗