A trial was conducted to study the effectiveness of arterial hypertension treatment using a new drug, compared with traditional therapy. There were 3,000 participants in the trial, divided into two identical groups, taking into account their age, sex, stage of the disease, etc. One group was receiving treatment with the new drug, while the other was receiving traditional therapy and was the control group. The trial participants did not know which therapy they were receiving. What type of trial was conducted in this case?