In a presentation at the 2024 Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer, Alex Francoeur, MD, University of California, Irvine, and colleagues discussed the findings from their study on the cost-effectiveness of immunotherapy regimes in upfront treatment with chemotherapy for patients with endometrial cancer. The study looked at patients with mismatch repair deficiency (MMRd) or mismatch repair proficiency (MMRp).

For the analysis, the authors used Markov models, which were based on available US Food and Drug Administration labeling information for dostarlimab, and on data from the RUBY and NRG-GY018 trials. They estimated incremental cost-effectiveness ratios (ICERs) based on progression-free-life-year saved (PF-LYS). In addition, they pulled the costs of the immunotherapy treatments (carboplatin, paclitaxel, dostarlimab, and pembrolizumab) from Medicare pricing.

The findings showed that when carboplatin and paclitaxel were used alone the cost was $636 per cycle (once every 3 weeks for a total of 6 cycles). The estimated costs of combination therapies were higher, with carboplatin, paclitaxel, and dostarlimab at $11,982 per cycle (once every 3 weeks for a total of 6 cycles), and carboplatin, paclitaxel, and pembrolizumab at $11,598 per cycle. For maintenance dostarlimab, the estimated cost was $11,346/cycle (once every three weeks for up to 3 years or 42 additional cycles). Compared to maintenance dostarlimad, the estimated cost of maintenance pembrolizumab was much higher at $21,924 per cycle (once every 6 weeks maintenance cycles at double the dose for up to 2 years, or 13 additional cycles).

For patients in the MMRp cohort, the ICER based on PF-LYS was $772,241 if they received dostarlimab and $522,711 if they received pembrolizumab. For the MMRd cohort, the study found that dostarlimab provides an estimated benefit of 22.6 months in progression-free survival (PFS), which correlates to an ICER of $241,020. Although the median PFS was not reached in the trial for pembrolizumab, it was longer than chemotherapy alone (36 months compared to 7.6 months, respectively).

In terms of extended treatment periods, when the authors estimated a 28.4-month benefit to PFS with a median PFS of 36 months, the ICER of pembrolizumab came out to $148,198. If PFS in the pembrolizumab group were to be extended to 40 months, the ICER would be $129,920. For pembrolizumab, each month of additional PFS beyond 36 months decreased by $5,021.

Overall, the study found that pembrolizumab may be more cost-effective than dostarlimab.

Source: Francoeur AA, Richardson MT, Johnson CR, Liang SY, Tewari KS, Chan JK. Cost effectiveness analysis of immunotherapy regimens in advanced or recurrent endometrial cancer: An analysis of the NRG-GY018 and RUBY Trials. Presented at the 2024 Society of Gynecologic Oncology (SGO) Annual Meeting on Women’s Cancer; March 16-March 18, 2024. San Diego, California.