Question 3: What are 30% and 15% in this statement and from where do they come?
30% is the proportion of patients undergoing paediatric haemopoietic stem-cell transplantation who will develop veno-occlusive disease. This is derived from several studies, to which references are given. 15% is the proportion after treatment which this trial is designed to be able to detect. It is not clear from the statement how this was chosen, nor could I find any other comment on it in the paper. It could be the difference that would lead to a change in treatment policy, or it could be what they hoped the drug would achieve. It could be what the sample size they could achieve would be able to detect, but I doubt this. As we see later, they increased the sample size.
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Last updated: 3 February, 2020.