Source – GSK
GSK’s vaccine for gonorrhea has received a fast-track designation from the FDA, signaling its potential to combat the rising global prevalence of the sexually transmitted infection. The vaccine, known as NgG, is currently undergoing a Phase III trial targeting adults aged 18 to 50 who are at risk of Neisseria gonorrhoeae infection, the bacteria responsible for the disease.
Fast-track status is granted to novel drugs and vaccines that aim to address serious conditions with limited or no alternative treatments available. Gonorrhea, which affected 82 million individuals in 2020 and is rapidly developing resistance to antimicrobial medicines, is a major concern for the World Health Organization (WHO). In the United States alone, reported cases have increased by 118% from 2009 to 2021, surpassing 710,000 cases.
With certain strains of gonorrhea becoming untreatable using existing antibiotic classes, the need for effective vaccines to prevent initial infections is urgent. Notably, prior infection does not provide long-term protection against re-infection, further emphasizing the significance of a preventive vaccine.
Developing a successful vaccine for N. gonorrhoeae has been challenging due to the rapid evolution of targeted structures on the bacterial envelope, making it difficult to identify an antigen combination with broad protective efficacy against various strains. GSK’s NgG vaccine employs generalised modules for membrane antigen (GMMA) technology, which utilizes outer membrane vesicles (OMVs) released by the bacteria during growth and containing multiple antigens. GMMA technology has garnered attention for its potential to overcome envelope variability.
Currently in the Phase II stage of a Phase I/II study involving approximately 750 healthy adult participants across several countries, including the US, UK, France, Germany, Spain, Brazil, the Philippines, and South Africa, NgG’s results are expected in 2025.
Meanwhile, preliminary research suggests that vaccines targeting N. meningitidis, such as GSK’s MenB vaccine Bexsero, designed to protect against meningitis, may also provide partial protection against gonorrhea. An investigator-led study presented at a recent conference observed a 50% reduction in gonorrhea cases among at-risk gay and bisexual men who received two doses of Bexsero, although the study involved a limited number of patients. Bexsero is currently undergoing a Phase III trial to assess its efficacy in preventing gonorrhea in this population, with results expected next year. However, a vaccine specifically tailored to N. gonorrhoeae could offer enhanced protection and have broader applications.
Administering a vaccine with a protective efficacy of only 31% to 14-year-olds as a routine vaccination could lead to a decrease of 50,000 cases of infection over a period of 10 years. This aspect further emphasizes the advantages of safeguarding against invasive meningococcal disease.
Another biotech company, Intravacc, is also engaged in the development of a dedicated vaccine for gonorrhea. The Dutch company received nearly $15 million in funding from the US government last year to progress its Avacc 11 OMV-based vaccine, which is currently in the preclinical development stage.
