Use of microbiome analysis as a complementary endpoint in clinical trials.

The ROSCO-CF study evaluated the safety and effect of oral R-roscovitine in people with cystic fibrosis chronically colonized by Pseudomonas aeruginosa. While no direct impact on the respiratory pathogen was detected, lung and gut microbiomes were analyzed to explore broader effects of the treatment. Sputum and fecal samples collected before and after treatment were examined using 16S rDNA sequencing. Despite overall stability in alpha diversity, dose-dependent shifts in beta diversity suggested subtle restructuring of microbial communities. Temporal analyses indicated emerging patterns in microbial coordination at higher doses. Specific taxa, such as Tannerella and Granulicatella elegans, showed increased abundance, while Streptococcus decreased with dose. These results suggest that R-roscovitine may influence microbial dynamics in a personalized and dose-dependent manner, supporting the inclusion of microbiome profiling as an exploratory endpoint in clinical trials.