In this study, the investigators looked at the different types of bacteria found in faeces (the gut microbiome) and compared patients who had received immunotherapy with those who had not to see if there was a difference in outcomes. They also looked at the treatment-related changes in the microbiome over time in patients taking immunotherapy.
Faeces were collected from 31 patients before the start of nivolumab (77%) or nivolumab plus ipilimumab (23%) treatment, of whom 58% experienced clinical benefit. The patients who had better clinical outcomes from immunotherapy had greater diversity of bacteria in their guts. Those patients with an increase in a bacterium called Akkermansia muciniphila seemed to derive clinical benefit from immunotherapy.
In summary, for patients with RCC, a higher microbial diversity in the gut is associated with better treatment outcomes. Treatment response is characterised by changes in the species of bacteria over the course of treatment.