Managing Osimertinib Toxicity and Treatment Adherence in Adjuvant EGFR-Mutated NSCLC

Dr. Herbst asks Dr. Kareff about the real clinical challenge of managing osimertinib toxicity across a 3-year adjuvant course, noting a fundamental difference from the metastatic setting where patients are symptomatic at baseline and often feel dramatically better when targeted therapy starts. In the adjuvant setting, patients have had curative-intent surgery, are often feeling well, and must be motivated to tolerate ongoing drug-related adverse events for a disease they can no longer feel.

Dr. Kareff identifies fatigue and diarrhea as the most clinically significant tolerability issues in his adjuvant osimertinib patients. Although dermatologic toxicities such as rash and paronychia are manageable with evolving prophylactic strategies (informed by experience with amivantamab and other EGFR-targeting agents), gastrointestinal toxicities require active dose management. He describes using multiple dosing strategies to maintain patients on therapy: dose reduction from 80 mg to 40 mg daily, alternate-day 80 mg dosing, and alternating 80 mg and 40 mg dosing, choosing whichever approach a patient can tolerate to preserve the full 3-year adjuvant exposure. He emphasizes the multidisciplinary team role, including advanced practice providers and nurses, in coaching patients through toxicity-related challenges.

When a patient requests early discontinuation, Dr. Kareff uses transparent data sharing: presenting the quantified survival benefit at each time point to help the patient understand what is at stake, while remaining open to dose reduction or treatment holiday if quality of life is severely compromised. He describes this as genuine shared decision-making between clinician and patient rather than simply following a fixed protocol.