Economic evaluation of antibody-drug conjugates (ADCs) in patients with breast cancer: systematic review.

Introduction: Metastatic breast cancer (mBC) is a major global health challenge. Antibody-drug conjugates (ADCs), including trastuzumab emtansine (T-DM1), trastuzumab deruxtecan (T-DXd), and sacituzumab govitecan (SG), offer clinical benefits but are associated with high costs, making cost-effectiveness assessments essential for policy decisions.

Methods: This systematic review analyzed economic evaluations comparing T-DM1, T-DXd, and SG with conventional treatments in breast cancer. A search of four databases and gray Literature up to November 2024 included studies reporting ICERs, QALYs, and LYGs. Data were extracted per PRISMA and CHEERS guidelines.

Results: Twenty-nine studies from the USA, China, Brazil, Germany, Finland, Singapore, and Canada were reviewed. In the USA, ICERs for T-DXd ranged from $194,424/QALY (HR-) to $406,900/QALY, often exceeding WTP thresholds ($100K-$200K). It was cost-effective in HR- patients and those with good ECOG. In China, ICERs > $50,000/QALY exceeded the national threshold (~ $36,475/QALY). In Finland, T-DXd was cost-effective vs. T-DM1 (€55,360/QALY). T-DM1 was cost-effective in Canada (-$3,844/QALY) and select U.S. studies, but not in Brazil ($99,699/QALY) or China. Drug pricing was a key driver; U.S. results varied, perhaps due to modeling differences and sponsor bias. SG was not cost-effective in any country. ICERs ranged from $237,816/QALY (Singapore) to > $1.3 million/QALY (USA). In China, the cost-effectiveness probability was 0% at current prices.

Conclusion: T-DXd and T-DM1 may be cost-effective in select groups and high-income countries. SG is not cost-effective anywhere. Drug prices are the main determinant of value, highlighting the need for price negotiations and more regional studies.