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Preclinical research phases
Explorative phase – identifying active hit compounds.
Lead identification – identifying feasible compounds with
drugable potential.
Optimization phase – this stage is focused on producing the optimal compound/compound class possessing pharmaceutical potential. Towards the end of this phase, CDs (candidate drugs) are designated.
IND – late preclinical development – the final working phase before designated CDs enter clinical studies. This phase is authority regulated and includes extensive safety studies, pharmacokinetics, metabolism studies and is when the first kilogram-scale amounts of the active compound are produced. Applications for regulatory approval for
clinical trials of designated CDs are also filed.
Clinical development phases
Phase I – trials of the CD on healthy volunteers, usually involving 20 to
50 individuals. Phase I is divided into two parts. In phase Ia, a single dose of increasing strength, then repeat doses, are administered to healthy volunteers. Sometimes, phase Ib studies are conducted, on a small
group of patients for a short period.
Phase II – the first trials on patients suffering from the target disorder. Studies usually encompass 100 to 500 patients, with efficacy and safety assessed. Phase II is also divided into two parts. Phase IIa is intended to demonstrate that the course of the disease can genuinely be influenced. Phase IIb demonstrates the efficacy of various doses on the course of
the disease.
Phase III – comparative trials on a large sample of patients to measure efficacy in relation to other treatments, if any exist, as well as safety.
NDA – New Drug Application, which often requires Phase III trials as documentation.
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