Last summer, 48-week data won FDA approval for Complera (see the November/December 2011 "Briefly" for the complicated details). At IDSA, 96-week data were presented from the ECHO and THRIVE studies that pitted the new Complera against Atripla. Complera continued to be non-inferior to Atripla, but also continued to have more virologic failure in people who started therapy at viral loads greater than 500,000.

There was bad news for people who began Complera with a viral load of greater than 100,000, as well. The researchers conducted a so-called "snapshot" analysis, looking at viral load measurements made between 96 and 103 weeks. Here, the virologic failure was almost twice as high for Complera: 22% vs. 12% for Atripla. Moreover, virologic failures leading to treatment discontinuation were also higher with Complera: 12% vs. 4% for Atripla.

On the plus side, Complera also continued to be more tolerable. The treatment discontinuation rate for adverse events was 4% for Complera compared to 9% for Atripla, a statistically significant difference. These figures were about double those of week 48 (2% vs. 5% respectively).

As leading HIV specialist and researcher Cal Cohen of the Community Research Initiative of New England said, "For the right person, Complera is a good drug. and it's important to consider for those who want the benefit of taking a single tablet once daily, and for whom Atripla isn't the right choice."