Background: In the phase 3 ZOE-50 trial, the HZ/su investigational subunit vaccine, containing the varicella-zoster virus glycoprotein E and the AS01B Adjuvant System, overall vaccine efficacy was 97.2% for the prevention of herpes zoster (HZ) in adults ≥50 years of age.1 The worldwide recruitment of subjects allows for additional analyses by region. Here we present initial results on disease incidence and vaccine efficacy (VE) by study region.
Methods: We conducted a randomized, observer-blind, placebo-controlled phase 3 trial in 18 countries in Europe, North America, Latin America, and Asia/Australia to evaluate the efficacy and safety of HZ/su in adults ≥50 years of age. Subjects were randomized 1:1 to receive 2 doses of HZ/su or placebo (saline solution) by intramuscular injection 2 months apart. VE in reducing the incidence of HZ compared to placebo was analyzed in subjects who received two doses and who did not develop a confirmed case of HZ within one month after dose 2 (modified total vaccinated cohort; mTVC). All suspected HZ cases were confirmed by polymerase chain reaction and/or a case adjudication committee.
Results: A total of 15,411 evaluable subjects received at least one dose of HZ/su or placebo. Most subjects were from Europe (51.2%), followed by Asia/Australia (21.3%), North America (17.4%), and Latin America (10.1%). After a mean follow-up of 3.2 years, 408 subjects overall presented with a suspected case of HZ, of whom 244 were confirmed as HZ. In the mTVC, 216 subjects had a confirmed case of HZ (HZ/su: 6; placebo: 210). VE against HZ did not differ between study regions, and ranged from 94.6% in Asia/Australia to 98.9% in Europe (Figure). HZ incidence in the placebo group was lower in Europe than in the other regions (7.5 vs. 10.3–11.6 cases per 1000 person-years).
Conclusion: HZ/su vaccine efficacy against HZ in adults ≥50 years of age was consistently very high across all study regions. The ZOE-50 trial also allowed us to determine regional HZ incidence based on a thorough and globally consistent disease confirmation method (NCT01165177).
1 Lal H, Cunningham TC, Godeaux O, et al. 2015 New Engl J Med
A. L. Cunningham,
Merck International: Scientific Advisor , Consulting fee
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M. Levin, GSK Vaccines: Grant Investigator and Scientific Advisor , Consulting fee and Research grant
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A. Poder, None
J. Puig-Barbera, None
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T. Vesikari, GSK Vaccines: Grant Investigator , Research grant and Speaker honorarium
Merck: Grant Investigator , Research grant and Speaker honorarium
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O. Godeaux, GSK Vaccines: Employee and Shareholder , Salary
T. Zahaf, GSK Vaccines: Employee and Shareholder , Salary
H. Lal, GSK Vaccines: Employee and Shareholder , Salary
T. Heineman, GSK Vaccines: Employee and Shareholder , Salary