MBX Biosciences has submitted an Investigational New Drug (IND) application to the U.S. Food and Drug Administration for MBX 4291, a long-acting GLP-1/GIP receptor co-agonist prodrug designed for once-monthly administration in obesity treatment. The submission marks a significant milestone for the clinical-stage biopharmaceutical company as it advances its novel precision peptide therapy toward human testing.
Novel Monthly Dosing Approach
MBX 4291 represents a potential advancement in obesity treatment through its once-monthly injectable design, which could offer significant advantages over currently approved weekly therapies. The drug is engineered to provide less frequent dosing and improved gastrointestinal tolerability, potentially resulting in better patient adherence and increased maximal weight loss.
"MBX 4291 is designed to be a potential best-in-class, once-monthly injectable for the treatment of obesity," said Kent Hawryluk, President and Chief Executive Officer of MBX Biosciences. "We believe MBX 4291 could potentially offer less frequent dosing and improved gastrointestinal tolerability, which may result in better adherence and increased maximal weight loss."
Promising Preclinical Results
In preclinical studies, the active component of MBX 4291 demonstrated a similar activity profile and body weight loss efficacy to tirzepatide, an approved weekly GLP-1/GIP co-agonist. Importantly, extended duration of action was observed in additional preclinical studies compared to tirzepatide, supporting the potential for once-monthly administration.
The drug was developed using MBX's proprietary Precision Endocrine Peptide (PEP) platform, which is designed to overcome key limitations of unmodified and modified peptide therapies. PEPs are selectively engineered to have optimized pharmaceutical properties, including extended time-action profiles and consistent drug concentrations with low peak-to-trough concentration ratios.
Clinical Development Timeline
Pending IND clearance from the FDA, MBX plans to initiate a Phase 1 clinical trial in the third quarter of 2025. The study will evaluate MBX 4291 in healthy overweight volunteers, representing the first human testing of this novel obesity treatment candidate.
Broader Pipeline Development
MBX 4291 is part of MBX Biosciences' broader pipeline of precision peptide therapies for endocrine and metabolic disorders. The company's other lead candidates include canvuparatide (MBX 2109), currently in Phase 2 development for chronic hypoparathyroidism, and imapextide (MBX 1416), in Phase 1 development for post-bariatric hypoglycemia.
The company is also advancing multiple early-stage obesity candidates using its proprietary platform to build precision peptides with differentiating characteristics. Founded by industry experts in peptide drug design, MBX Biosciences is based in Carmel, Indiana, and focuses on improving clinical outcomes and simplifying disease management for patients with endocrine and metabolic disorders.
