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

## TL;DR

This study finds that CPX-351-treated AML patients have a high rate of perianal infections, which are linked to longer hospital stays and multidrug-resistant bacteria.

## Contribution

The study is the first to report a high incidence of perianal infections in CPX-351-treated secondary AML patients and suggests routine rectal swab surveillance as a potential preventive measure.

## Key findings

- Perianal infections occurred in 31.8% of CPX-351-treated secondary AML patients.
- Infections were associated with longer hospital stays and presence of Klebsiella pneumoniae.
- Routine rectal swab surveillance may help identify high-risk patients.

## Abstract

Despite CPX-351’s design to minimize gastrointestinal issues, its effect on serious infectious complications, such as perianal infections (PIs), remains uncertain in patients affected by acute myeloid leukemia (AML). Our study revealed a notably high incidence of PIs in our secondary AML cohort that underwent CPX-351. The development of a PI was strongly linked to a significantly longer hospital stay and correlated with signs of mucosal damage and the presence of multidrug-resistant organisms, particularly Klebsiella pneumoniae. While patient outcomes concerning early mortality were favorable, the substantial morbidity and prolonged hospitalizations underscore the clinical burden of PIs. This suggests that implementing routine rectal swab surveillance may be a valuable approach for identifying high-risk patients and guiding preemptive interventions.

Background: 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. Methods: 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. Results: The incidence of PIs in the cohort was 31.8%. Microbiological cultures from the lesions commonly yielded Klebsiella pneumoniae and Enterococcus species. The development of a PI was associated with a significantly longer hospital stay (mean, 49.6 vs. 37.7 days; p = 0.034). An increased odds ratio of having PIs was noted for mucositis and positive rectal swabs (17.961, p = 0.062; 5.554, p = 0.391, respectively), with two patients (28.5%) having a positive pre-infection swab for Klebsiella pneumoniae. Surgical intervention was guided by patient pain levels and hematological criteria. Surgical patients had significantly higher pain levels (p = 0.001) and a platelet count greater than 20 × 109/L (p = 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. Conclusions: 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.