MBX Biosciences Begins Phase 2 Trial of MBX 2109 for Hypoparathyroidism

MBX Biosciences, Inc., a clinical-stage biopharmaceutical company, has commenced dosing in its Phase 2 Avail™ trial for MBX 2109, a long-acting parathyroid hormone (PTH) peptide prodrug designed for the treatment of chronic hypoparathyroidism (HP). This innovative therapy aims to offer a once-weekly administration, potentially reducing the frequency of dosing compared to existing treatments.

Kent Hawryluk, President and CEO of MBX Biosciences, expressed satisfaction with the progress, highlighting the promising results from Phase 1 studies which indicated favorable safety, pharmacokinetics, and pharmacodynamics profiles for MBX 2109. These findings support its potential as a pioneering once-weekly PTH therapy for HP. The company anticipates topline results from the Phase 2 trial by the third quarter of 2025.

The Avail trial is a randomized, double-blind, placebo-controlled study involving around 48 adult HP patients. Participants are divided into four groups receiving either a placebo or varying doses (400 μg, 600 μg, 800 μg) of MBX 2109 through weekly subcutaneous injections. The 12-week treatment phase includes a 4-week fixed dose period followed by an 8-week titration period. During titration, dosage adjustments are made based on patients' ability to reduce or discontinue active vitamin D and calcium supplements while maintaining normal serum calcium levels. The primary endpoint is the proportion of patients who can maintain these conditions after 12 weeks. Secondary endpoints cover safety, tolerability, pharmacokinetics, pharmacodynamics, and quality of life measures.

Upon completing the 12-week trial, patients are eligible for a 104-week extension study where all will receive MBX 2109. This extended phase will further assess the long-term efficacy and safety of the treatment.

Hypoparathyroidism, a rare endocrine disorder, is characterized by insufficient PTH production, leading to low calcium levels (hypocalcemia) in the blood. Symptoms range from muscle cramps and neurological issues to severe complications like seizures and cardiac arrhythmias, significantly affecting patients' quality of life. The disorder affects about 120,000 people in the U.S. alone, with a broader impact in Europe. The most common cause, affecting roughly 75% of cases, is accidental damage or removal of the parathyroid glands during neck surgery. Current treatments primarily involve high doses of oral calcium and active vitamin D, which do not address the underlying PTH deficiency.

MBX 2109, leveraging MBX Biosciences' Precision Endocrine Peptide™ (PEP™) platform, aims to provide a more consistent and convenient treatment option. The company's proprietary technology is designed to enhance the duration and stability of peptide therapies, offering lower peak-to-trough ratios and less frequent dosing requirements. MBX 2109 has obtained orphan drug designation from the U.S. Food and Drug Administration (FDA) for HP treatment.

MBX Biosciences, headquartered in Carmel, Indiana, specializes in developing novel precision peptide therapies for endocrine and metabolic disorders. The company's pipeline features several candidates, including MBX 1416 for post-bariatric hypoglycemia and multiple obesity treatments in various stages of development. The company is supported by prominent life science investors and aims to address significant unmet medical needs with its innovative approach to peptide drug design.