CCTG 595: Text Messaging Intervention to Improve Adherence to PrEP in High-risk MSM

Inclusion Criteria: * Man or transgender M to F who has sex with men. * Age 18 years or older. * Subjects must have substantial ongoing risk of acquisition of HIV as evident by one or more of the following: * Has at least one HIV infected sexual partner for ≥4 weeks. * No condom use during anal intercourse with ≥3 male sex partners who are HIV-positive or of unknown HIV status during the last 3 months. * No condom use during anal sex with ≥1 male partner and STI diagnosis during the last 3 months. * Negative for HIV infection by rapid HIV test and confirmed negative by NAT or other sensitive method such as antibody- antigen test. * Acceptable laboratory values in the past 30 days: * Calculated creatinine clearance of at least 60 mL/min by the Cockcroft-Gault formula (eCcr (male) in mL/min = \[(140 - age in years) x (lean body weight in kg)\] / (72 x serum creatinine in mg/dL) * Alanine aminotransferase (ALT) and/ or aspartate aminotransferase (AST) \< 3 x upper limit of normal (ULN) * Hemoglobin \> 9 g/dL * Absolute neutrophil count \> 750/ mm3 * Platelets \> 75,000/ mm3 Exclusion Criteria: * Unable to give informed consent. * Active hepatitis B (positive hepatitis B surface antigen (HBSAg) or HBSAg negative/ HB core antibody positive/ HBV PCR positive). * Has substantial medical condition, that in the opinion of the investigator would preclude participation, as defined by * cardiovascular condition that may lead to an increased risk of complication if…