The main purpose of this legislation is to address the issue of double patenting in the pharmaceutical industry. It aims to prevent companies from obtaining multiple patents for the same drug or biological product, which can lead to extended periods of exclusivity and higher drug prices for consumers. Key provisions of the law include a new requirement that if a patent on a drug expires, any subsequent patents related to that drug will be presumed to have been disclaimed unless the patent holder can prove that these patents cover distinct inventions.