In February 2024 LimmaTech Biologics announced positive interim data from a Phase I/II trial evaluating Shigella4V (S4V). S4V is a tetravalent bioconjugate vaccine candidate against shigellosis, an infectious disease that is cause by Shigella bacteria. Shigellosis is the second leading cause of fatal diarrhoeal disease and is most dangerous in infants in low- and middle-income countries. The vaccine candidate has been in-licensed from GSK to advance clinical development.
LimmaTech states that an estiamted 188 million infections are due to Shigella, of which 62.3 million are in children under five. ALthough the standard treatment is oral rehydration and antibiotic therapy, the bacteria have acquired resistance to many antibiotics and there is no licensed vaccine.
S4V in trial
The vaccine candidate is a tetravalent bioconjugate vaccine that encompasses the O-antigen polysaccharides of S. flexneri 2a, 3a, 6, and S. sonnei. It targets that four predominant pathogenic Shigella serotypes responsible for “up to 85%” of global infections.
The Phase I/II study is conducted in Kenya; it is a randomised, double-blind, dose-finding, age-descending clinical trial to assess the safety and immunogenicity of S4V. The trial is divided into two elements, the first of which evaluated the vaccine candidate’s safety in adults, children (aged 2-5), and infants. The second part evaluated S4V’s safety and immunogenicity in the nine-month-old target population to determine the preferred dose.
Positive results
The latest data from the second part of the trial includes 472 infants who received two intramuscular injections at one of four dose levels, with or without an adjuvant. S4V was “well tolerated” with most reactions being “mild” and “similarly distributed” over the different groups. No vaccine-related serious adverse events (SAEs) were reported.
Dr Patricia Martin, Chief Operating Officer at LimmaTech, commented that the “positive interim results” demonstrate “very good immunogenicity” in infants, the “population that needs it the most”.
“Shigellosis is a serious disease caused by a pathogen continuously evolving and becoming increasingly resistant to antibiotics. Our vaccine candidate has the potential to prevent an infection that threatens the lives of many children.”
Furthermore, the candidate could have uses for “travellers and military personnel”. Dr Martin is excited for the continued clinical development of the vaccine.
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