High Line Bio

High Line Bio was a New York-based biotech entity formed by TrialSpark in January 2022 to develop sprifermin for osteoarthritis after licensing global rights from Merck KGaA, Darmstadt, Germany. The company appears to have been created as a single-asset subsidiary or special-purpose development vehicle rather than as a broad standalone platform company. Its lead and only clearly disclosed program was sprifermin, a recombinant human fibroblast growth factor 18 analog intended as a disease-modifying therapy for osteoarthritis. Publicly available evidence suggests High Line Bio is no longer active as an operating standalone company, with the asset and related activities having been folded into TrialSpark, later renamed Formation Bio.