Correlation of baseline molecular and clinical variables with ALK inhibitor efficacy in ALTA-1L.
D. Ross Camidge, Huifeng Niu, Hye Ryun Kim, James Chih‐Hsin Yang, Myung‐Ju Ahn, Jacky Yu-Chung Li, Maximilian J. Hochmair, Angelo Delmonte, Alexander I. Spira, Rosario García Campelo, Fabrice Barlési, Geoffrey Liu, Marcello Tiseo, Cong Li, Miguel Williams, Hyunjin Shin, Pingkuan Zhang, Sanjay Popat
Abstract
9517 Background: Efficacy of ALK TKIs in patients (pts) with ALK+ non-small cell lung cancer (NSCLC) varies. We evaluated the impact of EML4-ALK fusion variants and other baseline (BL) molecular and clinical variables on clinical efficacy of brigatinib (BRG) vs crizotinib (CRZ) as first ALK TKI therapy in pts with ALK+ NSCLC in the phase 3 ALTA-1L (NCT02737501) trial. Methods: Plasma samples were collected at screening for molecular genetic analysis of ALK and other genes implicated in NSCLC by next-generation sequencing. Exploratory analyses were performed to identify associations of clinical outcomes with oncogenic alterations including ALK fusion variants and TP53 status. Results: 124 BL samples were collected from 136 BRG-treated pts and 127 from 137 CRZ-treated pts. Pts with plasma samples were representative of the intent-to-treat population. BL ALK fusion detection rate was 52% (65/124) and 54% (68/127) in the BRG and CRZ arms, respectively, of which 83% (54/65) and 93% (63/68) were EML4-ALK fusions. In pts with detectable EML4-ALK fusions, the three predominant EML4-ALK fusion variants (V1, V2, V3) were equally distributed between arms; V1 and V3 were most prevalent (BRG/CRZ: V1, 42%/47%; V3, 42%/33%) but V1 was more frequent than V3 in pts without BL brain metastasis (47% vs 36%) or prior chemotherapy (45% vs 35%). Gender and age did not impact variant type. BRG showed higher ORR and improved mPFS vs CRZ in all variant subgroups; pts with V3 had poorer PFS compared with V1 and V2 regardless of treatment (Table). In pts with V3, BRG showed significantly improved PFS (HR=0.273, 95% CI 0.125, 0.597) and higher ORR (84% vs 67%) vs CRZ. TP53 mutation was detected in 30% (37/124) of pts in BRG arm and 26% (33/127) in CRZ arm. In pts with detectable ALK fusion, TP53 mutation showed poorer PFS in both arms than nonmutant/undetected cases (Table). BRG had better ORR and PFS vs CRZ in pts regardless of TP53 mutation status. Additional analyses of BL variables are ongoing. Conclusions: EML4-ALK fusion variant 3 and TP53 mutation were identified as poor prognosis biomarkers in ALK+ NSCLC. BRG demonstrated better efficacy than CRZ as first-line therapy in pts regardless of EML4-ALK fusion variant and TP53 mutation status. These findings may help define areas of greatest unmet need. Clinical trial information: NCT02737501 . [Table: see text]