the enose contains sensors to detect chemicals called volatile organic compounds, which make up about 1% of the air people exhale.
to determine whether the sniffer could use those chemicals to identify patients would respond to immunotherapy, the researchers found patients who were about to undergo immunotherapy with so-called anti pd-1 drugs, pembrolizumab or nivolumaband, and who were willing to join the study.
overall, 143 patients volunteered. before immunotherapy, volunteers were asked to take a deep breath, hold it for five seconds and then slowly exhale into the enose.
the researchers used the breath data and actual three-month outcomes from the first 92 patients to calibrate, or “train,” the algorithm that analyzed enose data to predict responders and non-responders. then the data from the other 51 patients was used to determine whether the electronic sniffer could correctly identify who would and would not respond to immunotherapy.
while immunotherapy “is well-tolerated, 10% to 20% of patients develop side effects, which can be severe, such as hepatitis or colitis,” muller said.
“patients who do not respond to immunotherapy can still develop a side effect. therefore it would be better not to give therapy to patients who will not respond.”