In January 2023 Intravacc announced that the intranasal gonorrhoea candidate vaccine it is developing in partnership with Therapyx inc. had performed well in pre-clinical studies. The results, published in mSphere of the American Society of Microbiology, reflect protection against infection with Neisseria gonorrhoeae (NG). The candidate, Avacc 11, is a “proprietary outer membrane vesicle (OMV) platform-based” vaccine “combined with encapsulated IL-12″.  

The problem of gonorrhoea 

The publication, produced by researchers at Intravacc and Therapyx, describes how “despite public health efforts”, gonorrhoea remains “highly prevalent”. Infection with Neisseria gonorrhoeae, (NG) is an “urgent threat” because of the emergence of “resistance to currently available antibiotics”.  

Across the world, incidence is estimated at 87 million new infections a year. Although it is “not usually lethal”, gonococcal infection is a “major cause of reproductive tract morbidity”, particularly in women. Furthermore, infection during pregnancy can “result in adverse outcomes”.  

The symptoms include a pus-like discharge from the vagina or penis, pain when weeing, or bleeding between periods. However, almost half of infected women and 1 in 10 infected men experience no symptoms.  

The pursuit of effective antibiotics continues, but the authors suggest that NG’s ability to “rapidly” develop resistance to “each antibiotic deployed against it” indicates that “this approach might only afford a temporary solution”. Enter: vaccines.  

Vaccine development 

The study acknowledges that “previous efforts” were “unsuccessful”, but that recent “advances in comprehending immunity” combined with the discovery that “immunisation against the related organism Neisseria meningitidis might provide modest cross-protective immunity” have “reinvigorated efforts”.  

In October 2022 Intravacc was awarded a $14.6 million NIH/NIAD contract to “further develop” its intranasal candidate vaccine. A previous study demonstrated that intravaginal administration of the candidate vaccine provided resistance to infection. However, as this is “inapplicable for males and may not be acceptable to women”, a new approach was required.  

This study vaccinated mice through the intranasal route, providing “similar” results as the intravaginal study.  

“Intranasal immunisation resulted in high serum IgG, salivary IgA, and vaginal IgG and IgA anti-gonococcal antibodies when OMVs were administered with IL-12 ms.” 

The response was consistent across both male and female mice. CEO of Intravacc, Dr Jan Groen, suggested that the company and its partner Therapyx are “pleased with the preclinical data”.  

We will hear more from Intravacc on other pursuits at the World Vaccine Congress in Washington 2023. Join us by purchasing your tickets here.