Economic evaluation of the novel PD-1 inhibitor toripalimab in recurrent or metastatic nasopharyngeal carcinoma: Cost-efficiency and expanded access modeling versus pembrolizumab.

Abstract

e18015 Background: Toripalimab, a novel anti-PD-1 antibody recently approved in the US as a breakthrough therapy in combination with gemcitabine and cisplatin (GemCis) for first-line treatment of adults with metastatic or recurrent locally advanced nasopharyngeal carcinoma (R/M NPC), is a category 1, NCCN-recommended preferred regimen. Although not FDA-approved for this indication, other PD-1 inhibitors, including pembrolizumab, are NCCN-recommended in combination with GemCis (category 2A but without direct evidence). The wholesale acquisition cost (WAC) of toripalimab at market entry is 80% that of pembrolizumab. This simulation modeling evaluates the cost-efficiency of toripalimab+GemCis versus pembrolizumab+GemCis in R/M NPC and the budget-neutral expanded access to the toripalimab regimen enabled by savings. Methods: Utilizing WAC drug costs and treatment administration costs, we modeled the cost-efficiency over a treatment duration equivalent to the toripalimab JUPITER-02 trial median PFS of 21.4 months (m). Without trial evidence for pembrolizumab+GemCis in R/M NPC, we assumed that such a regimen would be comparable to toripalimab+GemCis in median PFS. We also assumed that 31 cycles of PD-1 inhibitor (with GemCis in cycles 1-6) are administered over a median PFS of 21.4m. Using the cost-efficiency savings, we simulated the potential for budget-neutral expanded access to toripalimab treatment. A second model utilizing an ex ante toripalimab average sales price (ASP) of 80% of pembrolizumab ASP was estimated. Results: The WAC model estimated the toripalimab regimen to cost $292,316 (all agents over 21.4m or 31 cycles) while the pembrolizumab regimen costs $361,229, for savings of $68,913 per patient. These savings enable 7.7 additional toripalimab maintenance cycles to be purchased on a budget-neutral basis for every patient treated. For every 4.24 patients treated with toripalimab+GemCis instead of pembrolizumab+GemCis, one additional patient can be treated with the full toripalimab regimen (all agents) for 21.4m. Extrapolated to the 2024 US incident R/M NPC population of 1207 patients, if 50% of patients are treated with toripalimab+GemCis instead of pembrolizumab+GemCis savings of $41,589,183 provide access to 4,513 additional toripalimab maintenance cycles or 142 full toripalimab regimens (all agents for 21.4m) budget-neutrally. Similar results were demonstrated in the ASP model. Conclusions: With a market entry WAC that is 20% lower than pembrolizumab, toripalimab can generate approximate savings of $69,000 per patient over the median PFS treatment duration of 21.4m. If 50% of R/M NPC incident patients are treated with toripalimab, savings provide access to the full toripalimab+GemCis regimen to an additional 142 patients—effectively raising the treatment rate to 62% at no additional cost.