Which phase of a clinical trial assesses safety in healthy individuals?

Phase 1 of a clinical trial is specifically designed to assess the safety and tolerability of a drug or treatment in healthy individuals. This initial phase typically involves a small group of participants and focuses on determining the pharmacokinetics (how the drug is processed in the body) and pharmacodynamics (the effects of the drug on the body) of the compound being tested. Researchers monitor participants closely for any adverse effects, looking to establish the appropriate dosage range and understanding how the drug affects the body.

In contrast, subsequent phases have different focuses; Phase 2 trials evaluate the efficacy of the drug in a larger group of participants, often those who have the condition the drug is intended to treat, while Phase 3 trials compare the new drug to standard treatments or placebos in an even larger population to confirm its effectiveness and monitor adverse reactions. Phase 4, or post-marketing surveillance, occurs after a drug has been approved and is being used in the general population, providing ongoing safety information and identifying rare side effects that may not have been apparent in earlier trials.