Palatin Announces Positive Preclinical Efficacy Data for Oral MC4R Agonist PL7737 in Animal Model of Obesity
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Oral PL7737 monotherapy produced rapid and significant weight loss after just 4 days of treatment
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Combination of oral PL7737 and tirzepatide resulted in additive weight loss effects
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IND-enabling toxicology program ongoing
- IND submission planned for 4Q2025; Clinical data expected in 1H2026
The preclinical study evaluated the weight loss effects of three oral doses of PL7737, both alone and in combination with tirzepatide (a GLP-1/GIP agonist), in a diet-induced obese (DIO) rat model. After 4 days of treatment, all results were statistically significant compared to vehicle control:
- PL7737 – Middle Dose: 5% weight loss
- PL7737 – High Dose: 10% weight loss
- Tirzepatide Alone: 5% weight loss
- PL7737 Middle Dose + Tirzepatide: 11% weight loss
- PL7737 High Dose + Tirzepatide: 15% weight loss
"The rapid and significant weight loss seen with oral PL7737, both as monotherapy and in combination with tirzepatide in this established animal model, is impressive and suggests the potential for meaningful weight reduction in humans," said
Earlier this year, Palatin reported positive Phase 2 results from a study evaluating the combination of bremelanotide (an MC4R agonist) and tirzepatide (a GLP-1/GIP agonist). The study met its primary endpoint over the 8-week treatment period with highly statistically significant results. Additionally, Palatin announced that the FDA granted orphan drug designation to PL7737 for the treatment of leptin receptor (LEPR) deficiency-related obesity, a rare genetic disorder that disrupts MC4R signaling due to mutations in the LEPR gene. The leptin-melanocortin pathway, located in the hypothalamus, regulates hunger, energy balance, and body weight. Individuals with LEPR deficiency often experience constant, intense hunger from a young age, leading to severe early-onset obesity. PL7737, an MC4R agonist, is designed to restore this disrupted signaling.
Melanocortin-4 Receptor Agonists Effect on Obesity
Hypothalamic neurons expressing the melanocortin-4 receptor (MC4R) play a central role in regulating stored energy, food intake, and body weight. Genetic mutations that inhibit signaling through the MC4R pathway lead to hyperphagia, decreased energy expenditure and early-onset obesity; such mutations have been identified as the cause of several rare genetic obesity disorders. MC4R agonism represents an attractive target for potential obesity treatments.
About Hypothalamic Obesity
Hypothalamic obesity is a rare and severe form of obesity caused by dysfunction or damage to the hypothalamus, the region of the brain that regulates appetite, satiety, and energy balance. Hypothalamic obesity can occur as an acquired condition, most commonly after surgery or radiation therapy for brain tumors such as craniopharyngioma, or as a congenital disorder associated with genetic syndromes and developmental abnormalities affecting hypothalamic function. Individuals with hypothalamic obesity typically experience rapid, excessive weight gain, uncontrollable hunger, and profound metabolic disturbances that are resistant to conventional diet, exercise, and behavioral interventions. There are currently no approved pharmacologic treatments specifically indicated for hypothalamic obesity, representing a significant unmet medical need.
About Melanocortin Receptor Agonists
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.
About Palatin
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.
Forward-looking Statements
Statements in this press release that are not historical facts, including statements about future expectations of
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