Coviracil emtricitabine: Phase III

VIRS said that in a Phase III study (FTC-302) comparing once daily Coviracil to twice daily Epivir lamivudine 3TC in 468 HIV patients, 61 percent of Coviracil patients had <50 copies/ml of virus versus 65 percent of Epivir patients at 48 weeks. Both groups in the South African study received triple combination therapy. The groups had a similar incidence of virologic failure (defined as >400 copies/ml) due to resistance (3.6 percent on Coviracil versus 4.3 percent on Epivir). The Coviracil group had a higher incidence of virologic failure not caused by resistance (5.3 percent versus 1.3 percent). Last year, the FTC-302 study was placed on hold by the FDA due to a higher-than-expected incidence of liver toxicity (see BioCentury, April 10, 2000). In the study, severe liver toxicity was seen in 17 percent of the patients also receiving Boehringer Ingelheim's Viramune nevirapine (14 percent in the Coviracil arm versus 19 percent in the 3TC arm), but none of the patients also receiving DuPont's Sustiva efavirenz with 3TC or Coviracil had liver toxicity. According to VIRS, the FDA had said that due to the factors underlying the hold, the FTC-302 study may not provide adequate support as part of an NDA submission.

VIRS also presented 48-week data from its Phase III FTC-303 study of 440 HIV patients receiving BioChem Pharma Inc.'s Epivir or Coviracil in which the loss of virologic suppression was 8 percent in each arm. ...