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Pharmacovigilance is the practice of detecting, assessing, understanding and preventing the adverse effects of medicines. Pharmacovigilance enhances patient safety and public health by providing reliable information on the risks and benefits of medicines.

Pharmacovigilance and Risk Assessment Committee

Phase 0 Trials

Phase 0 trials are conducted with sub-therapeutic doses to see if a medicine behaves in the body in the way that earlier laboratory studies (non-clinical trials) predicted.

Phase I Trials

Normally, the first studies in humans with a new medicine are Phase I trials.

Phase I trials are usually conducted in a small number of healthy volunteers (although some trials recruit patients). The aim of Phase I trials is to find out the safe dose range, and to look for any side effects. The initial dose given will be very small, and gradually increased if no or only mild side effects are observed. A new medicine has to meet certain pre-set requirements before it can continue to Phase II trials. Phase I, II, and III trials are commonly known together as 'clinical development'.

Phase II Trials

Phase II trials are generally the first studies with a new medicine in patients. They are usually conducted in a small number of patients who are monitored closely. These trials are often larger than Phase I trials.

Phase II studies are designed to find out if the medicine has a beneficial effect on the disease in question: They might compare the new medicine to an existing treatment or to a placebo. They also set out to determine the best dose range and how often the medicine should be given, and investigate the best way to manage any side effects.

A new medicine has to meet certain pre-set requirements before it can continue to Phase III trials. Phase I, II, and III trials are commonly known as 'clinical development'.

Phase III Trials

Phase III trials are generally large (comprising thousands of patients) and involve several study sites, sometimes in different countries. They compare the new medicine to existing treatments or a placebo, in order to show the safety and efficacy of the new medicine. Most Phase III trials are randomised.

Phase I, II, and III trials are commonly known as 'clinical development'. Phase III studies are critical to applications for marketing authorisation.

Phase IV Trials

Phase IV trials are usually conducted after marketing authorisation is granted and the medicine is in general use.

Phase IV studies are also known as post-authorisation safety studies (PASS) and may be voluntary or imposed by the regulatory authorities. The possibility also exists of requesting the marketing authorisation holder to conduct post-authorisation efficacy studies (PAESs) in order to complement efficacy data that are available at the time of the initial authorisation. Phase IV studies collect additional information about side-effects and safety, long-term risks and benefits, and/or how well the medicine works when used widely.

Physical health

Physical health is defined as the condition of your body, taking into consideration everything from the absence of disease to fitness level.

Physical health is critical for overall well-being, and can be affected by:

  • Lifestyle: diet, level of physical activity, and behaviour (for instance, smoking)
  • Human biology: a person™s genetics and physiology may make it easier or harder to achieve good physical health

Pivotal Study

A pivotal study is normally a Phase III study of a new intervention which is designed to provide the necessary data for a decision by a regulatory agency.

For example, the European Medicines Agency (EMA) requires specific safety and efficacy information about new medicines before it can issue a marketing authorisation. A pivotal study will be conducted to Good Clinical Practice standards. It will generally be randomised and controlled (an RCT). It will be of adequate size and, whenever possible, double-blind.


In clinical trials, a placebo is a medicine that contains no active ingredients. Placebos have no known medical effects.

The 'placebo effect' is a benefit or side effect perceived by patients taking a placebo, despite the fact that no medicine is involved.

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