 Analysis of that imaging data allowed an optimal dose of labelled antibody to be calculated, which was then administered once a day, for up to seven days.Each time the labelled antibody was administered, it was always preceded by unlabelled antibody because early clinical trials had shown that total body residence times of radioactivity were longer in people who first received unlabelled antibody, so that a lower dose of labelled antibody was needed to deliver the required total dose of radiation; additionally labelled antibody targeted tumors better in people pre-treated with unlabelled antibody.This drug combination was developed by Corixa which was purchased by GlaxoSmithKline in 2005.