The road for investigational medicines to reach the patient is long and specific.One leg of this journey is represented by clinical trials where medicines are tested in the treatment of specific patients at medical treatment institutions (hospitals). Before medicines are used in clinical trials, they are tested in laboratories and preclinical studies.
Clinical trials are performed to discover or verify the effects of investigational medicines, to identify adverse reactions to investigational medicines and/or to investigate their absorption, distribution within the organism, metabolism and elimination from the organism.
It is important to verify what happens to investigational medicines in the human organism: how are they absorbed or broken down, how are they eliminated from the organism. These questions are addressed in phase I of clinical trials.
Phase II of clinical trials investigates what could be the most appropriate dosage of medicines.
In phase III of clinical trials, the efficacy of medicines in the treatment of specific illnesses is determined and the product is compared with other existing medicines in order to find out whether the new medicinal product is more effective.
Before starting a clinical trial, the sponsor (person or company responsible for performing the clinical trial) must receive authorisation from the State Agency of Medicines and Ethics Committee (list available in Latvian) for the conduct of a clinical trial in Latvia. The State Agency of Medicines and Ethics Committee are responsible for monitoring whether all patient rights are protected.
The number patients involved in clinical research grows with every clinical trial phase: phase I involves less patients and phase three involves more patients.