DP042 | IMPACT OF ANTIFUNGAL PROPHYLAXIS ON TRANSPLANT-RELATED MORTALITY IN MISMATCHED ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION (HSCT): A PROSPECTIVE EXPERIENCE FROM A SINGLE TRANSPLANT PROGRAM

Background In the allogeneic HSCT, the incidence of Invasive Fungal Disease is 7-9% with high rate of mortality. Although the antifungal prophylaxis is crucial, the role of anidulafungin is unknown. This prospective study aims to evaluate the efficacy and safety of anidulafungin as antifungal prophylaxis in the mismatched allogeneic HSCT. Methods From December 2019 to January 2024, a cohort of 36 mismatched allogeneic HSCT (10 from unrelated and 26 from haploidentical donor) received anidulafungin as antifungal prophylaxis, starting from day +1 until the PMN engraftment. All patients were affected by malignant disease (CR=75%; active disease= 25%) and the median age was 52 years (range 21-68). The conditioning regimen intensity was intermediate in 21 and low in 15 cases. As GVHD prophylaxis, all received CSA, MMF, and PT-Cy 50 mg/kg for 2 days and 94.5% (n=34, CMV+) received letermovir,as CMV prophylaxis. Stem cell sources included bone marrow and peripheral blood in 44.5% and 55.5% of cases, respectively. Results All patients achieved polymorphonuclear (PMN) and platelets (PLTs) engraftment, with median times of 19 (range 16–38) and 23 days (range 12–45), respectively. The 100-day and 1year-NRM were 0% and 8.3% (Figure 1), while the 2-yrs OS was 58.3%. Acute and chronic GVHD occurred in 30.5% (grade ≤2 in all but one case) and 8.3% of patients, respectively. Anidulafungin-related toxicity was observed in 36.1% (n=13) of patients, exclusively as liver WHO grading <2 and resolved within 3 days of stopping the drug. 11/13 (84.6%) patients were switched to other antifungal prophylaxis while 2 (15.3%) continued anidulafungin as the toxicity was self-limiting. The median duration of prophylaxis was 15 days (range 10-35). During the pre-engraftment period, 15 (41.6%) patients developed infectious fever, bacterial in 13 and viral in 2 cases. CMV reactivation occurred in 2 patients. Late fungal infections occurred in 2 patients (5.6%), at day +150 (suspected) and day +180 (proven), during immunosuppressive therapy for Pure Red Cell Aplasia and GVHD treatment, respectively. Conclusions In the mismatched allogeneic HSCT subset, anidulafungin prophylaxis during the pre-engraftment period is effective in preventing early fungal infections and reducing NRM. However, our data indicate that liver toxicity occurs in 36.1% of cases highlighting the need for careful monitoring and timely discontinuation of the drug.