Figure 1. One-way sensitivity analysis on the cost-effectiveness of IBA+OBR compared to OBR for people with MDR HIV in the US.

This tornado diagram shows the ICERs (x-axis) for IBA+OBR compared to OBR for multiple input parameters (y-axis). The base case value for each input parameter is listed in parentheses before the semi-colon. The range across which we varied each parameter is listed after the semi-colon, with the value resulting in the lowest ICER before the hyphen and the value resulting in the highest ICER after the hyphen. The dotted grey line shows the $100,000/QALY cost-effectiveness threshold. Since people were switched from ibalizumab combined with OBR to OBR alone if they developed a serious adverse event, an increasing probability of serious adverse events modestly decreased the ICER; this is because of the substantial cost difference between OBR alone and ibalizumab combined with OBR. In addition, when including the probability of failing ibalizumab after initial suppression, the cost savings associated with a shorter time on ibalizumab for those in the IBA+OBR strategy outweighed the life expectancy decrement, making the ICER somewhat lower than the base case ICER.

IBA: ibalizumab. ART: antiretroviral therapy. IBA+OBR: ibalizumab and optimized background regimen treatment strategy. OBR: optimized background regimen only treatment strategy. ICER: incremental cost-effectiveness ratio. QALY: quality-adjusted life year.

^aThese results reflect variation in the cost of both the loading dose and subsequent monthly doses, but only the monthly costs are listed.