Clinical trial services refer to research investigations conducted on volunteering participants for testing new interventions for the objective of preventing, diagnosing, treating or managing different illnesses and medical conditions. Clinical research studies are carried out on humans with the aim of offering new therapies (drugs and treatments), diagnostic procedures and vaccines.
The proposed clinical study is reviewed ethically prior to the start of trials to ensure the safety of human volunteers. Trials are carried out on drugs to prove consistency and accuracy in the level of safety and effectiveness. Most trials are possible because of resources that have been invested in the clinical development of new therapies offered by pharma companies. All four stages of clinical trials, including testing and approval, need around ten to fifteen years for completion before licensing or marketing the drug.
Clinical trials are categorized into four stages, referred to as phases. These are defined by the FDA in case of drug testing. Early phase trials investigate the safety of a drug and the side –effects caused by it. Later trials examine whether a new drug is better than an existing one.
Phase 1 trial: safety
The four clinical trial phases after Phase 0, often overlap. Phases 1 to 4 must be completed before granting a license to a new drug.
Phase 1 involves:
Around 20 to 80 volunteers with good health (mostly healthy human volunteers and not diseased individuals, except in rare cases)
Verification of the most typical side effects of the drug.
Investigation of the metabolism and excretion of new drug
Phase 2: effectiveness
Phase 2 trials involve:
36 to 300 participants
Collection of preliminary data on the effectiveness of a drug in treating persons with a specific condition.
Controlled trials for comparing those using the drug to persons using a different drug or a placebo.
Continual evaluation of safety.
Study of side-effects in the short term.
Phase 3 trials: last confirmation of safety and effectiveness
When Phase 2 trials have confirmed the effectiveness of a drug, the sponsors and FDA will decide on how to conduct big-scale studies in Phase 3 by clinical trial consulting. This includes:
Around 300 to 3000 participants
Collection of additional information about effectiveness and safety.
Studies on varied populations
Examination of different dosages for determining the ideal amount for a prescription.
Usage of drug combined with other drugs for determining effectiveness.
Once this phase is completed, total information about the new drug is submitted to medical authorities seeking license to market.
Review meeting
After the FDA approves the product for marketing, there will be studies conducted on its production and post-marketing needs. Such studies are used by FDA to collect additional optimum use, safety and efficacy information regarding the new drug.
Application of new drug
After the review of the application and prior to Phase 4 trials, the reviewers of the FDA will either issue a response letter or approve the new drug. The sponsor of a new drug will finish an NDA (New Drug Application) to request the FDA to approve the marketing of the new drug in the US. The FDA can take up to 60 days to review the file.
After the filing of NDA, the following steps must take place:
Drug labeling
Inspection of facility
Approval of drug.
Phase 4 trials: studies about sales
Phase 4 trials are conducted after the drug has been approved for marketing. They involve:
More than 1000 patients
Comparing and combining with other treatments
Comprehensive experience in judging the efficacy and safety of a new drug in a huge group of patients.
Examining side-effects of the drug in the long term.
Detecting less typical adverse events
Cost-effectiveness of drug therapy.
In sum, after FDA approves the drug, the stage of post-marketing will start. The sponsor, typically the manufacturer, has to submit periodic updates on safety to the FDA. This is the way clinical trials help in new drug development.
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