Shanghai-based pharmaceutical company WuXi AppTec plans to expand into a fourth building to be constructed for it in South Philadelphia's Navy Yard, which will make it the largest tenant of the former military base's central business park.

Wayne-based Liberty Property Trust and Synterra Partners of Philadelphia, the Navy Yard's main developers, said in a release Thursday that they plan to break ground early next month on a 95,000-square-foot lab-and-office building for WuXi AppTec that will span longer than a city block at 400 Rouse Blvd.

When the new building is completed in late 2019, the WuXi AppTec division doing business in the Navy Yard, its Advanced Therapies Business Unit, will become Liberty's largest tenant in the campus, occupying in more than 380,000 square feet, according to the release.

Headcount at the WuXi AppTec division has grown from 150 to 600 since 2004, when Liberty completed its first building for the firm at 4751 League Island Blvd., the release said.