Men who have sex with men (MSM) experience over half of new HIV infections annually in Baltimore city. Oral pre-exposure prophylaxis (PrEP) and antiretroviral therapy (ART) are likely to play central roles in reducing the risk of HIV transmission. However, the likely combined impact of these interventions remains uncertain. We propose an individual-based simulation approach to project the population-level impact of implementing PrEP for high-risk MSM in Baltimore, with different levels of coverage and adherence. The primary outcome is the HIV incidence over five years. We project non-linear relationships between program coverage, individual-level adherence, and population-level impact. The impact of PrEP increases with time but is not sustained if PrEP provision ceases. Expansion of ART coverage can augment the impact of PrEP on HIV incidence over the next decade.