Gritstone Says Omicron Mutations Minimally Impact T-Cell Epitope Sequences In Its COVID-19 Vaccines

Gritstone bio Inc GRTS announced that the SARS-CoV-2 T cell epitopes (TCEs) administered within its self-amplifying mRNA (SAM) COVID-19 vaccines are minimally impacted by the Omicron (B.1.1.529) variant.

• Gritstone says that its second-generation SARS-CoV-2 vaccine platform delivers a stabilized Spike protein and highly conserved TCEs derived from other SARS-CoV-2 viral genes, offering potentially more durable protection and broader immunity against the variants. 
• Related Link: Gritstone Bio Secures CEPI Funding For Its Differentiated COVID-19 Vaccine Candidate.
• Sequence analysis suggests that Omicron minimally impacts Gritstone's TCEs. 
• Specifically, of the 146 non-Spike TCE delivered within Gritstone's vaccine currently in clinical trials in the U.K. and U.S., only 3 (~2%) are impacted by Omicron. 
• A similar minimal impact of Omicron is observed in two new vaccine TCE constructs expected to enter clinical trials in South Africa by the end of 2021.
• The Company expects initial clinical data from its U.K. trial in early 2022.
• Price Action: GRTS shares are down 0.52% at $11.05 during the market session on the last check Monday.