Parabilis Medicines Inc (Nasdaq: PBLS), a clinical-stage oncology company developing the first reported direct inhibitor of the β-catenin interaction, raised USD 670 million in an upsized IPO priced above the marketed range, setting what appears to be a new record for the largest biotech IPO ever. The company sold 33.5 million shares at USD 20.00 each, exceeding both its original target of approximately USD 450 million and revised terms issued earlier on Tuesday. Including a concurrent USD 75 million private placement by Regeneron Pharmaceuticals, total proceeds reached approximately USD 745 million, underscoring strong investor appetite for platform-based oncology companies with clinical validation ahead of registrational studies.
The offering follows more than USD 800 million in private financing from investors including ARCH Venture Partners, Cormorant Asset Management, Fidelity Investments, GV, RA Capital Management, and venBio. Cormorant, RA Capital, and Fidelity are among the most active crossover investors in biotechnology and their participation was widely viewed as a signal of institutional demand ahead of the company's public debut.
The offering beats Kailera Therapeutics' USD 625 million raise completed in May this year.
Company background
Parabilis was founded in 2015 based on technology in-licensed from the laboratory of Greg Verdine at Harvard University. The company has spent a decade building what it describes as a proprietary Helicon discovery platform — a system integrating AI- and physics-based computational modelling with high-throughput peptide synthesis to design stabilized helical peptides capable of engaging intracellular protein targets that have resisted conventional drug design. The filing states that the platform's current operation is not dependent on the originally in-licensed technology or any third-party intellectual property.
Parabilis' lead asset, zolucatetide (formerly FOG-001), targets the Wnt/β-catenin signaling pathway and is being developed primarily for desmoid tumors, a rare soft tissue tumor driven by β-catenin pathway alterations. According to the company, 25 response-evaluable patients treated as of February 2026 all experienced some degree of tumor reduction, while 74% of 19 patients with at least two post-baseline scans achieved an objective response under RECIST 1.1 criteria. Zolucatetide has received US FDA Orphan Drug and Fast Track designations, and the company plans to initiate a global Phase III trial in H1 2027.