ImmuneSensor Therapeutics Initiates Dosing in Phase 1 Trial of Lead cGAS Inhibitor Drug Candidate

ImmuneSensor Therapeutics recently announced the first dose level cohort of healthy volunteers has been dosed in a Phase 1 randomized, double-blinded, placebo-controlled clinical trial of its lead oral cGAS inhibitor drug candidate, IMSB301, which is being developed for the treatment of a range of inflammatory and autoimmune diseases. The company’s approach and technology are based on the discoveries of Dr. Zhijian “James” Chen, whose groundbreaking work was recognized with the 2024 Albert Lasker Basic Medical Research Award.

“The cGAS-STING pathway is a central mediator of inflammation, and inhibiting the cGAS enzyme provides a therapeutic approach that has the potential to address diverse unmet medical needs across diverse inflammatory diseases,” said Tom Dubensky, PhD, ImmuneSensor’s President and Chief Executive Officer. “We anticipate having safety, pharmacokinetic, and target engagement data from our Phase 1 trial in healthy volunteers by the end of 2024, positioning us to efficiently transition into Phase 1b/2 clinical studies for patients with severe inflammatory conditions, specifically Type 1 interferonopathies. Our clinical strategy is to first evaluate IMSB301 in patients with Aicardi-Goutières syndrome (AGS), a rare inflammatory disease driven by chronic activation of the cGAS pathway. We will then assess IMSB301 in defined patient populations with cutaneous lupus erythematosus (CLE) and systemic lupus erythematosus (SLE).”

ImmuneSensor’s Phase 1 randomized, placebo-controlled, double-blinded clinical trial of IMSB301 is being conducted in healthy volunteers in Australia. The primary endpoint of the clinical study is safety and tolerability, along with pharmacokinetics (PK) and engagement (inhibition) of the cGAS target. The study will enroll cohorts of eight subjects each (two subjects receive placebo and six subjects receive IMSB301 at each dose) with up to five single ascending dose (SAD) levels, and subsequently up to three multiple ascending dose (MAD) levels. PK will be assessed in both SAD and MAD arms and cGAS target engagement will be evaluated in the MAD arm using an ex vivo whole blood DNA stimulation assay. The first dose cohort of the SAD arm has been completed with the observed exposure levels and PK as predicted from nonclinical IND-enabling studies.

The cGAS-STING pathway works to detect (“sense”) both host-derived and foreign cytoplasmic DNA produced as a result of infection or cell damage due to inflammation or malignancy. In autoimmune diseases, the innate immune response is chronically activated, directly promoting inflammation and the development of autoimmunity, both in the periphery and the central nervous system (CNS). IMSB301 is a novel, orally available small molecule designed to specifically inhibit the cGAS enzyme to prevent production of the cGAMP signaling molecule and halt pathologic inflammation. In preclinical studies, IMSB301 has been demonstrated to be a potent and specific inhibitor of cGAS enzymatic activity that results in a profound suppression of cytokine production and rescue of the disease phenotype and premature death in a model of AGS. ImmuneSensor is developing IMSB301 initially in cGAS-driven Type I interferonopathies including AGS, as well as CLE and selected patient populations with SLE. IMSB301 has the potential to address other diverse therapeutic areas that are characterized by cGAS-driven inflammation including diabetic kidney diseases, age-related macular degeneration, and other autoimmune disorders.

AGS is a rare genetic severe inflammatory disease in pediatric and adult populations, affecting the brain (demyelination) and peripheral tissues (lungs, liver, heart, skin) caused by germline mutations in upstream cytosolic nuclease genes, including TREX-1, that triggers chronic production of Type I interferon (IFN-I) and pro-inflammatory cytokines resulting from chronic activation of cGAS and the production of downstream signaling molecules. The disease has no cure and is currently treated with drugs designed to manage symptoms.

SLE is a complex autoimmune disorder that can be associated with the dysregulated production of IFN-I and other pro-inflammatory cytokines, which is thought to play a pivotal role in the pathogenesis of the disease. The disease is characterized by heterogeneous clinical manifestations, involving the skin, blood vessels, kidneys and central nervous system, which can result in serious organ damage and appears to develop when individuals with a genetic predisposition for the disease come into contact with an environmental “trigger.” The CDC estimates that approximately 204,000 people in the US have SLE, the most common type of lupus, with nine times as many women as men likely to develop the disease. Current standard of care involves treatment with anti-inflammatory drugs and immunosuppressants.

CLE is an autoimmune disease that causes the body’s immune system to attack healthy skin cells, resulting in a red, scaly rash. There are several types of CLE that are often triggered by sunlight, it can also arise as a complication of SLE. While it can affect people of any age or gender, it is most common among women 20 to 50 years old. There is no cure for CLE, and its symptoms are currently managed with anti-inflammatory drugs, immunosuppressants and lifestyle changes.

ImmuneSensor is a privately held, clinical-stage company founded on the groundbreaking discovery of cGAS and cGAMP along with their combined role in regulating immunity, by Dr. Zhijian Chen’s laboratory at the University of Texas Southwestern Medical Center, a breakthrough that has profoundly impacted both the scientific and pharmaceutical fields. ImmuneSensor is dedicated to developing best-in-class small molecule inhibitors and agonists of the cGAS-STING signaling pathway to potentially address therapeutic areas with significant unmet medical need in autoimmunity, inflammation and oncology. For more information, visit www.immunesensor.com.