Palatin Technologies has announced the completion of enrollment in its Phase 2 clinical trial, BMT-801, which is investigating 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 trial, titled "A Phase II, Randomized, Double-Blind, Placebo-Controlled, Clinical Study Investigating the Safety, Tolerability, and Effectiveness of the Co-Administration of Bremelanotide with Tirzepatide (GLP-1/GIP) for the Treatment of Obesity," enrolled approximately twice the target of 60 patients, reaching around 120 participants across four US sites, driven by strong patient interest and efficient clinical trial operations. Topline results are anticipated in the first quarter of 2025.
Carl Spana, Ph.D., President and Chief Executive Officer of Palatin, stated, "We believe the study data will demonstrate that combination of an MC4R agonist, such as bremelanotide, with a glucagon-like peptide 1/gastric inhibitory polypeptide (GLP-1/GIP), such as tirzepatide, may result in synergistic effects on weight loss, allowing for increased weight loss at lower and better tolerated doses."
The BMT-801 trial's primary endpoint is to assess the safety and enhanced efficacy of combining 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 trial includes multiple safety and efficacy assessments to evaluate bremelanotide's effectiveness as a standalone treatment or in conjunction with GLP-1/GIP therapy. Additional details about the trial can be found at ClinicalTrials.gov (identifier: NCT06565611).
Rationale for MC4R Agonism in Obesity
Genetic studies have identified the melanocortin 4 receptor (MC4R) as a critical component in appetite regulation, located in the paraventricular nucleus of the hypothalamus. Disruptions in the MC4R signaling pathway can lead to hyperphagia, reduced energy expenditure, and early-onset obesity. Agonists of the MC4R, such as α- and β-melanocyte-stimulating hormone, promote satiety, making MC4R agonism a promising target for obesity treatments.
The Broader Context of Obesity
Obesity, defined as a body mass index (BMI) ≥30 kg/m2, is a growing global health concern associated with increased mortality and serious health conditions, including hypertension, hypercholesterolemia, type 2 diabetes, coronary heart disease, stroke, and certain cancers. In the United States, approximately 42% of adults and one in five adolescents aged 12-19 are affected by obesity. The global rise in obesity prevalence poses significant cost implications for healthcare systems, underscoring the need for safe and effective treatments.
Dr. Spana also noted the limitations of current GLP-1/GIP therapies, stating, "Weight loss is quick and substantial with GLP-1/GIP therapies, but both healthcare professionals and patients are seeking alternative treatments to these therapies due to 67% of patients discontinuing treatment because of side effects and a plateau effect in the first year. This often results in a rebound effect, with patients gaining back significant weight."
