Emerging Resistance Mechanisms and ADC Development

MET pathway involvement in EGFR resistance varies by initial treatment regimen. Dr. Devarakonda explains that MET amplification represents the most common known resistance mechanism following osimertinib-chemotherapy combinations, allowing EGFR blockade bypass.

MET amplification detection uses FISH or next-generation sequencing with arbitrary copy number cutoffs (typically 6-10 copies) lacking scientific standardization. Off-label tepotinib addition to osimertinib achieves 50% to 60% response rates, particularly with higher MET copy numbers. SAVANNAH study data confirm this approach, with formal clinical trials ongoing.

Amivantamab provides dual EGFR-MET blockade, representing an advantage in MET-amplified resistance settings. Alternative approaches include tepotinib combinations.

Dr. Rotow contextualizes antibody-drug conjugate development in EGFR-mutant disease, noting historical limitations of single-agent chemotherapy following targeted therapy and platinum failure. ADCs represent novel cytotoxic delivery mechanisms with potentially improved efficacy and tolerability profiles.

Datopotamab deruxtecan, a TROP2-directed ADC with topoisomerase I payload, demonstrates 40% response rates with approximately 6-month PFS in pooled EGFR-mutant analyses from TROPION studies. The agent slots into treatment sequences following third-generation TKI and platinum doublet therapy.

ADCs introduce unique toxicity profiles requiring lung oncologist adaptation, including stomatitis and ocular toxicity management through prophylactic mouthwashes and eyedrops. Interstitial lung disease represents a particular concern requiring careful monitoring and potentially affecting future clinical trial eligibility.