Parabilis Medicines moved to the public markets, filing for an IPO days after signing a major strategic research collaboration with Regeneron to pursue “undruggable” targets. The Regeneron deal pairs Helicon stabilized, cell-penetrant helical peptides with Regeneron’s antibody capabilities, funding five initial targets and enabling both standalone Helicon therapies and Antibody-Helicon Conjugates. Under the partnership, Parabilis is set to receive $50 million upfront and an additional $75 million equity investment in its next financing round, with development, regulatory and commercial milestones totaling up to roughly $2.3 billion-plus. The collaboration also supports manufacturing and global commercialization once discovery-stage candidates progress. Separately, Parabilis filed additional IPO materials reflecting plans to fund Phase 3 development of its Wnt/β-catenin pathway inhibitor zolucatetide (FOG-001) for desmoid tumors, targeting a registrational trial start in the first half of 2027. Earlier clinical results in desmoid tumors contributed to FDA fast-track and orphan-drug designations, according to the company’s filings. Together, the transactions underscore how late-stage private financing and large pharma science deals are increasingly bridging the IPO downturn, while keeping clinical catalysts in view for public-market investors.