Randomisation and blinding
Eligible patients were randomised using interactive response technology (IRT) 2:1:1:1:2 (block size 7) to receive placebo or BI 1467335 1 mg, 3 mg, 6 mg or 10 mg orally once daily for 12 weeks. Use of IRT provided a depersonalised patient identification code and ensured confidentiality of patient data; the randomisation list was generated using a validated system, which involved a pseudo-random number generator so that the resulting treatment was both reproducible and non-predictable. All trial participants, investigators and site staff were blinded to the assigned treatment.