Primrose Bio is heading to the 18th Annual PEGS Europe – Protein & Antibody Engineering Summit, November 16-19, 2026 at the Lisbon Congress Center, Lisbon, Portugal.
Jeff Allen, PhD, SVP Process and Analytical Development, will be presenting a scientific poster “The Pfenex Platform for Preclinical VHH-ADC Development”.
Amber suppression technology has matured over the past 25 years, enabling incorporation of non-canonical amino acids (ncAAs) for site-specific conjugation and expanded therapeutic functionality. However, implementation has been limited by toxicity from off-target ncAA incorporation and substantially reduced protein yields at fermentation scale. We adapted an orthogonal aminoacyl-tRNA synthetase/tRNA pair for Pseudomonas fluorescens, the basis of the Pfenex Expression Technology® platform, to overcome these limitations. The system successfully incorporated para-azidophenylalanine (pAzF) into a novel anti-GPCR VHH candidate while maintaining production titers of approximately 15 g/L at 2 L high-cell-density fermentation scale, comparable to its canonical counterpart. This approach preserves production economics while improving conjugation specificity and expanding protein functionality. We describe the identification of suitable conjugation sites, host-strain engineering, and scale-up to support preclinical in vivo evaluation.
Stop by booth #245 to connect with Alec Tzianabos, Manager, Business Development, and learn more about what we’re working on.
