This study is for people living with HIV (Human Immunodeficiency Virus) who are on a complicated treatment plan. It will look at how two study drugs, bictegravir (BIC) and lenacapavir (LEN), work compared to current treatments. There are two phases: Phase 2 and Phase 3. To join, your HIV levels must be very low (under 50 copies/mL), and you've been on a complex treatment for at least 6 months. A complex treatment might include taking more than one pill a day or using a mix of pills and shots. You cannot join if you've used LEN before or have certain other infections like tuberculosis or hepatitis B. Your kidneys should be working well. Always talk to your doctor to understand if this study is right for you.

• The study involves switching to new drugs and monitoring effects.
• Eligibility requires low HIV levels and complex current treatment.
• Participants should not have used LEN before or have specific infections.