Abstract P048: A phase 2 study of VS-6766 (dual RAF/MEK inhibitor) RAMP 202, as a single agent and in combination with defactinib (FAK inhibitor) in recurrent KRAS-mutant (KRAS-MT) non-small cell lung cancer (NSCLC)

Abstract

Abstract Background: VS-6766 is a unique small molecule inhibitor of both RAF and MEK. In contrast to several other MEK inhibitors available, VS-6766 blocks both MEK kinase activity and RAF phosphorylation of MEK. This sequential blockade mechanism enables VS-6766 to block MEK signaling more consistently without the compensatory and paradoxical activation of MEK that reduces the efficacy of other small molecule inhibitors of MEK and RAF. Defactinib (VS-6063), an orally active small molecule, is a potent adenosine 5'- triphosphate (ATP) competitive, reversible inhibitor of focal adhesion kinase (FAK). Defactinib has shown synergistic activity with BRAF and MEK inhibitors in both in vitro and in vivo preclinical solid tumor models. Specifically, in several human tumor cell lines with mutations in RAS or BRAF or wildtype RAS and BRAF, defactinib has shown synergy with MEK inhibitors or VS-6766. In mouse models of KRAS mutant ovarian cancer, BRAF-mutant melanoma or uveal melanoma, FAK inhibition has been shown to induce tumor regression when combined with RAF, MEK or RAF/MEK inhibitors, while the single agents have only induced tumor stasis. The combination of VS-6766 and defactinib is currently being evaluated in the Investigator Sponsored FRAME study. Preliminary efficacy results are available for a small number of subjects with KRAS mutated NSCLC treated with a combination of VS-6766 and defactinib. Of the 10 subjects with NSCLC, 1 subject with KRAS-G12V- mutated cancer achieved PR while 3/10 subjects received treatment for ≥24 weeks. In an updated analysis of response in 15 subjects with KRAS-mutant NSCLC, there were 2 PRs and 7 SDs (ORR: 13%). The two subjects with KRAS G12V- mutated NSCLC both achieved PR (ORR: 100%). Methods: This is an adaptive, two-part, Phase 2, multicenter, parallel cohort, randomized, open label study designed to evaluate the efficacy and safety of VS-6766 versus VS-6766 in combination with defactinib in subjects with recurrent NSCLC(NCT04620330). The study will be conducted in two parts. Part A will determine the optimal regimen, either VS-6766 monotherapy or VS-6766 in combination with defactinib based on confirmed overall response rate as assessed by independent radiology review. Part A will consist of three arms in KRAS mutated NSCLC Arm 1 monotherapy of VS-6766, Arm 2 the combination of VS-6766 and defactinib in KRAS G12V mutated and Arm 3 the combination in other KRAS mutated. Part B will determine the efficacy of the optimal regimen identified in Part A in KRAS mutated NSCLC. Subjects enrolled must have histologic or cytologic evidence of NSCLC, measurable disease according to RECIST V1.1 and known KRAS mutation. The study will enroll up to 377 subjects globally with 57 subjects (32 KRAS G12V & 25 KRAS other) in Part A and an additional 144 KRAS G12V and 176 KRAS other in Part B. This study is open for enrollment. Citation Format: D. Ross Camidge, Jonathan Pachter, Andrew Koustenis, Gloria Patrick, David R. Spigel. A phase 2 study of VS-6766 (dual RAF/MEK inhibitor) RAMP 202, as a single agent and in combination with defactinib (FAK inhibitor) in recurrent KRAS-mutant (KRAS-MT) non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P048.