LimmaTech Biologics AG, announced encouraging interim results from its Phase I/II clinical trial evaluating Shigella4V (S4V), a promising tetravalent bioconjugate vaccine candidate targeting shigellosis, a severe infectious disease caused by Shigella bacteria. Shigellosis poses a significant health threat, especially to infants in low- and middle-income nations, where it remains a leading cause of fatal diarrheal illness. Initial findings from the trial's target demographic of nine-month-old infants indicate a favorable safety profile and robust immunogenicity against the four prevalent pathogenic Shigella serotypes, including S. flexneri 2a, 3a, 6, and S. sonnei. The completion of the Phase I/II trial, conducted in Kenya, is anticipated to yield comprehensive results in the first half of 2024.

LimmaTech's S4V vaccine candidate exhibited promising safety outcomes across all age groups during the initial phase of the clinical trial. The latest data update from the trial's second phase includes findings from 472 infants (aged nine months ± one month) who received two intramuscular injections at varying dose levels, with or without an adjuvant. S4V demonstrated excellent tolerability, with the majority of reported local and systemic reactions being mild. Importantly, no vaccine-related serious adverse events (SAEs) were recorded. A statistically significant increase in serum IgG levels was observed following either the first or second injection, contingent on the dosage and formulation.

"These positive interim results with S4V establish the robust immunogenicity potential of our bioconjugate vaccine candidate in the vulnerable nine-month-old infant population," remarked Dr. Patricia Martin, Chief Operating Officer of LimmaTech. "Shigellosis poses a grave threat, particularly in regions with limited healthcare access and rising antibiotic resistance. Our vaccine candidate holds promise in combating this infectious disease, potentially safeguarding countless lives, including those of children, travelers, and military personnel. We eagerly anticipate advancing its clinical development through an upcoming study slated for initiation in 2024."

The interim Phase I/II findings were previously presented at the BactiVac 4th Annual Network Meeting 2023 held in Birmingham, UK.

Conducted in Kenya, the Phase I/II trial is a randomized, double-blind, dose-finding investigation aimed at evaluating the safety and immunogenicity of Shigella4V (S4V). The study comprises two segments. Part 1 focused on safety assessment across adult, pediatric (two-five years), and infant populations, while Part 2 involved dose optimization and immunogenicity evaluation in the nine-month-old target group.

In 2015, LimmaTech entered into a research collaboration agreement with GlaxoSmithKline (GSK) to develop novel bioconjugate antigen-based vaccines, including a monovalent Shigella vaccine supported by the Wellcome Trust. Following promising outcomes from a proof-of-concept trial with the monovalent vaccine, LimmaTech and GSK embarked on developing a multivalent Shigella vaccine, partly funded by a Wellcome Trust grant. In July 2023, LimmaTech acquired the S4V Shigella bioconjugate vaccine candidate from GSK, assuming leadership in advancing the program's further development.