Skip links

What are DESI Drugs?

DESI drugs are a great source for 505(b)(2) development since many will qualify for 5 years data exclusivity. In this post, we will define what they are.

Once upon a time….

In 1938 the FD&C Act was established that required that drugs be proven safe before coming to the market. It wasn’t until the Kefauver-Harris Amendments to the Act in 1962 that drugs also had to be proven efficacious before they could be approved. The passage of this law created a problem – what about all of the products that had been approved under NDA’s between 1938 and 1962 that were on the market? In addition to these NDA-products, there were a large number of ” identical, related, and similar” products to such drugs. The answer was that the products could stay on the market but would be reviewed and ‘approved’. Unfortunately, FDA did not have the resources to conduct this review so in 1966 a contract was made with the National Academy of Sciences/National Research Council. In 1968, FDA set up a process called DESI – Drug Efficacy Study Implementation, to implement the recommendations of these reviews.

The gist of the process was to have teams review existing information and decide on the medical and scientific merits of the product, classifying the drugs as effective, ineffective, or needing further study. FDA would review these recommendations and publish the findings. The teams were academics, medical professionals and government employees. These teams reviewed classes of drugs by therapy rather than individual drugs (in 1973 the Supreme Court concurred with this approach). The information relied on was labeling, publications and information from sponsors and the opinion of the team members. The FDA publishes its conclusions in the Federal Register.

How did they do? The great unanswered and unanswerable question. Nobody, including FDA, knows how many DESI products there were/are. People ask me for a list. Nobody has a complete list. Nor is DESI complete! There are many groups of drugs for which no DESI notice has been published – in 2007 FDA estimated about 20 categories are left in some stage of review or notice. Moreover, many of these products and/or labeling have changed over the years so it is a moving target.