Cardiol Therapeutics Announces Study Results Demonstrating Protective Effects of CardiolRx™ in a Model of Acute Pericarditis

Oakville, ON – November 7, 2022 – Cardiol Therapeutics Inc. (NASDAQ: CRDL) (TSX: CRDL) (“Cardiol” or the “Company”), a clinical-stage life sciences company focused on the research and clinical development of anti-inflammatory and anti-fibrotic therapies for the treatment of heart diseases, announced today study results demonstrating that pharmaceutically manufactured cannabidiol (the active pharmaceutical ingredient in CardiolRx™) significantly reduces pericardial effusion and thickening in a pre-clinical model of acute pericarditis and significantly suppresses the secretion of key inflammatory markers interleukin-1β (“IL-1β”) and interleukin-6 (“IL-6”) in vitro. The data were presented by Cardiol’s research collaborators from Virginia Commonwealth University (“VCU”) at The American Heart Association Scientific Sessions 2022 (“AHA2022”).

The poster entitled “Protective Effects of Pharmaceutically Manufactured Cannabidiol in a Mouse Model of Acute Pericarditis” was presented on November 5^th within the “Late-Breaking Basic Science Posters” session of AHA2022. The authors concluded that the pharmaceutically manufactured cannabidiol administered in the study may represent a novel therapy for treating pericarditis and preventing its complications and recurrence. Data presented also demonstrated a dose-response effect on IL-1β in vitro. In addition, cannabidiol was shown in vitro to significantly inhibit the transcription of IL-1β and NLRP3, as measured by mRNA expression. NLRP3 is a sensor protein that comprises a part of the NLRP3 inflammasome, a large multiprotein complex that regulates inflammatory responses of the innate immune system. Cardiol has filed comprehensive patent applications with the U.S. patent office in connection with these new findings.

“The data presented at the AHA2022 by our research collaborators from VCU provides additional rationale for our recent decision to prioritize our Phase II pilot study in patients with recurrent pericarditis and offers new insight into the molecular targets and mechanism of action of CardiolRx™,” commented Dr. Andrew Hamer, Cardiol Therapeutics’ Chief Medical Officer and Head of Research & Development. “Pericarditis results from inflammation of the pericardium, the sac that surrounds the heart, and is manifested clinically by chest pain and by imaging signs of pericardial effusion and thickening. Significant accumulation of pericardial fluid and scarring can progress to life-threatening constriction of the heart. It is recognized that pericarditis is associated with aberrant inflammasome activation, an intracellular process leading to the release of pro-inflammatory cytokines, including IL-1β. The results presented over the weekend provide evidence that CardiolRx™ inhibits activation of the inflammasome pathway and other associated pro-inflammatory pathways. The magnitude of effect on multiple parameters as reported in the poster was notable and provides a strong scientific basis for investigating CardiolRx™ as a potential novel therapy in pericarditis care.”

The Company’s Phase II pilot study in recurrent pericarditis is expected to enroll 25 patients at major clinical centers in the United States specializing in pericarditis. The protocol has been designed in collaboration with thought leaders in pericardial disease. The study Chairman is Allan L. Klein, MD, Director of the Center of Pericardial Diseases and Professor of Medicine, Heart and Vascular Institute, at the Cleveland Clinic. The primary efficacy endpoint is the change, from baseline to 8 weeks, in patient-reported pericarditis pain using an 11-point numeric rating scale (“NRS”). The NRS is a validated clinical tool employed across multiple conditions with acute and chronic pain, including previous studies of recurrent pericarditis. Secondary endpoints include the pain score after 26 weeks of treatment, and changes in circulating levels of C-reactive protein, a commonly used clinical marker of inflammation.

In the pre-clinical in vivo study, acute pericarditis was induced by injecting Zymosan A, which activates NLRP3, into the pericardial sac thereby leading to the classical features of the inflamed pericardium: increased pericardial effusion and pericardial thickening; an accepted model of acute pericarditis. Groups were randomized to either receive intraperitoneal injections of cannabidiol, or an equal volume of vehicle control, administered following recovery from surgery. Pericarditis severity was assessed by the presence of effusion via echocardiography (measured as width of pericardial space) and pericardial thickening. Seven days after surgery the cannabidiol treated group had significantly reduced pericardial effusion (0.12 vs 0.26 mm, p<0.01) and pericardial thickness (3.6 vs 6.5 µm, p<0.05) when compared to the untreated control group.

In separate in vitro experiments, immune cells (J774.1 macrophages) were stimulated with lipopolysaccharide (“LPS”), adenosine triphosphate (“ATP”), or LPS+ATP, with or without cannabidiol. LPS+ATP induces IL‑1β secretion via NLRP3 inflammasome activation. Inflammatory cytokines IL-1β and IL-6 were measured by ELISA. The LPS+ATP combination increased IL-1β concentration vs control (449.1 vs 6.4 pg/ml, p<0.0001); however, addition of cannabidiol treatment significantly reduced IL-1β concentration (118.7 pg/ml, p<0.0001 vs. LPS+ATP). Furthermore, a dose-response reduction in IL-1β was observed with additional concentrations of cannabidiol. Separately, LPS alone was shown to significantly increase IL-6 concentration and that effect was abolished with cannabidiol treatment. LPS-induced IL-6 release is independent of NLRP3 activation, and the results suggest the effect of cannabidiol is not limited solely to the NLRP3 inflammasome pathway. Finally, gene expression using real-time polymerase chain reaction was performed for IL-1β and NLRP3 messenger RNA following LPS administration to J774.1 macrophages. LPS was shown to significantly increase the transcription of NLRP3 and IL-1β, but treatment with cannabidiol significantly reduced the level of transcription of both.

About The American Heart Association Scientific Sessions

Founded in 1924, the American Heart Association (“AHA”) is the oldest and largest voluntary organization dedicated to fighting heart disease and stroke. The AHA is a multidisciplinary organization who has invested more than $5 billion in research, making it the largest not-for-profit funding source for cardiovascular and cerebrovascular disease research next to the United States government. The AHA Scientific Sessions is an annual meeting that brings together academics, researchers, health care professionals, and industry to share the latest discoveries and biggest breakthroughs in cardiovascular science. Programming covers basic, clinical, and population science and is presented by global thought leaders.

About Recurrent Pericarditis

Recurrent pericarditis refers to inflammation of the pericardium (the membrane or sac that surrounds the heart) that follows an initial episode (frequently resulting from a viral infection). Patients may have multiple recurrences. Symptoms include debilitating chest pain, shortness of breath, and fatigue, resulting in physical limitations, reduced quality of life, emergency department visits, and hospitalizations. The only FDA-approved therapy for recurrent pericarditis, launched in 2021, is extraordinarily costly and is primarily used as a third-line intervention. The number of cases of patients seeking and receiving treatment for recurrent pericarditis annually in the U.S. is estimated at 38,000. Hospitalization due to recurrent pericarditis is often associated with a 6-8-day length of stay and cost per stay is estimated to range between $20,000 and $30,000 in the U.S.

About Inflammasomes

Inflammasomes are large multiprotein complexes which under normal conditions play an essential role in innate immunity and maintaining homeostasis. The inflammasome becomes abnormally activated under various conditions such as obesity, hypertension, diabetes, and autoimmunity. In the case of pericarditis, a trigger such as a virus may activate the inflammasome and elicit an inflammatory response through the release of pro-inflammatory cytokines such as IL-1β, thereby leading to the pericardial effusion and thickness characteristic of the disorder.