The final step was proving to FDA that the new drug is safe and effective. In total, as many as eight to 12 years of the original patent life are often used up by the testing and regulatory process. Before 1984, a generic drug company interested in marketing a copy had to prove the safety and efficacy of its product, just as the brand-name company did. Hatch-Waxman changed that, and much more. Under the law, a generic manufacturer no longer has to conduct costly clinical trials or show that its product is safe and effective.
Generic manufacturers do have to show that their products are bioequivalent to the brand-name drugs.
However, demonstrating that is much less costly than proving safety and efficacy. Congress also sought to increase the number of generic drugs by providing incentives in the Act for generic companies to challenge the validity of patents on brand-name drugs. Successful challengers get a head start on the competition. More precisely, generic companies that successfully challenge a patent in court can market their product for 180 days without competition from any other generic manufacturer. Rather, it restores some of the patent life lost as a result of clinical trials and regulatory review.