Cost-effectiveness of pembrolizumab for previously treated MSI-H/dMMR solid tumours in the UK.

OBJECTIVES: Patients with previously treated microsatellite instability-high (MSI-H)/mismatch repair deficient (dMMR) tumours have limited chemotherapeutic treatment options. Pembrolizumab received approval from the EMA in 2022 for the treatment of colorectal, endometrial, gastric, small intestine, and biliary MSI-H/dMMR tumour types. This approval was supported by data from the KEYNOTE-164 and KEYNOTE-158 clinical trials. This study evaluated the cost-effectiveness of pembrolizumab compared with standard of care (SoC) for previously treated MSI-H/dMMR solid tumours in line with the approved EMA label from a UK healthcare payer perspective. METHODS: A multi-tumour partitioned survival model was built consisting of pre-progression, progressed disease, and dead health states. Pembrolizumab survival outcomes were extrapolated using Bayesian hierarchical models (BHMs) fitted to pooled data from KEYNOTE-164 and KEYNOTE-158. Comparator outcomes were informed by published sources. Tumour sites were modelled independently and then combined, weighted by tumour site distribution. A SoC comparator was used to formulate the overall cost-effectiveness result with pembrolizumab as the intervention. SoC comprised a weighted average of the comparators by tumour site based on market share. Drug acquisition, administration, adverse events, monitoring, subsequent treatment, end-of-life costs, and testing costs were included. Sensitivity and scenario analyses were performed, including modelling pembrolizumab efficacy using standard parametric survival models. RESULTS: Pembrolizumab, at list price, was associated with £129,469 in total costs, 8.30 LYs, and 3.88 QALYs across the pooled tumour sites. SoC was associated with £28,222 in total costs, 1.14 LYs, and 0.72 QALYs across the pooled tumour sites. This yields an incremental cost-effectiveness ratio (ICER) of £32,085 per QALY. Results were robust to sensitivity and scenario analyses. CONCLUSIONS: This model demonstrates pembrolizumab provides a valuable new alternative therapy for UK patients with MSH-H/dMMR cancer at the cost of £32,085 per QALY, with confidential discounts anticipated to improve cost-effectiveness further.

Association of guideline-concordant initial systemic treatment with clinical and economic outcomes among older women with metastatic breast cancer in the United States.

PURPOSE: We examined guideline-concordant initial systemic treatment among women with metastatic breast cancer, its predictors, and if guideline-concordant treatment was associated with mortality, healthcare utilization and Medicare expenditures. METHODS: This retrospective observational cohort study was conducted using the Surveillance, Epidemiology, End Results-Medicare linked database. Women aged 66-90 years diagnosed with metastatic breast cancer during 2010-2013 (N = 1282) were included. The National Comprehensive Cancer Network treatment guidelines were used to determine the guideline-concordant initial systemic treatment following cancer diagnosis. A logistic regression analysis was conducted to examine significant predictors of guideline-concordant treatment. Generalized linear regressions were used to examine the association between guideline-concordant treatment and healthcare utilization and average monthly Medicare expenditures. RESULTS: About 74% of the study cohort received guideline-concordant initial systemic treatment. Women who received guideline-concordant treatment were significantly more likely to be comparatively younger (p < 0.05), were married/partnered (p = 0.0038), had HER2 positive tumors, and had good performance status. Adjusted hazards ratios for all-cause (2.364, p < 0.0001) and breast-cancer specific mortality (2.179, p < 0.0001) were higher for women who did not receive guideline-concordant treatment. Rates of healthcare utilization were also higher for women not receiving guideline-concordant treatment. Average monthly Medicare expenditures were 100.4% higher (95% confidence interval: $77.3%-126.5%) for women who did not receive guideline-concordant treatment compared to those who received guideline-concordant treatment (p < 0.0001). CONCLUSION: One fourth of the study cohort did not receive guideline-concordant initial systemic treatment. Guideline-concordant initial treatment was associated with reduced mortality, and lower healthcare utilization and Medicare expenditures in women with metastatic breast cancer.