Harnessing Recombinant Human Polyclonal Antibodies for Potential HBV Treatment, Cure

GigaGen, a subsidiary of a company called Grifols, has been developing a platform in the treatment and cure of HBV. Their investigational therapy, GIGA-2339 is a HBV recombinant polyclonal therapy in development, and consists of more than 1000 anti-HBV antibodies made in the laboratory by reproducing the antibodies generated during a natural immune response. This approach could ensure that the therapy covers the large diversity of circulating HBV variants.

Starting with the blood from donors that have been vaccinated against HBV, GigaGen captures millions of individual antibody-producing B cells. It then extracts their antibody-coding DNA and creates cell lines that express the recombinant (synthetic) human antibodies of interest for that particular disease. (See the image below for further explanation of the process.)

The product is the result of a platform that has enabled engineering of the first recombinant human polyclonal antibody therapies. Such therapies are comprised of antibodies that recreate the immune responses of the best human donors against a particular disease of biological threat—in this case thousands of antibodies against HBV surface antigen.

“There's a real benefit to being able to attack a disease from multiple angles,” Carter Keller, senior vice president, Grifols and CEO of the company’s GigaGen subsidiary, said.

“We captured immune systems, from people who've been vaccinated with hepatitis B vaccine, and we took the best immune responses, and ran those through our platform,” Keller said. “And then from the diversity of those immune responses, we filtered out the antibodies that were focused just on hepatitis B surface antigen…we believe it has a real chance to cure [HBV].”

GIGA-2339 is one of the leading candidates in GigaGen’s pipeline, and they are prepared for a pre-IND submission in the second half 2023. 

Grifols acquired GigaGen in 2021, buying the remaining 56% of the company after Grifols had initially bought 44% of GigaGen’s stake in 2017. Grifols is a global healthcare company.

Keller and his team are looking not just for GIGA-2339 to stop HBV replication, but their goal is to have the therapy lead to a functional cure.

Contagion spoke to Keller about GIGA-2339, their expected timeline for getting the investigational antibody into clinical trials, and its potential place in the market, pending FDA approval.