Valneva Evaluates Next Steps for Bacterial Infection Vaccine Following Successful Phase 2 Studies

Valneva SE (NASDAQ:VALN) announced positive data from two Phase 2 clinical trials evaluating Shigella4V2 (S4V2), the world’s most clinically advanced tetravalent bioconjugate candidate targeting shigellosis.

The specialty vaccine maker is reviewing the complete dataset from both an infant trial and an adult human challenge trial to determine the next development steps for the potential first-in-class shot.

Global Public Health Imperative

Shigellosis represents the second leading cause of fatal diarrheal disease globally, contributing heavily to pediatric illness and mortality.

Estimates indicate that Shigella causes up to 165 million infections every year, with children younger than five years accounting for 62.3 million cases.

Encouraging Infant Trial Findings In Kenya

The S4V02 Phase 2 trial evaluated the safety and immunogenicity of two S4V2 dose levels against a control meningococcal vaccine in 110 nine-month-old infants in Kenya across a two-dose schedule.

S4V2 demonstrated a favorable safety and tolerability profile across both tested doses.

Most reported adverse events were mild to moderate, showed no statistical difference from the control group, and resolved without complications.

Additionally, S4V2 generated statistically significant increases in anti-LPS IgG antibody titers across all four targeted Shigella serotypes relative to control.

Antibody levels peaked following the second vaccination and remained above baseline six months later.

These findings highlight promising immunogenicity while signaling the need for further dose and schedule optimization.

Strong Efficacy In Adult Challenge Study

In the United States, the Phase 2 S4V03 controlled human infection model (CHIM) study examined S4V2 in approximately 120 healthy, Shigella-seronegative adults aged 18 to 50.

After confirming the target dose, researchers administered two doses of S4V2 or placebo one month apart.

One month after the second dose, investigators challenged participants with the Shigella sonnei 53G strain. S4V2 met its primary endpoint, achieving a statistically significant reduction in S. sonnei shigellosis incidence compared to placebo.

LimmaTech sponsored both clinical trials, and the Gates Foundation funded the infant study.

VALN Price Action: Valneva shares were trading 5.26% higher at $5.80 at the time of publication on Monday, according to Benzinga Pro data.

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