A new vaccine candidate, GonoVac, is about to be tested in humans for the first time to see if it can prevent gonorrhoea. This matters because gonorrhoea is becoming resistant to nearly all available antibiotics, with roughly 82 million new infections occurring globally each year. The bacteria that cause it rarely trigger a protective immune response during natural infection, making vaccine development difficult. However, a related vaccine against meningococcus B (Bexsero) has shown some cross-protection against gonorrhoea in real-world use, suggesting a dedicated gonorrhoea vaccine is achievable. GonoVac, made from the outer membrane vesicles of the gonorrhoea bacterium, cleared the infection more rapidly than Bexsero in mouse studies. If this Phase 1 trial in healthy UK adults shows GonoVac is safe and provokes a strong immune response, the next step would be larger Phase 2 trials to test whether it actually prevents infection. A successful vaccine would reduce the need for antibiotics, slow the spread of antimicrobial resistance globally, and improve sexual and reproductive health—particularly in low- and middle-income countries where infection rates can reach 6% of the population, and among high-risk groups such as young adults and men who have sex with men.
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Context Gonorrhoea is a global public health problem with approximately 82 million new cases each year. Low- and middle-income countries (LMIC) are disproportionately affected with up to 6% of individuals infected in some settings. In addition to causing significant reproductive health problems in women, gonorrhoea is a major driver of antimicrobial resistance (AMR). With gonorrhoea developing resistance to nearly all available antibiotic agents, a vaccine that can protect against gonorrhoea and reduce the need for antibiotics is greatly needed. Development of a such a protective vaccine represents a major healthcare challenge, since natural infection with gonorrhoea rarely results in protective immunity and correlates of protection (COP) against gonorrhoea are poorly understood. However, recent evidence from clinical studies demonstrating that outer membrane vesicle (OMV) containing vaccines against serogroup B meningococcus, such as Bexsero (4CMenB) are effective at providing some protection against gonorrhoea has reinvigorated the field, suggesting development of an efficacious gonorrhoea vaccine is achievable. Aims and objectives GonoVac is a gonococcal OMV based candidate vaccine, which can clear the bacteria that cause gonorrhoea more rapidly than Bexsero in a mouse model of gonococcal infection. Mice vaccinated with GonoVac develop an antibody response, including functional activity, against a range of currently circulating gonococcal strains. This proposal aims to perform the early clinical development to support onward development of GonoVac through to licensure and introduction. To fulfil this aim, we will conduct a Phase 1, first-in-human (FIH) clinical trial to assess the side effects and immune responses induced by GonoVac in healthy UK adults. This trial will also assess if combining GonoVac with aluminium hydroxide (Al(OH)3), a substance commonly added to OMV vaccines, affects the side effect profile or immune response seen following GonoVac vaccination. Potential applications and benefits These findings will help us decide if GonoVac should progress further in clinical development. This work will also help narrow down the optimal dose(s) of GonoVac to assess in future clinical trials and whether GonoVac should be co-administrated with Al(OH)3 or not. Provided safety and immunogenicity data from this proposed project is supportive, the next steps in GonoVac’s development will be Phase 2 trial(s) to assess the efficacy of the GonoVac against gonorrhoea, ideally in collaboration with a manufacturing partner. Ultimately, the applications and benefits of the vaccine, if successful, will be to prevent gonorrhoea infection, resulting in greater sexual and reproductive health equity, a fall in antimicrobial prescribing and a reduction in levels and transmission of AMR bacteria globally. Such a vaccine would benefit both global populations, particularly where incidence of gonorrhoea is highest, and high-risk groups including young adults, men who have sex with men (MSM) and commercial sex workers.
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