On Tuesday, June 14, I was fortunate enough to be able to attend the HPTN/IMPAACT annual meeting in Arlington, Virginia. The conference offered various plenary sessions to discuss the many facets of HIV prevention and management. 

The HPTN Modelling Plenary was moderated by Dr. Deborah Donnell, and featured Drs. Marie-Claude Boily (the leader of the HPTN Modelling Center), Kate Mitchell, and Dobromir Dimitrov as speakers. Speakers discussed the application of mathematical modelling in evaluating the long term impacts of potential interventions. For example, the HPTN 078 study assessed linkage to care of men who have sex with men (MSM) in the cities of Baltimore, Atlanta, Birmingham, and Boston. Mathematical modelling was utilized in the early stages for protocol design, during the study for model development and data analysis, and in the aftermath to predict the final impact of the interventions on HIV incidence. I found the breadth of data that the Center used astounding; hundreds of variables were taken into account when making predictions. This really allowed the researchers to make judgements based on data received at the individual level, personalizing the prevention process and tailoring the outcomes to the patient. 

As a statistics student, the HPTN Statistical Plenary was of particular interest to me. It featured Drs. James Hughes, Brett Hanscom, and Ying Qing Chen as presenters. Surprisingly, the talks were quite accessible, not requiring a comprehensive knowledge of the subject matter to understand. Dr. Hughes presented methods for correcting data for underreported behavior, specifically the development of the Underreporting Correction Factor (UCF). This metric would serve to improve estimates of prevalence of risky/stigmatized behavior. I thought it was fascinating how simple probability could be applied to something so nuanced as human behavior. The speakers also discussed the statistical and logistical issues of the Cabotegravir trials. Cabotegravir is a long acting injectable HIV prevention method. However, the existing standard of care – daily oral antiretroviral treatment – is extremely effective. Therefore, the Cabotegravir trials must be run as non-inferiority trials, which present some complications when the non-inferiority margin is dependent on control group adherence. Dr. Hanscom discussed the use of regression of existing data to determine non-inferiority margins for target populations with certain adherence levels.

The large HPTN PrEP Plenary, moderated by Dr. Sinead Delany-Moretlwe and Dr. Kenneth Mayer, gave a chance for researchers to present findings and updates on HPTN studies. Much of the research focused on adherence and implementation of interventions. The focus on this social aspect of HIV prevention is becoming more common as researchers are realizing that getting people to take medicine is just as hard, if not more so, than developing the drug. Another topic that stood out to me was the use of monoclonal antibodies for prevention (vaccine). Study design for antibody trials is difficult because oral PrEP is so effective. However, if the research proves fruitful, it would dramatically change the landscape of HIV research. There have already been waves of advancement in the field, from the first antiretroviral, to the use of antiretrovirals as prevention. Validation of monoclonal antibodies as a vaccine would no doubt be the next huge step if it were to happen. 

During discussion, the panel drew attention towards incorporating adolescents into clinical trials, as this is quickly becoming the most affected demographic. I think it is impressive how the prevention community is able to identify and target different demographics; the prevention process is truly both dynamic and proactive, as clinicians must go out and actively seek patients to test and treat. The community works tirelessly to ensure that treatment is optimal and widespread.