US Cost-utility Model of Lenacapavir Plus Optimized Background Regimen (OBR) Vs Fostemsavir Plus OBR and Ibalizumab Plus OBR for People with HIV with Multidrug Resistance

Background: Heavily treatment-experienced (HTE) people with HIV (PWH) have limited treatment options owing to multidrug resistance (MDR). Lenacapavir (LEN) is indicated, in combination with other antiretrovirals, for the treatment of adults with MDR HIV-1 experiencing failure of their current antiretroviral regimen because of resistance, intolerance, or safety considerations.

Objective: To evaluate the cost-utility of LEN in combination with an optimized background regimen (OBR) vs alternative recently approved treatments for HTE PWH, fostemsavir (FTR)+OBR and ibalizumab (IBA)+OBR, for the treatment of PWH with MDR, from a mixed US health care payer perspective.

Methods: A Markov state-transition model with a lifetime time horizon was developed. Transition probabilities between viral load categories were based on individual participant data from the CAPELLA trial for LEN+OBR and on relative efficacy parameters obtained from indirect treatment comparisons for comparators. Health state utilities were sourced from the literature. Costs included drug acquisition costs, drug administration costs, disease management costs, adverse event costs, AIDS-related event costs, and treatment switching costs and were sourced from red book costs, Medicare and Medicaid fees, and the literature. Costs and outcomes were discounted at 3% annually. The model was used to estimate total and incremental costs, life-years (LYs), quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios. A deterministic and a probabilistic sensitivity analysis, as well as scenario analyses, were performed to address elements of uncertainty in the model and to explore the robustness of the results.

Results: Over a lifetime time horizon, LEN+OBR was associated with the highest absolute QALYs (9.41) and the greatest number of LYs (12.09) compared with FTR+OBR (QALYs: 8.75; LYs: 11.26) and IBA+OBR (QALYs: 8.36; LYs: 10.78). LEN+OBR was also associated with the lowest total lifetime costs of the 3 interventions (LEN+OBR: $1,441,122 [US dollars]; FTR+OBR: $1,504,986; IBA+OBR: $1,524,396) and therefore was dominant over both comparators in the base case. LEN+OBR remained dominant vs FTR+OBR and IBA+OBR across the range of scenarios tested and LEN+OBR had a 99% probability of being cost-effective compared with FTR+OBR and IBA+OBR in the probabilistic sensitivity analysis at a willingness-to-pay threshold of $50,000/QALY.

Conclusions: This economic evaluation demonstrated that LEN+OBR provides meaningful increases in QALYs and LYs, and is dominant over a lifetime time horizon, compared with FTR+OBR and IBA+OBR for the treatment of PWH with MDR in the United States.