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Palatin to investigate MC4R agonist as a potentially effective and safe treatment for obesity

Palatin Technologies, a biopharmaceutical company developing first-in-class medicines based on molecules that modulate the activity of the melanocortin receptor system, plans to initiate a clinical study of melanocortin 4 receptor (MC4R) agonist, bremelanotide, an FDA approved product and 100% owned by Palatin, in combination with a Glucagon Like Peptide-1 (GLP-1) agonist, in patients with obesity in the first quarter of calendar year 2024.

GLP-1 agonists are currently the standard of care treatment for obesity. However, real-world use data shows that more than two-thirds (68%) of patients with obesity discontinue use in the first year. Side effects, especially at higher dose levels and a plateau effect, contribute to the high discontinuation rate.

Palatin's approach aims to address these issues by improving treatment adherence and promoting consistent long term weight loss through combination therapy. By co-administering an MC4R agonist with a GLP-1 agonist, Palatin anticipates achieving significant weight loss at lower doses, with improved tolerability. Combination drug therapy will be a key part of improving the overall health and quality of life for obese patients.

"With the increased use of FDA-approved GLP-1 agonists for treating obesity there is an unmet need for treatments with alternative mechanisms of action that will help obese patients meet and maintain their weight loss objectives. We believe the MC4R agonist is the best validated mechanism for adjunctive therapy with GLP-1 agonists and weight loss maintenance," said Dr Carl Spana, President and CEO of Palatin. "With our extensive experience in obesity research, a portfolio of novel selective MC4R agonists, and access to bremelanotide, an FDA approved MC4R agonist, we are well positioned to advance an MC4R agonist as a potentially effective and safe treatment for obesity."

In addition, Palatin announced a poster presentation of preclinical data, entitled ‘Melanocortin receptor 4 agonist PL8905 in Combination with Glucagon Like Peptide-1 Produces Synergistic Weight Loss, Reduced Food Intake, and Greater Glucose Control in Diet-Induced Obese (DIO) Rats’ (Dodd et al.), at the Peptide Therapeutics Symposium, in La Jolla, CA. The poster presented data evaluating the selective MCR4 agonist PL8905 from preclinical studies in which diet-induced obese animals were treated for 5 days with vehicle control, subcutaneous PL8905 alone and in combination with continuous infusion of a GLP-1 agonist. The poster revealed that:

  • Vehicle control and infused GLP-1 alone slightly increased body weight.

  • PL8905 monotherapy produced significant declines of 1.6% to 3.4% (p<0.01 vs vehicle).

  • PL8905 combined with GLP-1, had larger declines in body weight than monotherapy of 2.9% to 5.1% (p<0.01).

  • PL8905 combined with GLP-1 also showed a significant (p<0.01) reduction of blood glucose levels.

The use of combination therapy is supported by preclinical data with MC4R agonist PL8905 and two previous clinical studies with MC4R agonist bremelanotide demonstrating statistically significant effects on reducing food intake and weight loss in obese patients (published data; Spana C, Jordan R, Fischkoff S. Effect of bremelanotide on body weight of obese women: Data from two phase 1 randomized controlled trials. Diabetes Obes Metab. 2022;1-10).


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