Safety and Acceptability Study of Oral Emtricitabine/Tenofovir Disoproxil Fumarate Tablet and Rectally-Applied Tenofovir Reduced-Glycerin 1% Gel

Inclusion Criteria: 1. Male or transgender female \> age of 18 at Screening 2. Able and willing to provide written informed consent 3. HIV-1 uninfected at Screening and Enrollment 4. Able and willing to provide adequate locator information, as defined in site SOP 5. Available to return for all study visits, barring unforeseen circumstances and willing to comply with study participation requirements 6. In general good health at Screening and Enrollment, as determined by the site IoR or designee 7. Per participant report, a history of consensual RAI at least once in the past 3 months 8. Per participant report at Screening and Enrollment, agrees not to engage in receptive or insertive sexual activity with another study participant for the duration of study participation. 9. Willing to use study-provided condoms for the duration of the study for penetrative intercourse 10. Willing to not take part in other research studies involving drugs, medical devices, vaccines or genital products for the duration of study participation (including the time between Screening and Enrollment) 11. Men and transgender females who agree to take part in the PK, PD and Mucosal Immunology Subset, must also agree to abstain from: * Inserting anything into the rectum, including abstaining from RAI for 72 hours after the collection of biopsies * Taking non-steroidal anti-inflammatory drugs (NSAIDs), aspirin and/or other drugs that are associated with increased likelihood of bleeding following mucosal biopsy collection for 72 hours prior to and following the collection of biopsies. Exclusion Criteria: 1. At Screening, participant-reported symptoms, and/or clinical or laboratory diagnosis of active anorectal or reproductive tract infection requiring treatment per current World Health Organization (WHO) guidelines or symptomatic urinary tract infection (UTI). Infections requiring treatment include symptomatic Chlamydia trachomatis (CT) infection, Neisseria gonorrhea (GC), syphilis, active herpes simplex virus (HSV) lesions, anogenital sores or ulcers, or symptomatic genital warts. Note: HSV-1 or HSV-2 seropositive diagnosis with no active lesions is allowed, since treatment is not required. In cases of non-anorectal GC/CT identified at screening, one re-screening 2 months after the screening visit will be allowed 2. History of inflammatory bowel disease as reported by participant history 3. At Screening: * Positive for hepatitis B surface antigen * Positive for hepatitis C antibody * Hemoglobin \< 10.0 g/dL * Platelet count less than 100,000/mm3 * White blood cell count \< 2,000 cells/mm3 or \> 15,000 cells/mm3 * Calculated creatinine clearance less than 60 mL/min by the Cockcroft-Gault formula where creatinine clearance in mL/min = (140 - age in years) x (weight in kg) x (1 for male)/72 x (serum creatinine in mg/dL) * Serum creatinine \> 1.3 x the site laboratory upper limit of normal (ULN) * Alanine transaminase (ALT) and/or aspartate aminotransferase (AST) \> 2.5× the site laboratory ULN * PK, PD and Immunological Subset only: International normalized ratio (INR) \> 1.5× the site laboratory ULN or partial thromboplastin time (PTT) \> 1.25× the site laboratory ULN 4. Known allergy to methylparaben and/or propylparaben 5. Known allergy to any of the study products. 6. Per participant report, use of the following medications and/or products within 12 weeks prior to screening, and/or anticipated use or unwillingness to abstain from use throughout study participation: * Any investigational products * Systemic immunomodulatory medications * Use of Heparin, including Lovenox® * Warfarin * Plavix® (clopidogrel bisulfate) * Rectally-administered medications or products, containing N-9 or corticosteroids 7. By participant report, use of post-exposure prophylaxis (PEP) for HIV exposure within the 12 weeks prior to screening or anticipated use during study participation. 8. Symptoms suggestive of acute HIV seroconversion at Screening and Enrollment 9. Has any other condition that, in the opinion of the Investigator of Record (IoR)/designee, would preclude informed consent, make study participation unsafe, complicate interpretation of study outcome data, or otherwise interfere with achieving the study objectives would make the patient unsuitable for the study or unable/unwilling to comply with the study requirements. Such conditions may include, but are not limited to, colorectal abnormalities, substance abuse, or renal, hepatic, hematological, gastrointestinal, endocrine, pulmonary, neurological or psychiatric disease.