The booming life sciences sector is continuing to drive activity in Montgomery County with the expansion of a Rockville biotechnology company into a newly built headquarters.

RegenxBio announced Wednesday it signed a 15-year, 132K SF lease with Alexandria Real Estate Equities for a build-to-suit headquarters and research facility at 9800 Medical Center Drive in Rockville.

The company also has the option to move into the remainder of the 175K SF facility, which is expected to be operational in 2020. It is the latest addition to the Alexandria Life Science and Translational Research Center, which currently consists of four buildings totaling 282K SF.

The property sits just south of the Adventist HealthCare Shady Grove Medical Center. RegenxBio is moving from multiple nearby sites, with its current footprint totaling 80K SF, including its main office roughly a half-mile away at 9600 Blackwell Road.

"Alexandria is uniquely positioned to create a premier facility on a dynamic campus that will offer REGENXBIO a compelling opportunity to recruit and retain top talent and to collaborate in pursuit of its mission to transform the lives of patients suffering from diseases with significant unmet needs," Alexandria Real Estate Equities co-Chief Operating Officer Larry Diamond said in a release.

Montgomery County has emerged as one of the leading biotech hubs in the nation in recent years, spurred on by the presence of federal agencies like the National Institutes of Health and the Federal Drug Administration. A surge of absorption from large corporations and startups alike has driven the I-270 corridor's lab vacancy below 5%, according to JLL, a fraction of the area's vacancy rate for traditional suburban office.

Some developers are looking to capitalize on that by building speculative lab space, including StonebridgeCarras and The Donohoe Cos. with a new project in Downtown Bethesda.