ADCs and Oral SERDs Reshape Breast Cancer Pharmacy Role: Tiffany Meng, PharmD

Antibody-drug conjugates (ADCs) and oral selective estrogen receptor degraders (SERDs) are changing how breast cancer is treated and creating new responsibilities for oncology pharmacists, according to Tiffany Meng, PharmD, an oncology pharmacist at University of California, San Francisco, Health Mission Bay.

ADCs Reduce Reliance on Traditional Chemotherapy

In an interview at an Institute for Value-Based Medicine® event in San Francisco on August 11, 2026, hosted by The American Journal of Managed Care^®, Meng said the growing use of ADCs has shifted practice away from traditional chemotherapy. Because ADCs tend to produce more targeted adverse effects rather than the broad toxicity associated with conventional agents—including hair loss and widespread cell depletion—patients often tolerate treatment better.

"Things we used to look out for with traditional chemotherapy side effects may not be applicable with these new therapies,” she explained.

That shift brings new challenges for pharmacists, Meng said. As these newer agents move from later lines of therapy into frontline use, pharmacists must reassess treatment sequencing on an ongoing basis.

HER2 Testing Has Become More Nuanced

The rise of HER2-targeted ADCs, such as trastuzumab deruxtecan (Enhertu; Daiichi Sankyo, AstraZeneca), has also complicated biomarker testing, Meng said. HER2 status is no longer a binary positive or negative classification; the emergence of HER2-low and HER2-ultralow categories now allows patients who previously did not qualify for HER2-targeted therapy to receive one.

Oral SERDs are similarly changing care delivery, Meng said. For years, fulvestrant injections—requiring infusion center visits every 4 weeks—were the only SERD option. Oral alternatives now let patients manage treatment at home, but they introduce new barriers around adherence, insurance coverage, and adverse effect monitoring.

Meng said these changes require pharmacists to continually update their knowledge of new agents, noting that toxicity profiles familiar from traditional chemotherapy often do not apply to newer targeted therapies.