What are Clinical trials?
Clinical trials are research studies involving human subjects to know the safety, and effectiveness of medical interventions such as drugs, medical devices, biological products, and radiological procedures. People generally volunteer to take part in these studies and the conduct of these studies requires prior approval.
These studies are conducted in phases based on the outcome of the previous phase and are very carefully designed, and reviewed and these follow a rigorous protocol. Protocol describes all the aspects of the study like study objective, study methodology or design, and also some statistical considerations.
Note: According to WHO, people of all ages can participate in clinical trials including children.
Phase -1 Clinical trials are also called safety trials and these studies involve testing of new drugs in small groups of people, 20-100 healthy volunteers to determine the following
- Tolerability of the drug – safe dosage range
- Route of administration
- identify side effects
- Initial Pharmacokinetic information
Phase -2 studies are conducted in much larger volunteers and involves patients usually 100 – 500 patients. This study is conducted when results of Phase -1 studies show acceptable and following information is gathered from this phase of studies.
- Information on efficacy
- Monitor adverse effects
- determine the best dose
- Study duration – months to 2 years.
Phase -3 also known as confirmatory studies are conducted in much larger patient’s number usually 1000 – 5000 patients to confirm the effectiveness and monitor adverse reactions. These are conducted in different regions as per WHO information. Duration of studies ranges from 1 – 4 years.
Phase – 4 clinical trials are also known as post approval studies as these studies are conducted after marketing approval of the drug. These studies come under post marketing surveillance. These studies are ongoing studies.
Phase 0 studies are introduced recently, and these studies are also called microdosing studies and comes under exploratory IND application. These studies are conducted to ensure drug is promising for phase -1 studies.