Adaption and application of the four phase trials to traditional chinese medicines.

Four phases of trial are widely used in testing drugs, surgery, and diagnosis in Western medicine (WM). The staged testing process helps protect patients from unnecessary harms and control costs while assessing safety and efficacy. In this paper we adapt the four phase trials for traditional Chinese medicine (TCM). As TCM has been used in humans for thousands of years and there has been good preliminary clinical evidence on safety and efficacy for many of its therapies, in most cases its evaluation can start directly in humans, and preclinical laboratory research can be conducted in phase 4 trials after the efficacy is firmly demonstrated. Furthermore, unlike investigational drugs, TCM therapies are various in the certainty of their safety and efficacy and thus should not enter the evaluation process at the same stage. Unlike in WM, clarifying and refining PICO (patients, intervention, comparator, and outcome) are an important part of evaluation of newly designed TCM therapies. The incommensurability between WM and TCM causes additional difficulties in TCM trials regarding defining and choosing PICO, for which some suggestions are made. Observational studies seem to have a greater role in evaluation for TCM although the efficacy must be confirmed with randomized trials.