Development of a drug: here’s how it is done
Research begins with an idea as to how an illness can be combatted. During the initial phase experimental studies are done to determine if the substance has the requisite properties for reaching the target towards which the therapy is to be directed. The work is time-consuming and many substances are tested before one or more candidate drugs can be identified. As early as possible, the idea and/or candidate drugs are patented. Then, the selected substances are studied and documented, so that they can be administered to humans. The preclinical phase normally takes from three to five years. Subsequently, studies are conducted in the clinical phase, as follows:
Phase I. Studies aim to determine whether the substance can be administered to humans with an acceptable level of safety. The doses that can be given are defined, as well as how the substance is taken up, how it is distributed in the body, if it is broken down and how it is removed from the body.
Phase II. The substance is tested on patients suffering from the disease/condition that is to be treated with the aim of demonstrating that it has the postulated effect. An optimal dose is determined and researchers continue to document safety and tolerability.
Phase III. Major studies are conducted, usually on large groups of patients, in which the efficacy of the substance is assessed in comparison with that of current standard treatment forms, if such exist, or with a placebo. If the product has an equivalent or better effect, it is developed further. Concurrently, a range of other studies are conducted with respect to safety, interaction with other drugs, preparation forms, etc. After the clinical studies the documentation is compiled in a registration application that is submitted to regulatory authorities in the country/countries in question.
Phase IV. After approval, so-called Phase IV-studies are conducted to document how the drug performs in an everyday clinical setting. Regulatory authorities sometimes require that, for approval, the company must, within a given period, generate certain specific knowledge about the drug, something for which Phase IV studies are often used.