Targeting NFE2L2/KEAP1 Mutations in Advanced NSCLC with the TORC1/2 Inhibitor TAK-228.

9085 Background: Despite efforts over the past decade, no targeted therapy options exist for SQCLC pts. We have identified a heretofore untargeted oncogene (NFE2L2)/tumor suppressor (KEAP1) pair, each mutated in ~20% of patients with SQCLC. NFE2L2 encodes Nrf2, a transcription factor involved in the oxidative stress response which is targeted for degradation by Keap1. NFE2L2 mutations occur exclusively in an exon 2 hotspot that encodes the Neh2 domain (aa.1-86), which is the binding site for Keap1. Mutations in this region disrupt Keap1 binding, leading to Nrf2 nuclear translocation and increased mTOR signaling through RagD (Shibata Cancer Res 2010). We report translational studies and results from an ongoing phase 2 trial of the oral TORC1/2 inhibitor TAK-228. Methods: Cytotoxicity, signaling, and xenograft experiments were performed using LK-2 SQCLC cells (NFE2L2 E79K mut) treated with TAK-228, everolimus, rapamycin, or deforolimus. Pts with stage IV SQCLC harboring NFE2L2 or KEAP1 mutations and NSCLC harboring KRAS + NFE2L2 or KEAP1 co-mutations are treated on an NCI CTEP phase 2 study of TAK228 3mg po qd (continuous 28 day cycles; NCT02417701). Primary endpoint: ORR. Secondary endpoints: PFS. The study utilizes a Simon 2-stage design for each cohort with H0 = 5% (N≥1/5 responses), HA = 40% (N≥2/10 responses). Results: TAK-228 exhibited increased anti-tumor activity over TORC1 rapalogs in LK-2 cells. TAK-228 alone was cytotoxic at sub-[μM] (IC50 68nM); all other rapalogs exhibited IC50s > 10μM. This was associated with marked decrease in pS6, pAKT, and pERK. Tumor response (-55%) was seen in an LK-2 xenograft treated with TAK228. No anti-tumor/growth inhibitory response was seen with any other rapalog. N = 15 evaluable pts have been treated on study (7 NFE2L2, 3 KEAP1, 5 KRAS + NFE2L2 or KEAP1). 2 related-SAEs (G3 hyperglycemia, G3 confusion) were seen; there were no unexpected AEs. Within SQCLC NFE2L2 pts ORR = 29% (2/7 PR) and DCR = 100%. Prolonged duration of response is present, with PFS = 10.5mo, 11.4mo (18.2mo tx beyond PD), 6mo (8mo tx beyond PD), 5.5mo+, 4.5mo, and 1.5mo+. Within SQCLC KEAP1 pts DCR = 66% (2SD, 1PD) with PFS = 7.4mo+, 3mo+, 1mo. Data for the KRAS + NFE2L2/KEAP1 arm will be presented. Conclusions: TAK228 is tolerable with evidence of pre-clinical activity, radiographic responses, and prolonged DOR in biomarker-selected NSCLC pts. Accrual is ongoing. Clinical trial information: NCT02417701.