A double blind RCT to examine the safety and efficacy of Lactobacillus rhamnosus GG in pediatric febrile neutropenia

The probiotic was safe but showed poor gut colonization, indicating that higher doses or alternative strains may be needed. Probiotic supplementation led to a small, non-significant reduction in FN incidence. Studies have shown that dysbiosis precedes febrile neutropenia (FN). This study evaluated whether oral supplementation with Lactobacillus rhamnosus GG could reduce FN incidence in children receiving myelosuppressive chemotherapy during the period of expected neutropenia. Children aged 2–18 years were stratified by diagnosis (leukaemia or solid tumour) and randomly assigned to probiotic or placebo before their first chemotherapy cycle. The intervention continued for 30 days and 14 days respectively in children with leukaemia and solid tumours. Patients were monitored for FN until the next chemotherapy cycle and for adverse events for one week post-intervention. Stool samples from seven randomly selected patients underwent 16S RNA sequencing. Eighty patients were randomized (36 probiotic, 44 placebo). FN occurred in 18 (50%) probiotic and 23 (52%) placebo patients (risk ratio 0.95 [0.62–1.47]; p=0.83). No significant differences were observed in time to FN or antibiotic duration. No Lactobacillus bacteraemia was detected. Stool sequencing revealed suboptimal probiotic colonization at the dose used. Probiotic supplementation led to a small, non-supplementation did not lead to significant reduction in FN incidence but was safe and feasible. Lack of colonization suggests a need to optimize the dose or select a different probiotic for future studies .