On May 18, 2026 Parabilis Medicines reported a strategic research collaboration with Regeneron Pharmaceuticals, Inc. to discover and develop multiple therapeutic candidates based on Parabilis’s Helicon peptide platform, with a particular focus on Antibody-Helicon Conjugates (AHCs), a novel class of therapeutics designed to target challenging and historically "undruggable" targets.
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Helicons are stabilized, cell-penetrant alpha-helical peptides designed to engage intracellular protein targets, including flat surfaces not well suited to traditional small molecule binding. The collaboration is designed to explore the use of Helicons both as stand-alone therapies and as part of AHCs.
Antibody–drug conjugates traditionally use antibodies to selectively deliver drug payloads into target cells to drive cell death from within. The AHCs envisioned by this collaboration are underpinned by the same delivery principle: pairing antibody-targeted cell access with Helicon payloads designed to selectively modulate specific intracellular proteins, including some long considered undruggable.
"Through our own pipeline, we have demonstrated the potential of Helicon peptides to directly inhibit or degrade several disease-driving proteins in oncology that have long been considered out of reach," said Mathai Mammen, M.D., Ph.D., Chairman, CEO and President of Parabilis Medicines. "We are thrilled to enter into a collaboration with Regeneron that builds on this foundation, combining the intracellular access and binding capabilities of our Helicons against challenging targets with antibodies from Regeneron."
Under the terms of the agreement, Parabilis is to receive $125 million from Regeneron in the form of a $50 million upfront payment and a commitment to invest $75 million in Parabilis’s next equity financing, subject to certain conditions. Parabilis is also eligible to receive milestone payments for development, regulatory, and commercial milestones, as well as tiered royalties up to the low double digits on future net sales of any approved medicines resulting from the collaboration. With five initial targets, the agreement provides the potential for up to approximately $2.2 billion in total milestone payments to Parabilis. Under the terms of the agreement, additional targets may be pursued upon additional option payments from Regeneron.
The agreement provides for the parties to collaborate to discover new Helicons and AHCs, which Regeneron will then be responsible for advancing through development, manufacturing and worldwide commercialization.
(Press release, Parabilis Medicines, MAY 18, 2026, View Source [SID1234666534])