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What is a Clinical Research Organization?

Clinical Research Organization (CRO) is a company contracted by a pharmaceutical, biological or medical device manufacturer to manage clinical research studies and other services to support product development. There are four phases of clinical trials:

Phase I

  • Establishes the effect of a new drug in humans
  • Usually conducted on small (12-50) populations of healthy volunteers and/or patients
  • Determines a drug's toxicity, absorption, distribution, metabolism and excretion

Phase II

  • Tests a drug for safety and efficacy in a relatively small (200-500) population of patients
  • Patients are afflicted with the disease or condition for which the drug is being developed

Phase III

  • Tests the drug in relatively large populations of patients (500-5,000 or more)
  • Usually compares the new drug to placebo or to the standard therapy currently being used for the disease of interest
  • Results usually provide package insert info (Prescribing Information for doctors, and Patient Information materials)

Phase IV

  • Conducted after a drug has been approved by a Regulatory Authority
  • Compares the drug to competitor drugs, to explore additional patient populations or disease indications, or to further assess the safety of the drug

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