572. Antiviral Toxicities Among Pediatric Solid Organ Transplant Recipients

BACKGROUND: Ganciclovir (GCV) and valganciclovir (VGCV) are used for prophylaxis (PPX) and treatment for CMV in pediatric solid organ transplant (SOT) recipients, but the frequency and impact of toxicities from these medications are not well described. METHODS: Retrospective cohort study of children undergoing SOT at Children’s Hospital of Philadelphia from Jan 2012 - Jun 2018. EMR were reviewed to identify laboratory-based toxicities between 15 days and 1 year post-transplant; medication management within 14 days of toxicity onset was recorded. Toxicities were defined as GCV or VGCV-associated if a patient was on the antiviral at toxicity onset. We defined acute kidney injury (AKI) as ≥50% change in creatinine (Cr) from 30 days prior, leukopenia as WBC < 3500/µL, neutropenia as ANC < 1000/µL, and thrombocytopenia as < 100K/µL. Incidence rates of toxicities on PPX and treatment were compared to rates during no antiviral using univariate Poisson regression. RESULTS: 285 children received 299 SOTs: 108 liver, 91 kidney, 69 heart, 31 lung. Nearly half (46%) of toxicities during the first year after transplant occurred while on GCV or VGCV PPX or treatment, but their use accounted for only 23% of all follow-up time. Receipt of VGCV and GCV PPX and treatment were associated with significantly higher incidence rates of toxicities compared to no antiviral (Fig 1). Of 259 GCV or VGCV-associated toxicities, 44% (n=113) were leukopenia, 26% (66) neutropenia, 26% (66) AKI, and 6% (15) thrombocytopenia (Table 1). Most recipients of VGCV PPX (64%) sustained at least one toxicity while on PPX. AKI during VGCV PPX led to stopping/dose-adjusting of VGCV in 43% and of immunosuppression in 57% of cases. Neutropenia during VGCV PPX resulted in stopping/dose-adjusting of VGCV in 63%, of immunosuppression in 36%, and of TMPX/SMX PPX in 36% of cases. During VGCV PPX, 81% of AKI was stage II/III (≥100% change in Cr) and 65% of neutropenia was severe (< 500/µL); 11% of both AKI (n=6) and neutropenia (n=7) during VGCV PPX resulted in hospitalization. Figure 1. Incidence Rates of Toxicities from Day 15 through 1 Year After Transplant [Image: see text] Table 1. Antiviral Use and Toxicity 2 Weeks to 1 Year After Transplant [Image: see text] CONCLUSION: GCV and VGCV use was associated with significant renal and hematological toxicities in pediatric SOT recipients. While VGCV and GCV are effective at preventing CMV disease in pediatric SOT, clinicians should consider risk of toxicity when evaluating CMV prevention strategies. DISCLOSURES: Kevin J. Downes, MD, Merck, Inc. (Grant/Research Support)