Immunogenicity of Inactivated Varicella Zoster Vaccine in Autologous Hematopoietic Stem Cell Transplant Recipients and Patients With Solid or Hematologic Cancer

Background: In phase 3 trials, inactivated varicella zoster virus (VZV) vaccine (ZV_IN) was well tolerated and efficacious against herpes zoster (HZ) in autologous hematopoietic stem cell transplant (auto-HSCT) recipients and patients with solid tumor malignancies receiving chemotherapy (STMc) but did not reduce HZ incidence in patients with hematologic malignancies (HMs). Here, we describe ZV_IN immunogenicity from these studies.

Methods: Patients were randomized to ZV_IN or placebo (4 doses). Immunogenicity was assessed by glycoprotein enzyme-linked immunosorbent assay (gpELISA) and VZV interferon (IFN)-γ enzyme-linked immunospot (ELISPOT) assay in patients receiving all 4 doses without developing HZ at the time of blood sampling.

Results: Estimated geometric mean fold rise ratios (ZV_IN/placebo) by gpELISA and IFN-y ELISPOT ~28 days post-dose 4 were 2.02 (95% confidence interval [CI], 1.53-2.67) and 5.41 (95% CI, 3.60-8.12) in auto-HSCT recipients; 1.88 (95% CI, 1.79-1.98) and 2.10 (95% CI, 1.69-2.62) in patients with STMc; and not assessed and 2.35 (95% CI, 1.81-3.05) in patients with HM.

Conclusions: ZV_IN immunogenicity was directionally consistent with clinical efficacy in auto-HSCT recipients and patients with STMc even though HZ protection and VZV immunity were not statistically correlated. Despite a lack of clinical efficacy in patients with HM, ZV_IN immunogenicity was observed in this population. Immunological results did not predict vaccine efficacy in these 3 populations.

Clinical trial registration: NCT01229267, NCT01254630.