What are the steps and principles of clinical trials?

Clinical trials are an essential step before a drug is marketed, and they are designed to confirm the effectiveness and safety of the drug. Due to the special nature of the method, means and purpose of drug clinical trials, it must follow the three basic principles of ethical and moral principles, scientific principles, GCP and current laws and regulations. Moreover, drug clinical trials must have sufficient scientific basis. Before conducting human trials, the purpose of the trial and the problems to be solved must be carefully considered, and the expected benefits and risks to the subjects and public health should be weighed, and the expected benefits should exceed the possible damages. The choice of clinical trial methods must be consistent with scientific and ethical requirements.

Drug clinical trials are generally categorized into phase I, II, III, and IV clinical trials.

Phase I clinical trials: preliminary clinical pharmacology and human safety evaluation tests. Observe the degree of tolerance of the human body to the new drug and the pharmacokinetics of the new drug in the body, in order to provide a basis for the development of drug delivery programs.

Phase II clinical trials: preliminary evaluation of the therapeutic effect and safety of the drug in patients with the target indications, which also includes providing a basis for the design of phase III clinical trials and the determination of the dosage regimen. The study design in this phase can take various forms, including randomized blinded controlled clinical trials, depending on the specific research objectives, and clinical trials are conducted by drug clinical trial organizations.

Phase III clinical trials: is the continuation of phase II clinical trials, the purpose is to further verify the therapeutic effect of the drug on the target indications of patients and safety, evaluation of the relationship between the benefits and risks, and ultimately for the approval of the application for registration of the drug to provide a sufficient basis. The trial should generally be a randomized blinded controlled trial with sufficient sample size.

Phase IV clinical trials: the applicant's own applied research phase after the new drug is listed, also known as post-marketing surveillance. Its purpose is to examine the efficacy of the drug in a wide range of conditions of use, indications and adverse reactions; evaluation of the relationship between the benefits and risks of use in the general or special populations; improve the dosage of the drug, to guide the rational use of clinical drugs.