M401 Dr. Perrillo (OC): In this instance, we chose lamivudine therapy because it's more potent actually than adefovir. And it is also significantly cheaper. Lamivudine mono therapy costs about $150.00 US dollars per month. Whereas with adefovir, it's about $550 to $600.00. So there was a consideration of financial cost. We also felt that if the patient developed lamivudine resistance, we could roll the patient over to adefovir therapy at that time.... In fact, many authorities tend to go with this approach.