Jesse Gelsinger gene therapy death (1999)
Jesse Gelsinger, an 18-year-old with a mild liver disorder called ornithine transcarbamylase deficiency, died four days after receiving an experimental adenoviral gene therapy at the University of Pennsylvania. His immune system mounted an overwhelming inflammatory response to the viral vector. Investigations revealed undisclosed safety problems in earlier patients and conflicts of interest among the researchers.
The FDA halted multiple gene therapy trials nationwide. The principal investigator, James Wilson, was barred from conducting FDA-regulated research for five years. Public trust in gene therapy collapsed.
The field pivoted to safer adeno-associated virus (AAV) vectors instead of adenoviruses, developed more rigorous safety monitoring protocols, and took nearly two decades to recover. The caution instilled by this case shaped every subsequent gene therapy trial design, including ER-100's.
The Gelsinger case is the cautionary backdrop for every first-in-human gene therapy trial. Life Biosciences' decision to target the eye — a small, enclosed organ where damage stays localized — and to include a doxycycline safety switch reflects lessons learned from this tragedy. Any serious adverse event in the ER-100 trial would be measured against this precedent.