Silicon Therapeutics Presents Preclinical Data Showing a Systemic Small Molecule STING Agonist Drives Tumor Regression through a Potent Anti-Tumor Immune Response

Data Presented at AACR-NCI-EORTC Molecular Targets and Cancer Therapeutics Conference

Boston, MA, October 27, 2019 – Silicon Therapeutics today presented preclinical studies on its novel, small molecule, intravenously delivered STING (stimulator of interferon genes) agonist SITX-799, demonstrating the compound produced robust and durable anti-tumor immunity and tumor regression. Based on these and other promising studies, the company expects to begin clinical trials with SITX-799 in 2020. The data were presented at a poster session at the annual AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics in Boston, MA.

“STING is widely recognized as a very attractive but challenging immuno-oncology target because its activation requires both binding and conformational changes while maintaining the physical-chemical drug properties required for systemic exposure,” said Christopher Winter, PhD, Silicon’s Chief of R&D. “The first STING agonists to reach the clinic lack the drug properties required for systemic exposure and therefore are suitable only for patients with tumors accessible to intra-tumoral injection. The preclinical SITX-799 data demonstrating potent, systemic anti-tumor activity at doses that are well tolerated, suggest the compound has promising potential for broad utility as a cancer immune-therapeutic.”

“These data underscore the promise of our proprietary, physics-driven, discovery approach, which integrates physics with chemistry and biology, to develop novel therapeutics against difficult targets,” said Lanny Sun, Silicon Therapeutics co-founder and CEO. “Our STING agonist program, including SITX-799, is the most advanced of several programs in our innate immune pipeline.”

STING is a master regulator of type I interferons and a key mediator of innate immunity. Activation of STING provides two critical anti-tumor responses – (1) the “spark” for initiating a robust innate immune response and (2) priming and activation of a potent T cell-mediated anti-tumor adaptive response. By serving as a bridge between the two arms of the immune system, STING activation has the potential to transform the tumor microenvironment from immunologically “cold” to “hot” (inflamed), converting otherwise resistant tumors respond to checkpoint blockade as well as other T cell targeting immunotherapies.

In vivo studies presented at the conference show that a single dose of SITX-799 produced complete regression of colon cancer tumors in mice and robust induction of type I interferons. Cured mice were re-challenged with tumors 90 days after initial treatment and remained tumor free, demonstrating durable, anti-tumor immunity. No anti-tumor response to treatment was observed in mice lacking a functional immune system, demonstrating the immune-therapeutic mechanism of action. SITX-799 was shown to be well tolerated and demonstrated a favorable pharmacokinetic profile. In the poster, the company also presented in vitro data demonstrating potent, selective activity against all common human STING variants, rapid activation of the STING pathway, and induction of Type I interferon in human donor immune cells.

About Silicon Therapeutics

Silicon Therapeutics (“SiTX”) is a physics-driven drug discovery company focused on small molecule therapeutics for cancer that target innate immunity to “light the spark” within immunologically cold tumors. The company’s unique computational physics-based platform can accurately simulate the physical motions and properties of biological targets at atomistic resolution to reveal unique insights into the drug design process. The platform is cohesively integrated with a world-class wet lab including biophysics, chemistry, and biology to enable rapid hypothesis-driven data generation to advance drug discovery projects on targets that have traditionally been considered undruggable. The SiTX lead program is a small molecule STING agonist for systemic delivery in I/O that is slated to enter the clinic in mid-2020. The company’s headquarters and laboratories are in Boston, MA with additional operations in Suzhou, China.
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