• Collaboration with The William Harvey Research Institute and Queen Mary University of London
• PL-8177 displayed pro-resolving and anti-arthritic effects in rodents

CRANBURY, N.J., Jan. 10, 2023 /PRNewswire/ -- Palatin Technologies, Inc. (NYSE American: PTN), a biopharmaceutical company developing first-in-class medicines based on molecules that modulate the activity of the melanocortin receptor system, today announced Frontiers in Immunology published a manuscript, "Pro-resolving and anti-arthritic Properties of the MC1 Selective Agonist PL8177",  summarizing data demonstrating PL8177 provides therapeutic effects in inflammatory conditions, including arthritis.

Palatin, in collaboration with The William Harvey Research Institute, Queen Mary University of London, in London, UK, conducted the study to assess the immunopharmacology of a PL8177 in vitro and in a mouse model of inflammatory arthritis. Key findings included PL8177 activation of mouse and human MC1 receptors and that PL8177 displayed pro-resolving activity (enhanced macrophage efferocytosis) and counteracted the inflammatory profile of zymosan-stimulated macrophages, reducing the release of IL-1β, IL-6, TNF-α and CCL-2. In the context of joint inflammation, PL8177 reduced the clinical score, paw swelling and incidence of severe disease as well as the recruitment of immune cells into the arthritic joint. 

"These results demonstrate that melanocortin-based therapies, and specifically those targeting the MC1 receptor (MC1r), are a promising strategy to manage chronic inflammatory diseases," said Carl Spana, Ph.D., President and CEO of Palatin. "This data adds to the robust body of pre-clinical and clinical safety and efficacy data for PL8177, demonstrating its anti-inflammatory and pro-resolving effects, including for inflammatory arthritis. We are excited to continue the PL8177 Phase 2 clinical trial for patients with ulcerative colitis, as well as other internal MC1r agonist development programs, to address unmet medical needs of the many patients suffering from inflammatory conditions."

The authors on the paper were Jose Garrido-Mesa and Bethan Lynne Thomas of The William Harvey Research Institute, John Dodd and Carl Spana of Palatin, and Mauro Perretti and Trinidad Montero-Melendez of The William Harvey Research Institute and the Centre for Inflammation and Therapeutic Innovation, Queen Mary University of London. The citation is https://www.frontiersin.org/articles/10.3389/fimmu.2022.1078678.

Drugs targeting the melanocortin system have emerged as promising therapeutics for several conditions, including inflammatory diseases, obesity and sexual dysfunction, with several already FDA approved. As illustrated in the publication, melanocortins are peptides that have anti-inflammatory and pro-resolving effects. Many of these effects are mediated by the melanocortin receptor 1 as reported in several experimental settings. As such, MC1r can be a viable target for the development of new therapies that mimic endogenous pro-resolving mediators. Palatin has multiple MC1r agonist candidates in pre-clinical and clinical development.

Palatin is conducting a Phase 2 multi-center, randomized, double-blind, placebo-controlled, adaptive design, clinical study of PL8177, with once daily (QD) oral dosing in adult UC subjects. The study is designed to enroll up to 28 adult subjects with active UC from approximately 22 sites. All subjects who meet the eligibility criteria will be randomized to receive either placebo or oral PL8177.

The PL8177-205 interim assessment is expected to occur in the first quarter of calendar year 2023, with final topline data anticipated in the second quarter of calendar year 2023. Additional trial information, including inclusion and exclusion criteria, can be found at https://clinicaltrials.gov/ via the identifier NCT05466890.

PL8177 is a synthetic cyclic heptapeptide with demonstrated efficacy in multiple animal inflammatory bowel disease models. PL8177 is a potent, selective agonist at the human melanocortin receptor-1, with sub-nanomolar affinity binding and EC₅₀ functional values. Palatin data demonstrates that the oral formulation of PL8177 was protected from degradation in the stomach and small intestine and delivered to the large intestine and colon over an extended period. In addition, orally administered PL8177 had a significant effect on resolving inflammation in a rat bowel inflammation model.

PL8177 in oral formulations has demonstrated repeated, robust efficacy in ulcerative colitis disease models. MC1r is found on epithelial cells and resident macrophages of the colon which are accessible from the lumen of the colon. Orally administered PL8177 is not systemically absorbed. PL8177 has the potential for excellent efficacy without safety concerns.

Ulcerative colitis is a chronic disease of the large intestine (colon), with inflammation and ulcerations that can cause significant abdominal pain, persistent diarrhea, loss of appetite and other symptoms. An estimated 1 million individuals in the United States are affected by ulcerative colitis, with over 350,000 diagnosed with moderate-to-severe disease. Existing treatments are not effective in a substantial portion of patients with moderate-to-severe ulcerative colitis, with certain severe cases resulting in surgical removal of the colon.

The melanocortin receptor ("MCr") system has effects on inflammation, immune system responses, metabolism, food intake, and sexual function. There are five melanocortin receptors, MC1r through MC5r. Modulation of these receptors, through use of receptor-specific agonists, which activate receptor function, or receptor-specific antagonists, which block receptor function, can have medically significant pharmacological effects. Many tissues and immune cells located throughout the body, including the gut, kidney and eye, express melanocortin receptors, empowering our opportunity to directly activate natural pathways to resolve disease inflammation.

Palatin is a biopharmaceutical company developing first-in-class medicines based on molecules that modulate the activity of the melanocortin receptor systems, with targeted, receptor-specific product candidates for the treatment of diseases with significant unmet medical need and commercial potential. Palatin's strategy is to develop products and then form marketing collaborations with industry leaders to maximize their commercial potential. For additional information regarding Palatin, please visit Palatin's website at www.Palatin.com and follow Palatin on Twitter at @PalatinTech.

Statements in this press release that are not historical facts, including statements about future expectations of Palatin, such as statements about PL8177 clinical trials and results, are "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933, Section 21E of the Securities Exchange Act of 1934 and as that term is defined in the Private Securities Litigation Reform Act of 1995. Palatin intends that such forward-looking statements be subject to the safe harbors created thereby. Such forward-looking statements involve known and unknown risks, uncertainties and other factors that could cause Palatin's actual results to be materially different from its historical results or from any results expressed or implied by such forward-looking statements. Palatin's actual results may differ materially from those discussed in the forward-looking statements for reasons including, but not limited to, results of clinical trials, regulatory actions by the FDA and other regulatory and the need for regulatory approvals, Palatin's ability to fund development of its technology and establish and successfully complete clinical trials, the length of time and cost required to complete clinical trials and submit applications for regulatory approvals, products developed by competing pharmaceutical, biopharmaceutical and biotechnology companies, commercial acceptance of Palatin's products, and other factors discussed in Palatin's periodic filings with the Securities and Exchange Commission. Palatin is not responsible for updating for events that occur after the date of this press release.

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