Results from a phase 3 study of the investigational shingles vaccine Shingrix (GlaxoSmithKline) have shown 90% efficacy in adults 70 years of age and older that was maintained for at least four years. The new findings were published in the New England Journal of Medicine.
Shingrix is a nonlive, adjuvanted, subunit (HZ/su) candidate vaccine to help prevent herpes zoster and its complications. The vaccine combines glycoprotein E, a protein found on the varicella zoster virus (VZV) that causes shingles, with an adjuvant system, AS01B, which is intended to enhance the immunological response to the antigen.
The phase 3 ZOE-70 (ZOster Efficacy in Adults Aged 70 Years and Over) trial was a randomized, observer-blinded, placebo-controlled (saline solution), multinational (North America, Europe, Latin America, and Asia-Pacific) study involving more than 14,800 adults 70 years of age and older. Two doses were administered intramuscularly two months apart. The study, which started in August 2010, included subjects in the age ranges of 70 to 79 years, and greater than or equal to 80 years. The study’s primary objective was overall vaccine efficacy against shingles in people 70 years of age and older compared with placebo.
The study showed that the two-dose candidate shingles vaccine had 90% efficacy (95% confidence interval [CI], 84%–94%) compared with placebo in people 70 years of age. Vaccine efficacy was maintained across the various age groups included in the study, ranging between 90% (95% CI, 83%–94%) in people ages 70 to 79 years and 89% (95% CI, 74%–96%) in those ages 80 years and older.
The high efficacy rates were in line with results from the ZOE-50 trial, a study in people older than 50 years of age, which showed a 97% efficacy rate (95% CI, 93%–99%). A pooled analysis of data from both the ZOE-70 and ZOE-50 trials showed that the vaccine demonstrated 91% efficacy against shingles (95% CI, 86%–95%) in adults ages 70 years and older compared with placebo. This efficacy was maintained with an 88% reduction in the risk of shingles (95% CI, 73%–95%) in the fourth year after vaccination.
The risk of serious adverse events, potential immune-mediated diseases, or deaths observed in the ZOE-70 trial was similar in subjects receiving Shingrix or placebo. The most commonly reported local adverse event was injection-site pain, and the most common systemic adverse event was fatigue. Most of the injection-site and systemic adverse events occurred within seven days of vaccination, with most lasting one to three days.
In addition, a pooled analysis of data from the ZOE-70 and ZOE-50 studies showed that the candidate vaccine effectively reduced the risk of subsequent postherpetic neuralgia (PHN), which is the most common complication of shingles. The vaccine was shown to be 89% effective (95% CI, 68%–97%) in preventing PHN in people ages 70 years and older and 91% effective (95% CI, 75%–98%) in people ages 50 years and older.
Source: GlaxoSmithKline; September 14, 2016.