DOI: 10.6084/m9.figshare.26318740.v1
title: Budget impact analysis of the novel PD-1 inhibitor toripalimab versus pembrolizumab in recurrent or metastatic nasopharyngeal carcinoma

description: To estimate the budget impact of adding a toripalimab regimen as a treatment option to the existing pembrolizumab regimen, both including gemcitabine and cisplatin, in untreated recurrent/metastatic nasopharyngeal carcinoma (R/M NPC) using the published wholesale acquisition cost (WAC) and average sales price (ASP). Budget impact analysis comparing a treatment mix “without” versus “with” the toripalimab regimen in the US eligible annual incident R/M NPC population, a 3-year time horizon, toripalimab/pembrolizumab market splits of 60/40 (Y1) and 80/20 (Y2/3), and medication adjustments for discontinuation or progression. Cost inputs included drugs, administration, and adverse event (AE) management. The models were replicated for a hypothetical 1-million-member health plan in which costs per-member-per-month (PMPM) and per-member-per-year (PMPY) were estimated. One-way (OWSA) and probabilistic sensitivity analyses (PSA) as well as scenario analyses were performed. In the “without” scenario, the 3-year WAC-based costs for the pembrolizumab regimen total $1,449,695,333 ($1,305,632,448 for treatment and $144,062,885 for managing AEs). In the “with” scenario, total 3-year costs for pembrolizumab decline to $380,012,135 with toripalimab adding $885,505,900 ($779,206,567 for treatment and $106,299,333 for AE management). Annual net savings range from $46,526,152 in 2024 to $71,194,214 in 2026, for 3-year savings of $184,177,298. Associated net savings in a 1-million-member health plan are $543,068 over 3 years with savings of $0.045 PMPM and $0.543 PMPY. The ASP-based model shows similar patterns with 3-year net savings of $174,235,983 in the US incident population and savings of $0.043 PMPM and $0.514 PMPY in a 1-million-member health plan. The PSA support base case findings; OWSA and scenario analyses reveal how parameter variability impacts results. Savings between $174 million and $184 million can be achieved from treating 60% of R/M NPC patients in year 1 and 80% in years 2 and 3 with the toripalimab regimen over a similar pembrolizumab regimen. Toripalimab, a human monoclonal anti-body that targets PD-1, was recently approved by the US Food and Drug Administration (FDA) for the first-line treatment of adults with metastatic or recurrent, locally advanced nasopharyngeal carcinoma (NPC), in combination with gemcitabine and cisplatin. We evaluated how much it would cost a payor to cover the FDA-approved toripalimab plus gemcitabine and cisplatin regimen (the toripalimab regimen) to a non-FDA-approved pembrolizumab plus gemcitabine and cisplatin regimen (the pembrolizumab regimen). With no trial data available for such pembrolizumab regimen, we assumed that it would be comparable to the toripalimab regimen in efficacy and safety. Our model adopted a 3-year time horizon and assumed a 60/40 market share split in year 1 and an 80/20 market split in years 2 and 3. It included two US cost inputs: the wholesale acquisition cost (WAC) or “list price” at market entry and, as no average sales price (ASP) will be available for toripalimab for several quarters, a toripalimab price point of 80% of the pembrolizumab ASP. We adjusted for patients whose cancer progressed or who discontinued treatment to determine the number of fully-treated-patient-equivalents. We found that treating 60% of NPC patients in year 1 and 80% in years 2 and 3 with the toripalimab regimen instead of the pembrolizumab regimen generates, for the entire adjusted patient population, savings ranging from $174 million when using ASP to $184 million when using WAC.