Parabilis filed for an initial public offering on the heels of a strategic research collaboration with Regeneron. The partnership spans up to $2.3 billion in potential payments and covers development of antibody-Helicon conjugates targeting historically undruggable protein interactions. Regeneron is set to buy about $75 million of Parabilis common stock in a concurrent private placement at 90% of the IPO price per share, reinforcing the strength of the commercial narrative around Parabilis’ Helicon platform and its lead Helicon peptide candidate zolucatetide. Parabilis indicated it intends to continue clinical development across desmoid tumors and other indications, including preparation for a Phase III registrational trial, as it seeks to fund platform scale and late-stage execution through public capital markets.