Parabilis Medicines priced and began trading its IPO at the largest drug-developer offering on record in the U.S., raising $770.5 million in gross proceeds after an upsized share sale. The company sold 33.5 million shares at $20 each, with the underwriters exercising an additional 5.025 million share option, lifting total gross proceeds above the initial $670 million. Parabilis develops drugs and antibody-drug conjugates built on Helicon-stabilized helical peptides targeting historically difficult proteins. The debut follows a period of heightened selectivity in biotech financing, making the scale of the raise a clear read-through on investor appetite for platform-driven oncology and ADC strategies.