Chapman, Arlene B.

Abstract Background Pain is the highest prioritized patient-reported outcome in people with autosomal dominant polycystic kidney disease (ADPKD) but remains infrequently and inconsistently measured in clinical trials and poorly managed in clinical settings. A recently completed systematic review of pain in ADPKD identified 26 different outcome measures. None of these measures were considered appropriate as a core outcome measure due to the lack of patient-important dimensions, inadequate content, relatively long duration of completion time and limited evidence to support psychometric robustness. Methods We convened an international Standardized Outcomes in Nephrology–Polycystic Kidney Disease consensus workshop involving 21 patients/caregivers and 40 health professionals (clinicians, nurses, researchers, policy makers and industry representatives) from 18 countries to discuss the identification or development of a core outcome measure for pain. Results Four themes were identified highlighting fundamental issues for the measurement of pain in ADPKD: distressing and disrupting life participation; variability and ambiguity in defining pain; stigma, frustration and adaptation to pain; and ensuring validity and feasibility of pain measures. Conclusions Existing measures were found to be insufficient in capturing pain as a core outcome and there was consensus on the need for a new validated measure that is simple, succinct and addresses the impact of pain on life participation. This measure will facilitate the appropriate prioritization of pain in all trials and guide clinical decision making in people with ADPKD.

Significance Statement Patients with autosomal dominant polycystic kidney disease are treated with tolvaptan, a V2 receptor antagonist, to slow progression toward ESKD. In theory, tolvaptan could have both BP-increasing and BP-decreasing effects. To investigate the magnitude and time course of the effect of tolvaptan use on BP, the authors conducted a post hoc analysis of data from the TEMPO 3:4 trial, which randomized 1445 patients with autosomal dominant polycystic kidney disease to tolvaptan or placebo. Their analysis shows that directly after start of tolvaptan therapy, BP does not change, but in the long term, BP gradually becomes lower in patients with tolvaptan compared with placebo. This observation might be attributed to the beneficial effect of tolvaptan on disease progression, a sustained natriuretic effect, or both. Background The V2 receptor antagonist tolvaptan is prescribed to patients with autosomal dominant polycystic kidney disease to slow disease progression. Tolvaptan may alter BP via various acute and chronic effects. Methods To investigate the magnitude and time course of the effect of tolvaptan use on BP, we conducted a post hoc study of the TEMPO 3:4 trial, which included 1445 patients with autosomal dominant polycystic kidney disease randomized 2:1 to tolvaptan or placebo for 3 years. We evaluated systolic and diastolic BP, mean arterial pressure, hypertension status, and use and dosing of antihypertensive drugs over the course of the trial. Results At baseline, BP did not differ between study arms. After 3 weeks of tolvaptan use, mean body weight had decreased from 79.7 to 78.8 kg, and mean plasma sodium increased from 140.4 to 142.6 mmol/L (both P <0.001), suggesting a decrease in circulating volume. We observed none of these changes in the placebo arm. Nonetheless, BP remained similar in the study arms. After 3 years of treatment, however, mean systolic BP was significantly lower in participants receiving tolvaptan versus placebo (126 versus 129 mm Hg, respectively; P =0.002), as was mean diastolic BP (81.2 versus 82.6 mm Hg, respectively; P =0.01). These differences leveled off at follow-up 3 weeks after discontinuation of the study medication. Use of antihypertensive drugs remained similar in both study arms during the entire study. Conclusions Long-term treatment with tolvaptan gradually lowered BP compared with placebo, which may be attributed to a beneficial effect on disease progression, a continued natriuretic effect, or both. Clinical Trial registry name and registration number: TEMPO 3:4, NCT00428948

Background and objectives Tolvaptan slows kidney function decline in patients with autosomal dominant polycystic kidney disease (ADPKD) at risk of rapid progression. In the 3-year Tolvaptan Efficacy and Safety in Management of ADPKD and Its Outcomes (TEMPO) 3:4, 2-year extension to TEMPO 3:4 (TEMPO 4:4), and 1-year Replicating Evidence of Preserved Renal Function: An Investigation of Tolvaptan Safety and Efficacy in ADPKD (REPRISE) trials, aquaretic adverse events were common. Serum alanine aminotransferase (ALT) or aspartate aminotransferase (AST) elevations occurred in all three studies. Three patients met Hy Law criteria (ALT or AST more than three times and total bilirubin more than two times the upper limit of normal) for severe drug-induced liver injury (two in TEMPO 3:4 and one in TEMPO 4:4). In REPRISE, liver enzyme monitoring frequency was increased to monthly, with no Hy Law cases. A long-term, phase 3 safety study has further characterized tolvaptan safety. Design, setting, participants, & measurements Subjects who completed TEMPO 4:4, REPRISE, or other tolvaptan trials could enroll in this prospective, multinational, open-label safety study. Assessments included monthly liver enzyme testing during the first 18 months of tolvaptan exposure and every 3 months thereafter. Results Among 1803 subjects, median tolvaptan exposure during the extension was 651 days (interquartile range, 538–924), and cumulative exposure (extension and previous trials) was ≤11 years. Subjects entering from REPRISE placebo experienced more aquaretic adverse events compared with subjects from TEMPO 4:4 or REPRISE tolvaptan ( i.e ., patients with prior long-term tolvaptan exposure). Liver enzyme elevations also occurred more frequently in subjects from REPRISE placebo. Percentages experiencing ALT ≥3/≥5/ ≥10/≥20 times the upper limit of normal were 3.2%/2.1%/0.9%/0.7%, respectively, in subjects from REPRISE placebo and 0.6%–1.1%/0.0%–0.1%/0%/0%, respectively, in those from REPRISE tolvaptan and TEMPO 4:4. Percentages experiencing AST ≥3/ ≥5/≥10/≥20 times the upper limit of normal were 6.9%/3.8%/2.3%/0.8%, respectively, in subjects from REPRISE placebo and 0.9%–2.0%/0.0%–1.0%/0%/0%, respectively, in those from REPRISE tolvaptan and TEMPO 4:4. No Hy Law cases occurred. Conclusions No new safety signals emerged during this long-term extension. Monthly liver function testing for the first 18 months of treatment appeared to enable effective detection and management of transaminase elevations. Clinical Trial registry name and registration number: Open Label Extension of TEMPO 3:4, NCT02251275

Background and objectives Presymptomatic testing is available for early diagnosis of hereditary autosomal dominant polycystic kidney disease (ADPKD). However, the complex ethical and psychosocial implications can make decision-making challenging and require an understanding of patients’ values, goals and priorities. This study aims to describe patient and caregiver beliefs and expectations regarding presymptomatic testing for ADPKD. Design, setting and participants 154 participants (120 patients and 34 caregivers) aged 18 years and over from eight centres in Australia, France and Korea participated in 17 focus groups. Transcripts were analysed thematically. Results We identified five themes: avoiding financial disadvantage (insecurity in the inability to obtain life insurance, limited work opportunities, financial burden); futility in uncertainty (erratic and diverse manifestations of disease limiting utility, taking preventive actions in vain, daunted by perplexity of results, unaware of risk of inheriting ADPKD); lacking autonomy and support in decisions (overwhelmed by ambiguous information, medicalising family planning, family pressures); seizing control of well-being (gaining confidence in early detection, allowing preparation for the future, reassurance in family resilience); and anticipating impact on quality of life (reassured by lack of symptoms, judging value of life with ADPKD). Conclusions For patients with ADPKD, presymptomatic testing provides an opportunity to take ownership of their health through family planning and preventive measures. However, these decisions can be wrought with tensions and uncertainty about prognostic implications, and the psychosocial and financial burden of testing. Healthcare professionals should focus on genetic counselling, mental health and providing education to patients’ families to support informed decision-making. Policymakers should consider the cost burden and risk of discrimination when informing government policies. Finally, patients are recommended to focus on self-care from an early age.

BACKGROUND A treatment option for autosomal dominant polycystic kidney disease (ADPKD) has highlighted the need to identify rapidly progressive patients. Kidney size/age and genotype have predictive power for renal outcomes, but their relative and additive value, plus associated trajectories of disease progression, are not well defined. METHODS The value of genotypic and/or kidney imaging data (Mayo Imaging Class; MIC) to predict the time to functional (end-stage kidney disease [ESKD] or decline in estimated glomerular filtration rate [eGFR]) or structural (increase in height-adjusted total kidney volume [htTKV]) outcomes were evaluated in a Mayo Clinic PKD1/PKD2 population, and eGFR and htTKV trajectories from 20–65 years of age were modeled and independently validated in similarly defined CRISP and HALT PKD patients. RESULTS Both genotypic and imaging groups strongly predicted ESKD and eGFR endpoints, with genotype improving the imaging predictions and vice versa; a multivariate model had strong discriminatory power (C-index = 0.845). However, imaging but not genotypic groups predicted htTKV growth, although more severe genotypic and imaging groups had larger kidneys at a young age. The trajectory of eGFR decline was linear from baseline in the most severe genotypic and imaging groups, but it was curvilinear in milder groups. Imaging class trajectories differentiated htTKV growth rates; severe classes had rapid early growth and large kidneys, but growth later slowed. CONCLUSION The value of imaging, genotypic, and combined data to identify rapidly progressive patients was demonstrated, and reference values for clinical trials were provided. Our data indicate that differences in kidney growth rates before adulthood significantly define patients with severe disease. FUNDING NIDDK grants: Mayo DK058816 and DK090728; CRISP DK056943, DK056956, DK056957, and DK056961; and HALT PKD DK062410, DK062408, DK062402, DK082230, DK062411, and DK062401.

Abstract Background and Aims ADPKD is a progressive inherited disease that causes end-stage renal disease (ESRD) in ∼50% of the affected individuals by 60 years of age. TOL, a selective vasopressin V2-receptor antagonist, has been shown in randomized, placebo-controlled trials to slow the progression of renal function decline in ADPKD subjects with an eGFR of 25 mL/min/1.73m2 or higher. The efficacy and safety of TOL in subjects with lower eGFR remain understudied. This post-hoc analysis evaluated the efficacy and safety of TOL in subjects with stage 4 ADPKD (eGFR of &lt;30 mL/min/1.73m2). Method This is a retrospective analysis of a subgroup of ADPKD subjects who enrolled in the TOL long-term open-label extension (OLE) trial (NCT02251275). Included subjects had a baseline eGFR of &lt;30 mL/min/1.73m2, received ≥ 1 TOL dose, and were randomized to the placebo group in the REPRISE trial (NCT02160145). Two subgroups of subjects were analyzed, one with baseline eGFR of 25-30 (Subgroup 1) and one with &lt;25 (Subgroup 2). The variables evaluated included: 1) demographics, 2) adverse event (AE) profile, 3) intra-subject comparison of change in annualized eGFR decline during the open-label study (treatment period) to that during placebo use in the REPRISE trial (control period). Annualized eGFR change slopes in the treatment period were calculated using eGFR values between Month 1 and 12 visits to compensate for the acute hemodynamic effect of tolvaptan. Comparison was made by linear mixed model. Results Of the 1,803 subjects enrolled, 159 (8.8%) subjects (76 in Subgroup 1 and 83 in Subgroup 2) met the selection criteria for analysis. Annualized eGFR change slopes for all subjects (n=148) were -5.28 (SE 0.27) in the control period and -3.16 (SE 0.30) in the treatment period with a treatment effect of 2.11 mL/min/1.73m2/year (95% CI 1.56, 2.66), p&lt;0.0001). Demographic information, baseline eGFR, treatment duration and effects in the 2 subgroups are shown in the Table below. Treatment-emergent AEs were observed in 95% and 90% of the subjects in the 2 subgroups, respectively. Discontinuation due to AEs occurred in 15% and 17% of the 2 subgroups, respectively. The 5 most common AEs for all subjects were thirst (32%), polyuria (30%), renal pain (25%), blood creatinine increase (23%) and nocturia (22%); the rates were similar between the 2 subgroups. One incidence of hepatic enzyme increase, hemodialysis and death (unrelated to TOL) was observed in Subgroup 2, but not in Subgroup 1. Conclusion This post-hoc analysis demonstrated that TOL significantly decreases the rate of eGFR decline in ADPKD subjects with stage 4 CKD, including those with an eGFR of &lt;25 mL/min/1.73m2.

Significance Statement Accurate prediction of risk for disease progression is crucial for clinical management of autosomal dominant polycystic kidney disease (ADPKD). The Mayo imaging classification of ADPKD uses height-adjusted total kidney volume (htTKV) and age to identify patients at highest risk. Because the current Mayo classification applies only to patients with typical diffuse cystic disease (class 1) and poorly predicts eGFR decline for the remaining 5%–10% of patients with atypical morphology (class 2), imaging-based risk modeling remains unresolved. The authors report an expanded imaging classification model in which use of a recalculated htTKV value that excludes prominent exophytic cysts improved prediction for eGFR trajectory. Using a recalculated htTKV may allow inclusion of class 2 patients in the Mayo classification of ADPKD and reclassification of class 1 patients with prominent exophytic cysts. Background The Mayo Clinic imaging classification of autosomal dominant polycystic kidney disease (ADPKD) uses height-adjusted total kidney volume (htTKV) and age to identify patients at highest risk for disease progression. However, this classification applies only to patients with typical diffuse cystic disease (class 1). Because htTKV poorly predicts eGFR decline for the 5%–10% of patients with atypical morphology (class 2), imaging-based risk modeling remains unresolved. Methods Of 558 adults with ADPKD in the HALT-A study, we identified 25 patients of class 2A with prominent exophytic cysts (class 2Ae) and 43 patients of class 1 with prominent exophytic cysts; we recalculated their htTKVs to exclude exophytic cysts. Using original and recalculated htTKVs in association with imaging classification in logistic and mixed linear models, we compared predictions for developing CKD stage 3 and for eGFR trajectory. Results Using recalculated htTKVs increased specificity for developing CKD stage 3 in all participants from 82.6% to 84.2% after adjustment for baseline age, eGFR, BMI, sex, and race. The predicted proportion of class 2Ae patients developing CKD stage 3 using a cutoff of 0.5 for predicting case status was better calibrated to the observed value of 13.0% with recalculated htTKVs (45.5%) versus original htTKVs (63.6%). Using recalculated htTKVs reduced the mean paired difference between predicted and observed eGFR from 17.6 (using original htTKVs) to 4.0 ml/min per 1.73 m 2 for class 2Ae, and from −1.7 (using original htTKVs) to 0.1 ml/min per 1.73 m 2 for class 1. Conclusions Use of a recalculated htTKV measure that excludes prominent exophytic cysts facilitates inclusion of class 2 patients and reclassification of class 1 patients in the Mayo classification model.

Background Higher serum intact fibroblast growth factor 23 (iFGF23) was associated with disease progression in participants with autosomal dominant polycystic kidney disease (ADPKD) in the HALT-PKD Studies. PKD mutation is also an important determinant of progression. We hypothesized that serum levels of iFGF23 and vitamin D metabolites (1,25-dihydroxyvitamin D [1,25(OH) 2 D] and 25-hydroxyvitamin D [25[OH]D]) differ according to ADPKD mutation and differentially predict clinical end points according to genotype (significant interaction between genotype and mineral metabolites). Methods A total of 864 individuals with ADPKD who participated in the HALT-PKD Study A or B and had measurements of mineral metabolites (1,25[OH] 2 D, 25[OH]D, iFGF23) were categorized by PKD mutation (PKD1 truncating, PKD1 nontruncating, PKD2, or no mutation detected [NMD]). The association of the interactions of genotype × iFGF23, genotype × 1,25(OH)2D, and genotype × 25(OH)D with ( 1 ) annualized change in eGFR; ( 2 ) mean annualized percentage change in height-corrected total kidney volume (Study A only); and ( 3 ) time to a composite of 50% reduction in eGFR, ESKD, or death were evaluated using linear regression and Cox proportional hazards regression. Results Median (interquartile range) iFGF23 differed (PKD1 truncating, 55.8 [40.7–76.8]; PKD1 nontruncating, 49.9 [37.7–71.0]; PKD2, 49.0 [33.8–70.5]; NMD, 50.3 [39.7–67.4] pg/ml; P =0.03) and mean±SD 1,25(OH) 2 D differed (PKD1 truncating, 32.8±12.8; PKD1 nontruncating, 33.4±12.5; PKD2, 34.1±13.1; NMD, 38.0±14.6 pg/ml; P =0.02) according to PKD genotype. There was a significant interaction between iFGF23 and genotype ( P =0.02) for the composite end point in fully adjusted models, but no significant interaction between 1,25(OH) 2 D or 25(OH)D and genotype for clinical end points. Conclusions ADPKD genotype interacts significantly with FGF23 to influence clinical end points. Whereas the worst outcomes were in individuals with a PKD1-truncating or -nontruncating mutation and the highest iFGF23 tertile, risk of the composite end point differed according to iFGF23 the most in the PKD1-nontruncating and PKD2 groups.