Candidate Shingles Vaccine Shows Promise in Older Adults

The study assessed the safety and immunogenicity of doses administered at longer intervals
The study assessed the safety and immunogenicity of doses administered at longer intervals

NEW ORLEANS, LA—Different dosing schedules for a two-dose candidate herpes zoster (HZ) subunit vaccine (HZ/su) exhibited similar immunogenicity and safety profiles among older adults, authors of a randomized, open-label, phase 3 multicenter Phase 3 study reported at IDWeek 2016.

Scheduling the second dose for month 6 was found to be non-inferior to a previously studied schedule that delivered the second dose of vaccine at month 2.

“HZ/su elicited robust anti-glycoprotein E (gE] immune responses that persisted for up to 12 months post-dose 2 in all study groups,” reported Brecht Geeraerts, PhD, of GSK Vaccines, in Wavre, Belgium, and coauthors. In addition, "HZ/su demonstrated an acceptable reactogenicity and safety profile regardless of the vaccination schedule."

Previous work had shown that two doses of HZ/su (50 µg varicella-zoster virus [VZV] gE and AS01B Adjuvant System), administered 2 months apart, demonstrated >89% efficacy in preventing HZ among adults age 50 years or older, with a “clinically acceptable” safety profile, the authors noted.

The new study was undertaken to assess the safety and immunogenicity of doses administered at longer intervals.

A total of 354 adults were enrolled in the US and Estonia, and randomly assigned (1:1:1) to be vaccinated at 0 and 2 months (0,2), 0 and 6 months (0,6), or 0 and 12 months (0,12). Blood samples were obtained prior to vaccination and again at months 1 and 12 after the second vaccine dose was administered. Adverse events were recorded at 7 and 30 days after vaccination, and serious adverse events and immune-mediated diseases were recorded throughout the study.

Among 346 participants who completed the study, 343 were included in the analysis as an according-to-protocol immunogenicity-assessment cohort. The mean age for the study groups was 64.5 years in the 0,2-month arm, 64.0 years in the 0,6-month arm, and 64.1 years in the 0,12-month arm. The majority of the patients were female, 75.6%, 64.7%, ad 68.1%, respectively and, with the exception of 3 patients in the 0,2-month arm who were African/African American and 1 in the 0,6-month arm who was "other," all of the study patients were white or Caucasian/European.

"For both 0,6-month and 0,12-month groups, the predefined success criterion for vaccine response rate was met," the authors reported. The subsequent non-inferiority for anti-gE immune response geometric mean concentrations versus the 0,2-month schedule was only demonstrated in the 0,6-month arm.

Two participants experienced a fatal adverse event (one from the 0,2-month group and one from the 0,12-month group), but neither these, nor the other reported serious adverse events, were determined to be vaccine-related. The number of subjects reporting serious adverse events from first vaccination until 12 months post-dose 2 was 5 in the 0,2-month arm, 9 in the 0,6-month arm, and 12 in the 0,12-month arm. 

No cases of immune-mediated disease following vaccination were reported.

The incidence of HZ increases from 50 years of age, "presumably due to age-related decline in VZV-specific cellular immunity," the authors noted.

The study was funded by GlaxoSmithKline Biologicals SA.