27th International Workshop on Clinical Pharmacology of HIV, Hepatitis, and Other Antiviral Drugs 2026

Key Take-Home Messages from This Edition

1. Long-acting antiretrovirals (LA-ART) continue to transform HIV treatment and prevention

Across multiple plenaries and oral presentations, long-acting therapies emerged as a dominant theme. Sessions explored implementation of long-acting cabotegravir and rilpivirine, lenacapavir targets for treatment vs. prevention, challenges and considerations for accelerating generic long-acting agents for global access, and next-generation agents in the HIV pipeline. New data demonstrated the potential for less frequent dosing, transitions between agents, novel delivery systems, and greater flexibility for people living with HIV and those using PrEP. Pharmacokinetic data from ACTG A5359/LATITUDE showed that long-acting injectable cabotegravir achieved sustained therapeutic exposure in people with HIV facing adherence challenges, providing further insight into maintaining drug activity in populations at highest risk of treatment failure.

2. Therapeutic drug monitoring (TDM) can be a valuable clinical tool for complex situations.

Multiple presentations demonstrated how TDM may be a tool when dealing with challenging clinical situations, including supratherapeutic concentrations following problematic injection techniques, complex drug interactions, bariatric surgery, and pediatrics. Investigators reported that TDM in patients receiving long-acting cabotegravir/rilpivirine with low-level viremia showed that most individuals maintained therapeutic drug concentrations, helping clinicians determine when treatment adjustments were truly necessary. However, abstracts also highlighted that a single TDM assessment may not be sufficient to support clinical decision making due to variability in drug exposure and that uncertainty remains about the interpretation of TDM findings for antiretrovirals without clear pharmacokinetic-pharmacodynamic targets for both treatment and prevention. Globally, access to TDM remains limited.

3. Drug-drug interactions remain a major challenge as antiretroviral options expand.

The plenary session on HIV/TB co-treatment highlighted the ongoing complexity of managing interactions between antiretrovirals and rifamycins, while additional studies examined interactions involving hormonal therapies, complementary medicines, and emerging antiviral agents. Advanced modeling approaches and real-world clinical data are helping clinicians better predict, prevent, and manage interactions that can compromise treatment effectiveness. A case study demonstrated that dose-adjusted lenacapavir achieved therapeutic concentrations despite concurrent rifabutin therapy. However, case-studies presented at the conference and discussions highlighted that clinical data are needed in addition to modeling predictions to provide valuable real-world evidence for managing challenging drug-interaction scenarios.

4. Pharmacology innovation is accelerating through modeling, AI, and novel technologies.

The workshop showcased how physiologically based pharmacokinetic (PBPK) modeling, population PK analyses, artificial intelligence, and new web-based simulation platforms are reshaping drug development and clinical decision-making. These tools are increasingly being used to optimize dosing, evaluate interactions, and guide the design of future therapies. Researchers showcased a new web-based PBPK simulation platform that accurately reproduced observed cabotegravir pharmacokinetics, illustrating how accessible modelling tools can support both research and clinical translation.

5. Key populations remain a priority for research and implementation.

New studies focused on children, adolescents, pregnant and breastfeeding individuals and other populations often underrepresented in clinical research. The findings emphasized the importance of generating pharmacologic evidence that supports equitable access to safe and effective antiviral therapies across diverse patient groups. A study of 21 mother-infant pairs found that infant exposure to antiretroviral drugs through breastfeeding was minimal, while no HIV RNA was detected in maternal plasma, breastmilk, or infant plasma, providing reassuring evidence to support breastfeeding among women living with HIV in settings with appropriate monitoring and care.