Glossary of Clinical Research - P

P

  • Patient advocate
A person who helps a patient work with others who have an effect on the patient's health, including doctors, insurance companies, employers, case managers, and lawyers. A patient advocate helps resolve issues about health care, medical bills, and job discrimination related to a patient's medical condition. (NCI)
  • Peer review
Review of a clinical trial by experts chosen by the study sponsor. These experts review the trials for scientific merit, participant safety, and ethical considerations. (NLM)
  • Per protocol set (Valid Cases, Efficacy Sample, Evaluable Subjects Sample)
The set of data generated by the subset of subjects who complied with the protocol sufficiently to ensure that these data would be likely to exhibit the effects of treatment, according to the underlying scientific model. Compliance covers such considerations as exposure to treatment, availability of measurements and absence of major protocol violations. (ICH E9)
  • Pharmacokinetics
The processes (in a living organism) of absorption, distribution, metabolism, and excretion of a drug or vaccine. (NLM)
  • Phase I trial
  • The first step in testing a new treatment in humans. These studies test the best way to give a new treatment (for example, by mouth, intravenous infusion, or injection) and the best dose. The dose is usually increased a little at a time in order to find the highest dose that does not cause harmful side effects. Because little is known about the possible risks and benefits of the treatments being tested, phase I trials usually include only a small number of patients who have not been helped by other treatments. (NCI)
  • Initial studies to determine the metabolism and pharmacologic actions of drugs in humans, the side effects associated with increasing doses, and to gain early evidence of effectiveness; may include healthy participants and/or patients. (NLM)
  • Phase 1 includes the initial introduction of an investigational new drug into humans. Phase 1 studies are typically closely monitored and may be conducted in patients or normal volunteer subjects. These studies are designed to determine the metabolism and pharmacologic actions of the drug in humans, the side effects associated with increasing doses, and, if possible, to gain early evidence on effectiveness. During Phase 1, sufficient information about the drug's pharmacokinetics and pharmacological effects should be obtained to permit the design of well-controlled, scientifically valid, Phase 2 studies. The total number of subjects and patients included in Phase 1 studies varies with the drug, but is generally in the range of 20 to 80. Phase 1 studies also include studies of drug metabolism, structure-activity relationships, and mechanism of action in humans, as well as studies in which investigational drugs are used as research tools to explore biological phenomena or disease processes. (21CFR312)
  • Phase I/II trial
A trial to study the safety, dosage levels, and response to a new treatment. (NCI)
  • Phase II trial
  • A study to test whether a new treatment has an effect (NCI)
  • Controlled clinical studies conducted to evaluate the effectiveness of the drug for a particular indication or indications in patients with the disease or condition under study and to determine the common short-term side effects and risks. (NLM)
  • Phase 2 includes the controlled clinical studies conducted to evaluate the effectiveness of the drug for a particular indication or indications in patients with the disease or condition under study and to determine the common short-term side effects and risks associated with the drug. Phase 2 studies are typically well controlled, closely monitored, and conducted in a relatively small number of patients, usually involving no more than several hundred subjects. (21CFR312)
  • Phase II/III trial
A trial to study response to a new treatment and the effectiveness of the treatment compared with the standard treatment regimen. (NCI)
  • Phase III trial
  • A study to compare the results of people taking a new treatment with the results of people taking the standard treatment (for example, which group has better survival rates or fewer side effects). In most cases, studies move into phase III only after a treatment seems to work in phases I and II. Phase III trials may include hundreds of people. (NCI)
  • Expanded controlled and uncontrolled trials after preliminary evidence suggesting effectiveness of the drug has been obtained, and are intended to gather additional information to evaluate the overall benefit-risk relationship of the drug and provide and adequate basis for physician labeling. (NLM)
  • Phase 3 studies are expanded controlled and uncontrolled trials. They are performed after preliminary evidence suggesting effectiveness of the drug has been obtained, and are intended to gather the additional information about effectiveness and safety that is needed to evaluate the overall benefit-risk relationship of the drug and to provide an adequate basis for physician labeling. Phase 3 studies usually include from several hundred to several thousand subjects. (21CFR312)
  • Phase IV trial
  • After a treatment has been approved and is being marketed, it is studied in a phase IV trial to evaluate side effects that were not apparent in the phase III trial. Thousands of people are involved in a phase IV trial. (NCI)
  • Post-marketing studies to delineate additional information including the drug's risks, benefits, and optimal use. (NLM)
  • Pilot study
The initial study examining a new method or treatment. (NCI)
  • Placebo
  • A placebo is an inactive pill, liquid, or powder that has no treatment value. In clinical trials, experimental treatments are often compared with placebos to assess the treatment's effectiveness. (NLM)
  • An inactive substance or treatment that looks the same as, and is given the same way as, an active drug or treatment being tested. The effects of the active drug or treatment are compared to the effects of the placebo. (NCI)
  • Placebo controlled study
  • A method of investigation of drugs in which an inactive substance (the placebo) is given to one group of participants, while the drug being tested is given to another group. The results obtained in the two groups are then compared to see if the investigational treatment is more effective in treating the condition. (NLM)
  • Refers to a clinical study in which the control patients receive a placebo. (NCI)
  • Placebo effect
A physical or emotional change, occurring after a substance is taken or administered, that is not the result of any special property of the substance. The change may be beneficial, reflecting the expectations of the participant and, often, the expectations of the person giving the substance. (NLM)
  • Placebo therapy
An inactive treatment or procedure that is intended to mimic as closely as possible a therapy in a clinical trial. Also called sham therapy. (NCI) The term also refers to psychotherapy that obtains its positive effect through the use of principles of social influence.
  • Population study
A study of a group of individuals taken from the general population who share a common characteristic, such as age, sex, or health condition. This group may be studied for different reasons, such as their response to a drug or risk of getting a disease. (NCI)
  • Preclinical
  • Refers to the testing of experimental drugs in the test tube or in animals - the testing that occurs before trials in humans may be carried out. (NLM)
  • Research using animals to find out if a drug, procedure, or treatment is likely to be useful. Preclinical studies take place before any testing in humans is done. (NCI)
  • Predictive factor
A situation or condition that may increase a person's risk of developing a certain disease or disorder. (NCI)
  • Prevention
In medicine, action taken to decrease the chance of getting a disease or condition. (NCI)
  • Prevention trials
Refers to trials to find better ways to prevent disease in people who have never had the disease or to prevent a disease from returning. These approaches may include medicines, vaccines, vitamins, minerals, or lifestyle changes. (NLM)
  • Preventive
Used to prevent disease. (NCI)
  • Primary endpoint
The main result that is measured at the end of a study to see if a given treatment worked (e.g., the number of deaths or the difference in survival between the treatment group and the control group). What the primary endpoint will be is decided before the study begins. (NCI)
  • Prospective
In medicine, a study or clinical trial in which participants are identified and then followed forward in time. (NCI)
  • Prospective cohort study
A research study that follows over time groups of individuals who are alike in many ways but differ by a certain characteristic (for example, female nurses who smoke and those who do not smoke) and compares them for a particular outcome. (NCI)
  • Clinical trial protocol
  • A study plan on which all clinical trials are based. The plan is carefully designed to safeguard the health of the participants as well as answer specific research questions. A protocol describes what types of people may participate in the trial; the schedule of tests, procedures, medications, and dosages; and the length of the study. While in a clinical trial, participants following a protocol are seen regularly by the research staff to monitor their health and to determine the safety and effectiveness of their treatment (NLM)
  • An action plan for a clinical trial. The plan states what the study will do, how, and why. It explains how many people will be in it, who is eligible to participate, what study agents or other interventions they will be given, what tests they will receive and how often, and what information will be gathered. (NCI)
  • A document that describes the objective(s), design, methodology, statistical considerations, and organization of a trial. The protocol usually also gives the background and rationale for the trial, but these could be provided in other protocol referenced documents. Throughout the ICH GCP Guidance, the term protocol refers to protocol and protocol amendments. (ICH E6)
  • Protocol Amendment
A written description of a change(s) to or formal clarification of a protocol. (ICH E6)

Read more about this topic:  Glossary Of Clinical Research