A phase II study of prednimustine in acute non-lymphocytic leukemia, smouldering leukemia, and refractory anemia with excess blasts.

Prednimustine, an ester of chlorambucil and prednisolone, was evaluated for efficacy and toxicity in a selected group of leukemia patients with a poor prognosis. Disease subsets consisted of patients with acute non-lymphocytic leukemia (ANLL) over age 60; ANLL refractory to standard therapy; smouldering leukemia; and refractory anemia with excess blasts (RAEB). In agreement with previous studies, toxicity from Prednimustine was relatively mild, consisting primarily of infrequent myelosuppression, gastrointestinal side-effects, and mild hyperglycemia. This study did not, however, confirm previously reported remission rates in ANLL: in 41 evaluable patients only two complete remissions were achieved. Both occurred in the subset of patients with smouldering leukemia. We conclude that Prednimustine has limited activity in this patient population.