Clinical trials are performed to test the effectiveness of the drug on human subjects and to find the acceptable dosage of usage of the drug. In addition, clinical trials are performed to evaluate the side effects caused by the drug. They also lead to solutions on how to manage them. Clinical trials also determine the quality of the drug from the manufacturers and its effectiveness in curing the disease or symptom under consideration. There could be better ways other than the one under study, all such possibilities are analyzed, and the data are managed well for the future studies. With phase 1 and phase 2 trials, the drug has passed the preliminary tests in identifying the side effects and dosage to be given to a patient. Not only with these, it has passed on to the phase 3 trial because it is as good as the drugs already available or much better treatment than the ones available for cure.

Phase 3 Trial

Unlike Phase 1 and Phase 2 Trials which involved only relatively fewer number of subjects, this phase 3 trial is larger and requires a large number of test subjects say from 300 – 3000 on average. The amount of test subjects depends on the disease under consideration. The phase 3 trials assure in developing the trials to find the definite amount of dosage and side effects caused by the drugs in comparison with the currently available ‘best standard treatment’ the ‘gold’ treatment. They require very large amount of test subjects and are multi centered. Test subjects may be subjected to the trials from various centers in the country or in various countries. Due to its vast requirement, it is highly expensive and time consuming. Along with these, it is highly complex to design and conduct trials, since the definite value of dosage and side effects are to be predicted.

The phase 3 trials continue to exist and test subjects even while the regulatory information for the usage of the drug is submitted to the concerned regulatory agency. This is an opportunity to serve the medicines which could be life saving for the patients considered until the drug is actually available on market for purchase. The phase 3 trials are alternatively performed for the sponsors for what they call as ‘label expansion’. The label expansion is to include the patients or animals, for them the drug works other than the patients considered for the disease under study. For example, a drug might have developed to cure body pain, but it can also be used on mild doses for headache, then the label expansion will include this information. The label expansion cannot be done simply, some phase III b companies take phase III b studies to support data for the label expansion procedure for the medical company.

Once a drug is approved, the information on the tests conducted, methods, test subjects, trials, designs, and the conditions involved are all compiled together which forms the regulatory submission. The entire compilation includes the method of preparation, its effects on animals, humans, formula, and manufacturing process. The regulatory authorities verify these and may approve the company or sponsor for marketing of the drug. Once in the market also, the drug is constantly under the phase III trial. If the drug is well and does not prove any adverse side effects, the drug goes on sale on the market for the consumers. However, if an issue arises on the side effects the drug caused or the toxicity of the drug is identified or a consumer reports an abnormal result of using the drug, the drug has to be recalled from the market from future sale.

Aims of Phase 3 trials

Phase 3 trials are aimed to find out
1.    How effective is the current treatment in comparison with the already existing best standard of treatment
2.    Idea to get a broader view on how the treatment works as a whole
3.    All the phase trial results are sometimes combined to form the Meta analyses.
4.    The side effects of the drug once released onto the market

Conclusion

With combining the results from phases 1, 2 and 3 trials, it is easy to determine how well the treatment identified now works in comparison with the treatment already available. By using these results, they can be used for estimating the effectiveness of the drug to all kind of people who can use it. In addition, the toxicity of the drug can be reported by public and the company can revise it.