Regulatory approval is a review of the evidence a drug developer has assembled. Regulators examine whether the trials were run properly, whether the benefit is real and meaningful, and whether the risks are acceptable for the condition being treated. A drug for a mild condition must clear a higher safety bar than a drug for a life-threatening one, because the acceptable balance between benefit and risk depends on what is being treated. Approval is not a rubber stamp; it is a separate judgment made by people who did not run the trials.
Post-approval monitoring continues after the drug is on the market. Clinical trials involve thousands of patients at most, so harms that occur in one person in ten thousand may never appear during testing. Once a drug is prescribed widely, those rare effects can surface, and monitoring systems exist to detect them. A drug can be restricted or withdrawn after approval if new evidence shows the risks are greater than expected. This means the journey does not end at approval; the evidence base keeps growing.
Every stage in this journey is a filter. Discovery and design, preclinical testing, the three trial phases, regulatory approval, and post-approval monitoring each remove candidates that are unsafe, ineffective, or not clearly better than existing options. The stages are not bureaucratic obstacles; they are the mechanism by which medicine avoids harming people with drugs that only looked promising.