Glossary of Clinical Research - O

O

• Objective improvement

An improvement that can be measured by the health care provider (NCI)

• Objective response

A measurable response. (NCI)

• Observation

Closely monitoring a patient's condition but withholding treatment until symptoms appear or change. Also called watchful waiting, active surveillance, and expectant management. (NCI)

• Observational study

A type of study in which individuals are observed or certain outcomes are measured. No attempt is made to affect the outcome (for example, no treatment is given). (NCI)

• Off-label

• Describes the legal use of a prescription drug to treat a disease or condition for which the drug has not been approved by the U.S. Food and Drug Administration. (NCI)
• A drug prescribed for conditions other than those approved by the FDA. (NLM)

• Open label study

• A type of study in which both the health providers and the patients are aware of the drug or treatment being given. (NCI)
• A clinical trial in which doctors and participants know which drug or vaccine is being administered. (NLM)

• Orphan drugs

An FDA category that refers to medications used to treat diseases and conditions that occur rarely. There is little financial incentive for the pharmaceutical industry to develop medications for these diseases or conditions. Orphan drug status, however, gives a manufacturer specific financial incentives to develop and provide such medications. (NLM)

• Outcome

A specific result or effect that can be measured. Examples of outcomes include decreased pain, reduced tumor size, and improvement of disease. (NCI)

• Outpatient

A patient who visits a health care facility for diagnosis or treatment without spending the night. Sometimes called a day patient. (NCI)

• Over-the-counter drug

A medicine that can be bought without a prescription (doctor's order). Examples include analgesics (pain relievers) such as aspirin and acetaminophen. Also called nonprescription and OTC. (NCI)