Passage BIO, Inc.

We are a clinical stage genetic medicines company focused on improving the lives of patients with neurodegenerative diseases. Our primary focus is the development and advancement of one-time gene therapies designed to target critical underlying pathologies in these conditions. We have developed an approach to developing treatments for central nervous system, or CNS, disorders that allows us to select and advance product candidates. Our lead clinical product candidate, PBFT02, seeks to elevate progranulin levels to enhance lysosomal function and slow disease progression across a variety of neurodegenerative diseases. PBFT02 is a gene replacement therapy that utilizes an adeno-associated virus serotype 1, or AAV1, capsid to deliver a functional granulin gene, or GRN, encoding progranulin, or PGRN, to the brain via intra cisterna magna, or ICM, administration. The lead indication for PBFT02 is frontotemporal dementia, or FTD, caused by progranulin deficiency, or FTD-GRN. We are currently studying PBFT02 in FTD-GRN, for which there are currently no approved disease-modifying therapies. In addition to the continued clinical development of PBFT02 to treat FTD-GRN, we intend to pursue PBFT02 in additional adult neurodegenerative diseases where increasing PGRN levels could provide benefit. Third-party preclinical studies have shown that increased PGRN levels reduce the pathologic accumulation of TAR DNA binding protein 43, or TDP-43. TDP-43 pathology is a hallmark of multiple neurodegenerative conditions, including FTD due to mutations in the C9orf72 gene, or FTD-C9orf72, approximately 95% of sporadic amyotrophic lateral sclerosis, or ALS, and approximately 50% of sporadic FTD.