Biomarker testing and treatment patterns in US patients (pts) with advanced/metastatic non-small cell lung cancer (NSCLC) harboring MET amplification

e21057 Background: Limited published evidence exists on pts with advanced stage NSCLC harboring MET amplification ( METamp), a rare oncogenic driver. We report here real-world biomarker testing and treatment patterns for these patients. Methods: This was a non-interventional, descriptive cohort study using ConcertAI electronic medical record data derived from US community oncology centers and linked with ASCO/CancerLinQ data. Eligible pts had stage IIIB–IV NSCLC and METamp. Study period: Jan 1, 2004 – Oct 31, 2021. Results: Of 8,454 lung cancer pts with minimum 1 molecular test including MET, 164 had METamp (1.9%). Pts were mainly identified from 2015 onwards and primarily in oncology in the Southern and Midwest regions (86.6%). Majority of pts were tested by tissue biopsy (67.1%), 20.7% by liquid biopsy and 12.2% not specified. At least 64.5% of pts were highly MET amplified (either gene copy number ≥8 or by liquid biopsy ++, +++). Other mutations screened for were ALK, ROS1 and EGFR (99.4%, 98.2% and 97.6%), with oncogenic ALK, ROS1 fusions and activating EGFR mutations in 0.6% and 13.1%, respectively. BRAF and KRAS were less frequently screened for (90.2% and 87.2%), with potential oncogenic alterations in 2.0% and 12.6%. Of 127 pts tested for PD-L1 (by immunohistochemistry), 63.0% were positive, and 72.5% had tumor proportion score ≥50. Eighteen pts had METamp detected after receiving an EGFR tyrosine kinase inhibitor (TKI), indicating METamp as a secondary oncogenic driver. RB1 loss and MYC amplification, as potential mechanisms of MET inhibition resistance, were not frequently screened for (30.5% and 46.3%). RB1 loss was identified in 2.0% and MYC amplification in 15.8%. Next generation sequencing was the most frequent diagnostic used overall. A total of 144 pts (87.8% of 164 pts) received first-line (1L) anticancer therapy; platinum-based chemotherapy 57/144 (39.6%), immune-checkpoint inhibitors 50/144 (34.7%) or EGFR TKI monotherapy 24/144 (16.7%), other 2/144 (1.4%) and MET TKIs (mainly crizotinib) were used in 11/144 pts (7.6%) in 1L, 14/78 (17.9) in second line and 7/42 (16.7%) in third line. Conclusions: In this cohort of pts identified in a US community oncology setting, biomarker screening even for rarer genetic alterations occurred. Concomitant genetic alterations to METamp were infrequent except for alterations of EGFR and KRAS. The frequency of pts with high level of METamp in the cohort may explain the lower frequency of other biomarkers, as high level of amplification indicates a cleaner MET profile. Overall MET inhibitor treatment was not common. Screening for novel and rare biomarkers such as METamp as a primary or secondary oncogenic driver is becoming increasingly important to enable efficacious targeted treatment.