A South Korean biotech firm is accelerating development of a norovirus vaccine on the strength of its virus-like particle (VLP) production technology. With front-runner Moderna's messenger RNA (mRNA) vaccine program stalled by difficulties in demonstrating efficacy, latecomers using newer approaches such as VLP are closing the gap by moving quickly on patents and clinical trials.
The U.S. Patent and Trademark Office (USPTO) recently published a patent application from South Korean biotech firm Intera titled "Recombinant expression vector and manufacturing method for a multivalent norovirus vaccine," according to pharmaceutical and biotech industry sources on the 30th.
Norovirus causes acute gastroenteritis and spreads through contaminated food or water and contact with infected people. At the core of the application is technology for efficiently producing the VLP antigen proteins used in norovirus vaccines. VLPs are particles assembled from the proteins that form a virus shell. They mimic the structure of an actual virus but contain no genetic material and therefore cannot cause infection, which makes them suitable as vaccine antigens.
Intera produces antigen proteins in large volumes by inserting the genes encoding them into E. coli. The bacterium can generate large quantities of protein quickly, and its culture and production processes are relatively simple, making it well suited to mass production of vaccine ingredients. The problem is that some norovirus antigen proteins do not dissolve well in water and can clump together when produced in E. coli. Clumped antigen proteins are difficult to assemble into the form required to build VLPs. Intera therefore focused on reducing insoluble protein formation to allow stable VLP assembly, using a modified version of RID, a protein fragment that aids antigen protein expression.
The patent covers technology applied to antigen protein production for INT-101, a trivalent norovirus VLP vaccine candidate targeting three genotypes that Intera is developing. The first dose in a Phase 1 trial was administered at Severance Hospital in August.
Alternative approaches such as VLP are drawing attention because mRNA vaccine development has run into obstacles, including norovirus's high genetic diversity and the difficulty of securing actual infection cases. Moderna said on July 31 this year that an interim analysis of the Phase 3 trial of its norovirus vaccine candidate mRNA-1403 failed to meet the statistical significance threshold for early success.
Industry officials said the market could expand substantially if a vaccine succeeds, given that norovirus recurs every year and no vaccine has been commercialized. The World Health Organization estimates that norovirus causes about 685 million cases of acute gastroenteritis annually.
