Trajectories of Kidney Function in Autosomal Dominant Polycystic Kidney Disease Patients Treated with Tolvaptan

<i>Background and Objectives:</i> Autosomal dominant polycystic kidney disease (ADPKD) is the most common monogenic kidney disease, and the only approved pharmacological therapy shown to slow disease progression is tolvaptan. This study presents a long-term observation of ADPKD patients treated at our center, focusing on changes in eGFR approximately one year before and at least 1 year after the initiation of tolvaptan therapy. <i>Materials and Methods:</i> A retrospective analysis of a cohort of ADPKD patients who have received tolvaptan treatment in our center. <i>Results:</i> In total, 20 patients were enrolled in the analysis. Their median time of observation since tolvaptan introduction was 23.5 months. No statistically significant difference was noted in the median monthly decrease in eGFR between the time prior to tolvaptan introduction and during tolvaptan therapy. Analysis of trajectories of eGFR in particular patients enabled the division of the cohort into three subgroups: beneficiaries (n = 7, 35%), stable (n = 8, 40%), and progressors (n = 5, n = 25%). <i>Conclusions:</i> Despite the low number of patients, together with a relatively short observation period, which are the main limitations of our study, our results suggest that, in real-world settings, the efficacy of tolvaptan may be lower than previously reported. There is an urgent need to identify factors responsible for the suboptimal effect of the medicine. Our findings underscore the need to re-evaluate the current inclusion criteria for tolvaptan, particularly in real-world settings where patient variability is broader than in controlled clinical trials. Tailoring treatment qualification to include more practical and region-specific factors may enhance therapeutic outcomes.