Cardiol Therapeutics Inc. announced 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-1ß ("IL-1ß") 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 5th 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-1ß in vitro. In addition, cannabidiol was shown in vitro to significantly inhibit the transcription of IL-1ß 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 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-1ß secretion via NLRP3 inflammasome activation. Inflammatory cytokines IL-1ß and IL-6 were measured by ELISA.

The LPS+ATP combination increased IL-1ß concentration vs control (449.1 vs 6.4 pg/ml, p<0.0001); however, addition of cannabidiol treatment significantly reduced IL-1ß concentration (118.7 pg/ml, p<0.0001 vs. LPS+ATP). Furthermore, a dose-response reduction in IL-1ß 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-1ß and NLRP3 messenger RNA following LPS administration to J774.1 macrophages.

LPS was shown to significantly increase the transcription of NLRP3 and IL-1ß, but treatment with cannabidiol significantly reduced the level of transcription of both.