What are Clinical Trials?

Clinical trials are sets of studies in the development of a drug that generate safety and efficacy data for health interventions. They’re conducted only after satisfactory information has been gathered on the safety of the intervention, and approval from a health authority to conduct the clinical trial(s) is granted.

Food and Drug Administration (FDA) categories for describing the clinical trial of a drug based on the study’s characteristics, such as the objective and number of participants. There are four phases:1

  • Phase 1: Studies that are usually conducted with healthy volunteers and that emphasize safety. The goal is to find out what the drug’s most frequent and serious adverse events are and, often, how the drug is metabolized and excreted.
  • Phase 2: Studies that gather preliminary data on effectiveness (whether the drug works in people who have a certain disease or condition). For example, participants receiving the drug may be compared with similar participants receiving a different treatment, usually an inactive substance (called a placebo) or a different drug. Safety continues to be evaluated, and short-term adverse events are studied.
  • Phase 3: Studies that gather more information about safety and effectiveness by studying different populations and different dosages and by using the drug in combination with other drugs.
  • Phase 4: Studies occurring after FDA has approved a drug for marketing. These including postmarket requirement and commitment studies that are required of or agreed to by the sponsor. These studies gather additional information about a drug’s safety, efficacy, or optimal use.

As one of the industry leaders in innovation and research related to the area of pain management, our physicians and scientists have expertise in neurology, internal medicine, anesthesiology, pharmacology, pharmaceutics, toxicology, molecular biology, combinatorial chemistry, and other scientific disciplines. They are collaborating to discover new treatment options for the management of pain and improve the effectiveness of existing therapies.

If you are interested in participating in one of Purdue’s upcoming clinical trials, please talk to your health care professional. Your participation will directly lead to further advancement of the current treatment options.

Ask your healthcare professional to contact Purdue Medical Services at 888-726-7595, option #1, for more information on how to be part of our research.


1 ClinicalTrials.gov Protocol Data Element Definitions – Draft. [webpage]. Bethesda (MD): National Library of Medicine (US). December 2015. https://prsinfo.clinicaltrials.gov/definitions.html#StudyPhase. Accessed January 2016.

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