Clinical Trial to Evaluate the Effects of Letermovir Prophylaxis on T-cell Immune Activation in Participants With Treated HIV-1 Infection

People living with HIV (PLWH), even with an undetectable viral load (VL) on antiretroviral treatment (ART), develop health conditions, such as heart disease, diabetes, various cancers, and conditions that can affect the brain, more commonly than the general population. These conditions occur earlier in PLWH compared to HIV negative individuals with similar lifestyles. Ongoing inflammation in the body despite antiretroviral therapy is thought to be contributing to the development of these conditions that can affect healthy ageing in PLWH. Cytomegalovirus (CMV) is a very common infection in PLWH and is an important driver of inflammation in the body that can affect the function of the immune immune cells in the body (defense system) causing unwanted activation and damage of the gut making it more leaky. A drug with potent activity against CMV called valganciclovir has previously shown to reduce this potentially damaging inflammation in the body. In this study, the investigators want to investigate if a new drug called Letermovir, in combination with HIV treatment, will prevent CMV from replicating (multiplying), and thereby reduce inflammation in the body. Letermovir has received approval to prevent CMV from multiplying in patients receiving bone marrow transplants. It has been shown to have a more favourable side-effect profile compared to other available drugs and is predicted to interact little with anti-HIV drugs. The aim of this study is to find out if the letermovir is safe and effective in reducing CMV related immune activation and inflammation PLWH. These findings will be used to help us design larger studies to identify individuals who would benefit most from this treatment to prevent the development of health conditions that can affect their quality of life.