Study of Lenacapavir as a Once-Yearly Injection for HIV Pre-exposure Prophylaxis (PrEP)

Key Inclusion Criteria: * At least 16 years of age at screening. * Receptive anal or vaginal sex in the past 6 months and at least 1 of the following: 1. Condomless receptive sex (vaginal or anal) with 1 or more sex partners of unknown HIV status during the past 6 months 2. For a person who has engaged in anal sex in the past 6 months: diagnosis of syphilis, gonorrhea, or chlamydia in the past 6 months 3. For a person who has engaged in vaginal sex in the past 6 months: diagnosis of syphilis or gonorrhea in the past 6 months 4. Sex with partner known to be living with HIV with an unknown or detectable viral load in the past 6 months * Negative local rapid fourth generation HIV-1/2 antibody (Ab)/antigen (Ag) test, central fourth generation HIV-1/2 Ab/Ag, and HIV-1 RNA quantitative nucleic acid amplification testing (NAAT) at screening. Key Exclusion Criteria: * Current signs or symptoms suggesting HIV infection * Acute viral hepatitis A, B, or C or evidence of chronic hepatitis B or C infection * Severe hepatic impairment or a history of or current clinical decompensated liver cirrhosis (eg, ascites, encephalopathy, variceal bleeding) * Past or current participation in HIV vaccine or HIV broadly neutralizing antibody study unless participant provides documentation of receipt of placebo (ie, not active product) * Prior use of oral LEN in the past 90 days or subcutaneous LEN in the past 18 months Note: Other protocol defined Inclusion/Exclusion criteria may apply.