What is the main reason for randomly allocating participants to treatment groups in a Randomised Controlled Trial (RCT)?

Researchers conduct a randomised controlled trial investigating the impact of an adherence intervention on achievement of virological suppression.  They recruit 9750 participants from 27 HIV clinics across the UK.  Participants from 14 of the clinics (a total of 4838 participants) are randomised to receive the new adherence intervention  Participants from the other 13 clinics (a total of 4912 participants) are randomised to receive the standard of care

Researchers conduct a randomised controlled trial (RCT) among antiretroviral-naïve individuals.  Participants are randomised to receive either (I) a novel treatment regimen, Regimen A or (ii) the current gold standard regimen, Regimen B.  The primary outcome is viral load <50 copies/ml at 48 weeks, using an Intent-to-treat (ITT) approach.  Which of the following statements describes an ITT analysis?

Researchers conduct a non-inferiority randomised controlled trial (RCT) among antiretroviral-naïve individuals.  Participants are randomised to receive either Ii) a novel treatment regimen, Regimen A or (ii) the current gold standard regimen, Regimen B.  Which of the following apply to non-inferiority studies?

Researchers conduct a randomised controlled trial (RCT) among antiretroviral-naïve individuals.  Participants are randomised to receive either Ii) a novel treatment regimen, Regimen A or (ii) the current gold standard regimen, Regimen B.  The study will be double-blinded.  What does double-blinded mean?