Sample size calculation will be done by means of Simon's method in 2 stages for phase II studies and will be based on the principal aim of the study (evaluation of the rate of objective response).
The hypothesis brings over of the efficiency of the treatment it will be accepted if a rate of objective response of at least 55 % is obtained, rejecting the efficiency of the treatment when the rate of response targets be lower than 35 %. In this case, considering an alpha error of 0.05 and 80 % power, 14 patients will be included in the first stage; the study would continue if more than 5 objective responses were found. The total number of patients to including in the study would be 44. The results will be significant if they find at least 20 objective responses.
Assuming a drop-out rate of 10 %, the total number of patients needed is 49 patients.
