Palatin Technologies Inc. (NYSE American: PTN) has announced the completion of enrollment in its Phase 2 clinical trial, BMT-801, which investigates the co-administration of bremelanotide, a melanocortin 4 receptor (MC4R) agonist, with tirzepatide, a glucagon-like peptide 1/gastric inhibitory polypeptide (GLP-1/GIP) receptor agonist, for the treatment of obesity. The study, conducted across four U.S. sites, enrolled approximately twice the initially targeted 60 patients due to strong patient demand.
The trial's primary endpoint is to assess the safety and increased efficacy of co-administering bremelanotide with tirzepatide in reducing body weight. Patients initially receive tirzepatide alone for four weeks before being randomized into one of four treatment regimens. The study involves multiple safety and efficacy assessments to profile the effectiveness of bremelanotide, both as a standalone treatment and in conjunction with GLP-1/GIP therapy. Topline data is expected before the end of March 2025.
Rationale for Combination Therapy
According to Carl Spana, Ph.D., President and Chief Executive Officer of Palatin, combining an MC4R agonist like bremelanotide with a GLP-1/GIP such as tirzepatide may lead to synergistic effects on weight loss. This could potentially allow for increased weight loss at lower, better-tolerated doses. Dr. Spana noted that while GLP-1/GIP therapies induce quick and substantial weight loss, a significant number of patients discontinue treatment due to side effects or experience a plateau effect, often leading to weight regain. Palatin believes that MC4R agonists, particularly their highly selective compounds, could play a crucial role in treating obesity, either as a monotherapy or in combination with other treatments.
The Role of MC4R in Obesity
The melanocortin 4 receptor (MC4R), located in the paraventricular nucleus of the hypothalamus, plays a central role in appetite regulation. Genetic mutations that inhibit signaling in the MC4R pathway can lead to hyperphagia, decreased energy expenditure, and early-onset obesity. Agonists of the MC4R, such as α- and β-melanocyte-stimulating hormone, promote satiety, making MC4R an attractive target for potential obesity treatments.
Obesity: A Growing Public Health Concern
Obesity, defined as a body mass index (BMI) ≥30 kg/m2, is a rising global health concern associated with increased risks of mortality and serious health conditions, including hypertension, high cholesterol, type 2 diabetes, coronary heart disease, stroke, and certain cancers. In the United States, approximately 42% of adults and one in five adolescents between 12 and 19 years old are affected by obesity. The development of safe and effective obesity treatments remains a critical unmet need.
Palatin's Broader Strategy
Palatin Technologies is focused on developing first-in-class medicines based on molecules that modulate the activity of melanocortin receptor systems. Their strategy involves developing products and forming marketing collaborations with industry leaders to maximize commercial potential. The data from this MC4R + GLP-1/GIP combination study is expected to inform and support Palatin's programs for treating general obesity, weight loss management, and potentially rare/orphan MC4R pathway diseases, including hypothalamic obesity. Additional trial information can be found at clinicaltrials.gov via the identifier NCT06565611.
