MBX Biosciences has added to the recent flurry of IPO filings. The biotech, which filed its paperwork weeks after raising $63.5 million privately, is seeking funding to take a would-be challenger to Ascendis Pharma’s rare endocrine disease drug Yorvipath into phase 3 development.
Indiana-based MBX is built on technology designed to address the limitations of both unmodified and modified peptide therapies. By engineering peptides to improve their druglike properties, the biotech is trying to reduce the frequency of dosing, ensure consistent drug concentrations and otherwise establish product characteristics that improve clinical outcomes and simplify the management of diseases.
MBX used the platform to create the hypoparathyroidism candidate MBX 2109. The biotech is trying to provide continuous exposure to parathyroid hormone (PTH) with once-weekly dosing. MBX 2109 was generally well tolerated in phase 1, with no serious drug-related effects, and is now in phase 2.
Management is aiming to report top-line data in the third quarter of 2025 and advance the molecule into phase 3 using the IPO cash. The strategy puts the biotech on a collision course with Ascendis, a biotech that sells a once-daily PTH replacement therapy. MBX sees a need for a more convenient treatment that can normalize serum and urine calcium. AstraZeneca has a once-daily asset, eneboparatide, in phase 3.
GLP-1, the peptide at the heart of the obesity drug boom, is central to the rest of MBX’s pipeline. The company has a once-weekly GLP-1 receptor antagonist, MBX 1416, in development. MBX sees the asset as a potential treatment of post-bariatric hypoglycemia, a chronic complication of weight loss surgery.
The drug is in phase 1 testing. Data are due this year, and MBX plans to move into phase 2 using the IPO cash.
MBX has also earmarked some money to take an obesity candidate into the clinic. The prospect, MBX 4291, is a GLP-1/GIP receptor co-agonist prodrug. Eli Lilly already sells a GLP-1/GIP receptor co-agonist, tirzepatide, as Mounjaro in diabetes and Zepbound in obesity. However, tirzepatide is given once a week. MBX is aiming to achieve once-monthly dosing when it files to test its asset in humans next year.
Amgen’s bispecific GLP-1/GIP drug candidate AMG 133 could also support once-monthly dosing, but most molecules are targeting once-weekly administration. MBX is trailing Amgen, which is running a phase 2 trial of its once-monthly prospect.
The biotech submitted its paperwork the day after Bicara Therapeutics and Zenas Biopharma filed to go public. Like MBX, Bicara and Zenas are seeking cash to take candidates into and through late-phase trials.