Tolvaptan in ADPKD Patients With Very Low Kidney Function

Introduction: Tolvaptan slowed estimated glomerular filtration rate (eGFR) decline in subjects with autosomal dominant polycystic kidney disease (ADPKD) in TEMPO 3:4 and REPRISE trials. Tolvaptan effects in subjects with eGFR 15 to 24 ml/min per 1.73 m² were not investigated. This post hoc analysis retrospectively investigated eGFR decline in REPRISE versus an open-label, phase 3b extension trial (open-label extension [OLE] NCT02251275) in subjects who received placebo in REPRISE and tolvaptan in OLE with eGFR 15 to 24 and 25 to 29 ml/min per 1.73 m², respectively. Methods: One data subset comprised subjects with OLE baseline eGFR 15 to 29 ml/min per 1.73 m² who had received placebo in REPRISE and began tolvaptan in OLE. The second comprised subjects who had received tolvaptan in REPRISE and were matched to REPRISE placebo-treated subjects for REPRISE baseline characteristics. Annualized eGFR slopes in REPRISE versus OLE were compared within the REPRISE placebo (i.e., placebo vs. tolvaptan treatment) and tolvaptan (i.e., 2 periods of tolvaptan treatment) subsets. Results: Mean annualized eGFR slopes (ml/min per 1.73 m²) during tolvaptan treatment in OLE versus placebo treatment in REPRISE were −3.4 versus −5.2 for subjects with OLE baseline eGFR 15 to 29 (difference, 1.7; P < 0.001), −3.6 versus −5.4 with baseline eGFR 15 to 24 (difference, 1.8; P < 0.001), and −3.3 versus −4.9 with baseline eGFR 25 to 29 (difference, 1.6; P < 0.001). In REPRISE tolvaptan subjects who continued tolvaptan in OLE, treatment effect was maintained (no difference between mean annualized eGFR slopes). Conclusion: Initiating or maintaining tolvaptan therapy significantly delayed eGFR decline in subjects with baseline eGFR 15 to 24 and 25 to 29 ml/min per 1.73 m².