Gut feeling.

The gut microbiome plays a surprisingly important role in immunotherapy response. This study explored whether broad-spectrum antibiotics before or during immune checkpoint inhibition (ICI) for multiple cancer types was associated with ICI response. The patients who received antibiotics up to 30 days prior to starting ICI had twice the rate of poor response (81%) compared to those who didn’t receive antibiotics (44%). On the other hand, antibiotics administered during ICI had no association with response or survival. Ok sure, there are tons of potential confounders at play here. But given what we already know about how gut bacteria may influence ICI, it’s plausible that drastically altering the microbiota with antibiotics could impact ICI response. TBL: We’re just beginning to understand the delicate ecosystem that is the human body. | Pinato, JAMA Oncol 2019