Discovery and development of medicines
By studying a disease, scientists can understand what causes the illness and which cells and their receptors are involved. This research can help scientists to develop new medicines to treat diseases and to relieve symptoms.
![A slide describing the decision points and development steps in the research and development (R&D) of medicines. There are four main phases of medicines R&D: Research & Discovery, Non-clinical development, Clinical Development, and post-approval life-cycle management and pharmacovigilance. Reasearch and discovery lasts from three to six years, from the development of the strategic framework to lead identification, at which point the number of medicinal candidates has been narrowed from approximately 8,000 to 250. Non-clinical development also occurs within the first three to six years, from the start of lead optimisation to the end of the non-clinical development period, at which point the 250 candidates have been narrowed down to just five medicines. The next six to seven years are occupied by clinical development. Clinical development is split into three phases: I, II, and III. After the completion of Phase I, the first trials in humans (with approximately 20 to 100 participants), phase IIa begins with a proof of concept study. Phase IIa usually sees testing in 100 to 500 participants. When the Proof of Concept has been confirmed, Phase IIb begins, with clinical trials of between 1,000 and 5,000 participants, narrowing candidates down to just one medicine. Phase III is the largest of trials, and ends in the submission of the medicine for regulatory review. The regulatory review process can take between two to five years. Only after approval from the regulatory boards can the medicine be launched and new therapies made accessible to patients. The review process and launch of the medicine mark the beginning of the post-approval life-cycle management and pharmacovigilance phase, during which change is monitored and managed, and which lasts until the medicine is terminated and removed from the market.](https://toolbox.eupati.eu/wp-content/uploads/sites/4/2020/07/development-steps-in-medicines-v1_EN.png)
It takes well over 10 years of careful planning and research for a medicine to go from molecule to a marketable treatment.
From discovery of molecules to development of medicine
Once a target receptor molecule or an enzyme has been identified, scientists begin to look for potential compounds that will interact with the target to correct disease-related activity. This research can involve searching through ‘libraries’ of millions of molecules that have been developed by pharmaceutical companies. Large-scale testing of potentially useful molecules from the ‘libraries’ (also called high-throughput screening), is conducted to discover which ones will bind to the target receptor.
![An image of part of the high-throughput screening process. A machine with many pipettes and vials allows the simultaneous testing a large amount of potentially useful molecules.](https://toolbox.eupati.eu/wp-content/uploads/sites/4/2020/07/high-throughput-screening-v1.jpeg)
Part of the high-throughput screening process. A machine with many pipettes and vials allows the simultaneous testing a large amount of potentially useful molecules.
The most promising molecules discovered will then be modified in many ways to try to make an effective medicine that has few negative side effects. When scientists find a molecule with the desired properties of a potential medicine, testing in animals is often necessary. If this testing shows the medicine is safe, the process will continue to testing in humans. Finally, regulatory authorities will consider whether or not to approve the medicine for use in humans.
The ideal molecule should:
- reach the right part of the body to hit the target (ideally only the target and no other healthy cells or enzymes)
- have few side effects
- be absorbed by the body
- remain in the body long enough to have the desired effect
- be able to be manufactured in sufficient quantities
- have a long shelf-life as a medicine.
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A presentation describing the discovery and development of medicines, which can be adapted for own use.
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