Spark Therapeutics, a gene therapy company based in University City, is expanding its office footprint to two locations within the neighborhood.

After setting off on its own from Children's Hospital of Philadelphia in 2013, it occupied 42k SF in the University City Science Center complex at 3737 Market St. Now Spark has announced a lease of 50k SF at the new FMC Tower, as well as 6,500 SF at 3711 Market St, also part of University City Science Center, according to the Philadelphia Inquirer.

The expansion is considered a stopgap for the fast-growing company, which enlisted JLL to broker the search for a unified headquarters. One rumored option: the soon-to-break-ground Schuylkill Yards, developed (like FMC Tower) by Brandywine Realty Trust with multiple office buildings that will need to be filled.

Spark is also considering locations in New Jersey and Delaware, but one might imagine that Schuylkill Yards and its proximity to the talent pipeline of Penn and Drexel would be hard to leave. [Philly]