Managing ADC-Associated Nausea: Olanzapine-Based Strategies for Delayed Emesis Control

Dr. Rugo, NP Stephanie McDonald, and NP Liz Castronovo discussed the distinct gastrointestinal challenges posed by antibody-drug conjugates (ADCs) such as trastuzumab deruxtecan and datopotamab deruxtecan, focusing on "long-delayed nausea" that can persist for days to a week after infusion, a pattern that sets these agents apart from conventional chemotherapy-induced nausea.

The panel converged on olanzapine-based prophylaxis as a cornerstone of management. One recommended approach includes olanzapine 5 mg nightly for 4–5 nights post-treatment, a 5-HT3 antagonist (ondansetron or palonosetron), and dexamethasone 8 mg for 3 days. This strategy draws support from the ERICA trial, a Phase III study showing that adding olanzapine significantly reduced delayed nausea risk. NCCN guidelines recommend a triplet of an NK1 receptor antagonist, corticosteroids, and a 5-HT3 antagonist, positioning olanzapine as post-treatment prophylaxis rather than pre-medication.

Tailoring regimens to the individual patient is essential. A dexamethasone taper, rather than abrupt discontinuation, can mitigate the fatigue "crash" some patients experience after short courses of high-dose steroids. Scheduling nadir visits provides an opportunity to reassess antiemetic efficacy while treatment details are still fresh.

Prevention from cycle 1 is paramount, as effective early prophylaxis preserves nutrition, hydration, and quality of life. Patient education is equally important: Clinicians should proactively counsel on common antiemetic side effects, particularly ondansetron-related constipation and olanzapine-associated fatigue, to support adherence and timely symptom reporting.