A placebo is anything that seems to be a "real" medical treatment -- but isn't. It could be a pill, a shot, or some other type of "fake" treatment. What all placebos have in common is that they do not contain an active substance meant to affect health.
Researchers use placebos during studies to help them understand what effect a new drug or some other treatment might have on a particular condition.
！！！For instance, some people in a study might be given a new drug to lower cholesterol. Others would get a placebo. None of the people in the study will know if they got the real treatment or the placebo.
！！！Researchers then compare the effects of the drug and the placebo on the people in the study. That way, they can determine the effectiveness of the new drug and check for side effects.
1）Ixekizumab, (Taltz的common name), 治疗银屑病（或者类似疾病如牛皮癣）
2）Etanercept (依那西普), 用于治疗类风湿关节炎（RA）和强直性脊柱炎（AS）的生物DMARD药物（改善病情的抗风湿药）。 但是effect table给的是 【【Etanercept PASI : Psoriasis area and severity index】】