A Portland development group that bought a prime West End property last year has dropped plans for market rate housing and is proposing affordable housing, including rooms for homeless women in recovery from opioid addiction.

The Developers Collaborative submitted plans to convert a three-story brick building at 66 State St. into a rooming house with onsite staff and services for women struggling with opioid use syndrome. It would be staffed by Amistad, a nonprofit social service agency that operates two similar residential programs in the Portland area.

The $8 million project also calls for the construction of a new, four-story building next door that would provide studio and one-bedroom apartments to low-income tenants, who are defined as earning no more than 60 percent of area median income.

Kevin Bunker, a founding principal of the Developers Collaborative, which bought the property from Catholic Charities last year for $1.3 million, had originally planned to build mostly market rate housing on the site. The building’s sale coincided with a boom in the construction of high-end and luxury condos throughout the Portland peninsula, including some units selling for well over $500,000 apiece.

But Bunker didn’t want to move forward until Amistad, which is headquartered there, could find another location to serve its clients, most of whom have severe and persistent mental illness. And, over time, Amistad advised him on the design and programming for the new project.