Many HBV-HIV co-infected patients are currently treated with dual activity drugs such as tenofovir and emtricitabine, often in combination. However, despite the potent antiviral activity of these drugs, the rate of HBe seroconversion is quite low, and not always sustained over time. HBe seroconversion is an important goal for anti-HBV treatment, since it is associated with a non progressive liver infection and a better clinical outcome. On the other hand, treatments with antiviral and immuno-modulator activity such as Peg-interferon, are infrequently used in co-infected patients, despite promising data in the field of HBV mono-infection with increased rates and sustained HBe seroconversions. This pilot study will evaluate the efficacy and the safety of a one-year Peg-interferon alpha 2a additional treatment (180 micro-g once a week, by injection), in 55 patients already treated by tenofovir and emtricitabine for at least 6 months, and who did not reached HBe seroconversion