MBX aims for $136M IPO to take potential rival to Ascendis' Yorvipath into phase 3

MBX has fleshed out plans to take in over $136 million from its IPO as the biotech looks to bring a potential challenger to Ascendis Pharma’s rare endocrine disease drug Yorvipath into phase 3.

The Indiana-based company unveiled its IPO ambitions last month—weeks after raising $63.5 million in series C funds—and explained in a Securities and Exchange Commission filing this morning that it is planning to sell 8.5 million shares priced between $14 and $16 apiece.

Assuming the final share price falls in the middle of this range, MBX is expecting to bring in $114.8 million in net proceeds. The number could rise to $132.6 million if the IPO underwriters fully take up their option to buy an additional 1.2 million shares.

MBX’s tech is 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.

The company plans to use the IPO proceeds to advance its two clinical-stage candidates, including the hypoparathyroidism therapy MBX 2109. The aim is to report top-line data from a phase 2 trial in the third quarter of 2025 and then take the drug into phase 3.

MBX 2109 could ultimately find itself going up against Ascendis’ once-daily PTH replacement therapy Yorvipath, as well as racing alongside AstraZeneca’s once-daily entrant eneboparatide, which is already in phase 3.

In addition, MBX's IPO funds will be used to move the once-weekly GLP-1 receptor antagonist MBX 1416 into phase 2 trials as a potential treatment for post-bariatric hypoglycemia and to take a GLP-1/GIP receptor co-agonist prodrug called MBX 4291 into the clinic.