GSK's Gonorrhea Drug Success and Shingrix Vaccine's Enduring Efficacy

GSK's infectious disease unit announced two significant clinical trial achievements. The first was a Phase III trial for a new antibiotic, gepotidacin, targeted at uncomplicated urogenital gonorrhea. Gepotidacin is an innovative oral antibiotic that inhibits bacterial DNA replication with a unique mechanism, potentially effective against antibiotic-resistant strains of gonorrhea and other pathogens.

In February 2024, GSK initially reported promising results but withheld detailed data. Recently, the company shared more specifics, revealing that two oral doses of gepotidacin eradicated the gonorrhea bacteria in 92.6% of patients. This success rate is comparable to the 91.2% efficacy of the standard treatment—an intramuscular injection of ceftriaxone combined with oral azithromycin.

Safety and tolerability data for gepotidacin aligned with previous Phase I and II trials, with gastrointestinal issues being the most commonly reported side effect. A single patient experienced a severe adverse event, although it was deemed unrelated to the drug. Other side effects were classified as mild or moderate.

GSK's study aims to address the rising rate of gonorrhea, which has more than doubled in the U.S. from 2009 to 2021. The CDC reported nearly 650,000 cases in 2022, half of which are resistant to at least one antibiotic. Gepotidacin’s success in treating both uncomplicated urinary tract infections and gonorrhea positions it as a potential high-revenue generator, alongside GSK’s other anti-infectives, tebipenem HBr and Brexafemme. Collectively, these drugs could achieve peak annual sales of £2 billion ($2.5 billion).

GSK also reinforced the effectiveness of Shingrix, its shingles vaccine that earned £3.4 billion ($4.2 billion) in sales last year, with projections exceeding £4 billion ($5 billion) for this year. The latest data came from extended Phase III trials involving adults over 50 and those 70 and older. Between six and eleven years post-vaccination, Shingrix showed cumulative efficacy rates of 79.7% in the over-50 group and 73.1% in those over 70.

“With the vaccine now included in many national immunization programs globally, this data enriches our understanding of Shingrix's long-term protection against shingles,” said Phil Dormitzer, head of vaccines R&D at GSK.

In the U.S., the immunization rate with Shingrix for people over 50 stands at 35%, indicating potential growth. However, GSK anticipates much of the sales increase in 2024 will be driven by international markets, where the vaccine is approved in close to 40 countries but has a penetration rate of less than 4% in most.

This overview highlights GSK's ongoing efforts and achievements in expanding treatments for infectious diseases and enhancing vaccine efficacy, suggesting a robust future pipeline in its pharmaceutical portfolio.