San Diego-based PMB Real Estate Services is planning a nearly 340,000-square-foot life science tower off of the Stewart Street exit from Interstate 5 at the north edge of downtown Seattle.

It’s the latest iteration of an ambitious proposal by Vancouver, British Columbia-based Arbutus Properties, and a major pivot. Before the Covid-19 pandemic, Arbutus had planned two 40-story residential towers for the irregularly shaped block.

In addition, Arbutus is planning a 45-story apartment project across the street at 1370 Stewart St. Arbutus bills the overall project as a gateway to downtown and the South Lake Union district.

PMB, which stands for Pacific Medical Buildings, is a health care real estate development company with a Seattle office. It says it has signed a purchase-and-sale agreement for the life science tower site at 1305 Stewart St.

The company has hired JTM Construction to build the 13-story project, which Perkins & Will is designing. The developer would like to start construction at the end of 2023 or early 2024 and said it will close on the acquisition of the half-acre-plus site when construction begins.

Live-music venue El Corazón and sister club the Funhouse operate on the property, and they’ll move back in after the tower opens. That’s according to plans submitted to the city ahead of a the scheduled July 6 early design guidance meeting.

PMB is the latest company with plans for a life science project in the Seattle, region where demand for new lab and research-and-development space is “skyrocketing,” according to a year-end report by commercial real estate services company CBRE.

At the end of September, companies were seeking 1.2 million square feet of lab space here, an increase of 138% over the prior six months, stated the report, which added, low vacancy in the South Lake Union submarket was “creating fierce leasing competition for available lab space and driving up rents.”

Asking rents at the time were up 12% in the Puget Sound region over the previous six months. In-city rates had increased more – up over 20% over the preceding 12 months.

At the time of the report, projects totaling 1.1 million square feet were under construction, with most activity in the South Lake Union submarket.

This amount will increase this week, with Intercontinental Real Estate Corp., and LPC West having scheduled a Wednesday groundbreaking ceremony for their 222 5th project, a nearly 200,000-square-foot development named for the site on Fifth Avenue North, where a McDonald’s operated for decades.