Randomization and blinding
Patients were randomized 1:1 to receive IV imatinib or placebo for 7 days. Randomization was done in the web-based application Castor electronic data capture using variable block sizes (4–6 patients per block) and stratification per participating center. Allocation of randomization group was only visible to the pharmacy staff preparing the treatment. The patients, clinical staff, investigators and statisticians remained blinded to randomization allocation during the entire study. Blinding was guaranteed by distribution of the study drug in amber-colored syringes and lines to conceal any color differences. The local pharmacies were responsible for the preparation of the study drug and, if necessary, for unblinding.