https://www.selleckchem.com/products/BIRB-796-(Doramapimod).html To examine patterns of long-term PrEP adherence and its association with HIV seroconversion in NSW, Australia. Population-based HIV PrEP implementation study. EPIC-NSW was an open-label study of daily oral PrEP which recruited participants from March 2016 to April 2018. Adherence was measured using dispensing records. PrEP discontinuation was defined as a ≥120-day period without PrEP coverage. Long-term adherence patterns were identified using group-based trajectory modelling. Participants dispensed at least once (n = 9586) were almost all male (98.5%), identified as gay (91.3%), with a median age of 34 years (range 18-86). Of the 6460 (67.4%) participants who had at least nine-months of follow-up since first dispensing, 1942 (30.1%) discontinued. Among these, 292 (15.0%) restarted later. Four distinct groups were identified ('Steep decline' in adherence (15.8%), 'Steady decline' (11.6%), 'Good adherence' (37.4%), and 'Excellent adherence' (35.2%)). Older (p < 0.001) and gay-identified (p < 0.001) participants were more likely to have higher adherence, so were those living in postcodes with a higher proportion of gay-identified male residents (p < 0.001). Conversely, those who at baseline reported recent crystal methamphetamine use and had a recent diagnosis of sexually transmitted infection (STI) had lower adherence (p < 0.001). Overall HIV incidence was 0.94 per 1000 person-years (95%CI 0.49-1.81; n = 9) and was highest in the 'steep decline' group (5.45 per 1000 person-years; p = 0.001). About 15% of participants stopped PrEP during study follow-up and were at increased risk of HIV infection. They were more likely to be younger and report a recent STI or methamphetamine use prior to PrEP initiation. About 15% of participants stopped PrEP during study follow-up and were at increased risk of HIV infection. They were more likely to be younger and report a recent STI or methamphetamine use prior to PrEP