Clinical Trial Phase 4
Introduction to Clinical Trial Phase 4
Clinical trials are often performed to identify the effect of a drug, its side effects, its treatment cure effectiveness, and dosage limits. Often drugs are verified for all these in all phases. Phase 1 is for basic test to determine the approximate range for the dosage of drug and to find the side effects. Phase 2 involves in proper estimation of the dosage and the side effects with over bigger population than the phase 1. Phase 3 involves in exact estimation of the dosage, side effects the drug causes and the treatment effectiveness in comparison with the methods that are already available in current standard. After all these tests are performed, still the drug may cause some side effect over a very long period of time. Such things are to be considered in phase 4.
Phase 4 Trial
Phase 1 trials evaluates completely on the dosage of the drug and the side effects. It does not actually calculate the exact amount of dosage that can be allowed on certain individuals. In Phase 2 trials, these things are taken into account, the dosage amount is set, and the side effects are analyzed for predetermined dosage level on a relatively larger test subjects. However, it is in the phase 3 trial, that the exact working of the drug and the comparative working of treatment available on market currently is analyzed. If the treatment found is as good as or much better than the one available on the market, the drug can be used for phase 3 trials. Phase 3 trials include test with over a large group of test subjects, divided into two. One group gets the new treatment, while the other gets the standard treatment. With the effectiveness in the drug, they can be compared and data are analyzed. Often, in market the phase 3 trials can be ongoing. Such on going trials are considered as phase 4. Phase 4 includes the post surveillance to the market trials.
With only the three phase trials (phase 1, 2 and 3), it is often enough to determine the treatment cure efficacy. However, sometimes, there could be patients who are not test subjects. In that case, the effects of the drugs on them are not known. Example, pregnant women are not likely to be the test subjects. Therefore, the drug effect on them is unknown or uncertain. So, the company or the sponsors take a special technical care in support of the drug after it is sold in the market. The regulatory authorities may themselves take steps to undertake the phase 4 trials. The companies also do phase 4 trials to identify newer potential market for the drug often. The safety surveillance of the phase 4 trial are designed so as to determine and identify any long or rare side effects due to the drug over a very large amount of time, which was not possible to be analyzed through the three phase trials. Any harmful effect identified or reported by the drug may require the drug never be sold on the market or sold under some regulations and restricted use.
Aims of phase 4 Trials
Phase 4 trials aims at finding out
1. How well the drug actually works with wide population rather than smaller amount of test subjects
2. The side effects that could be caused by used by various patients at various conditions, environment and more about the side effects.
3. What is the long-term risk associated with the drug?
4. What are the benefits with the drug, rather than the ones used currently?
Companies run phase 4 trials to know how efficient the drugs the doctors prescribe are from their product. These trials are performed once after the drug is sold in market. Phase 4 trials can also be used to identify the sale pattern of the drug and identify the market scope of the drug.
Conclusion:
Phase 4 is nothing but technical supports offered by the company willing to accept any reports and reconsider their product. Companies often use phase 4 studies to identify newer market and analyze the market scope of the product in comparison with the existing treatment.