Boston, October 23, 2025
News Summary
Eli Lilly and Co. has signed a lease for 75,000 additional square feet at 645 Summer Street, now named Lilly Harborside Research & Development Labs. This expansion solidifies their presence in Boston’s Seaport District, where they are establishing a significant regional hub for genetic medicine research and incubator space for biotech startups, ultimately enhancing local workforce opportunities in biosciences.
Boston
Eli Lilly and Co. has signed a new lease to gain full control of the building at 645 Summer Street in Boston’s Seaport District, expanding its local research footprint and making the company the sole occupant of the two-story laboratory facility. The company is leasing an additional 75,000 square feet, bringing its total space at the site to 150,000 square feet. The facility is now named Lilly Harborside Research & Development Labs.
Key details and immediate impact
The newly consolidated site gives Eli Lilly full control of a building that was originally constructed in 1966 and renovated in 2019. The building previously housed gene-editing startup Akouos, which was acquired by Eli Lilly in 2022. With this lease, Eli Lilly becomes the sole occupant of the two-story laboratory facility at 645 Summer Street.
The expansion at 645 Summer Street comes as part of a broader, visible push by Eli Lilly into Boston’s Seaport neighborhood. The move complements the company’s larger regional investment at the Lilly Seaport Innovation Center on Necco Street, a separate, newly opened hub dedicated to genetic medicine research and incubator activity.
About the Lilly Seaport Innovation Center
The Lilly Seaport Innovation Center is a 12-story, 346,000-square-foot hub that opened in 2024. The project cost approximately $700 million and is designed to accommodate approximately 700 biotech workers. Nearly two-thirds of the 346,000-square-foot facility consists of laboratory space, and the site serves as the main base for Eli Lilly’s genetic medicine research. The center also includes the East Coast branch of Lilly Gateway Labs, Lilly’s biotech incubator program.
Staffing, incubation and research focus
The combined Seaport initiatives support a sizeable local workforce dedicated to genetic therapies. The research facility employs 500 scientists and researchers dedicated to genetic therapies. Lilly plans to hire about 300 additional employees, aiming for a total of 500 in Massachusetts. The incubator within the Seaport center is designed to house 12 to 15 start-up companies, employing another 200 workers. Collaborative opportunities exist for incubator companies to work alongside Lilly scientists while retaining independent ownership of their intellectual property. As part of initial occupancy activity, Four biotech companies have either moved into or plan to move into the building.
Scientific priorities and pipeline
The new R&D facilities at both 645 Summer Street and the Lilly Seaport Innovation Center focus on advancing RNA and DNA-based therapies and discovering new drug targets. Research priorities include work on diseases and conditions such as diabetes, obesity, cardiovascular diseases, neurodegeneration, chronic pain, immunology, and hearing health. The buildings feature laboratories designed specifically for the development of genetic medicines, reflecting Eli Lilly’s reinvestment strategy into gene-based treatments and a growing pipeline that increasingly focuses on genetic medicines.
Regional strategy and context
The opening of the Lilly Seaport Innovation Center in 2024 signifies a regional shift for Eli Lilly, moving its regional R&D hub from Cambridge to the waterfront. The company’s Seaport expansion positions it as a growing presence in Boston’s life sciences cluster, seeking to capitalize on local talent and research infrastructure. The expansions come amid commercial success for the company’s recently launched drugs for diabetes and obesity, which have contributed to increases in the company’s market valuation.
Operational notes
The 645 Summer Street building was originally constructed in 1966 and was renovated in 2019. After acquiring Akouos in 2022, Eli Lilly has repurposed the site and renamed it Lilly Harborside Research & Development Labs. The company cited growing demand at the Seaport as a driver for securing full control of the building and expanding laboratory capacity there.
What this means for Boston’s life sciences cluster
By consolidating space at 645 Summer Street and operating the large Seaport hub, Eli Lilly is increasing available lab capacity, bringing academic and commercial interactions closer to Boston’s waterfront, and adding incubator capacity for startups. The combined facilities and hiring plans are expected to add hundreds of workers to the local life sciences workforce and to create new collaboration opportunities between Lilly and early-stage biotech companies.
FAQ
What lease did Eli Lilly sign at 645 Summer Street?
Eli Lilly and Co. has signed a new lease to gain full control of the building at 645 Summer Street in Boston’s Seaport District.
How much additional space did Eli Lilly lease at 645 Summer Street?
The company is leasing an additional 75,000 square feet, bringing its total space to 150,000 square feet.
What is the current occupancy status of the 645 Summer Street building?
Eli Lilly is now the sole occupant of the two-story laboratory facility.
What was the building at 645 Summer Street previously used for and when was it renovated?
The building was originally constructed in 1966 and renovated in 2019, previously housing gene-editing startup Akouos, which was acquired by Eli Lilly in 2022.
What is the new name of the facility at 645 Summer Street?
The facility is now named Lilly Harborside Research & Development Labs.
What is the Lilly Seaport Innovation Center?
The Lilly Seaport Innovation Center is a 12-story, 346,000-square-foot hub that opened in 2024.
How many workers will the Lilly Seaport Innovation Center accommodate?
The newly opened $700 million Lilly Seaport Innovation Center will accommodate approximately 700 biotech workers.
How many scientists and researchers work on genetic therapies at Lilly’s Seaport site?
The research facility employs 500 scientists and researchers dedicated to genetic therapies.
What areas of research do the new R&D facilities focus on?
The new R&D facilities focus on advancing RNA and DNA-based therapies and discovering new drug targets for various diseases, including diabetes, obesity, cardiovascular diseases, neurodegeneration, chronic pain, immunology, and hearing health.
How many start-ups will the incubator hold and how many workers will those start-ups employ?
The facility will also house a biotech incubator for 12 to 15 start-up companies, employing another 200 workers.
How many additional employees does Lilly plan to hire in Massachusetts?
Lilly plans to hire about 300 additional employees, aiming for a total of 500 in Massachusetts.
Quick reference table
| Item | Detail |
|---|---|
| Building address | 645 Summer Street, Boston’s Seaport District |
| New lease added | 75,000 square feet |
| Total space at 645 Summer Street | 150,000 square feet |
| Building original construction | 1966 |
| Renovation year | 2019 |
| Previous occupant | Akouos (acquired by Eli Lilly in 2022) |
| Facility name | Lilly Harborside Research & Development Labs |
| Seaport hub name | Lilly Seaport Innovation Center on Necco Street |
| Seaport hub size | 12-story, 346,000-square-foot hub |
| Seaport hub opening | Opened in 2024 |
| Seaport hub cost | $700 million |
| Workers accommodated at Seaport hub | Approximately 700 biotech workers |
| Scientists and researchers | 500 scientists and researchers dedicated to genetic therapies |
| Planned hires in Massachusetts | About 300 additional employees, aiming for a total of 500 in Massachusetts |
| Incubator capacity | 12 to 15 start-up companies, employing another 200 workers |
| Start-ups moving in | Four biotech companies have either moved into or plan to move into the building |
| Research areas | RNA and DNA-based therapies; diabetes; obesity; cardiovascular diseases; neurodegeneration; chronic pain; immunology; hearing health |
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Additional Resources
- Boston Real Estate Times
- Wikipedia: Eli Lilly and Company
- MassLive
- Google Search: Eli Lilly Boston Genetic Medicine
- Boston Globe
- Google Scholar: Eli Lilly Harborside Research & Development Labs
- Site Selection
- Encyclopedia Britannica: Boston Biotech
- Pharmaceutical Commerce
- Google News: Eli Lilly Boston
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