CHEMOTHERAPY OF ADVANCED MOUSE LEUKEMIA L1210: COMPARISON OF METHOTREXATE ALONE AND IN SEQUENTIAL THERAPY.

The sequential treatment of mice with advanced leukemia L1210 employing a single injection of 2-chloro-4′,4″-di-2-imidazolin-2-ylterephthalanilide, dihydrochloride (NSC-38280) or cyclophosphamide followed by multiple treatment with methotrexate (MTX) was examined. Mice that received a single injection of NSC-38280 or cyclophosphamide followed by MTX given daily or every 4 days displayed more extensive increases in median survival time than did mice receiving MTX alone on a daily or every-4-day treatment schedule. An initial treatment with either NSC-38280 or cyclophosphamide followed by daily MTX was approximately twice as effective as daily MTX alone, whereas NSC-38280 or cyclophosphamide followed by MTX every 4 days was 3–4 times more effective than MTX alone every 4 days.