| Bernoulli trial | A single random event for which there are two and only two possible outcomes that are mutually exclusive and have a priori fixed (and complementary) probabilities of resulting. The trial is the realization of this process. Conventionally one outcome is termed a success and is assigned the score 1, the other is a failure and has the score zero. Thus the outcome might be 0 (no heads, one tail) or 1 (1 head, no tails). (05 Mar 2000) |
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| randomised controlled trial | A clinical trial that involves at least one test treatment and one control treatment, concurrent enrollment and follow-up of the test- and control-treated groups, and in which the treatments to be administered are selected by a random process, such as the use of a random-numbers table. Treatment allocations using coin flips, odd-even numbers, patient social security numbers, days of the week, medical record numbers, or other such pseudo- or quasi-random processes, are not truly randomised and a trial employing any of these techniques for patient assignment is designated simply a controlled clinical trial. (12 Dec 1998) |
| randomised trial | <statistics> A clinical trial in which patients have been randomly assigned to receive either the study drug or alternative treatment, in which neither the patient nor the physician conducting the study know which treatment is being given the patient, and in which the alternative to the study drug is a placebo, the study is conducted at several centres. (09 Oct 1997) |
| phase I clinical trial | <pharmacology> The earliest stage clinical trial for studying an experimental drug in humans. Phase I trials are generally comparatively small and are used to determine toxicity and maximum dose. They provide an initial evaluation of a drug's safety and pharmacokinetics-how the drug is absorbed, what tissues it reaches and how long it takes to leave the body. Such studies also usually test various doses of the drug (dose-ranging) to obtain an indication of the appropriate dose to use in later studies. The patients in these trials usually have advanced disease and have already received best available chemotherapy, therefore, seeing a repose is significant partially because this means there is a lack of cross-resistance between two anti-cancer drugs. (31 Dec 1997) |
| phase II clinical trial | <pharmacology> Usually focus on the activity of the new product as a single agent in a noncomparative, open study. (31 Dec 1997) |
| phase III clinical trial | <pharmacology> An advanced stage clinical trial that should conclusively show how well a drug works as compared to other treatments. Phase III trials are large, frequently multi-institution tests. They generally compare the relative value of the new drug compared with the current standard treatment and measure whether a new drug extends survival or otherwise improves the health of patients on treatment (clinical improvement) rather than just provide surrogate marker data. These studies generally last longer and are larger than phase II trials. (31 Dec 1997) |
| clinical trial | <pharmacology> Research study conducted with patients, usually to evaluate a new treatment or drug. Each trial is designed to answer scientific questions and to find better ways to treat individuals with a specific disease. (12 May 1997) |
| clinical trial, phase I | A pre-planned, usually controlled, clinical study of the safety and efficacy of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques based on a small number of healthy persons and conducted over the period of about a year in either the united states or a foreign country. (12 Dec 1998) |
| clinical trial, phase II | A pre-planned, usually controlled, clinical study of the safety and efficacy of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques based on several hundred volunteers, including a limited number of patients, and conducted over a period of about two years in either the united states or a foreign country. (12 Dec 1998) |
| clinical trial, phase III | A pre-planned, usually controlled, clinical study of the safety and efficacy of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques after phase II trials. A large enough group of patients is studied and closely monitored by physicians for adverse response to long-term exposure, over a period of about three years in either the united states or a foreign country. (12 Dec 1998) |
| clinical trial, phase IV | Planned post-marketing studies of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques that have been approved for general sale after clinical trials, phases I, II, and III. These studies, conducted in the united states or a foreign country, often garner additional data about the safety and efficacy of a product. (12 Dec 1998) |
| controlled clinical trial | A clinical trial involving one or more test treatments, at least one control treatment, specified outcome measures for evaluating the studied intervention, and a bias-free method for assigning patients to the test treatment. The treatment may be drugs, devices, or procedures studied for diagnostic, therapeutic, or prophylactic effectiveness. Control measures include placebos, active medicine, no-treatment, dosage forms and regimens, historical comparisons, etc. When randomization using mathematical techniques, such as the use of a random numbers table, is employed to assign patients to test or control treatments, the trial is characterised as a randomised controlled trial. However, trials employing treatment allocation methods such as coin flips, odd-even numbers, patient social security numbers, days of the week, medical record numbers, or other such pseudo- or quasi-random processes are simply designated as controlled clinical trials. (12 Dec 1998) |
| controlled trial | A clinical study in which one group of participants receives an experimental drug while another group receives either a placebo or an approved standard therapy. When participants do not know which group they are in, the trial is blinded. See: Double-Blind. (09 Oct 1997) |
| prospective, randomised, double-blind clinical trial | <statistics> A clinical trial in which the method for analysing data has been specified in the protocol before the study has begun (prospective), the patients have been randomly assigned to receive either the study drug or alternative treatment, and in which neither the patient nor the physician conducting the study know which treatment is being given to the patient. (13 Nov 1997) |
| human clinical trial | <pharmacology> Controlled clinical studies in human volunteers to test the safety and efficacy of pharmaceutical candidates. There are usually three distinct phases of human clinical testing: Phases I, II, and III. Phase I trials are safety studies of volunteers, usually healthy controls. Phase II trials are studies to confirm safety and study optimum dose and initial efficacy. Phase III trials are studies to prove safety and efficacy in a specific patient population. (14 Nov 1997) |