Positive trial news pumped up shares of a few biotech companies, including Cortex Pharmaceuticals ( COR), on Tuesday while others bared their earnings. Cortex Pharmaceuticals said Tuesday that the Food and Drug Administration gave it a green light to resume enrollment in its Alzheimer's treatment Ampakine cx717. On the basis of data submitted in April, the agency has approved a protocol with all dose levels for the study, after previously putting a hold on 600-mg and 1200-mg doses. The limitations were related to concerns over data from preclinical animal trials, according to the company. Cortex rose 64 cents, or 24%, to $3.31. Another winner, Durect ( DRRX), announced positive results in a phase IIb clinical trial of Posidur for post-operative pain in patients undergoing inguinal hernia repair. It was the study that Durect and Nycomed are basing the advancement of Posidur into phase III trials, and the results trigger an $8 million milestone payment from Nycomed. Durect, which gained 68 cents, or 18.2%, to $4.41, said it has scheduled an end-of-phase II meeting with the FDA in preparation for Posidur's phase III program. Also, Nastech Pharmaceuticals ( NSTK) was issued two U.S. patents for its Parathyroid Hormone Nasal Spray to treat osteoporosis and PYY nasal spray for treatment of obesity. Nastech added $1, or 8.4%, to $12.89. Durect and Nastech Pharmaceuticals are both components of the Nasdaq Biotechnology index, which was up 0.45, or 0.05%, to 818.69.