Prevention of Ommaya Reservoir-Associated Bacterial Meningitis With Prophylactic Intraventricular Vancomycin.

Abstract

Intraventricular chemotherapy administered through an Ommaya reservoir (OmR) constitutes an integral part of therapy for patients with leptomeningeal metastasis. Unfortunately, OmR infections remain a frequent, costly, morbid, and occasionally fatal complication, limiting the benefit of this approach. We evaluate the efficacy, cost savings, and toxicity of vancomycin coadministered with intraventricular chemotherapy for the prevention of OmR-associated bacterial meningitis. This was a cohort study comparing a treatment group treated from May 1, 2021, to April 30, 2022, and a retrospective control group treated from 2016 to 2021. Patients were included if they had a diagnosis of leptomeningeal metastasis and subsequent placement of an OmR, followed by delivery of planned intraventricular chemotherapy. Patients in the treatment group received a 10-mg dose of intraventricular vancomycin in addition to their standard chemotherapy regimen at each treatment. We compared this group to a retrospective cohort from the preceding 5 years who did not receive intraventricular vancomycin, evaluating the rate of infection, adverse events, and associated treatment costs between groups. The infection rate was 0% (95% CI 0%-6.75%) among the 63 patients and 0% (0%-0.76%) in the 501 consecutive treatments administered over the 12-month study period, compared with 10.25% (7.39%-14.0%) among the 322 patients and 1.71% (1.22%-2.39%) in 1932 treatments over the preceding 5 years. The absolute risk reduction was 10.3% (3.83-14.04), P = .0028. The number needed to treat was 10 (7-26). Cost per vancomycin dose was $10.00 ($5010 over 12 months). The cost of nonsurgical treatment of 1 OmR-associated infection is $88 372, which translates into $618 604 for the estimated 7 patients over 12 months who developed an OmR-associated infection. No treatment-associated toxicity was observed. Prophylactic intraventricular vancomycin eliminated OmR-associated infections without added toxicity and with dramatic cost savings.