B/F/TAF has been included as first-line HIV treatment guidelines in China, the United States, and WHO due to its outstanding clinical efficacy. However, its relatively higher cost has limited its widespread clinical application. Therefore, a pharmacoeconomic evaluation is necessary to determine if the higher medication cost leads to greater health benefits. This study aims to evaluate the cost-effectiveness of B/F/TAF in comparison to DTG/3TC for treatment-native adults of HIV-1 Infection in China, utilizing Markov and dynamic models. When compared to DTG/3TC, the ICER of B/F/TAF was $14,081.23 and $6,524.03 per QALY in the Markov model and dynamic model, respectively. We attempted to analyze the reasons supporting the cost-effectiveness of B/F/TAF. Firstly, B/F/TAF demonstrated higher clinical effectiveness than DTG/3TC, resulting in a reduction in ADEs occurrence, HIV-related deaths, and new HIV cases. These gained extended beyond individual health improvements to encompass savings in direct non-medical and indirect costs, coupled with a decrease in the likelihood of transmission. Secondly, as HIV is a chronic infectious disease, its treatment costs are intricate, with antiretroviral drugs constituting only around 50% of the overall costs, and first-line drugs comprising merely 20%. Consequently, the price advantage of DTG/3TC lacked significant clinical and macro-application impact.
The results from the two models showed a significant disparity in the ICER, with the dynamic model yielding more economically favorable outcomes for the B/F/TAF group compared to the Markov model. This difference was attributed to the dynamic model's enhanced consideration of externalities, explained specifically as follows. Firstly, the B/F/TAF group had fewer newly diagnosed HIV cases compared to the DTG/3TC group. Secondly, by reducing the transmission risk for a greater number of individuals infected with HIV, the B/F/TAF group indirectly protected the susceptible population. Therefore, compared to the Markov model, the dynamic model took into account more health benefits and cost savings associated with avoiding transmission risks, resulting in a smaller ICER. When economically evaluating ART with slight efficacy differences, like B/F/TAF and DTG/3TC, the dynamic model tends to magnify outcomes as opposed to the Markov model.
The two models exhibited fundamental differences, particularly in their roles within economic evaluation and their emphasis on algorithmic aspects. The Markov model simulated the details of ART for treating HIV, including switching treatment plans. In clinical drug selection, patient demands took precedence, making a Markov model based on patient cohorts more aligned with actual needs. In contrast, the dynamic model took into account transmission factors and assessed the preventive effects of ART, offering improved guidance for HIV prevention and control. A dynamic model, which thoroughly incorporates both treatment and transmission risk prevention, exhibits greater theoretical robustness in the economic assessment of various ART options. From an algorithmic perspective, the dynamic model, in addition to incorporating clinical, cost, and utility parameters from Markov, required population parameters and transmission-related parameters for five subgroups. This also precisely explains why the dynamic model has lower precision compared to the Markov model, resulting from diverse parameter types and more complex algorithmic processes. While the Markov model carefully simulated the course of ART treatment for HIV, this aspect of the dynamic model was simpler. Specifically, the Markov model carefully considered the distinct effects and costs of second and third-line treatments, while the dynamic model used average data of them. Moreover, regarding AEs, the Markov model addressed a period after changing medication, whereas the dynamic model handled AEs for each year.
We have included international findings for comparative analysis with our results. In an economic evaluation of DTG-based regimens in Ethiopia, 15.3 QALYs per patient (≥ 18 years of age ) over a lifetime were obtained compared to EFV-based regimens (vs 14.7 QALYs)[4]. The Ethiopian study reported slightly higher results than the QALYs obtained in our Markov model, mainly due to the inclusion of disutility associated with ADEs and AEs, which was not considered in the Ethiopian study. In an economic evaluation of DTG-based treatment regimens in the United States, compared with EFV-based regimens, the cost was calculated from the perspective of the US payer: 88.20% for medicines (vs 88.42%), 8.39% for tests (vs 8.18%), and 3.41% for events (vs 3.40%)[39]. The order of cost distribution in our study, from highest to lowest, was the cost of medicine, the cost of tests, and the cost of event management.
At present, HIV/AIDS treatment in China has entered the era of "Troika" optimization, ensuring the provision of low-end (free drugs), mid-end (Medicare drugs), and high-end (self-financed drugs) options for patients[68]. This setup allows individuals to select treatments aligned with their preferences. For example, economically well-off HIV patients may select pricier yet highly effective and durable drugs, exemplifying the market positioning of B/F/TAF. With the introduction of innovative antiretroviral therapies and the evolution of China's economic landscape, the HIV treatment environment has gradually been optimized. Consequently, patients may increasingly prefer B/F/TAF despite higher costs, gaining wider acceptance in the evolving HIV treatment landscape.
However, it's crucial to recognize limitations. Firstly, achieving precise control over the clinical trial effectiveness of both interventions is nearly impossible. There are no direct trials establishing efficacy, and the support from network meta-analysis for indirect clinical evidence is insufficient. Secondly, to ensure the smooth progress of our study, individuals discontinuing first-line treatment transitioned entirely to second-line therapy, and those discontinuing second-line moved directly to third-line therapy. Some practical aspects, such as adherence and patient choice, are overlooked in this setup. Lastly, the lack of Chinese research on certain parameters, such as utility values, compelled us to adopt foreign parameters for substitution. Despite introducing uncertainty in long-term extrapolation, we addressed it with sensitivity analyses in the study.
If these data become available in the future, our study will be supplemented. Furthermore, the limitation of our study lies in that the results are only applicable to the cohort of Chinese patients.