The FDA denied two Citizen Petitions -- including one filed by Eisai and Arena Pharmaceuticals ( ARNA) -- requesting additional New Chemical Entity (NCE) market exclusivity to make up for the commercial launch delay caused by need to wait for DEA scheduling.
Eisai and Arena received FDA approval to market the weight-loss drug Belviq on June 27, 2012. The approval data also triggered the start of the drug's five-year market exclusivity as a New Chemical Entity (NCE), per FDA regulations. However, FDA would not allow Eisai and Arena to start selling Belviq until DEA scheduling was completed, given the drug's abuse potential. The final order for DEA scheduling was filed on June 7, 2013, meaning Eisai and Arena lost almost one year of market exclusivity.
In a Citizen Petition, Eisai argued the clock on NCE market exclusivity should start no the date the drug can be marketed, not the formal approval date.
In response, the FDA said no.
Here's a link to the FDA's ruling on the Citzen Petitions.
FDA Law Blog has also posted on the matter.