Gilead Sciences Inc. said its reverse transcriptase inhibitor, Preveon (adefovir dipivoxil), for AIDS showed antiviral activity in Phase II/III trial patients who had developed resistance to the common HIV drugs AZT (zidovudine) and 3TC (lamivudine).
Once-daily treatment with Preveon for 24 weeks did not lead to adefovir-associated resistance mutations identified in vitro, according to the data collected from 142 patients in the placebo-controlled trial. Entering the study, 76 percent of patients had the mutation associated with the use of 3TC, sold by London-based Glaxo Wellcome plc.
"We currently have a whole series of Phase III pivotal studies ongoing," said Lana Lauher, spokeswoman for Foster City, Calif.-based Gilead. "We're talking to the FDA about what the filing strategy will be."
The study tested patients who had undergone HIV treatments, randomizing them to receive Preveon or a placebo, once daily with other approved anti-HIV therapies, including protease inhibitors. Results indicated Preveon decreased HIV RNA, which measures viral infection, while increasing CD4 cell counts, suggesting improved immune function.
"These data are only the subset of a larger trial in heavily pretreated patients," Lauher said. Other studies are testing treatment-naïve patients and evaluating Preveon in other drug combinations.
More than 5,000 patients have received Preveon through clinical trials, including more than 3,200 in the U.S. expanded access program.
Gilead's stock (NASDAQ:GILD) closed Thursday at $33.75, down $0.75. — Randall Osborne