The Food and Drug Administration gave Pfizer's ( PFE) HIV drug its blessing Monday while rumors of good data lifted another health stock.

The FDA granted accelerated approval to Pfizer's Selzentry tablets for HIV based on 24-week data. The drug is the first in a class (called CCR5 antagonists) that stop the R5 virus on the outside surface of cells before it enters, rather than fighting the virus inside as do all other classes of oral HIV medicines, according the company.

"The approval of Selzentry for treatment-experienced patients is a significant breakthrough, and we continue its development in a spectrum of other patients living with HIV/AIDS," said Joseph Feczko, Pfizer's chief medical officer. Selzentry is expected to be available in the U.S. by the middle of September. The company recently received a positive opinion from the Committee for Medicinal Products for Human Use in the EU, and plans to commercialize it as Celsentri outside of the U.S. The stock was up 54 cents, or 2.3%, at $24.05.

Vertex Pharmaceuticals ( VRTX) gained $2.92, or 8.8%, to $36.14 after analysts at Leerink Swann & Co. issued a note indicating a favorable outlook for interim data from the PROVE-1 study of Telaprevir in Hepatitis C patients. The analysts also said that management comments suggest the key clinical data from PROVE-1 will be presented at the American Association for the Study of Liver Diseases meeting in November and not the Interscience Conference on Antimicrobial Agents and Chemotherapy in September.

The Nasdaq biotechnology index, which includes Vertex, was up 13.3 points, or 1.7%, to 793.95.

On the earnings front, Ariad Pharmaceuticals ( ARIA) gave up 22 cents, or 5.1%, to $3.91 Monday after reporting quarterly results. The company reported a net loss of $17 million, or 25 cents a share, compared to $17 million, or 27 cents a share, in the year prior. Analysts surveyed by Thomson Financial had expected a loss of 24 cents a share.

Ariad received an up-front payment of $75 million from Merck ( MRK) related to their collaboration agreement for cancer drug, deforolimus, and expects a milestone payment of $13.5 million in the third quarter for the commencement of the phase III trial of oral deforolimus in patients with metastatic sarcomas. Taking into account the Merck agreement, Ariad said it expects positive cash flow from operations for the year in the range of $30 million to $35 million.

Biopharmaceutical company Acadia ( ACAD) edged up 41 cents, or 2.8%, to $15.28 before post-market close earnings. Analysts surveyed by Thomson Financial were looking for a loss of 39 cents on revenue of $2.25 million.

Also, Mentor ( MNT), which makes aesthetic products including breast implants, moved 3.5% higher to $41.60 before after-the-bell earnings. The Thomson Financial consensus target calls for earnings of 34 cents a share on revenue of $88.36 million.

Last, an eye-care update: After putting an end to its bid for rival Bausch and Lomb ( BOL) last week, Advanced Medical Optics ( EYE) found itself subject to credit analyst speculation.

S&P revised its CreditWatch listing on Advanced Medical Optics to "CreditWatch with negative implications" from "CreditWatch with developing implications" -- where it was placed on May 24.

The credit rating agency noted that Advanced Medical Optics, which has been "extremely acquisitive over the past several years" tipped its hand. "The B&L bid revealed the company's willingness to increase debt leverage to a greater level (over 6.5 times on an adjusted basis) than that incurred in previous transactions."

S&P also noted the company's recall of the MoisturePlus multipurpose lens care solution, which damaged revenue and potentially market share -- and also the decrease in guidance earlier in the year. The agency said it will resolve the CreditWatch listing within the next few weeks. Still, Advanced Medical Optics was up 53 cents, or 1.7%, to $31.86.

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