The expanding oral SERD class is reshaping endocrine therapy, with implications that go far beyond convenience. These agents rely on biomarker-driven selection, particularly ESR1 mutations detected via ctDNA, which is becoming standard for guiding treatment switches. As more SERDs gain approval and real-world data emerge, differentiation in efficacy, tolerability and sequencing will inform both clinical and payer strategies.¹⁴ Health plans will need to decide whether to designate a preferred agent or support broader access based on patient-specific factors like mutation subtype and prior CDK4/6 exposure. Formulary design, diagnostics and adherence strategies must evolve together to ensure access to this expanding class. 

PROTACs: Targeted protein degradation enters the breast cancer arena 
PROTACs represent a novel therapeutic class designed to degrade disease-driving proteins rather than inhibit them. In breast cancer, investigational PROTACs targeting the estrogen receptor are showing promise in overcoming endocrine resistance, particularly in ER+/HER2– tumors. Agents like vepdegestrant are in Phase III trials, and early data suggest potential synergy with CDK4/6 inhibitors. As these therapies advance, they may offer new options for patients with limited responses to current endocrine strategies.¹⁵

Breast cancer treatment is evolving at an unprecedented pace, marked by increasing complexity and cost. From ADCs and oral SERDs to emerging PROTACs, breast cancer treatment is entering a new era of precision, personalization and therapeutic delivery. For managed care and oncology pharmacy leaders, the imperative is clear: stay up to date, adapt quickly, support biomarker-driven access, optimize site-of-care strategies and strike a balance between cost containment and equitable access to innovation.