A single-center review of pre-exposure prophylaxis with tixagevimab-cilgavimab in solid organ transplant recipients.

BACKGROUND: Coronavirus disease 2019 (COVID-19) continues to negatively impact solid organ transplant recipients (SOTr). Data on the use of tixagevimab-cilgavimab (tix-cil) in vaccinated SOTr during circulation of Omicron and its subvariants are limited. Therefore, this single-center review was conducted to evaluate tix-cil efficacy in multiple organ transplant groups during a study period where Omicron B.1.1.529, BA.2.12.1, and BA.5 predominated. METHODS: In this single-center retrospective study, we evaluated the incidence of COVID-19 infection in adult SOTr who did or did not receive pre-exposure prophylaxis (PrEP) with tix-cil. SOTr were included if they were at least 18 years of age and met emergency use authorization criteria for tix-cil use. The primary outcome analyzed was the incidence of COVID-19 infection. RESULTS: Ninety SOTr met inclusion criteria and comprised of two groups, tix-cil PrEP (n = 45) and no tix-cil PrEP (n = 45). Of SOTr who received tix-cil PrEP, three (6.7%) developed COVID-19 infection, compared to eight (17.8%) in the no tix-cil PrEP group (p = .20). Of the 11 SOTr diagnosed with COVID-19, 15 (82.2%) were fully vaccinated against COVID-19 prior to transplantation. Moreover, 18.2% and 81.8% of the COVID-19 cases observed were asymptomatic and mild-to-moderate, respectively. DISCUSSION: Our study results, which included months when BA.5 was in increased circulation, suggest no significant difference in COVID-19 infection with or without use of tix-cil PrEP in our solid organ transplant groups. As the COVID-19 pandemic continues to evolve, clinical utility of tix-cil should be evaluated against new, emerging strains.

New UNOS allocation system associated with no added benefit in waitlist outcomes and worse post-transplant survival in heart-kidney patients.

BACKGROUND: The 2018 United Network for Organ Sharing (UNOS) heart transplant policy change (PC) sought to improve waitlist risk stratification to decrease waitlist mortality and promote geographically broader sharing for high-acuity patients awaiting heart transplantation. Our analysis sought to determine the effect of the UNOS PC on outcomes in patients waiting for, or who have received, a heart-kidney transplantation. METHODS: We analyzed adult (≥18 years old), first-time, heart-only and heart-kidney transplant candidates and recipients from the UNOS Registry. Patients were divided into pre-PC (PRE: October 18, 2016-May 30, 2018) and post-PC (POST: October 18, 2018-May 30, 2020) groups for comparison. Competing risks analysis (subdistribution and cause-specific hazards analyses) was performed to assess for differences in waitlist death/deterioration or heart transplantation. One-year post-transplant survival was assessed with Kaplan-Meier and Cox analyses. We included an interaction term (policy era × heart ± kidney) in our analyses to evaluate the effect of PC on outcomes in heart-kidney patients. RESULTS: One-year post-transplant survival was similar (p = 0.83) for PRE heart-kidney and heart-only recipients, but worse (p < 0.001) for POST heart-kidney vs heart-only recipients. There was a policy-era interaction between heart-kidney and heart-only recipients (HR 1.92[1.04,3.55], p = 0.038) indicating a detrimental effect of policy on 1-year survival in POST vs PRE heart-kidney recipients. No added beneficial effect of PC on waitlist outcomes in heart-kidney vs heart-only candidates was observed. CONCLUSIONS: There was no added policy-era benefit on waitlist outcomes for heart-kidney candidates when compared to heart-only candidates. POST heart-kidney recipients experienced worse 1-year survival compared to PRE heart-kidney recipients with no policy effect on heart-only recipients.

Effect of the UNOS policy change on rates of rejection, infection, and hospital readmission following heart transplantation.

BACKGROUND: The 2018 adult heart allocation policy sought to improve waitlist risk stratification, reduce waitlist mortality, and increase organ access. This system prioritized patients at greatest risk for waitlist mortality, especially individuals requiring temporary mechanical circulatory support (tMCS). Posttransplant complications are significantly higher in patients on tMCS before transplantation, and early posttransplant complications impact long-term mortality. We sought to determine if policy change affected early posttransplant complication rates of rejection, infection, and hospitalization. METHODS: We included all adult, heart-only, single-organ heart transplant recipients from the UNOS registry with pre-policy (PRE) individuals transplanted between November 1, 2016, and October 31, 2017, and post-policy (POST) between November 1, 2018, and October 31, 2019. We used a multivariable logistic regression analysis to assess the effect of policy change on posttransplant rejection, infection, and hospitalization. Two COVID-19 eras (2019-2020, 2020-2021) were included in our analysis. RESULTS: The majority of baseline characteristics were comparable between PRE and POST era recipients. The odds of treated rejection (p = 0.8), hospitalization (p = 0.69), and hospitalization due to rejection (p = 0.76) and infection (p = 0.66) were similar between PRE and POST eras; there was a trend towards reduced odds of rejection (p = 0.08). In both COVID eras, there was a clear reduction in rejection and treated rejection with no effect on hospitalization for rejection or infection. Odds of all-cause hospitalization was increased in both COVID eras. CONCLUSIONS: The UNOS policy change improves access to heart transplantation for higher acuity patients without increasing early posttransplant rates of treated rejection or hospitalization for rejection or infection, factors which portend risk for long-term posttransplant mortality.