To date, pre-exposure prophylaxis (PrEP) trials have been plagued by poor adherence to both orally and vaginally administered pre/peri-coital and daily product regimens. Low adherence not only complicates  results, but also undermines the effectiveness of products brought to market. RTI is developing a highly innovative approach to providing sustained delivery of an antiretroviral (ARV) agent for PrEP through the use of a thin-film polymer device (TFPD) that is subcutaneously injected and biodegradable but remains retrievable before therapeutic depletion. This anti-HIV product offers many improvements over existing microbicide delivery systems. The TFPD is user-independent and will offer long-term protection (three months or more) against HIV. The TFPD also provides maximum discretion of use, thus overcoming several of the social and logistical adherence challenges associated with user-dependent methods such as tablets and gels. Preliminary discussion with the U.S. Food and Drug Administration (FDA) suggests that the TFPD is likely to be considered a delivery system only and not an investigational device, so RTI International is developing this concept using an Investigational New Drug (IND) pathway, which should simplify regulatory approval.