23. Are the oral treatments for hepatitis B complimentary in treating resistance? (lamivudine resistance and adefovir)

One of the beautiful things about the oral agents is they are complimentary in terms of treating resistance. In people who develop resistance with a YMDD mutation, adefovir is active against that mutation, and the flip-flop occurs. Here’s a study by Marion Peters, who’s up at UCSF, just published, she did a study and took a group of people that had development of lamivudine resistance. Now, I told you how we define that: the DNA going up one log. But in this study, they actually measure what we call sequence analysis, to absolutely confirm that this was the YMDD mutation. And then they randomized patients in a research study into either continuing lamivudine, adding adefovir to lamivudine in the green, or in the yellow, switching to adefovir. And you can see that you can just switch to adefovir, and the DNA level which is here on the ordinate goes down to the same degree. You don’t need to have both lamivudine and adefovir. When the YMDD mutation occurs, you can switch to adefovir and you will get an equally good response.