Mustang Bio shares surge 29.63% premarket after FDA grants orphan drug designation for MB-101 brain cancer therapy.

Mustang Bio (NASDAQ:MBIO) surged 29.63% in premarket trading following the U.S. FDA’s grant of Orphan Drug Designation for its investigational therapy MB-101 (IL13Ra2-targeted CAR T-cells) to treat astrocytomas and glioblastoma. This regulatory milestone, first reported on July 7, 2025, by multiple outlets including GlobeNewswire and Benzinga, signals potential market exclusivity and reduced development costs for the company’s brain cancer candidate. The designation, which applies to therapies targeting rare diseases, typically offers incentives such as tax credits and expedited review, reinforcing investor confidence in Mustang Bio’s pipeline. Earlier news, including asset sales and Nasdaq compliance updates, occurred weeks prior and did not align with the magnitude of the premarket rally.