Abstract: Clinical trials are used throughout the world to determine the safety and efficacy of a chemical or biological compound with respect to its actions on symptoms or a known disease process. Trials are closely monitored by an investigator and the pharmaceutical company involved in the research and development of a medicinal product. But, the process also benefits from autonomous review by Independent Review Boards, Ethics Committees and drug safety firms. This is where pharmacovigilance fits into this process; to provide an extra level of security to ensure that safe and effective products reach patients. As part of the global healthcare and pharmaceutical system, manufacturers, drug developers, and investigators all have the responsibility to provide the best possible care for the patients and consumers around the world.

 
Pharmacovigilance, also referred to as drug safety, is the science of understanding the adverse effects caused by a drug and assessing whether the benefit will outweigh the risk. This includes detection of adverse effects during the clinical trial and post marketed phases, monitoring and updating the risk-benefit ratio based on relevant findings, prevention or minimization of adverse effects and, most importantly, harmonized communication of these findings to the affected global regulatory authorities in a timely manner.

 
There are four distinct phases of a drug’s clinical trial cycle after animal studies have been completed. Phase I trials examine the pharmacological and metabolic actions of a medication when first used by human subjects. These trials involve a very small group (<100) of healthy volunteers or volunteers with the targeted disease. The studies are unblinded, uncontrolled and usually last less than one month. Phases II trials observe the efficacy, dose response and tolerance, and adverse effects of the drug. These trials include a larger group of subjects (normally 200-300) with the targeted disease process and have very well defined and controlled inclusion/exclusion criteria. Phase II trials are usually placebo-controlled or active-controlled comparison studies and last several months. Phase III trials are the final step before the drug developer can apply for marketing authorization. The group of subjects with the targeted disease may range from several hundred to several thousand volunteers who are followed for many years. Phase III trials focus on the drug’s safety and efficacy in diverse sub-groups with broader inclusion/exclusion criteria including concomitant medications and concurrent diseases than Phase II trials. The risk-benefit ratio is developed, monitored and updated accordingly. After successful completion of Phase III clinical trials and authorization for marketing, the pharmaceutical company may conduct phase IV trials in order to continue to monitor the drug on a much larger scale and in a less controlled real world environment.