After a new drug is approved for marketing, a patent will generally protect the financial interests of the drug’s developer for a number of years. The traditional protection period is for 17 years. In reality, however, the period is much less due to the extended period of time needed to gain approval before marketing can begin. Recognizing that a considerable part of a drug’s patent life may be tied up in the approval process, in 1984 the U.S. Congress passed a law providing patent extension for drugs whose commercial sale may have been unduly delayed by the approval process.
Any manufacturer can apply for permission to produce and market a drug after the patent for the drug has expired. Following a procedure called an Abbreviated New Drug Application (ANDA), the applicant must show that its product is bioequivalent to the original product. Although the extensive clinical testing completed by the originator during the drug’s development does not have to be repeated, comparative testing between the products must be done to ensure that they will be therapeutically equivalent.
After an NDA or an ANDA has been approved for a product, the manufacturer must then meet all requirements relating to production. These include the FDA’s current Good Manufacturing Practice regulations and any applicable standards relating to strength, quality, purity, packaging, and labeling that are established by the United States Pharmacopeia (USP).
Routine product testing by the manufacturer is required by the Good Manufacturing Practice regulations of the FDA (the FDA itself does not routinely test all products, except in cases where there is a suspicion that something is wrong). In addition to governmental requirements, drug products must meet public standards of strength, quality, and purity that are published in the USP. In order to market their products, all manufacturers in the United States must meet USP-established standards unless they specifically choose not to meet the standards for a particular product. In this case, that product’s label must state that it is “not USP” and how it differs from USP standards (this occurs very rarely).
Source: Health Net