Therapeutic drug monitoring in treatment-experienced HIV-infected patients receiving darunavir-based salvage regimens: A case series

Impact of Therapeutic Drug Monitoring of Antiretroviral Drugs in Routine Clinical Management of People Living With HIV: A Narrative Review

BACKGROUND

The treatment of HIV infection has evolved significantly since the advent of highly active antiretroviral therapy. As a result, a response rate of 90%-95% now represents a realistically achievable target. Given this background, it is difficult to imagine the additional benefits that therapeutic drug monitoring (TDM) could provide in the management of HIV infection.

METHODS

This article is not intended to provide a systematic literature review on TDM of antiretroviral agents; rather, the authors aim to discuss the potential added value of TDM in the optimal management of people living with HIV (PLWH) in selected real-life clinical scenarios based on data collected over 10 years by their TDM service.

RESULTS

Some clinical situations, in which the selection of the optimal antiretroviral therapy is challenging, have been identified. These include poorly compliant patients, suboptimal antiretroviral therapies (in terms of both efficacy and toxicity), polypharmacy with a high risk of drug-drug interactions, and different patient populations, such as pregnant women.

CONCLUSIONS

The transformation of HIV infection from a near-universally fatal illness to a lifelong chronic disease has resulted in an HIV population that is growing and aging, placing new and increasing demands on public programs and health services. Increasingly, the management of comorbidities, polypharmacy, and drug-drug interaction, and their impact on antiretroviral therapy will have to be undertaken. These clinical settings represent some of the new frontiers for the use of TDM with the goal of achieving optimal prescription and outcome for PLWH.

Clinical outcomes of once-daily darunavir in treatment-experienced patients with darunavir resistance-associated mutations through 48 weeks of treatment

Darunavir (DRV) is approved for once-daily use in patients with no DRV resistance-associated mutations (RAMs) and twice-daily use in those with DRV RAMs. Several studies suggest that once-daily DRV retains efficacy in the setting of 1-2 DRV RAMs whereas three or more DRV RAMs are needed for DRV resistance. There are few data to support the long-term use of once-daily DRV in patients with DRV RAMs. This observational study evaluated 48-week clinical outcomes of 22 treatment-experienced patients with ≥1 DRV RAMs switched to once-daily DRV between 2014 and 2017. The primary endpoint was HIV-1 RNA <50 copies/ml at week 48. Safety parameters were analyzed throughout the study. The median age of the sample was 53 years, 18 (82%) had baseline HIV-1 RNA <50 copies/ml, and the median number of historical DRV RAMs was 2. At week 48, 20 (91%) had HIV-1 RNA < 50 copies/ml, and 2 (9%) had HIV-1 RNA of 82 and 59,637 copies/ml and reported non-adherence. No adverse drug reactions were observed through week 48. Once-daily DRV maintained virologic control in patients with ≥1 historical DRV RAMs and was safe and well-tolerated. Further data are needed to validate this as a viable treatment option in this population.