Abstract C003: RAMP 205: A phase 1b/2a study of gemcitabine, nab-paclitaxel, avutometinib, and defactinib in untreated metastatic pancreatic ductal adenocarcinoma

Abstract

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) accounts for ~90% of pancreatic cancer. Surgery is the only curative treatment. Unfortunately, most patients are diagnosed with advanced disease and are not candidates for resection. Combination chemotherapy approaches have provided incremental improvements to PDAC outcomes. However, impact on survival for patients with inoperable disease remains modest, with a 2-year survival rate of less than 7%. Activating mutations in the KRAS oncogene are a key initiating event in ~80-90% of PDAC. Permanent activation of KRAS drives tumor cell proliferation and survival, tumor microenvironment modulation, and metabolic alterations in PDAC. Patients with KRAS mutant PDAC have worse outcomes compared to those with KRAS wild-type PDAC. In addition, hyperactivation of focal adhesion kinase (FAK) has been correlated with high stromal density, resulting in therapeutic resistance and poor survival. Avutometinib is a first-in-class oral RAF/MEK clamp that potently inhibits MEK kinase activity while also blocking the compensatory reactivation of MEK by upstream RAF. Defactinib is a selective inhibitor of focal adhesion kinase (FAK), which has been shown to mediate resistance to multiple anticancer agents. Preclinical data have shown that the combination of avutometinib + FAK inhibition (FAKi) + chemotherapy (gemcitabine + paclitaxel as a surrogate for nab-paclitaxel) induced tumor regression in a autochthonous KRAS/TP53 mutant PDAC mouse model. Prior clinical experience of defactinib + pembrolizumab + chemotherapy was safe, showed responses, decreased stromal density, and increased CD8+ T cell infiltration in patients with PDAC (NCT02546531). Methods: RAMP 205 is a multi-center, open-label, single arm Phase 1b/2a study of gemcitabine and nab-paclitaxel in combination with avutometinib and defactinib in patients with previously untreated metastatic PDAC (NCT05669482). The study is being conducted in 2 parts: Parts A (dose evaluation) and Part B (dose expansion). The starting dose is 2.4 mg avutometinib orally (PO) twice weekly + 200 mg defactinib PO twice per day, in combination with standard once weekly gemcitabine/nab-paclitaxel (QW IV). All study drugs are dosed 3 weeks on, 1 week off. Following determination of the Recommended Phase 2 Dose (RP2D) in Part A, Part B will evaluate efficacy of the RP2D via objective response rate (primary endpoint). Mandatory tumor biopsies and blood samples will be collected for correlative studies, including circulating tumor DNA, molecular profiling and pharmacodynamic markers. Eligible patients must have histologic or cytologic evidence of metastatic PDAC and measurable disease according to RECIST v1.1. Patients with prior or concomitant treatment for metastatic PDAC or prior treatment with RAS/MAPK or FAK inhibitors are not eligible. The study will enroll ~35 patients with 6-12 patients in Part A, and 23 patients in Part B. Citation Format: Kian-Haut Lim, Manuel Hidalgo, Mark H. O'Hara, Kristen R. Spencer, Ignacio Garrido-Laguna, David G. DeNardo, Vijeta Bhambhani, Gloria Patrick, Yaofeng Cheng, Silvia Coma, Jonathan A. Pachter, Louis J. Denis. RAMP 205: A phase 1b/2a study of gemcitabine, nab-paclitaxel, avutometinib, and defactinib in untreated metastatic pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr C003.