Regeneron agreed to buy a stake in Parabilis as part of a multi-target Helicon tie-up valued at up to $2.2 billion, adding an equity component and milestone-heavy economics. The collaboration uses Parabilis’ Helicon peptide platform to develop therapies against five undisclosed targets, with Regeneron committing $125 million up front and up to approximately $2.2 billion in additional milestone payments plus royalties. The deal comes as Regeneron faces pressure after its recent late-stage immunotherapy setbacks. Strategically, it shifts focus toward next-generation targeted delivery modalities that could improve binding or penetration in “hard-to-catch” tumor microenvironments.