Drug clinical trial phase

All drugs on the market have gone through three stages: preclinical research, new drug clinical research application, and clinical research. They are tested by a large number of testers to observe whether the drugs really have the expected effects and whether the drug's tolerability is acceptable to people. Only after passing these three stages can the drugs be mass-produced. The purposes of the phases of drug clinical trials vary, so you can learn about them.

A drug clinical trial refers to any systematic study of a drug conducted on humans (patients or healthy volunteers) to confirm or discover the clinical, pharmacological and/or other pharmacodynamic effects, adverse reactions and/or absorption, distribution, metabolism and excretion of the investigational drug, with the aim of determining the safety and efficacy of the investigational drug.

Drug clinical trials are generally divided into Phase I, II, III, and IV clinical trials and drug bioequivalence trials and human bioavailability trials.

1. Clinical trials are conducted in phases, and each phase has its own different purpose.

1. Phase I clinical trial: preliminary clinical pharmacology and human safety evaluation test. Observe the human body's tolerance and pharmacokinetics of new drugs to provide a basis for formulating dosing plans. This phase requires a smaller number of cases, generally 20-80 cases.

2. Phase II clinical trial: the preliminary evaluation stage of therapeutic effects. Its purpose is to preliminarily evaluate the therapeutic effect and safety of the drug on patients with the target indication, and also to provide a basis for the design of Phase III clinical trials and the determination of dosing regimens. The research design at this stage can take a variety of forms, including randomized, blinded, controlled clinical trials, depending on the specific research objectives. The number of cases in this phase is greater than that in the first phase, generally ranging from 100 to 300 cases.

3. Phase III clinical trial: the stage of confirming the therapeutic effect. Its purpose is to further verify the therapeutic effect and safety of the drug on patients with the target indication, evaluate the benefit-risk relationship, and ultimately provide sufficient basis for the approval of the drug registration application. The trial should generally be a randomized, blinded, controlled trial with sufficient sample size. The number of cases in this period is larger, generally 1000-3000.

4. Phase IV clinical trial: The applied research stage conducted independently by the applicant after the new drug is launched on the market. Its purpose is to examine the efficacy and adverse reactions of drugs under conditions of widespread use; to evaluate the benefit-risk relationship of using drugs in general or special populations; to improve dosage, etc.

2. Precautions

A bioequivalence test refers to a human trial that uses the bioavailability research method and pharmacokinetic parameters as indicators to compare the same or different dosage forms of the same drug to see if there are statistical differences in the degree and rate of absorption of the active ingredients under the same test conditions.