Abstract PR-10: Phase 1b study of maintenance soluble beta-glucan (Odetiglucan) in combination with a CD40 agonistic monoclonal antibody (CDX-1140) in patients with metastatic pancreatic adenocarcinoma that had not progressed on first-line chemotherapy
Authors: O'Hara Mark H , Wattenberg Max , Garrido-Laguna Ignacio , O'Reilly Eileen M , Yellin Michael , Keler Tibor , Gargano Michele , Niles Nick , Drees Jeremy , Bose Nandita , Beatty Gregory L 
Published: September 2024

Background: Metastatic pancreatic ductal adenocarcinoma (mPDAC) has a dismal 5-year overall survival (OS) rate of 3%. Current standard of care provides only modest anti-cancer impact. Preclinical models show that combinations of myeloid agonists can induce strong anti-tumor activity in PDAC tumors resistant to immunotherapy, including immune checkpoint blockade (anti-CTLA4, anti-PD1). This study combines odetiglucan, a beta glucan pathogen-associated molecular pattern (PAMP), with CDX-1140, a fully human Ig2K agonistic monoclonal CD40 antibody, in the maintenance setting after cytotoxic chemotherapy induction. Preliminary findings are presented as the study was closed early for financial reasons. Methods: Patients with mPDAC who had not progressed after 4-8 months of 1L chemotherapy were enrolled and received weekly odetiglucan (4 mg/kg) plus every 3-week dosing of CDX-1140 (1.5 mg/kg). The primary endpoints were safety, MTD and RP2D, with secondary endpoints including DOR, PFS, ORR, and OS. Tissue and blood samples were collected at baseline and during treatment to evaluate immune pharmacodynamic responses. Results: A total of 5 patients received treatment on study including 4 patients who were efficacy evaluable and 1 patient who withdrew due to adverse event (arthralgia) after beginning treatment. Treatment-related emergent adverse events were seen in all patients with most common AEs including grade 1-2 arthralgia, chills, and fatigue. Grade 3 AEs included arthralgia (n=1), fatigue (n=1), and leukopenia (n=2). The ORR included 1 PR, 1 SD, and 2 PD. Two patients remained on treatment for &gt;100 days. The pharmacodynamic profile was consistent with the mode of action of odetiglucan and CDX-1140, including a reduction in peripheral Dectin-1 expressing monocytes and transient decreases in peripheral B cells. Patients with disease control (PR or SD, n=2) compared to patients with progression (PD, n=2) showed expansion of peripheral Ki67+ CD8+ T cells following treatment. Analysis of a paired tumor biopsy from 1 patient with PD confirmed penetration of odetiglucan into a liver metastasis with expansion of CD11b+ macrophages and a reduction of cytokeratin+ tumor content, but without significant changes in T cell infiltration. Conclusions: The combination of odetiglucan and CDX-1140 was feasible and safe when administered as maintenance therapy in patients with mPDAC whose disease had not progressed on 1L chemotherapy. Treatment produced encouraging activity with changes in immunological correlates associated with disease control. These early results support further investigation combining odetiglucan with a CD40 agonist in mPDAC.

Citation Format: Mark H O'Hara, Max Wattenberg, Ignacio Garrido-Laguna, Eileen M O'Reilly, Michael Yellin, Tibor Keler, Michele Gargano, Nick Niles, Jeremy Drees, Nandita Bose, Gregory L Beatty. Phase 1b study of maintenance soluble beta-glucan (Odetiglucan) in combination with a CD40 agonistic monoclonal antibody (CDX-1140) in patients with metastatic pancreatic adenocarcinoma that had not progressed on first-line chemotherapy [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr PR-10.