Abstract CT163: FIT-001: A phase 1 clinical trial of the farnesyl transferase inhibitor KO-2806 alone or as part of combination therapy for advanced solid tumors

Abstract

Abstract Background: Farnesyl transferase inhibitors (FTIs) block post-translational modification of RAS and other farnesylated proteins. HRAS-driven tumors are highly sensitive to FTI treatment. Recent clinical trials (NCT03719690, NCT02383927) of the FTI, tipifarnib, in patients with HRAS-mutant (HRAS-m) head and neck squamous cell carcinoma harboring high variant allele frequency mutations (VAF ≥20%), showed objective response rates of up to 50% and favorable long-term outcomes. KO-2806 is a next-generation FTI that has increased potency and improved pharmacokinetic properties. In preclinical studies, KO-2806 has been shown to: (1) enhance tumor growth inhibition of tyrosine kinase inhibitors, including cabozantinib, in multiple clear cell renal cell carcinoma (ccRCC) cell line- and patient-derived xenograft models; and (2) enhance activity of KRAS inhibitors, including adagrasib, in KRAS mutant non-small cell lung cancer (NSCLC), colorectal cancer (CRC), and pancreatic ductal adenocarcinoma (PDAC) mouse models. These preclinical data support clinical investigation of KO-2806 alone and in combination therapy. Study Design: FIT-001 is a first-in-human, multicenter, open-label clinical trial that will evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics (Pd), and preliminary antitumor activity of KO-2806 as monotherapy or in combination therapy in advanced solid tumors (KO-2806-001; NCT06026410). Up to 270 patients will be enrolled in phase 1a and phase 1b combined across 50 sites. Phase 1a will have separate monotherapy and combination dose-escalation arms. As monotherapy, the study will enroll patients with N/K/HRAS alterations in specific solid tumor types, such as NSCLC, CRC, and PDAC, who are refractory to standard-of-care therapies. KO-2806 and cabozantinib will be combined in patients with advanced or metastatic ccRCC who progressed on ≥1 prior line of immunotherapy-based systemic therapy; KO-2806 and adagrasib will be combined in patients with KRAS-G12C mutant locally advanced or metastatic NSCLC who received ≥1 prior systemic therapy. On the basis of emerging data from phase 1a, two Pd cohorts (n≤12) with mandatory pre- and on-treatment tumor biopsies may be enrolled. In each Phase 1b dose expansion, patients will receive the recommended phase 2 dose [RP2D] of KO-2806 with cabozantinib (in ccRCC) or adagrasib (in NSCLC), or will be randomized by dose if 2 potential KO-2806 RP2Ds are identified for a combination. Other combination arms may also be considered. The study began accrual in October 2023. Citation Format: Glenn J. Hanna, Douglas R. Adkins, Jacob S. Thomas, Justine Y. Bruce, Manish R. Patel, Guru Sonpavde, Jason Henry, Nawal Bendris, Zijing Zhang, Amitava Mitra, Amaya Gascó, Andrew Saunders, Stephen Dale. FIT-001: A phase 1 clinical trial of the farnesyl transferase inhibitor KO-2806 alone or as part of combination therapy for advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT163.