PHASE III : STATISTICAL EVALUATION ::
Here the results obtained in Phase II at limited centers are confirmed at more centers and are subjected to the statistical analysis if the results are in accordance with each other the new drug is released for the market
Phase III studies are randomized controlled trials on large patient groups (300-3000 or more depending upon the condition ) and are aimed at being the definitive assessment of the efficacy of the new therapy in comparison with current Gold Standard treatment Phase III trials are the most expensive time consuming and difficult trials to design and run especially in therapies for chronic conditions once a drug has proven satisfactory over phase III trials the trial results are usually combined into a large document containing a comprehensive description of the methods and results of human and animal studies manufacturing procedures formulation details and shelf life This collection of information makes up the regulatory submission that is provided for review to various regulatory authoritiesin different countries for marketing approval
It is also common practice with many drugs whose approval is pending that certain phase III trials will continue This typically serves to provide lifesaving products after involvement in a clinical trial until the marketed product can be obtained other reasons for performing trials at this stage include attempts at label expansion to prove additional efficacy for uses beyond the original use for which the drug was designed to obtain additional safety data or to support marketing claims Studies in this phase are by some companies categorised as Phase IIIB studies
while not required in all studies it is typically expected that there be at least two successful phase III trials proving drug s safety and efficacy for approval from the standard regulatory agencies (FDA DCGI etc)
As mentioned above phase II and phase III trials are normally Randomized trials A randomized controlled trial (RCT) is a scientific procedure most commonly used in testing medicines or medical procedure it is a trial that uses randomized control This is considered the most reliable form of scientific evidence because it eliminates all forms of spurious causality (Some people call it a randomized control trial ) The term RCT is also sometimes used to abbreviate randomized clinical trial which is a form of clinical trial However randomized control trials are used in other sectors (e.g. judicial educational social ) so the clinical sector does not have a monopoly of this technique The basic idea is that treatments are allocated to subjects at random This ensures that the different treatment groups are statistically equivalent Trials are used to establish average efficacy of a treatment as well as learn about its most frequently occurring side effects This is meant to address the following concerns First effects of a treatment may be small and therefore undetectable except when studied systematically on a large population Second biological organisms (including humans ) are complex and do not react to the same stimulus in the same way which makes inference from single clinical reports very unreliable and generally unaceptable as scientific evidence Third some conditions will spontaneously go into remission with many extant reports of miraculous cures for no discernible reason Finally it is well -known and has been proven that the simple process of administering the treatment may have direct psychological effects on the patient some times very powerful what is known as the placebo effect
Randomized trials are employed to test efficacy while avoiding these factors Trials may be open blind or double -blind
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