Antitumor activity of TAK-788 in NSCLC With EGFR exon 20 insertions

Abstract

Abstract Background We report results of a phase 1/2 open-label, multicenter study of TAK-788 (NCT02716116), an oral investigational EGFR/HER2 inhibitor. Methods Pts with advanced, previously treated NSCLC received daily TAK-788 in dose escalation and expansion cohorts based on tumor genotype. Antitumor activity was determined for pts with EGFR exon 20 insertions who received TAK-788 at the RP2D. Safety is reported for all pts across all doses and at 160 mg. Results As of 14 Sep 2018, 101 pts (median age, 61 y; female, 70%; ≥2 prior anticancer therapies, 76%; brain metastases, 53%) were treated with TAK-788 at 5-180 mg qd. RP2D was determined to be 160 mg. 28 pts with EGFR exon 20 insertions were treated with 160 mg qd during dose escalation or in expansion cohort 1 (3.6 mo on treatment; 3.8 treatment cycles [medians]); 24 pts remain on treatment. At data cutoff, best response (by RECIST v1.1) among 26 pts with ≥1 disease assessment was PR, n = 14; SD, n = 9; and PD, n = 1; 2 pts were not evaluable. 7/14 objective responses (all PR) were confirmed, with 6 awaiting confirmation and 1 unconfirmed PR at 160 mg qd; median time to response in these 14 pts was 56 days. 23/26 pts achieved disease control. 23/24 evaluable pts with EGFR exon 20 insertions treated at 160 mg qd had decreased target lesion measurements (median best percent change, -32.6% [-79.1%, 3.8%]). Most common TEAEs (≥20%) in pts treated with 160 mg qd: diarrhea (85%), rash (43%), nausea (41%), vomiting (30%), decreased appetite (28%), and stomatitis (22%); gr ≥ 3 TEAEs (≥5%): diarrhea (26%); hypokalemia, nausea, and stomatitis (7% each). Among pts treated with 160 mg qd, median dose intensity was 93%, and the rate of treatment discontinuation due to AEs was 10.7%. There is no clear trend that response to TAK-788 is enriched in any single EGFR exon 20 insertion variant. Conclusions In NSCLC pts with EGFR exon 20 insertions, TAK-788 demonstrated antitumor activity and an AE profile consistent with other EGFR TKIs.