Economic evaluation for the US of relatlimab and nivolumab (RELA+NIVO) versus nivolumab (NIVO) monotherapy in untreated advanced melanoma.

Abstract

9539 Background: The RELATIVITY-047 trial demonstrated longer median progression-free survival (PFS) with the combination of RELA+NIVO (10.1 months, 95% CI = 6.4 to 15.7) over NIVO (4.6 months, 95%CI = 3.4 to 5.6) in patients with untreated advanced melanoma (hazard ratio for progression or death = 0.75, 95%CI = 0.62 to 0.92). This economic evaluation aimed to estimate the cost-effectiveness/utility of RELA+NIVO vs. NIVO monotherapy in this setting. Methods: A two state partitioned survival model (PFS, progressed/death) was developed to compare costs and PFS outcome associated with both treatments. PFS curves were digitized and parametric functions fitted. A 5-year time horizon from a US payer perspective with a 3% discount rate/year was considered. Costs of treatment (average sales price), administration and monitoring parameters were derived from Centers for Medicare & Medicaid Services databases; cost of adverse events (grade 3/4 with rate >5%) were derived from prior advanced melanoma economic evaluations. Incremental costs, PFS life years (PFSLY), and PFS quality adjusted life years (PFSQALY) gained (g) were estimated in base case (BCA) and probabilistic sensitivity analyses (PSA). A cost-effectiveness acceptability curve (CEAC) was plotted to determine the probability of either treatment to be cost-effective over the other at different willingness to pay (WTP) thresholds. Results: Exponential regression was used to extrapolate RELA+NIVO and NIVO survival curves. According to the result table shown below, the BCA (PSA) shows an incremental cost of RELA+NIVO over NIVO of $405,663 ($402,936), incremental PFSLY of 0.326 (0.325), and incremental PFSQALY of 0.260 (0.256). The BCA (PSA) ICERs indicated an additional $1,244,365 ($1,239,803) per PFSLY gained (g) and an additional $1,560,242 ($1,573,969) per PFSQALYg. The CEAC curve shows that RELA+NIVO treatment had a 50% probability of being cost-effective regimen at a WTP threshold value of $1,525,000 and 100% probability at a threshold of $3,050,000 or above. Conclusions: In the setting of advanced melanoma, this economic evaluation showed that RELA+NIVO is associated with improvement in LY and QALY, however, at a marked incremental cost, requiring a very high WTP threshold. [Table: see text]