ABSTRACT
Heart transplanted (HT) patients (pts) are poor responders to booster doses;there is an unmet need to find strategies to protect this fragile category of pts in the context of Omicron variants. It has been suggested that MMF could limit the immune response to vaccine. Tixagevimab/cilgavimab (T/C) has been approved for prophylaxis, but there are still few data on its safety and efficacy. We present our experience with T/C and with the reduction of MMF after the third (booster dose). All HT pts followed in our Center after November 2021 (when Omicron became the dominant in our Country) without significant anti-RBD antibodies (<100 ng/ml) after the booster dose were selected: before T/C availability, we reduced of 50% the dose of MMF one week before and after the forth dose if there was no recent rejection;after its availability, we interrupted this approach. The endpoint is the incidence of SARS-CoV-2 infection at two months in both strategies and the safety of T/C. 379 pts (23.1% vaccinated with 4 doses, 62% with 3 doses, 11.5% 2 doses, 3.4% not vaccinated) had 103 infections (4 reinfections), with an incidence of 20.0±2.2% at 6 months from the last dose of vaccine;17.4% were hospitalized, 3 pts (2.9%) died, one of whom was not vaccinated. 24.2% received antivirals, 13.5% sotrovimab without adverse effects and 100% survival.38% of 200 pts had low anti-RBD antibodies after the third dose. Among 84 undergoing to the forth dose, 41/57 for whom antibodies were known had low levels: 8 underwent to MMF reduction, in 23 the dose ws unchanged. The incidence of COVID-19 infection was 18.8±6.9% at two months and 26.5±8.1% at 6 months, with a borderline significant difference between the group were MMF was reduced compared to the one where it was unchanged (p=0.06).28 patients underwent to tixagevimab/cilgavimab (T/C) administration;the incidence of COVID-19 was 6.6±6.4% at two months. No adverse effects were noticed. While confirming the good outcomes of Omicron variants in a HT pts with high prevalence of vaccination and with the actuarial therapies, this small observational study suggests that in patients without detectable anti-RBD antibodies after the booster dose, MMF reduction may be somehow v beneficial, but T/C appears to give a better protection against the infection in the first two months. Larger studies are needed to confirm these results. [ABSTRACT FROM AUTHOR] Copyright of Journal of Heart & Lung Transplantation is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)