Passage Bio, a gene therapy firm founded by University of Pennsylvania scientist James Wilson, plans to raise $125 million in an initial public offering. Since formally launching in February 2019, Passage has raised over $225 million from private investors. The firm licensed its six preclinical gene therapies for rare central nervous system diseases from Penn and plans to begin clinical trials for three of them next year. Passage relies on Penn for its preclinical work and has an option to license six more gene therapies through 2022. Passage has already paid Penn more than $40 million, and Penn could earn up to $55 million for each program.