Alnylam Pharmaceuticals has announced plans to significantly expand its manufacturing footprint in Norton, Massachusetts, committing an investment of $250 million to build what it says will be the biopharmaceutical industry’s first fully dedicated, proprietary siRNA enzymatic-ligation manufacturing facility. The move reflects Alnylam’s confidence in the long-term growth of RNA interference (RNAi) therapeutics and its ambition to support a growing pipeline of potential new medicines with more efficient, large-scale production.
The expansion will center on Alnylam’s next-generation manufacturing platform, known as siRELIS™, which uses an enzymatic ligation process to produce small interfering RNA (siRNA) therapies. According to the company, this approach is designed to significantly increase manufacturing capacity while reducing production costs and resource use compared with conventional oligonucleotide manufacturing methods. Alnylam believes the investment will help position it to meet future commercial demand as additional RNAi therapies progress toward regulatory approval.
In a notable regulatory milestone, Alnylam also disclosed that its siRELIS™ platform has been accepted into the U.S. Food and Drug Administration’s Emerging Technology Program. Participation in the program is intended to accelerate dialogue between the company and regulators on innovative manufacturing approaches, particularly for complex oligonucleotide-based medicines. Acceptance follows the successful production of pilot-scale batches of zilebesiran, a drug candidate being studied to reduce cardiovascular risk in patients with hypertension, and nucresiran, which is in development for transthyretin-mediated amyloidosis.
Chief Executive Officer Yvonne Greenstreet described the expansion as a critical step as Alnylam’s research pipeline broadens beyond rare genetic diseases into more prevalent conditions. She said scaling up siRNA manufacturing will be essential to support potential future treatments for large patient populations, including those with hypertension, type 2 diabetes and obesity.
The Norton facility, which opened in 2021 and spans roughly 200,000 square feet, currently plays a central role in supplying both clinical and early commercial material for Alnylam’s RNAi programs. The planned expansion will enhance the site’s ability to produce both clinical and commercial drug substance locally for global distribution. Construction is already underway, with the new capabilities expected to be fully operational by late 2027.
State and regional leaders welcomed the announcement, highlighting the broader economic and scientific impact of the investment. Massachusetts Governor Maura Healey said Alnylam’s continued growth underscores the state’s strength as a global life sciences hub, noting that the company’s advances in RNAi manufacturing have translated into both innovative therapies and high-quality jobs. Officials from the Massachusetts Life Sciences Center echoed those sentiments, emphasizing that the expansion will contribute to workforce development and reinforce the Commonwealth’s leadership in advanced biomanufacturing.
From a technical perspective, Alnylam executives argue that innovations like siRELIS™ are becoming increasingly important as demand for oligonucleotide-based medicines grows. Traditional manufacturing methods are complex and resource-intensive, potentially limiting scalability. By contrast, the enzymatic ligation process is designed to be more reproducible and less time-consuming, increasing throughput while maintaining stringent quality standards.
Timothy Maines, Alnylam’s Chief Technical Operations and Quality Officer, said the Norton expansion offers an opportunity to rethink how RNAi medicines are manufactured at scale. He noted that the company has already demonstrated the platform’s reliability at pilot scale and now aims to translate those gains into sustainable, large-scale production.
With the $250 million investment, Alnylam is signaling that manufacturing innovation will be as central to its future as drug discovery, positioning the company to support a broader range of RNAi therapies and a potentially much larger global patient population.