This study aims to explore a new drug, GS-3242, for people living with HIV-1, a virus that attacks the immune system. The study is part of a larger research project focused on new medicines that stop the virus from multiplying, called antiretrovirals or *ARVs*. Participants should have specific levels of the virus in their blood and a certain number of immune cells, known as CD4 cells. They should not have taken other experimental HIV drugs recently and must have good kidney function. Some people cannot join, like those with certain liver problems or other serious infections. Participants will need to start a new treatment provided by the study and follow meal instructions on certain days. The study will not include people resistant to major HIV drug classes or those who are pregnant or planning to breastfeed. Also, you cannot join if you have used some specific injectable HIV drugs before. **Key Study Points**: - **Participation involves**: Starting a new HIV treatment and following meal guidelines. - **Exclusion criteria**: Liver problems, pregnancy, or previous use of certain injectable treatments. - **Considerations**: The study involves specific health criteria and drug restrictions. Note: More criteria could apply.