Open Label refers to a trial in which masking is not used and all patients receive the treatment on trial. This means that all parties involved in the trial know which patients received clinical interventions. This differs from masked trials, such as "Double-blind, placebo controlled", where neither the investigator not patient knows who is receiving a treatment and who is receiving an inactive treatment.
Why the difference? Essentially, its the ethics associated with treating terminally ill patients. It's generally considered unethical to not treat patients with terminal illnesses (ie stage 3-4 melanoma) or undergoing surgery.
The upside for the owners of the treatment (like us) is that any results can be reported as they see fit (and the merits of each approach debated on hotcopper). However, Open Label trials do have statistical bias downside, which cannot be overlooked.
