In the last year alone, second quarter vacancy rates in East Cambridge, considered the epicenter of the area's booming biotech industry, has dropped from 26.1% to 9.1%. That trend doesn't seem to be abating, according to Brendan Carroll, a researcher with Richards Barry Joyce & Partners, a real estate firm that advises life science companies and landlords, tells GlobeSt.com.

"A growing industry requires more space and that's just what we're seeing here," says Carroll. "There's been heavy demand."

Several large deals, among them French pharmaceutical maker sanofi-aventis' recent lease of 73,000 sf of space at 270 Albany St. in Cambridge just blocks from the Massachusetts Institute of Technology, is tightening the market and driving rent rates, says Carroll. That lab space two years ago demanded $45 per sf and is now nearing $60 per sf, about equal to the previous market peak in 2001.

The demand for biotech space in the region is so strong and the rents so high, in fact, that some companies have been forced to look for space as far away as Route 495, about 30 miles from Kendall Square, the state's life science center.

It's unlikely that demand will abate anytime soon, Carroll notes, despite pressure from other states to attract biotech firms away from Massachusetts. Fueling that demand, he says, is the region's large number of research institutions, including the Massachusetts Institute of Technology and Harvard University, along with a skilled workforce and a strong venture capital presence.

"We expect [the demand for biotech space] will grow in other places, but the skill infrastructure that is in place in Boston because of the educational and medical institutions has created an ecosystem that is difficult to replicate," he says. "That's a big advantage and one that is difficult to see lessening over time."