Regeneron Pharmaceuticals Inc. (NASDAQ: REGN) announced a strategic research collaboration with Parabilis Medicines to develop therapeutic candidates using Parabilis' Helicon peptide platform, according to a company statement.

The agreement provides for Parabilis to receive $125 million from Regeneron, consisting of a $50 million upfront payment and a $75 million equity commitment in Parabilis' next financing round. Parabilis is eligible for up to approximately $2.2 billion in additional milestone payments plus tiered royalties up to the low double-digits on future net sales.

The collaboration focuses on Antibody-Helicon Conjugates, which combine Regeneron's antibody capabilities with Parabilis' stabilized peptides designed to target intracellular proteins. The initial agreement covers five targets, with additional targets possible through option payments.

"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," said George Yancopoulos, Regeneron's president and chief scientific officer.

Helicons are cell-penetrant alpha-helical peptides designed to engage intracellular protein targets, including flat surfaces not suited to traditional small molecule binding. The collaboration will explore using Helicons both as standalone therapies and as part of antibody-drug conjugates.

Under the agreement, the companies will collaborate to discover new Helicons and conjugates, while Regeneron will handle development, manufacturing and worldwide commercialization of resulting products.