Parabilis filed for an IPO a day after signing an up-to-$2.3 billion-plus strategic research collaboration with Regeneron. The Helicon platform company is seeking market funding while advancing its pipeline, including zolucatetide (formerly FOG-001), which Parabilis frames as a first-in-industry inhibitor of the β-catenin:TCF interaction. Regeneron agreed to purchase about $75 million of Parabilis common stock in a concurrent private placement at 90% of the IPO price per share. Parabilis’ S-1 includes a placeholder $100 million figure that is expected to be revised, and it also points to continued clinical development across desmoid tumors and other indications. The filing underscores how platform-focused oncology and ADC peers are leveraging large strategic payments to support both clinical programs and public-market readiness.