Tenofovir Alafenamide Fumarate (TAF), a tri-therapy antiretroviral drug used to treat HIV, was introduced as an alternative to Tenofovir Disoproxil Fumarate (TDF), an effective treatment option in lowering viral load levels, but a drug associated with renal toxicity and bone impairment. TAF offers a more potent formula for patients, decreasing the necessary dosage and therefore decreasing toxicity and other adverse effects.
In order to determine the cost-effectiveness of using TAF in combination with TDF compared to using TDF alone, we conducted a Markov microsimulation considering age, sex, CD4 level, viral load, whether or not the patient had used intravenous drugs and whether or not the patient had experienced an AIDS-defining event. In this model, we stimulated the speed of viral load evolution for both patients switching to TAF from TDF and patients remaining on TDF, thus allowing us to predict patients’ survival and outcomes, including risk of opportunistic infection.
We relied on a double-blind switch study, utilizing patients controlled via TDF, and considering data from an uncontrolled study conducted to determine each patient’s tolerance to TAF in terms of its impact on renal and bone functions.
In concluding the study, we found that although the parameters of the drug’s function do not directly affect the evolution of the HIV infection in patients, it decreases a patient’s likelihood of impaired kidney or bone function, two symptoms associated with a increased mortality risk.