Parabilis Medicines filed for an initial public offering after inking a strategic collaboration with Regeneron focused on Helicon-based antibody-peptide conjugates. Parabilis’ IPO filing follows a partnership that includes upfront and equity-linked funding and multiple milestone and royalty opportunities tied to development and commercialization. The deal centers on Antibody-Helicon Conjugates (AHCs), pairing Regeneron’s antibody capabilities with Parabilis’ Helicon peptides designed to engage intracellular “undruggable” targets, including flat-surface protein interactions. Regeneron committed $50 million upfront and additional equity investment for Parabilis, with total potential value cited around $2.3 billion. In the IPO context, Parabilis said proceeds would support continued clinical development of zolucatetide (FOG-001) and a Phase 3 desmoid tumor program, with the company indicating multiple additional indication opportunities for the Wnt/β-catenin pathway inhibitor.