Incidence and Characteristics of Perianal Infections in CPX-351-Treated AML Patients

<b>Background:</b> Perianal infections (PIs) are a serious threat in patients with acute myeloid leukemia (AML). While CPX-351 is designed to reduce gastrointestinal toxicity, its impact on the incidence of PIs is unknown. This study aims to evaluate the incidence and characteristics of PIs in a cohort of CPX-351-treated AML patients. <b>Methods:</b> We enrolled 22 adult patients diagnosed with secondary AML receiving CPX-351 between May 2020 and July 2025 at Policlinico Tor Vergata Hospital. Statistical analysis used descriptive statistics and multivariate analysis. <b>Results:</b> The incidence of PIs in the cohort was 31.8%. Microbiological cultures from the lesions commonly yielded <i>Klebsiella pneumoniae</i> and <i>Enterococcus species</i>. The development of a PI was associated with a significantly longer hospital stay (mean, 49.6 vs. 37.7 days; <i>p</i> = 0.034). An increased odds ratio of having PIs was noted for mucositis and positive rectal swabs (17.961, <i>p</i> = 0.062; 5.554, <i>p</i> = 0.391, respectively), with two patients (28.5%) having a positive pre-infection swab for <i>Klebsiella pneumoniae</i>. Surgical intervention was guided by patient pain levels and hematological criteria. Surgical patients had significantly higher pain levels (<i>p</i> = 0.001) and a platelet count greater than 20 × 10⁹/L (<i>p</i> = 0.028). All patients were alive at 30 days, with low rates of septic shock (14.2%, n = 1) and no infection-related mortality or recurrence. <b>Conclusions:</b> Despite CPX-351's known reduced gastrointestinal toxicity, our study showed a significantly higher incidence of PIs compared to literature data. While the outcomes were favorable, PIs led to prolonged hospitalization. Routine rectal swab surveillance could be a valuable tool for risk stratification and preemptive strategies.