Pharmacovigilance: A tool to accumulate longer-term safety data for drugs

Medicinal products are launched into the market after having tested their efficacy during clinical trials. Starting from preclinical studies to clinical studies various tests regarding safety and effectiveness are done. Many people or generally all think that at the time of approval of the drug, i.e. at the time approval of marketing authorisation, everything about the drug is known. But this is not all true. Clinical trials (Phase I – III) are considered as a floor test for any medicinal products because it is the first time that it is tested on humans. Similarly, Phase IV is considered as a real-world test as the medicinal product is tested in a real-world with real consumers. Primary reasons due to which there arises a need for Phase IV Post Marketing Surveillance are as follow:

  • Not possible to conduct clinical trials on more than a  few thousand patients
  • It is not worth continuously spend more money and time on pre-launch
  • Spending more on pre-launch would make the drug more expensive.

Despite thorough evaluation from the regulators about the product, there is also a need to consider the effectiveness of the drug. A clinical trial can evaluate efficacy but the real effectiveness is checked once the drug reaches the market and how it is used in a large population.

Once the drug is marketed, the role of Post Marketing Surveillance (PMS) teams begins to monitor the report of the adverse event for their product. The role of PMS is not limited to monitoring, after collection they assess the data to find any safety concerns. Manufacturers and Regulatory holds the meeting to evaluate the risk-benefit ratio of the concerned product and if they found risk overweigh the benefit, they may recommend the label change or withdrawal of the drug in severe risk.

The outcome of such studies could be pharmacoepidemiological information, signals, labeling changes with modified undesirable effects section, withdrawal. One should be cleared that every PMS study is a Phase IV study but not all Phase IV studies are post-marketing surveillance (PMS) studies. Thus PMS studies allow us to evaluate the whole profile of product including rare adverse event, drug-drug interactions, contraindications, and use in different ethnicity and race. As long as the product is marketed, PMS never ends.

The information available at the time of drug approval is incomplete and the safety of new drugs should be considered provisional. More information can be obtained as the drug ages into the market and a wide category of people use that product.

Author: Manan Shah (16FTPHDP41)

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