Parabilis Medicines priced what it described as the largest-ever U.S. IPO by a drug developer, raising $770.5 million in gross proceeds. The company sold 33.5 million shares at $20 each (with an overallotment option exercised), bringing total net proceeds reported in the prospectus to about $711.7 million. The stock jumped after trading began, closing the first full day at $31.60 before profit-taking and additional decline during the week. Parabilis is developing drugs and antibody-drug conjugates (ADCs) targeting traditionally hard-to-drug protein targets using Helicons—stabilized helical peptides. The listing underscores continued investor appetite for platform-led oncology and ADC strategies, even amid a still-challenging funding environment referenced by analysts in coverage.