Over 1 year, a study is conducted to assess the antileukemic activity of a new tyrosine kinase inhibitor in patients
with chronic myeloid leukemia in blast crisis. All patients enrolled in the study are informed that they would be
treated with the tyrosine kinase inhibitor. They are assigned to successive dose cohorts of 300 to 1000 mg/day of the
drug. Six to eight patients are assigned to each dose. Treatment efficacy is determined based on the results of
complete blood counts and bone marrow assessments conducted regularly throughout the study. This study is best
described as which of the following?
(A) Case-control study
(B) Crossover study
© Open-labeled clinical trial
(D) Randomized clinical trial
(E) Single-blind, randomized, controlled trial