GMP and GLP: quality you can prove
Two quality systems run underneath everything in development, and they are easy to confuse. Good Laboratory Practice (GLP) governs the *safety studies* — chiefly the preclinical toxicology — making them documented, traceable, and trustworthy. Good Manufacturing Practice (GMP) governs how the *drug is actually made*: every batch of the active pharmaceutical ingredient and finished product must be produced under controlled, validated, fully recorded conditions.
Winning regulatory approval
When Phase III succeeds, the sponsor assembles everything — every study, every batch record, every safety signal — into a marketing application (a New Drug Application or its biologics equivalent). Regulators such as the FDA or EMA review it in depth and decide whether the evidence shows the drug's benefits outweigh its risks for a specific indication and population. A positive decision is regulatory approval: legal permission to sell the medicine for that use.
Approval is narrow and conditional, not a blank cheque. It is granted for a defined indication, dose, and label; selling or promoting the drug beyond that is off-limits. Regulators also offer special pathways — for example orphan drug designation for very rare diseases — that give incentives and a smoother route when the patient population is too small to support a normal-sized program.
The job is not over: pharmacovigilance
Even a 5,000-patient Phase III program cannot reveal a side effect that strikes one person in 50,000. So safety surveillance continues for the entire life of the drug. This ongoing, real-world monitoring is pharmacovigilance: collecting and analyzing every reported adverse drug reaction from millions of treated patients to detect rare or delayed harms that trials were simply too small to find.