All eligible participants will be put into one of two groups by chance (as in the flip of a coin). One group will receive 600 mg of LdT (3 tablets) plus a lamivudine placebo capsule (1 sugar pill) daily. While the other group will be receiving 100 mg of lamivudine (1 capsule) plus 3 LdT tablets (3 sugar pills) daily. Participants will take the study drug daily for a total of 104 weeks (2 years).