The fifth-largest life sciences cluster in the nation is not actually a cluster at all: It’s a long ribbon of laboratories and corporate campuses strung along Maryland’s Interstate 270, from Rockville through Gaithersburg, Germantown and Clarksburg.

With the proximity of the National Institutes of Health in Bethesda — as well as over half a billion dollars in funding from the same agency — the I-270 corridor has been picking up leases from massive biotech and pharma companies, as well as incubating new startups at its higher learning institutions.

Development of new laboratory space has been relatively slow in recent years, and JLL estimates that there is a backlogged demand for at least 460K SF of new laboratory space. Laboratory vacancy in the cluster is sitting just about 5%, compared to the office vacancy rate in suburban Maryland is at almost 19%, according to Cushman & Wakefield.

Unlike the largest biotech clusters in the nation, including Boston-Cambridge, New York and the Bay Area, the I-270 corridor remains strongly suburban, with researchers and scientists commuting to work each day by car.

A decades-long initiative to bring rapid transit to I-270, dubbed the Corridor Cities Transitway, was shelved by the Maryland Department of Transportation in September, with state officials saying Montgomery County should shoulder the cost of the new system.

However, locals worry that a lack of viable transit could hamper the growth of the biotech corridor, especially as the area looks to attract young talent. Developers and officials alike have asked MDOT to reconsider and save the program.