Jiang Zhu, PhD, from Scripps Research in La Jolla, CA, posted a study in bioRxiv on September 14 that proposed a new spike antigen design (S2GΔHR2) and displayed it on several SApNPs as COVID-19 vaccine candidates. The spike is missing the heptad repeat 2 (HR2) stalk that is considered a major cause of spike metastability -- the mechanism responsible for masking the COVID-19 spike from immune recognition.

Ufovax's studies directly compared the S2GΔHR2 spike alone (not carried on a nanoparticle) as well as the S2P spike alone, which is used in many other COVID-19 vaccine designs. The firm saw consistent eight- to 10-fold increases in neutralizing antibody titers in mice using this approach and it induced T-cell immunity.

The firm expects to begin a phase I clinical trial in early 2021.