Once a drug is approved for an indication, many years of its patent life have usually expired. Information gathered from Phase III clinical trials or from use of the drug under normal conditions (postmarketing) may suggest alternative indications that may extend the patent life. For an invention to be patented in the USA, it must be a new and useful improvement and not obvious (see also Chapter 35). Patentable categories in drug development include pharmaceutically active compounds, processes for making compounds, and compositions comprising an active compound and a pharmaceutical carrier (Hammer 1990). New formulations may satisfy these criteria and extend the patent life, e.g. minoxidil (originally used orally as an antihypertensive agent) as a topical preparation for the treatment of hair loss. New indications also help to keep up the 'noise level' for the product, enabling the marketing team to capitalize on new information that could potentially expand the market for existing indications.
The independent investigator can play an important role in identifying new indications by identifying and studying a particular drug effect. When published, such findings may lead to widespread use of the product for a new indication and, ultimately, adoption by the medical establishment. This process can occur without the intervention of the product sponsor or any formal clinical development program. However, generally new indications are evaluated in a formal trial and submitted as a supplemental NDA (sNDA). To assist independent investigators with this process, many large pharmaceutical companies have set up investigator grant programs.
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