Phase IV clinical trials

Phase IV. Studies or trials conducted after a medicine is marketed to provide additional details about the medicine s efficacy or safety profile. Different formulations, dosages, durations of treatment, medicine interactions, and other medicine comparisons may be evaluated. New age groups, races, and other types of patients can be studied. Detection and definition of previously unknown or inadequately quantified adverse reactions and related risk factors are an important aspect of many Phase IV studies. If a marketed medicine is to be evaluated for another (i.e., new) indication, then those clinical trials are considered Phase II clinical trials. The term postmarketing surveillance is frequently used to describe those clinical studies in Phase IV (i.e., the period following marketing) that are primarily observational or nonexperimental in nature, to distinguish them from well-controlled Phase IV clinical trials or marketing studies. 

Phase IV clinical trials and prospective observational cohort studies have been criticised as no more than promotional devices used by aggressive pharmaceutical companies. The fact that misuse has sometimes happened should not be allowed to obscure the greatly more important needs of safety evaluation and the further development of new and improved therapies. A set of guidelines has been published in the United Kingdom which are specifically intended to provide the high standards of study design and methodology necessary for observational cohort studies. It is to be hoped that similar procedures will be adopted internationally. 

Phase IV Clinical Trials Conducted after approval of a drug has been obtained to gather data supporting new or revised labeling, marketing or advertising claims. 

In some cases approval may be given under the condition that further clinical trials must be performed to address unknown aspects, such as efficacy and safety in population subgroups. These trials are referred to as post-marketing or Phase IV clinical trial. 

Does it work and is it safe in aii patients (Phase IV clinical trials or post-marketing surveillance)... 

Table 10.1 Typical goals and tactics of phase IV clinical trials...

A variety of regulatory approaches are needed when adding to the range of formulations, and each, in turn, dictates a different phase IV clinical trial design. When the route of administration does not change (e.g. the wafer vs. tablet example above), then orthodox bioequivalence and absence of formulation-dependent intolerability might be all that is needed. A pseudo-phase I... 

A common system of categorization for preap-proval clinical trials includes Phase 1, Phase 11, and Phase 111 clinical trials (Phase IV clinical trials are conducted postapproval to collect additional information about a marketed drug). Phase 1, 11, and 111 clinical trials can be summarized as follows ... 

The efficacy of naltrexone for use in alcohol dependence has been investigated in three placebo-controUed clinical trials, and is currently being evaluated in several phase IV clinical trials. Patients randomized to receive 50 mg naltrexone daily for 12 weeks were more likely to remain abstinent and to avoid relapse to heavy... 

I Phase IV clinical trials refer to the various methods of surveillance (see below) to establish the frequency of any serious or rmexpected adverse effects of a drag once it has been licensed and introduced into regular clinical practice ... 

Phase IV clinical trials are post-marketing approval trials to monitor the efficacy and side effects of the drug in an uncontrolled real-life situation. This is also known as a post-market surveillance trial. Information about the effectiveness of the drug compared with established treatment, side effects, patient7s quality of life, and cost-effectiveness is collated. 

Phase III and phase IV clinical trials involve larger populations. During phase III trials, which can last two to eight years, a drug is often brought to market. Phase IV studies continue after the drug is being marketed. 

As with other new technologies, it is possible that the first licensed DNA vaccines will receive conditional approval. In this case, postlicensing Phase IV clinical trials may be requested to address and monitor remaining unresolved issues by specific studies or on a larger scale. Furthermore, as for any medicinal product, effective and intensive pharmacovigilance procedures will be used to closely monitor the appearance of any side effects, while the vaccine is applied widely and routinely. 

Further investigation to determine if a medication may have other uses is the purpose of a Phase IV clinical trial. 

The scope and goals of Phase IV clinical trials are broader than Phases I-III. In general, the trials are larger (often having up to several thousand patients), the inclusion/exclusion conditions are less restrictive, and the end-points may be less objective (e.g. quality of life ). 

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