Therapeutic drug monitoring (TDM) of antiretroviral drugs has optimized treatment of HIV-infected patients in resource-rich countries especially in selected ‘difficult to treat’ situations (1). The measurement of drug levels in serum samples enables timely diagnosis of low drug levels, which put patients at risk of developing treatment failure, as well as too high levels which foster toxicity of the drugs. While antiretroviral treatment is generally well tolerated and highly efficacious, a considerable risk of treatment failure, as well as toxicity remains at hand, especially in vulnerable patient groups such as children and adolescents in resource-limited countries (2). In Uganda, it has been reported that up to 34% of children fail first line antiretroviral treatment (3) which is an alarming rate especially since access to second- and third-line treatment is limited in this setting. All efforts to prevent treatment failure should be of highest priority.
We propose to develop and validate a high-performance liquid chromatography with ultraviolet detection (HPLC-UV) multiplex assay for the measurement of antiretroviral drugs currently in use in Uganda. This assay will simultaneously measure the concentration of all protease inhibitors and non-nucleoside reverse transcriptase inhibitors (NNRTI) currently in use in Uganda using locally available machines. Our multiplex assay aims to precisely and accurately analyze the levels of efavirenz, nevirapine, etravirine, atazanavir, lopinavir, darunavir, and raltegravir. For our second aim, serum samples of participants of a currently ongoing study on HIV drug resistance (Study on Resistance in HIV-infected adults in North and South, RHINOS study) will be analyzed, focusing on especially vulnerable patients who are diagnosed with treatment failure and/or report side effects. We hypothesize that the multiplex assay will - for the first time - make it possible to measure all antiretroviral drugs mentioned above in one assay using HPLC-UV. We further hypothesize, that low drug levels are a risk factor for treatment failure as well as the development of HIV drug resistance mutations, while levels above the reference range may put patients at increased risk of toxicities and side effects. If successful, this multiplex assay can be offered to clinicians caring for HIV-infected patients across East Africa and transform the pharmacokinetic laboratory at the Infectious Diseases Institute (IDI) in Kampala into a regional referral center, thus benefitting thousands of patients in need of optimized antiretroviral treatment.