Why Icosavax (ICVX) Shares Are Trading Higher Today

Icosavax Inc ICVX provided a six-month immunogenicity update from its Phase 1/1b trial of IVX-121 against Respiratory Syncytial Virus (RSV), demonstrating a sustained neutralizing antibody (nAb) response against RSV, lasting at least six months after a single administration of IVX-121.
William Blair analyst thinks the best comparison for IVX-121 is Pfizer Inc’s PFE RSVpreF vaccine.
The estimated percentage of retained titers for RSV-A from 28 days to 180 days post-immunization was roughly 45% with 120 µg of Pfizer’s RSVpreF in older adults.
For the same time frame, percentages of retained titers were 64%, 98%, and 72%, with 25 µg (roughly 14 µg of antigen), 75 µg (roughly 42 µg of antigen), and 250 µg (roughly 140 µg of antigen) of IVX-121, respectively, for older adults.
Regarding GSK plc GSK and Pfizer’s vaccine candidates, RSVPreF3 (from GSK) is associated with a more severe safety profile, which may be attributed to the adjuvant.
Icosavax’s candidate showed no serious adverse events.
Price Action: ICVX shares are up 32.1% at $5.55 on the last check Wednesday.

Comparing With Pfizer's Vaccine, Icosavax RSV Candidate 'Could Establish Differentiation,' Analyst Says