Background and Objective Small-cell lung cancer (SCLC) is highly aggressive, and outcomes after relapse following platinum-based therapy remain poor. Tarlatamab, a DLL3-targeted bispecific T-cell engager, has demonstrated survival benefits in phase III trials. Given rising oncology expenditures, we evaluated the cost-effectiveness of tarlatamab versus chemotherapy from U. S. and Chinese payer perspectives. Methods We developed a three-state Markov model using efficacy inputs reconstructed from DeLLphi-304. Parametric survival extrapolation and Bayesian model averaging were applied over a lifetime horizon with 1-month cycles. Direct medical costs included drug acquisition and administration, monitoring, management of grade ≥3 adverse events, subsequent therapies, supportive care, and end-of-life care; utilities were obtained from published sources. Costs were expressed in 2025 U. S. dollars. Base-case willingness-to-pay (WTP) thresholds were 150, 000 per quality-adjusted life-years (QALYs) (U. S. ) and three times per capita GDP (China). Price-simulation analyses evaluated tarlatamab price ranges in both settings and identified per-mg threshold prices that satisfied WTP criteria. Results Tarlatamab yielded a 0. 15-QALY gain versus chemotherapy. Incremental costs were 198, 914. 10 in the United States and 61, 878. 59 in China, corresponding to ICERs of 1, 306, 254. 68 and 406, 352. 26 per QALY, respectively—both exceeding country-specific WTP thresholds. ICERs increased monotonically with the drug price. Deterministic and probabilistic sensitivity analyses indicated robustness; no plausible parameter variation reduced ICERs below prespecified thresholds. Subgroup results paralleled survival benefits, but all subgroup ICERs remained above WTP thresholds. Conclusion At current prices, tarlatamab is not cost-effective for SCLC after platinum-based therapy in the United States or China. Achieving cost-effectiveness would require prices at or below the thresholds identified in the simulations. Affordability constraints are more stringent in China than in the United States. These findings inform value-based pricing, reimbursement negotiations, and equitable access strategies.
Liu et al. (Fri,) studied this question.