Alnylam Pharmaceuticals is set to invest $250m in the expansion of its facility in Norton, Massachusetts, US, to meet the growing global demand for RNA interference (RNAi) therapeutics.

This is claimed to become the first fully dedicated small-interfering RNA (siRNA) enzymatic-ligation manufacturing facility.

The facility expansion is intended to increase capacity, lower production expenses, and enable support for future medicine launches from the company’s development pipeline.

As part of this, the company’s next-generation, scalable enzymatic ligation manufacturing platform, known as siRELIS, has been accepted into the US Food and Drug Administration’s Emerging Technology Program.

The programme is expected to facilitate discussions with global health authorities regarding manufacturing approaches for oligonucleotide-based medicines.

This acceptance comes after pilot-scale production of zilebesiran, which is under investigation for decreasing the risk of major adverse cardiovascular events in hypertension patients, and nucresiran, being developed for transthyretin-mediated amyloidosis (ATTR).

The siRELIS platform enables RNAi therapeutic manufacturing with reduced material and plant resource requirements, supporting sustainable, large-scale production.

The company’s 200,000ft² Norton facility expansion allows for local production of both clinical and commercial supplies of siRNA oligonucleotide drug substance for patients worldwide.

Operational since 2021, the facility has contributed to the growth of Alnylam’s clinical pipeline and supports early-stage programmes targeting various tissue types, including the central nervous system (CNS), liver, muscle, and adipose tissue.

Construction at the site is currently underway, with the new offerings anticipated to be completely operational by late 2027.

Alnylam Pharmaceuticals CEO Yvonne Greenstreet said: “At this pivotal time with our expanding pipeline of RNAi therapeutics, Alnylam is accelerating development of siRNA manufacturing and changing what’s possible in a single facility.

“This advance will be a critical enabler in the scaling of our pipeline to include potential treatments for diseases such as hypertension, type 2 diabetes, and obesity.”

In June 2025, the European Commission approved Alnylam’s Amvuttra (vutrisiran) for the treatment of wild-type or hereditary transthyretin amyloidosis with cardiomyopathy in adults.