First-line serplulimab plus chemotherapy versus chemotherapy in PD-L1-positive esophageal squamous-cell carcinoma: a cost-effectiveness analysis

Patients with PD-L1-positive esophageal squamous-cell carcinoma (ESCC) were significantly more likely to survive when treated with serplulimab plus cisplatin plus 5-fluorouracil (serplulimab-CF). At this point, it is unknown whether this expensive therapy is cost-effective. From the Chinese healthcare system's perspective, we aimed to evaluate serplulimab-CF versus CF alone for cost-effectiveness. A partitioned survival model was constructed based on the ASTRUM-007 trial. Quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratio (ICER) were calculated. A further analysis of subgroups and scenarios was conducted. The willingness to pay (WTP) threshold of $38,258/QALY or $84,866/QALY is defined as three times the per capita gross domestic product value of the general region or affluent region. Compared with CF alone, in the overall (scenario 1), patients with PD-L1 expression level of 1 ≤ CPS < 10 (scenario 2), and patients with PD-L1 CPS ≥ 10 (scenario 3) populations, the ICERs were $69,025/QALY, $82,533/QALY, and $75,436/QALY for serplulimab-CF. Nevertheless, the probability of serplulimab-CF becoming cost-effective based on scenarios 1, 2, and 3 is only 2.71%, 0.94%, and 2.84%, respectively, at a WTP threshold of $38,258/QALY. When serplulimab costs < $4.84/mg, serplulimab-CF may be cost-effective at the WTP threshold of $38,258/QALY; otherwise, CF was preferred. Similar results were obtained from sensitivity analyses, suggesting the robustness of these findings. There was no cost-effectiveness in general regions of China for serplulimab-CF in PD-L1-positive ESCC compared to CF, although it is probably considered cost-effective in affluent regions. Serplulimab-CF may achieve favorable cost-effectiveness by lowering the price of serplulimab.