Non-alcoholic steatohepatitis (NASH) is characterized by fatty changes in the liver with inflammation and hepatocellular injury that in advanced stages leads to fibrosis and cirrhosis and high mortality rates. NASH is frequently associated with other common metabolic abnormalities, such as insulin resistance and visceral obesity. Liver transplantation is currently the only therapeutic approach for severe NASH or other forms of liver fibrosis with no approved drug treatments. Organ transplantation is a difficult, risky and costly procedure with scarce organ availability and increased risk of developing cirrhosis in the transplanted liver from the original, highlighting the major unmet need for new therapeutic options. Protease-activated receptor-2 (PAR2) is a signaling receptor that is highly abundant in liver cells and inflammatory cells which controls inflammatory and fibrotic processes that lead towards severe NASH and liver cirrhosis. The cell-penetrating, lipidated PAR2 inhibitor PZ-235 was developed using pepducin technology and offers a unique opportunity to target the intracellular surface of G-protein coupled receptors (GPCRs) such as PAR2 with exquisite specificity, potency and long half-lives. PZ-235 is an advanced anti-inflammatory/anti-fibrotic drug candidate that targets PAR2 and blocks PAR2 signaling in hepatic stellate and inflammatory cells. PZ-235 reduces fatty liver steatosis and hypertriglyceridemia by up to 50%, and suppresses lobular inflammation and systemic alanine aminotransferase (ALT) levels in mouse models of diet-induced NASH similar to effects in a PAR2-deficient mouse strain. PZ-235 treatment gave a major improvement in NASH activity scores (NAS) in mice, which corresponded to suppression of histologic disease-progression. PZ-235 also significantly protected against severe pancreatitis, a common sequela seen with several of the newly approved type-II diabetes drugs. Together, these preclinical data identify PZ-235 as a potent and potentially effective drug candidate for NASH treatment.
In Aim 1, we will test the pharmacologic properties of PZ-235 with the milestones of showing significant delivery into liver and efficacy data to demonstrate blockade of the late 2nd fibrotic hit in liver/NASH mouse models, and provide pilot safety/tox data (systemic parameters, liver enzymes, body weight, injection site tolerability, hematology) in 60 day repeat dose daily administration in rodents.
Aim 2 will conduct GLP safety-toxicology and PK/PD studies of cGMP-produced PZ-235 in 2 species, with design of upcoming first-in- human phase I and II clinical trials in NASH patients with our gastroenterology and MR imaging clinical collaborators.
Nonalcoholic steatohepatitis (NASH) cirrhosis is one of the leading indications for liver transplantation in the United States with estimated 9-15 million Americans suffering from NASH. Protease-activated receptor-2 (PAR2) has been identified as an emerging therapeutic opportunity for the effective and safe treatment of NASH as a non-invasive pharmacologic therapy. This proposal provides a drug development blueprint for the rapid evaluation of a first-in-class PAR2 Pepducin inhibitor for the treatment of NASH.
|Shearer, Andrew M; Rana, Rajashree; Austin, Karyn et al. (2016) Targeting Liver Fibrosis with a Cell-penetrating Protease-activated Receptor-2 (PAR2) Pepducin. J Biol Chem 291:23188-23198|