Clinical trials are conducted on individuals to identify the functioning of a drug, its safety, tolerance and other effects of the drug within the body. The clinical trials are performed usually on one center in a country or if needed multiple centers in the country. With these clinical trials, newer products are brought into market. When a drug is introduced in the market, it has to undergo various trial phases. This includes phase 1 to phase 4. In phase 1 trial, the drug is used and checked for its tolerance and safety limit. With the data manipulated, the organization manages the data collected and carries it over to the phase 2 trials.

Phase 2 trial

The phase 1 trial is performed to a smaller group of individuals. Usually 20 – 80 people are involved in the phase 1 trials. Not all drugs tested in the phase 1-trial passes to the phase 2 trials. Sometimes the drugs may be eliminated due to adverse side effects with even the minimum dose range in the phase 1 trial itself. However, typically if a drug is tested to fail, it is through the phase 2 trials. Phase 2 trials typically involve a larger group of test subjects from 20 – 300.

The drugs effects of pharmacokinetics and pharmacodynamics are again tested, but with a larger group of volunteers. The drug tests fail and the drug is rejected if the test results are not as planned or the tolerance to the drug is high. The toxicity of the drug can be well identified with the phase 2 trials. Phase 2 trials continue to assess the phase 1 trials with the larger number of volunteers. The phase 2 trials include the early clinical preliminary studies to obtain the preliminary data results of the drug behavior for a particular symptom or a specific disease or a specific condition of patients. This test also helps to determine the short-term side effects of using the drug and the common risks associated with using the drug and the dosage of the drug. Phase 2 trials are well controlled and monitored under supervision of experts.

Characteristics

Phase 2 trials are sometimes written as phase II. The trials of the Phase II are even further classified as Phase II a and Phase II b.

Phase II a:
This test is performed to assess with the dosage requirements. The dose escalation study is employed here. The groups of test subjects are given various dosages of the drugs over a period. Their test results are manipulated over a period to identify any effect caused due to the dosage of the drug.

Phase II b:
This test is usually performed to study how well the drug works with the subjects at the doses specified. For example, some drugs may work well for with minor dosage for age limits 15-18, while some may require higher dosage, depending on age factors, stage of the disease or the symptoms. All such things are analyzed in the phase II b trials.

Sometimes trials of phase 1 and phase 2 are combined and performed together to study the effects of the drug. The trials of phase II are either case series, where the subjects are given treatments and tracked with a similar treatment that was used previously for curing the disease. Other design of the trial may include randomized trial 2, in which case, few patients randomly receive the drug/dosage and few others receive normal treatment / standard treatment for the cure of the disease. Such variety of patients or subjects are compared over a period and evaluated.

Aims of Phase II trials

The phase II trials aim in finding out,

1.    If the treatment of the phase 2 works good enough to pass to the Phase 3 trials
2.    Which stages or type of disease considered, the treatment works well. Example: cancer. Various types of cancer patients may be involved. The drug may perform well for leukemia rather than lung cancer. Under circumstances, the effectiveness of the treatment is evaluated specific to the type of the cancer.
3.    Greater information on the dose and side effects of the drug used and how to manage them

The phase 1 trials include the dosage and side effects. Still, the doctors may not know the side effects occurring in the patients, which he might consider is a normal effect. Such information and details on the side effects of the drug and the drug dosage are finally evaluated.

With a relatively more population of several hundred people, the phase 2 trials perform the task very similar to Phase 1 trials. However, when slight side effects are not identified in phase 1 trials, they are identified and the treatment is tested for its effectiveness. When the treatment is found as good as the one available now, or much better than the one, the drug passes on to the larger phase 3 trials.