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Product Development

GigaGen aims to overcome supply limits, boost potency with recombinant convalescent sera substitute

Plus SAB gets additional funding from U.S. government, starts human trials

Aug 13, 2020 | 1:48 AM GMT

GigaGen is developing polyclonal antibodies for COVID-19 and other infectious diseases that could be more potent and easier to supply than convalescent plasma. 

GigaGen Inc. plans to submit an IND for its COVID-19 treatment, GIGA-2050, by year-end.

 It calls GIGA-2050 a recombinant hyperimmune product, and said it is akin to recombinant convalescent sera. 

GigaGen showed Monday in a bioRxiv publication that GIGA-2050 was 100 times more potent than convalescent sera. The company made the comparison using a microneutralization assay that measured the minimum antibody concentrations needed to prevent cytopathic effects induced by live SARS-CoV-2. 

GigaGen, which also demonstrated the approach’s applicability beyond coronaviruses by generating recombinant hyperimmunes against Zika virus and pneumococcus, has submitted the manuscript for peer review.

While the U.S. government’s Operation Warp Speed is focusing on convalescent plasma as one of several treatment options for COVID-19, the approach requires finding eligible donors, and antibody titers against SARS-CoV-2 are highly variable between donors (see “Warp Speed Bullish on Convalescent Plasma”).

To generate GIGA-2050, GigaGen made and sorted libraries of antibodies from 16 convalescent COVID-19 patients who had high titers against SARS-CoV-2. The therapy comprises 12,500 recombinant antibodies that have been cloned into a mammalian cell line. 

Co-founder and CEO David Johnson told BioCentury it took two to three months to generate GIGA-2050 about the same amount of time it took the leading developers of antiviral COVID-19 mAbs to create their lead candidates. Johnson added, “We use the same technology, at least for production, that monoclonals use. So it’s the same cost there.”

SAB’s transgenic cows

Like GigaGen, SAB Biotherapeutics Inc. has a technology with which it is developing polyclonal antibodies that could reduce the need for convalescent plasma donors. The South Dakota-based company’s platform uses transgenic cows to generate and manufacture human antibodies  (see “SAB’s Rapid Response to COVID-19”). 

SAB announced on Tuesday it had dosed the first healthy volunteer in a randomized, double-blind Phase I study of SAB-185; it plans to start a Phase Ib trial in COVID-19 patients this month.

On Thursday, the U.S. Department of Defense awarded the company an additional $35.6 million, bringing SAB’s total raised from federal agencies, including Biomedical Advanced Research and Development Authority (BARDA), to $72 million to expand its rapid response platform and support clinical development and manufacturing of SAB-185 for COVID-19.

The U.S. government is separately providing direct funding for the two Phase I studies of SAB-185.

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