A recent study reveals that use of antibiotics during immune checkpoint blockage or ICB has a significantly negative impact on the efficacy of immunotherapy. The greatest negative impact seems to occur when using antibiotics in the first 6 weeks after initiating ICB.
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Researchers evaluated the impact of the antibiotics on
the outcomes of patients with advanced or metastatic malignancy who were
treated with ICB. They also evaluated the use of antibiotics among patients receiving
ICB during a 12-week period before and after ICB initiation. Response to ICB
was the primary result. Histologic changes in the tumor microenvironment
following antibiotic use were also being evaluated.
There were total of 414 patients who received ICB were
identified between 1 January 2011 and 31 December 2018, of whom 207 or 50%
received antibiotics within 12 weeks before and after ICB initiation.
Using the univariate analysis, it revealed the
correlation of antibiotic use following ICB initiation with a significantly reduced
response. Use of antibiotics prior to ICB initiation showed no significant
impact on response to immunotherapy.
Negative impact of antibiotics reached its peak in the
first 6 weeks after initiating ICB and was independently associated with
markedly decreased likelihood of response to immunotherapy in multivariable
analysis.
Researchers said that antibiotic use can result in
reduced efficacy of ICB, presumably because of dysbiosis of the intestinal
microbiome.
Source: Am J Clin Oncol 2021;44:247-253