Robert Pirker, MD, Professor of Medicine and Program Director for Lung Cancer at the Medical University of Vienna, Austria, discussed the findings at the “Top Abstracts” session of the 16th World Conference on Lung Cancer.
Based on these results and the findings of similar studies, Dr. Pirker believes that epidermal growth factor receptor (EGFR) fluorescent in situ immunohistochemistry or H score (which includes the percentage of cells and staining intensity by immunohistochemistry) may serve as a useful biomarker for anti-EGFR antibody treatment. “The consistency of sites warrants their clinical implementation,” he said.
Favorable Trends
Multiple studies have documented favorable trends related to gene copy number or fluorescent in situ immunohistochemistry positivity. For cetuximab, besides SWOG 0819, they include the FLEX trial (hazard ratio [HR] = 0.87, P = .04) and a meta-analysis (HRs = 0.88 for intention to treat and 0.77 for squamous, P = .009).
Another recent study of chemoradiotherapy plus or minus cetuximab (RTOG 0617) also showed that in patients with an H score ≥ 200, median overall survival was 42 months with cetuximab, vs 21 months in the control arm (HR = 0.58, P = .03).1
The reproducibility at multiple sites and in multiple datasets, he suggested, makes EGFR fluorescent in situ immunohistochemistry or H score “an excellent example of a predictive biomarker,” although he emphasized the need for them to be validated, for pathologists to be trained in interpretation, and for quality controls to be in place. ■
Disclosure: Dr. Pirker reported financial relationships with AstraZeneca, Merck Sharp & Dohme, Synta Pharmaceuticals, Boehringer Ingelheim, Pfizer, and Pierre Fabre.
Reference
1. Bradley JD, et al: Standard-dose versus high-dose conformal radiotherapy with concurrent and consolidation carboplatin plus paclitaxel with or without cetuximab for patients with stage IIIA or IIIB non-small-cell lung cancer (RTOG 0617). Lancet Oncol 16:187-199, 2015.
