clinical trial

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 [tri´al, trīl]
a test or experiment.
clinical trial an experiment performed on human beings in order to evaluate the comparative efficacy of two or more therapies. See also single blind, double blind, and triple blind.

clinical trial

a controlled experiment involving a defined set of human subjects, having a clinical event as an outcome measure, and intended to yield scientifically valid information about the efficacy or safety of a drug, vaccine, diagnostic test, surgical procedure, or other form of medical intervention.

Four phases of clinical trial are distinguished. Phase I trials usually involve fewer than 100 healthy volunteers who are exposed to a new drug or procedure. Such studies seek to establish optimal dosage and route of administration and to detect adverse reactions. Phase II trials generally involve 200-500 volunteers randomly assigned to control and study groups. These are pilot efficacy studies, with emphasis on immunogenicity in the case of vaccines, and on relative efficacy and safety in the case of drugs, procedures, and devices. Phase III trials, often multicenter, involve thousands of volunteers, randomly assigned to control and study groups. The aim is to generate statistically relevant data. Phase IV trials are conducted after a national drug registration authority (in the U.S., the Food and Drug Administration) has approved an agent for distribution or sale. They may explore specific pharmacologic effects, adverse reactions, or long-term effects.

clinical trial

A research study using consenting human subjects that tests the effectiveness and safety of a treatment, a diagnostic tool, or a prophylactic intervention.

clinical trial

A research study involving human subjects designed to answer specific questions about the safety and efficacy of a biomedical intervention (drug, treatment, device), or new ways of using a known drug, treatment or device.

clinical trial

Clinical medical trial, clinical research trial Research A controlled study involving human subjects, designed to evaluate prospectively the safety and effectiveness of new drugs or devices or behavioral interventions. See Drug discovery, IND, Phase I, II, and III studies.

clin·i·cal trial

(klini-kăl trīăl)
A controlled experiment involving a defined set of human subjects, having a clinical event as an outcome measure, and intended to yield scientifically valid information about the efficacy or safety of a drug, vaccine, diagnostic test, surgical procedure, or other form of medical intervention.

clinical trial

a scientifically controlled study under specific conditions, to test, for example, the effectiveness of a drug/ treatment.

Clinical trial

All new drugs undergo clinical trials before approval. Clinical trials are carefully conducted tests in which effectiveness and side effects are studied, with the placebo effect eliminated.

trial, randomized controlled (RCT) 

An experimental design used for testing the effectiveness of a new medication or a new therapeutic procedure. Individuals are assigned randomly to a treatment group (experimental therapy) and a control group (placebo or standard therapy) and the outcomes are compared. The trial is strengthened by 'blinding' or masking (single-blind, double-blind or triple-blind study) and cross-over design. RCT is the most accepted scientific method of determining the benefit of a drug or a therapeutic procedure. It represents the best evidence available, which is integrated into the final decision about the management of a condition by healthcare practitioners in what is called evidence-based healthcare. Syn. randomized clinical trial. See sampling; significance; study.

clinical trial,

n a trial based upon the scientific method in which a control group and a test group are compared over time in order to study a single, differing factor.
References in periodicals archive ?
And none of the five decent-quality randomized trials that examined medical marijuana for relief of tremor in MS patients was positive.
Laparoscopic Burch colposuspension versus tension-free vaginal tape: a randomized trial.
Every randomized trial is not a single statistical analysis in isolation.
During this period, the Ypsi-lanti (Michigan) Preschool Demonstration Project was distinctive in using a randomized trial to estimate the High/Scope program's effect on children's achievement, But few other preschool programs were evaluated using randomized trials in the '60s; the Cochrane Collaboration database lists only six trials.
Cocoa flavanols and multivitamins are two of the most promising and exciting nutritional interventions available, and this new randomized trial is the natural next step in advancing our understanding of their potential benefits," says JoAnn Manson, MD, chief of the division of Preventive Medicine at BWH.
Doxorubicin plus sorafenib vs doxorubicin alone in patients with advanced hepatocellular carcinoma: A randomized trial.
In one randomized trial involving patients with irritable bowel syndrome, STPP plus treatment as usual was significantly more effective than treatment as usual.
This month, the Amgen-sponsored 750-patient multicenter randomized trial began enrolling DMARD-naive patients with aggressive disease of recent onset.
Research from Cornell University on 42 iron-depleted, non-anemic women with hemoglobin values in the low-normal range who received either a placebo or 100 milligrams of ferrous sulfate (iron supplementation) per day for six weeks in a double blind, randomized trial showed significant differences on the effect of exercise training.
This study was limited because it was not a randomized trial where patients were randomly assigned to use protease inhibitors or not, with long-term followup with liver biopsy.
In a prospective, randomized trial of catheters in place for an average of 15 to 16 days, use of a hub with the antiseptic chamber reduced the incidence of infection (RR 0.
Most researchers and doctors are calling for a randomized trial of the device.

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