Exicure Presents Cavrotolimod (AST-008) Clinical Data at AACR 2020 Virtual Meeting

Exicure, Inc. (NASDAQ: XCUR), the pioneer in gene regulatory and immunotherapeutic drugs utilizing spherical nucleic acid (SNA) constructs, is presenting updated pharmacodynamic and safety data at the American Association of Cancer Research (AACR) Virtual Annual Meeting II, occurring June 22 – 24, 2020.

The AACR poster, titled “Phase 1b/2 Study of an Intratumoral TLR9 Agonist Spherical Nucleic Acid (AST-008) and Pembrolizumab: Evidence of Immune Activation,” is presenting new preliminary pharmacodynamic and safety data of cavrotolimod (AST-008), alone and in combination with pembrolizumab, from Exicure’s ongoing Phase 1b/2 clinical trial (ClinicalTrials.gov identifier: NCT03684785). Cavrotolimod (AST-008) is a novel SNA configuration of a toll-like receptor 9 (TLR9) agonist oligonucleotide, designed to trigger anti-tumor immune responses.

Gene expression analysis data from patient tumor biopsies demonstrated increases in leukocytes in injected tumors after intratumoral (IT) cavrotolimod (AST-008) alone and in combination with pembrolizumab versus baseline. Uninjected tumors also showed increased immune cell levels after patients received cavrotolimod (AST-008) and pembrolizumab, suggesting immune cell trafficking.

Dose-dependent activation of key immune cells, including cytotoxic T cells and natural killer cells, as well as increases in cytokine/chemokine levels were observed in patient blood after IT cavrotolimod (AST-008) treatment alone, and cavrotolimod (AST-008) plus pembrolizumab treatment. We expect that activation of these cell types and expression of immune system signaling proteins may help produce anti-tumor effects.

Cavrotolimod (AST-008) was well-tolerated, with a safety profile consisting primarily of injection site reactions and flu-like symptoms, which is believed to reflect local and systemic immune activation. No cavrotolimod (AST-008)-related serious adverse events or dose limiting toxicity have been reported.

Using these data, a recommended Phase 2 dose of 32 mg cavrotolimod (AST-008) has been identified for the Phase 2 portion of the clinical trial now underway, where cavrotolimod (AST-008) will be given in combination with pembrolizumab or cemiplimab for the treatment of locally advanced or metastatic Merkel cell carcinoma or cutaneous squamous cell carcinoma, respectively, in patients with progression despite approved anti-PD-(L)1 therapy.