Second-Line Treatment Selection Among HER2-Directed Therapies: Comparing Efficacy, Safety, and Patient Factors

This episode focuses on practical decision-making for selecting among HER2-directed therapies after progression on chemo-immunotherapy. Sandra presents with confirmed HER2 Y772_A775dup mutation, brain metastases treated with stereotactic radiosurgery, normal hepatic and cardiac function, current medical leave status, and stated preference for oral therapy to minimize clinic visits. Dr. Doroshow emphasizes that without head-to-head trials demonstrating clear superiority, treatment selection becomes a genuinely shared decision between physician and patient. She outlines key factors informing patient discussions: efficacy profile of each agent, distinct side effect profiles, and practical considerations around insurance coverage and out-of-pocket costs. She notes an important paradox in drug coverage: intravenous therapies like trastuzumab deruxtecan may be covered through medical benefits with lower patient responsibility, while oral targeted therapies like zongertinib may fall under pharmaceutical benefits with significantly higher copays.

Regarding patient preferences around route of administration, Dr. Doroshow cautions against assumptions. While many patients prefer oral therapy to avoid routine infusion visits, others are comfortable with or even prefer intravenous administration, seeing it as reassurance they're receiving active treatment. The discussion turns to distinct safety signatures of available HER2-directed options. Trastuzumab deruxtecan carries risks of cytopenias, significant nausea and vomiting, and clinically meaningful interstitial lung disease or pneumonitis. HER2-selective tyrosine kinase inhibitors carry typical toxicities including elevated liver function tests, diarrhea, and rash. Sevabertinib causes more severe diarrhea and higher-grade EGFR-related toxicities compared to zongertinib because of off-target EGFR activity.

In the next episode, "Comparative Safety Profiles and Risk Management Counseling: ILD Risk and Patient Communication," Dr. Doroshow discusses her approach to safety counseling and emphasizes the critical importance of early symptom reporting.