NEW YORK (Reuters Health) - U.S. regulators will review Isentress, an investigational drug for HIV infection, on a priority basis, and a decision is anticipated by mid-October, Merck & Co. said on Wednesday.

The oral drug is the first in an HIV drug class called integrase inhibitors. It is generically known as raltegravir, and formerly known as MK-0518. The drug blocks the insertion of HIV's genetic material into human DNA and thereby prevents the virus from replicating. It should be taken twice daily, and can be taken with or without food.

The preliminary results of two phase III trials, presented earlier this year at 14th Annual Retroviral Conference, showed that raltegravir is active against HIV in patients resistant to all three previously approved drug classes for HIV infection.

Merck said the drug, if approved, will be used alongside standard oral HIV drugs by patients who are no longer adequately protected by their current treatments because of viral resistance.

The agency grants priority review to products that are considered to be potentially significant therapeutic advancements over existing therapies.

With priority review status, the U.S. Food and Drug Administration will make its decision on whether to approve the drug within 6 months, rather than the usual 10- to 12-month review period.

Merck tested Isentress in patients who continued to take a standard HIV drug regimen, although they were infected with strains of the virus that had become resistant to at least one drug in each drug class.

Merck added that it is also moving forward with marketing applications for the drug outside of the United States.

REUTERS