Duration of Antiviral Prophylaxis and Risk of Herpes Zoster (HZ) among Patients with Solid Tumor Malignancy on Chemotherapy (STMc)

• Published in: Open forum infectious diseases Vol. 4; no. suppl_1; p. S726
• Main Authors: Zhang, Dongmu, Weiss, Thomas, Finelli, Lynn
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 01.10.2017
• ISSN: 2328-8957; 2328-8957
• DOI: 10.1093/ofid/ofx163.1959

Abstract Background The incidence of HZ in patients with STM ranges from 12 to 40 per 1,000 person-years (PY) compared with 4 to 6 per 1,000 PY in the general population; however, there are no guidelines for routine antiviral prophylaxis (AP). The objectives of this study are to use real-world data to describe the use of AP and compare the incidence of HZ by AP duration in patients with STMc. Methods This is a retrospective, observational study using MarketScan® Commercial and Medicare Supplemental databases. We included patients ≥18 years old who: (1) had STM diagnosis during 2009–2013; (2) had chemotherapy after STM diagnosis (earliest chemotherapy date being the study enrollment date); (3) were continuously enrolled in health plans for at least 1 year before and after study enrollment date; (4) did not receive HZ vaccination; (5) did not have Herpes simplex virus or cytomegalovirus disease; (6) did not have HZ during 1 year before study enrollment date; and (7) did not have HZ during 7 days before or after the first AP prescription. AP duration was the sum of total days’ supply of AP prescriptions from 30 days before to 365 days after the study enrollment date. All patients were followed from the study enrollment date to end of continuous health plan enrollment, death, or 12/31/2014 to assess HZ incidence. Poisson regression was used to estimate the 95% confidence intervals (CI) of HZ incidence. Logistic regression was used to identify the factors associated with AP use. Results We identified 180,483 eligible STMc patients. Mean age was 62.6 years (SD=13.5), 46.9% were male, and 12,864 (7.1%) of patients were prescribed AP. Acyclovir was the most common agent (49.6%), followed by Valacyclovir (41.6%). Mean duration of AP use was 87 days (SD = 115; median = 30). HZ incidence was 11.3/1,000 PY (95% CI = [11.0,11.6] for the cohort. HZ incidence was 27.9/1,000 PY (95% CI = [25.7,30.3] for patients with 1–89 days of AP, and 15.3/1,000 PY (95% CI = [10.6,21.5] for patients who received ≥360 days of AP. Strong predictors of AP use were receiving Bortezomib (OR = 17.09, P < 0.001) and HIV infection (OR = 3.313, P < 0.001). Conclusion Some STMc patients remain at high risk for HZ, even when prescribed AP. A safe and effective vaccine against HZ for STMc patients may be a useful adjunctive prevention strategy for high-risk patients. Disclosures D. Zhang, Merck: Employee, Salary. T. Weiss, Merck: Employee, Salary; L. Finelli, Merck: Employee, Salary