We now have a substantial data base which clearly documents the fact that the histological changes of concern occur postmortem when the fixative solution is used to prepare the slides of the tissue specimens."

However, in October 2007 the FDA denied Cortex's IND application for a Phase IIb study of CX717 for treatment of ADHD, based on the same animal toxicology results.

Cortex believes that the IND application previously filed with the Division of Neurology Products of the FDA for the treatment of Alzheimer's disease will not be affected by the actions of the DPP.

"[8] The company hopes that after the use of the compound in treating a high-risk acute condition is approved and well-established, the risks of longer-term use at higher doses, such as for treatment of ADHD, will be shown to be less than the FDA had concluded.

These drugs were reasonably effective at reducing the symptoms of Alzheimer's and it was hoped that they could also slow the progression of the disease, but both CX-546 and CX-614 have poor bioavailability, and are only active at very high doses of 1000 mg or more.