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New AIDS Drug Approved

Pall bearers enter Westminster Hall in Baltimore with a casket during a reenactment of author Edgar Allan Poe's funeral Sunday, Oct. 11, 2009. The funeral, which this time was much larger than the first, was part of Baltimore's celebration of the 200th anniversary of Poe's birth. Poe is buried in Baltimore, outside of Westminster Hall. Fewer than 10 people attended Poe's funeral when he died in October 1849 at age 40. (AP Photo/ Steve Ruark)
AP Photo/Steve Ruark
The government approved a novel anti-AIDS pill on Friday, offering a new option for hard-to-treat patients.

Manufacturer Merck & Co. of Whitehouse Station, N.J., said Isentress should be on pharmacy shelves within two weeks.

The AIDS virus uses three different enzymes to reproduce and infect cells. Numerous drugs are available that target two of those enzymes, called protease and reverse transcriptase.

Isentress is the first in a new class of medicines that blocks the third enzyme, called integrase. Added to "cocktails" of other HIV medicines, the drug can lower the amount of HIV in the blood and help infection-fighting immune cells rebound.

HIV mutates rapidly to resist various treatments, and the Food and Drug Administration approved use of Isentress in patients over age 16 whose blood tests show they are resistant to common older medications.

Side effects include diarrhea, nausea, headache and itching.

Patients take Isentress, also known as raltegravir, twice a day. A Merck spokeswoman said the drug would cost $27 a day, or $9,855 a year - in the range of other competitors.

It is the second novel HIV drug to win FDA approval in two months. Pfizer Inc.'s Selzentry works by yet another method, blocking a passage that HIV often uses to enter white blood cells.