Primrose Bio Launches Two RNA Polymerases for High-Quality, Low-Cost mRNA

Up to 3x higher protein expression, >100x lower dsRNA, and major capping improvements

Primrose to present at AMM Ascent and the International mRNA Health Conference

SAN DIEGO, Oct. 14, 2026/PRNewswire/ -- Primrose Bio, Inc. ("Primrose"), a provider of production solutions for next-generation biologics, today announced the launch of two RNA polymerases:

• Prima RNApols® Cap AG is Primrose's best-performing enzyme optimized for AG-capped workflows. The higher-quality RNA produced with Prima Cap AG has shown up to 3x higher protein expression, while supporting >97% capping efficiency using less than half the cap analog per reaction, and a >100x reduction in dsRNA compared with T7.
  
  
• Prima RNApols® 7 Pro shows significant improvements in protein expression, capping efficiency and dsRNA reduction, while remaining compatible with the T7 promoter sequence and being optimized for both AG- and AU-capped mRNAs.

The RNA polymerase is the workhorse of in vitro transcription (IVT), the process that synthesizes RNA from a DNA template. Double-stranded RNA (dsRNA) byproducts can activate innate immune sensors and suppress protein production. Reducing these impurities can support stronger expression of the intended therapeutic protein or vaccine antigen with less unwanted immune activation.

"This launch reflects years of enzyme engineering to deliver RNA polymerases that we believe offer substantial improvements over what is currently available to drug developers," said Andrew Burch, Chief Executive Officer of Primrose Bio. "Our goal is to make high-quality RNA easier and more economical to produce for the next generation of RNA medicines. By supporting stronger protein expression with less unwanted immune activation, we aim to help developers advance effective medicines."

Primrose will showcase its two new polymerases at the Alliance for mRNA Medicines' second annual meeting, AMM Ascent, Oct. 28-30 in Coronado, and at the 14^th International mRNA Health Conference, Nov. 17-19 in Boston. Both products are available in research grade at www.prima.primrosebio.com/products/. For GMP-grade Prima RNApols, please contact [email protected].

About Prima RNApols®
Prima RNApols are purpose-built RNA polymerases engineered to improve RNA quality and manufacturing economics across all RNA workflows. The portfolio offers options for different template designs, capping chemistries and IVT conditions, including Prima RNApols Cap AG, for the best all-around Cap AG performance; Prima RNApols 7 Pro, for high performance with T7 promoter compatibility; and Prima RNApols Cap AU, for AU-capped and longer-template mRNA. Primrose also offers tailored RNA polymerase and mRNA optimization services to address specific manufacturing challenges. For more information, visit www.prima.primrosebio.com.

About Primrose Bio, Inc.
Primrose Bio develops and commercializes manufacturing technologies that close gaps in biologics, mRNA and vaccine production. Primrose's major offerings include Pfenex Expression Technology: a proprietary microbial production system used in six approved products with up to 20x higher yields and a strong record across diverse protein modalities; Prima RNApols: improved enzymes for mRNA manufacturing; and PeliCRM197: a commercially validated CRM197 carrier protein used for conjugate vaccines. Several of the world's leading pharmaceutical companies use Primrose's technologies in marketed products, including Merck, Jazz Pharmaceuticals, Alvogen and Serum Institute of India. For more information, please visit: www.primrosebio.com.

SOURCE Primrose Bio