Palatin Advances Oral MC4R Agonist PL7737 for Obesity Treatment with Promising Preclinical Data
核心洞察
Palatin Technologies presented data at ObesityWeek 2025 showing their oral MC4R (搜索) agonist PL7737 demonstrated dose-dependent weight loss and favorable safety profile in preclinical models.
Clinical data from the BMT-801 study revealed that combining an MC4R (搜索) agonist with tirzepatide led to greater weight loss than tirzepatide alone without additional safety concerns.
The FDA has granted Orphan Drug Designation to PL7737 for leptin receptor deficiency-related obesity, with IND filing and Phase 1 trials planned for the first half of 2026.
Palatin Technologies presented compelling preclinical and clinical data at ObesityWeek 2025 demonstrating the therapeutic potential of melanocortin-4 receptor (搜索) (MC4R (搜索)) agonists for obesity treatment, with their lead oral candidate PL7737 showing promising efficacy and safety profiles.
Preclinical Success for Oral MC4R Agonist
PL7737, an orally bioavailable selective small molecule MC4R (搜索) agonist, demonstrated robust weight loss capabilities in preclinical studies. In diet-induced obese mice, the compound produced dose-dependent, statistically significant weight loss with no observed effect on systolic blood pressure. The drug exhibited favorable pharmacokinetic properties, including approximately 50% oral bioavailability and a half-life exceeding three hours in rats.
Safety assessments revealed encouraging tolerability profiles, with no hERG or Ames assay findings and no toxicity observed in a 28-day non-GLP rat study. "These results position PL7737's potential as a differentiated oral therapy for obesity," said Carl Spana, Ph.D., President and Chief Executive Officer of Palatin. "While additional studies are underway, the strength and consistency of the early data reinforce confidence in its safety, efficacy, and broad therapeutic potential across diverse obesity mechanisms."
Clinical Evidence for Combination Therapy
The Phase II BMT-801 study evaluated the safety and efficacy of combining bremelanotide, a melanocortin-4 receptor (搜索) agonist, with tirzepatide in patients with obesity. Key findings demonstrated that adding a low dose of an MC4R (搜索) agonist led to greater weight loss compared to tirzepatide alone. The combination was well tolerated with no new safety concerns observed and no increase in gastrointestinal side effects.
Notably, sustained weight maintenance was achieved, as low-dose MC4R (搜索) activation helped prevent weight regain after stopping tirzepatide treatment. "The BMT-801 proof-of-concept study provides meaningful clinical evidence supporting the role of MC4R agonists as complementary to incretin-based therapies," continued Dr. Spana.
Regulatory Milestone and Development Timeline
The U.S. Food and Drug Administration has granted Orphan Drug Designation to PL7737 for the treatment of leptin receptor (LEPR) deficiency-related obesity, a rare genetic condition caused by disrupted MC4R (搜索) signaling. IND-enabling toxicology studies are currently ongoing, with an IND filing and initiation of a Phase 1 single- and multiple-ascending dose trial expected in the first half of 2026. Clinical data is anticipated in the second half of 2026.
Addressing Unmet Medical Need
Hypothalamic obesity represents a significant unmet medical need, characterized as a rare and severe form of obesity caused by dysfunction or damage to the hypothalamus. This condition can occur as an acquired condition, most commonly after surgery or radiation therapy for brain tumors such as craniopharyngioma, or as a congenital disorder. Individuals with hypothalamic obesity typically experience rapid, excessive weight gain, uncontrollable hunger, and profound metabolic disturbances that are resistant to conventional interventions. Currently, no approved pharmacologic treatments exist specifically for hypothalamic obesity.
Mechanism of Action
Hypothalamic neurons expressing the melanocortin-4 receptor (搜索) play a central role in regulating stored energy, food intake, and body weight. Genetic mutations that inhibit signaling through the MC4R (搜索) pathway lead to hyperphagia, decreased energy expenditure and early-onset obesity, making MC4R agonism an attractive target for potential obesity treatments.
Palatin is also developing next-generation selective peptide MC4R (搜索) agonists designed for once-weekly subcutaneous dosing, with an IND filing and Phase 1 trial planned for mid-2026. Phase 1 studies are expected to include patients with hypothalamic obesity, further expanding the therapeutic potential of this mechanism-based approach to obesity treatment.