Exicure Reports Activity of AST-008 in Patients with Merkel Cell Carcinoma and Will Enroll Patients in Phase 2 Study

Source:  Exicure, Inc. 12/11/19

- Phase 1b/2 dose escalation trial of AST-008 shows tolerability of Exicure drug candidate

- Preliminary data show signs of activity in patients with Merkel cell carcinoma

- Exicure to proceed to Phase 2 study in Merkel cell carcinoma

Exicure, Inc. (NASDAQ:XCUR), the pioneer in gene regulatory and immunotherapeutic drugs utilizing spherical nucleic acid (SNA™) technology, today announced an update from its Phase 1b/2 trial with AST-008 in patients with solid tumors. AST-008 is an investigational SNA consisting of toll-like receptor 9 (TLR9) agonists designed for immuno-oncology application, and is being evaluated in combination with pembrolizumab in patients with solid tumors.

“We’re very pleased with the preliminary data generated so far in our ongoing Phase 1b/2 trial and we look forward to enrolling patients in the Phase 2 portion of the trial,” said Dr. David Giljohann, CEO of Exicure. “Based on these results, we are considering adding additional cohorts to the trial in other cancers where AST-008 may have benefit,” concluded Dr. Giljohann. 

The primary objective of the dose escalation portion of the study is to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of AST-008 alone and in combination with pembrolizumab, and to produce a recommended Phase 2 dose. Fourteen patients have been enrolled and dosed with AST-008. No treatment-related serious adverse events or dose-limiting toxicities have been observed. The fifth and final dose escalation cohort is now open and enrolling.

The study has enrolled five melanoma patients, four Merkel cell carcinoma (MCC) patients, two cutaneous squamous cell carcinoma patients, two head and neck squamous cell carcinoma patients, and one mucosal melanoma patient. Prior to enrolling, most patients had progressive disease on anti-PD-(L)1 antibodies. 

Available data show:

• AST-008 administration, alone or in combination with pembrolizumab, produced cytokine and chemokine expression and immune cell activation in patient blood indicative of desired immune activation.
• Of the 4 MCC patients, one patient, which had previously progressed on anti-PD-1 antibody therapy, has confirmed stable disease with decreased target lesion diameters for a period in excess of twelve weeks, while a second MCC patient experienced a target lesion complete response and a confirmed overall partial response longer than 24 weeks.
• Nine patients had progressive disease, two patients have not yet been evaluated and one is not evaluable.

“The initial results are highly encouraging and warrant expansion of the trial, and I'm looking forward to participating,” stated Dr. Steven O’Day, Executive Director of the John Wayne Cancer Institute and Cancer Clinic, and a principal investigator on the study.

Detailed results are expected to be presented at major upcoming oncology meetings. Based on these early results, showing positive biomarker data and initial tumor responses, Exicure anticipates enrolling MCC patients, which have previously failed anti PD-1/PD-L1 therapy, in its Phase 2 study during the first quarter of 2020.

About Exicure, Inc. Exicure, Inc. is a clinical-stage biotechnology company developing therapeutics for immuno-oncology, inflammatory diseases and genetic disorders based on our proprietary Spherical Nucleic Acid, or SNA technology. Exicure believes that its proprietary SNA architecture has distinct chemical and biological properties that may provide advantages over other nucleic acid therapeutics and may have therapeutic potential to target diseases not typically addressed with other nucleic acid therapeutics. Exicure's lead program is in a Phase 1b/2 trial in patients with advanced solid tumors. Exicure is based outside of Chicago, IL and in Cambridge, MA.
For more information, visit Exicure’s website at www.exicuretx.com.