Roche Holding A.G., Europe's fifth-largest drug maker, said today that it had won United States Food and Drug Administration clearance to sell a new, more sensitive version of its Amplicor test, designed to measure the amount of H.I.V. in a patient's blood.
Roche said it could now offer patients and doctors the most sensitive device available to doctors to tell whether they are succeeding in wiping out a patient's H.I.V., the virus that causes AIDS. Amplicor is 10 times more sensitive than tests currently available, picking up H.I.V. concentrations as low as 50 copies of the virus per milliliter of blood, Roche said.
H.I.V. can elude even the most powerful combinations of drugs by slightly shifting its genetic material almost every time it reproduces. Existing drugs fail to contain the virus in about half of patients.
These kinds of tests will be of most immediate use to doctors managing drug-resistant patients -- the vast majority of H.I.V. patients on therapy. Analysts estimate 90,000 to 100,000 H.I.V. patients switch drugs every year in an effort to keep ahead of H.I.V.