Safety of levofloxacin as an antibiotic prophylaxis in the induction phase of children newly diagnosed with acute lymphoblastic leukemia: an interim analysis of a randomized, open-label trial in Brazil.

Background: Despite high cure rates, treatment-related mortality in children with acute lymphoblastic leukemia (ALL) remains significant. About 4% of patients die during remission induction therapy and approximately two-thirds of treatment-related deaths are due to infectious complications.

Methods: From May 2021 to June 2022, children aged one through 18 years, with a recent diagnosis of ALL, admitted to three pediatric oncology centers in Brazil, were enrolled in this multicenter, open-label, randomized, phase 3 clinical trial. Eligible patients were randomly divided into two groups, based on a 1:1 allocation ratio, to receive, or not, levofloxacin as a prophylactic agent during the induction phase. All patients were treated according to the IC-BFM 2009 chemotherapy protocol. Primary endpoints were carbapenemase-producing Enterobacteriaceae (CPE) colonization, Clostridioides difficile diarrhea, and other adverse events related to the use of levofloxacin. The secondary endpoint was febrile neutropenia during induction. The median follow-up was 289 days.

Results: Twenty patients were included in this trial, 10 in each group (control and levofloxacin). Mild adverse reactions related to levofloxacin were observed in three patients (30%). Three patients had Clostridioides difficile diarrhea, two in the levofloxacin group and one in the control group (p > 0.99). Only one patient presented colonization by CPE. This patient belonged to the levofloxacin group (p > 0.99). Nine patients presented febrile neutropenia, five in the control group and four in the levofloxacin intervention group (p > 0.99), one patient died due to febrile neutropenia.

Conclusion: The use of levofloxacin was shown to be safe in the induction phase in children with de novo ALL. The use of this medication did not increase the rate of colonization by CPE nor the rate of diarrhea by C. difficile. All adverse reactions were mild and remitted either spontaneously or after switching medicine administration from oral to intravenous route.