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  • Drug Development Process

    The drug development process requires many resources. Before a new drug is marketed, it must undergo extensive testing and be approved by regulatory agencies in the countries where it will be marketed. Human clinical trials generally consist of four phases, starting on a small scale to assess safety and then expanding to larger trials to test efficacy.

    Phase I
    Phase I trials involve testing the drug on a limited number of healthy individuals, typically 20 to 80 people, to determine the drug’s basic safety and pharmacological data. This phase of the drug development process lasts an average of six months to one year.

    Phase II
    Phase II trials involve testing a small number of volunteer patients, typically 100 to 200 people who suffer from the targeted disease or condition, to determine the drug’s effectiveness and dose response relationship. This phase of the drug development process lasts an average of one to two years.

    Phases IIIa-b
    Phase IIIa trials involve testing large numbers of patients, typically several hundred to several thousand persons, to verify efficacy on a large scale as well as safety. Phase IIIa trials are focused on regulatory approval issues and involve numerous sites and generally last two to three years. After the successful completion of Phase IIIa, the sponsor of a new drug submits a registration dossier containing all pre-clinical, pharmacologic, efficacy, and safety data; information about the drug’s composition; and the sponsor’s plans for producing, packaging and labeling the drug. The regulatory review process can take up to 30 months or longer, depending on the country, type of drug and other factors.

    Phase IIIb trials usually begin after submission of the registration dossier and prior to regulatory approval. These studies, which also involve large numbers of patients, generally focus on issues such as the study drug’s cost-effectiveness or its relative efficacy compared with approved drugs in the same therapeutic class or those that are used to treat the same disease.

    Phase IV
    Phase IV trials begin after regulatory approval and typically are used to prove safety and efficacy in new indications (uses); to test new dosage strengths and formulations, e.g., a sustained release capsule or a flavored solution for children; to confirm certain extra clinical benefits such as cost-effectiveness or improved quality of life; and to collect and analyze long-term safety data on patients treated with the drug in normal practice.