Regeneron Pharmaceuticals has signed a $2.32bn research collaboration with Parabilis Medicines to develop therapeutic candidates leveraging the latter’s Helicon peptide platform, with an emphasis on antibody-Helicon conjugates (AHCs).

Helicons are stabilised, cell-penetrant alpha-helical peptides engineered to interact with intracellular protein targets, including those with flat surfaces unsuitable for traditional small molecule engagement.

The partnership will investigate Helicons as standalone therapies and as components of AHCs for potential new therapies.

Regeneron board co-chair, president and chief scientific officer George Yancopoulos said: “This collaboration reflects Regeneron’s approach of advancing cutting-edge and diversified science to produce a robust portfolio of innovative medicines for patients in need.

“In addition to the potential of Helicons to address previously undruggable targets, the collaboration’s intent to couple Helicons to our VelocImmune-derived antibodies so as to precisely deliver them to cells of interest represents an exciting new approach with the potential to create an entirely new therapeutic class that can span multiple therapeutic areas.”

Through the new AHC platform, the aim is to use antibody targeting alongside Helicon payloads to modulate specific intracellular proteins.

Under the agreement, Parabilis is eligible for $125m, including a $50m upfront payment and a $75m investment from Regeneron in Parabilis' next equity financing, subject to agreed conditions.

The company will also receive up to $2.2bn in additional milestone payments along with tiered royalties. Additional targets can be pursued with further option payments from Regeneron.

The collaboration envisages joint discovery of new Helicons and AHCs, with Regeneron leading development, manufacturing and global commercialisation.

Last month, Telix and Regeneron Pharmaceuticals entered a partnership worth up to $4.3bn for the development and commercialisation of new radiopharmaceutical therapies.