For those drugs that make it to through phase 3, a submission for marketing authorisations is made to the national regulatory authority in most countries. The process of drug development and marketing authorisation is similar across the world.
Despite the rigorous testing that has already taken place, approximately 10% of medicines will still fail at this stage. In doing this the drug company needs to generate sufficient safety and efficacy data to demonstrate an overall risk-benefit for the medicine to allow a submission to be made for a licensing application to the regulatory authority. The aim of these phase 3 trials is to reconfirm the phase 2 findings in a larger population and to identify the best dosage regimen.
Those candidates that make it through phase 2 will then be tested in a much larger population of patients in phase 3 trials, often 1,000 to 5,000 across multiple international sites. Most drugs that fail during clinical trials do so at Phase 2 because they turn out to be ineffective, have safety problems or intolerable side effects. The aim of phase 2 studies is to determine the most effective dose and method of delivery (for example, oral or intravenous), the appropriate dosing interval, and to reconfirm product safety. To avoid unnecessarily exposing a volunteer to a potentially harmful substance, these studies use the fewest number of patients possible to provide sufficient statistical power to determine efficacy, usually 100–500 patients, who are monitored and assessed continuously. Phase 2 studies examine the efficacy of a compound in volunteer patients who have the condition the drug is intended to treat. At least half of compounds will usually be considered safe enough to progress to phase 2 trials. Small doses of the compound will be administered to a group of 20 to 100 healthy volunteers who are closely supervised. If a CTA application is granted, the safety and pharmacology of a candidate drug will be tested first in a small group of healthy volunteers in a phase 1 trial. As organisations merge or are acquired, the numbers may decrease Clinical trials Number of different companies that have gained approval for at least one new molecular entity (NME).
#THE JOURNEY PROFESSIONAL#
Source: FDA / Regulatory Affairs Professional Society Number of companies with at least one FDA-approved new molecular entity (NME)
#THE JOURNEY TRIAL#
The company will put in a clinical trial application (CTA), which will be reviewed by medical and scientific experts, who will decide whether or not sufficient preliminary research has been conducted to allow testing in humans to go ahead. In the UK, approval by the Medicines and Healthcare products Regulatory Agency (MHRA) is required before any testing in humans can occur. Around half of candidates make it through this pre-clinical testing stage and these five to 10 remaining compounds are now ready to be tested in humans for the first time. Before any molecules are given to humans, safety and efficacy tests are conducted using computerised models, cells and animals. The next stage is to confirm that these molecules have an effect and that they are safe. As many as 10,000 compounds may be considered and whittled down to just 10 to 20 that could theoretically interfere with the disease process. Historically, researchers have looked to natural compounds from plants, fungi or marine animals to provide the basis for these candidate drugs but, increasingly, scientists are using knowledge gained from the study of genetics and proteins to create new molecules using computers. Once a potential target has been identified, researchers will then search for a molecule or compound that acts on this target.
This might be a gene or protein instrumental to the disease process that a new treatment could interfere with, for example, by blocking an essential receptor. It is through better understanding of disease processes and pathways that targets for new treatments are identified. The journey will have begun in a university laboratory where researchers, with grants from the research bodies or the pharmaceutical industry, have undertaken basic research to understand the processes behind a disease, often at a cellular or molecular level. The research and development journey of those new drugs that make it to market will have taken around 12 years and cost around £1.15bn. Journal of Pharmaceutical Health Services ResearchĮach year sees a couple of dozen new drugs licensed for use, but in their wake there will be tens of thousands of candidate drugs that fell by the wayside.International Journal of Pharmacy Practice.Antimicrobial resistance and stewardship.
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