Study of Lenacapavir and Emtricitabine/Tenofovir Disoproxil Fumarate (F/TDF) for Prevention of HIV in People Who Inject Drugs (HPTN 103)

Key Inclusion Criteria: * Urine drug screen positive for any drug of misuse including, but not limited to, opioids (eg, fentanyl, heroin), stimulants (eg, cocaine, amphetamines), psychoactive drugs (eg, benzodiazepines), or a combination of these drugs. * Evidence of recent injection (eg, track marks). * Self-report of injection paraphernalia sharing in the prior 30 days. * Hepatitis B virus (HBV) surface antigen (HBsAg) negative. * Negative local rapid HIV-1/2 antibody (Ab)/antigen (Ag) test, central HIV-1/2 Ab/Ag, and HIV-1 RNA quantitative nucleic acid amplification testing (NAAT). * Estimated glomerular filtration rate (GFR) at least 60 mL/min at screening according to the Cockcroft-Gault formula for creatinine clearance (CLcr). Key Exclusion Criteria: * Self-reported history of previous positive results on an HIV test. * Any reactive or positive HIV test result at screening or enrollment, even if HIV infection is not confirmed. * Coenrollment in any other interventional research study or other concurrent studies that may interfere with this study (as provided by self-report or other available documentation) without prior approval from the Medical Monitor/Joint Clinical Management Committee while participating in this study. * Past or current participation in HIV vaccine or HIV broadly neutralizing antibody study unless individual provides documentation of receipt of placebo (ie, not active product). * Prior use of long-acting systemic pre-exposure prophylaxis (PrEP) (including cabotegravir (CAB) or islatravir studies). * Acute viral hepatitis A or acute or chronic hepatitis B or C infection. * Have a suspected or known active, serious infection(s) (eg, active tuberculosis, etc). * Evidence of moderate or severe liver fibrosis or a history of or current clinical decompensated liver cirrhosis (eg, ascites, encephalopathy, variceal bleeding). In individuals with active hepatitis C, Fibrosis-4 (FIB-4) score \> 3.25 (formula provided below). Note: Other protocol defined Inclusion/Exclusion criteria may apply.