Cost effectiveness analysis of immunotherapy regimens currently approved in advanced or recurrent endometrial cancer: An analysis of the NRG-GY 018, RUBY, and DUO-E trials

• Immunotherapy has become standard of care in advanced and recurrent endometrial cancer with multiple FDA approvals. • A cost effectiveness analysis was done with a partitioned survival model in FDA approved regimens for endometrial cancer. • Pembrolizumab appears to be more cost effective than dostarlimab and durvalumab but all regimens are costly. • More work is needed to improve the cost of novel therapeutics. The purpose of this project was to evaluate the cost-effectiveness of novel FDA approved regimens incorporating immunotherapy into upfront treatment with chemotherapy in advanced or recurrent endometrial cancer in the mismatch repair deficient (dMMR) and mismatch repair proficient (pMMR) cohorts. Partitioned survival models were established based on the RUBY, NRG-GY 018, and DUO-E trials, as well as available FDA data. Incremental cost-effectiveness ratios (ICERs) were estimated based on quality adjusted progression free life years saved (QA-PFLYS). Tree Age software was used to perform partitioned survival modeling. Outcomes for dMMR and pMMR groups were compared based on the current FDA approvals. Costs were obtained from Redbook Micromedex pricing and adjusted for inflation from study activation to public dissemination of trial results. The addition of pembrolizumab, dostarlimab, or durvalumab to chemotherapy in patients with dMMR tumors resulted in improvements in progression free life years saved. Based on QA-PFLYS, the ICER for pembrolizumab was $217,713, followed by $351,280 for durvalumab, and $451,750 for dostarlimab. When continuing durvalumab for 2 years, the ICER was $262,087. When looking at patients with pMMR tumors, the ICER for pembrolizumab was $250,535 while the ICER for dostarlimab was $1,349,776. Recognizing existing differences in study design, both pembrolizumab and durvalumab may be more cost effective than dostarlimab in our model. This appears to largely be driven by differences in duration of maintenance therapy rather than differences in effectiveness or individual drug cost. Immunotherapy does not appear to be as cost effective in the pMMR population.