When some innovative drugs appear on market of prescription weight loss products, absolutely all pharmaceutical company begin studying the molecular formula of these drugs.
Competing pharmaceutical companies study the chemical structure and composition of new diet drugs to create diet pills with similar mechanism of action.
New diet pills are protected by patent within 10-15 years after approval and the beginning of retail sales. Therefore, other diet pills with similar mechanism of action can be approved before the patent expires only if they contain other active ingredient.
For instance, in the middle of 2000’s, the new Rimonabant diet pills were approved in Europe. In 2006, these diet pills went on sale under the brand Acomplia. Sanofi-Aventis was the developer and global distributor of Acomplia (Rimonabant) pills.
This pharmaceutical company managed to create the diet pills that did not just suppress the appetite, but also reduced the fatty food cravings. In 2006, many specialists claimed that Sanofi-Aventis did a revolution on the global market of weight loss drugs.
The mechanism of action of Acomplia (Rimonabant) differed from that of any other weight loss drugs, available on the pharmaceutical market in 2006. This fact did not go unnoticed for global pharmaceutical giants.
Thus, some of them (including Pfizer and Merck) announced that they were planning to develop some new diet pills with mechanism of action similar to mechanism of action of Acomplia.
In 2007, Sanofi-Aventis did not get the approval for Rimonabant-containing pills (Zimulti) in the USA, and in 2008, the retail sales of Rimonabant pills were stopped in over 50 countries of the world.
After Acomplia diet pills had been withdrawn from European market because of serious mental side effects, Merck and Pfizer refused to develop new diet drugs similar to Acomplia.
In 2016, several new diet pills including Qsymia, Contrave and Belviq are available in the USA. Clinical studies demonstrate that the benefits of new diet pills outweigh the potential risks for health.
However, it is quite possible that after the estimation of post-marketing studies, one or maybe two new diet pills will be withdrawn from the US market. In addition, in 2008 (only 2 years after the start of retail sales) Acomplia diet pills were withdrawn from the markets in Europe and UK.