75 Hayden Ave. Image courtesy of King Street Properties

A pharmaceutical company that recently relocated its headquarters from West Cambridge to Lexington is leasing another 61,000 square feet in a neighboring building.

Dicerna Pharmaceuticals signed a 10-year lease for the fourth floor at King Street Properties’ 75 Hayden Ave., which is scheduled for completion in July. The firm will occupy the new space Oct. 1, according to a Middlesex County of Deeds filing.

Owner King Street Properties has secured a lease with an undisclosed tenant for another 61,000 square feet in the office-lab building, bringing occupancy up to 60 percent, said Mike DiMinico, an executive director at King Street. The firm is in discussions with multiple tenants looking for suburban lab space, DiMinico said.

Dicerna specializes in treatments for liver and cardiovascular diseases. It relocated its headquarters from 280 Arsenal St. in Watertown to 37,186 square feet at 87 Cambridgepark Drive in Cambridge’s Alewife section in 2014, before leasing 81,000 square feet at Boston Properties’ 33 Hayden Ave. last June for its new headquarters.

That lease called for aggregate fixed rent of $30.1 million during the seven-year term, according to an SEC filing.