A multicenter, randomized, placebo-controlled, double-blind phase 3 trial with open-arm comparison indicates safety and efficacy of nephroprotective therapy with ramipril in children with Alport’s syndrome

Children with Alport syndrome develop renal failure early in life. Since the safety and efficacy of preemptive nephroprotective therapy are uncertain we conducted a randomized, placebo-controlled, double-blind trial in 14 German sites of pediatric patients with ramipril for three to six years plus six months follow-up to determine these parameters. Pretreated children and those whose parents refused randomization became an open-arm control, which were compared to prospective real-world data from untreated children. The co-primary endpoints were safety (adverse drug reactions) and efficacy (time to progression). Out of 66 oligosymptomatic children, 22 were randomized and 44 joined the open-arm comparison. Ramipril therapy showed no safety issues (total of 216.4 patient-years on ramipril; adverse event rate-ratio 1.00; 95% confidence interval 0.66-1.53). Although not significant, our results cautiously showed that ramipril therapy was effective: in the randomized arm, Ramipril decreased the risk of disease progression by almost half (hazard ratio 0.51 (0.12–2.20)), diminished the slope of albuminuria progression and the decline in glomerular filtration. In adjusted analysis, indications of efficacy were supported by prospective data from participants treated open label compared with untreated children, in whom ramipril again seemed to reduce progression by almost half (0.53 (0.22-1.29)). Incorporating these results into the randomized data by Bayesian evidence synthesis resulted in a more precise estimate of the hazard-ratio of 0.52 (0.19-1.39). Thus, our study shows the safety of early initiation of therapy and supports the hope to slow renal failure by many years, emphasizing the value of preemptive therapy. Hence, screening programs for glomerular hematuria in children and young adults could benefit from inclusion of genetic testing for Alport-related gene-variants. Children with Alport syndrome develop renal failure early in life. Since the safety and efficacy of preemptive nephroprotective therapy are uncertain we conducted a randomized, placebo-controlled, double-blind trial in 14 German sites of pediatric patients with ramipril for three to six years plus six months follow-up to determine these parameters. Pretreated children and those whose parents refused randomization became an open-arm control, which were compared to prospective real-world data from untreated children. The co-primary endpoints were safety (adverse drug reactions) and efficacy (time to progression). Out of 66 oligosymptomatic children, 22 were randomized and 44 joined the open-arm comparison. Ramipril therapy showed no safety issues (total of 216.4 patient-years on ramipril; adverse event rate-ratio 1.00; 95% confidence interval 0.66-1.53). Although not significant, our results cautiously showed that ramipril therapy was effective: in the randomized arm, Ramipril decreased the risk of disease progression by almost half (hazard ratio 0.51 (0.12–2.20)), diminished the slope of albuminuria progression and the decline in glomerular filtration. In adjusted analysis, indications of efficacy were supported by prospective data from participants treated open label compared with untreated children, in whom ramipril again seemed to reduce progression by almost half (0.53 (0.22-1.29)). Incorporating these results into the randomized data by Bayesian evidence synthesis resulted in a more precise estimate of the hazard-ratio of 0.52 (0.19-1.39). Thus, our study shows the safety of early initiation of therapy and supports the hope to slow renal failure by many years, emphasizing the value of preemptive therapy. Hence, screening programs for glomerular hematuria in children and young adults could benefit from inclusion of genetic testing for Alport-related gene-variants. see commentary on page 1104 see commentary on page 1104 Chronic kidney disease (CKD) affects more than 10% of people worldwide.1Levin A. Tonelli M. Bonventre J. et al.Global kidney health 2017 and beyond: a roadmap for closing gaps in care, research, and policy.Lancet. 2017; 390: 1888-1917Abstract Full Text Full Text PDF PubMed Scopus (493) Google Scholar Renal fibrosis is the common endpoint of most CKD.2Assady S. Benzing T. Kretzler M. Skorecki K.L. Glomerular podocytes in kidney health and disease.Lancet. 2019; 393: 856-858Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar Therefore, preventing or delaying the progression of renal fibrosis is one of the most urgent goals in renoprotective medicine.2Assady S. Benzing T. Kretzler M. Skorecki K.L. Glomerular podocytes in kidney health and disease.Lancet. 2019; 393: 856-858Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar The type IV collagen disease Alport syndrome (AS) is the second most common monogenic cause of end-stage renal failure (ESRF), responsible for almost 4% of CKD in adults.3Groopman E.E. Marasa M. Cameron-Christie S. et al.Diagnostic utility of exome sequencing for kidney disease.N Engl J Med. 2019; 380: 142-151Crossref PubMed Scopus (268) Google Scholar, 4Hertz J.M. Thomassen M. Storey H. Flinter F. Clinical utility gene card for: Alport syndrome—update 2014.Eur J Hum Genet. 2015; 23https://doi.org/10.1038/ejhg.2014.254Crossref PubMed Scopus (34) Google Scholar, 5Hudson B.G. Tryggvason K. Sundaramoorthy M. Neilson E.G. Alport's syndrome, Goodpasture's syndrome, and type IV collagen.N Engl J Med. 2003; 348: 2543-2556Crossref PubMed Scopus (752) Google Scholar, 6Kruegel J. Rubel D. Gross O. Alport syndrome—insights from basic and clinical research.Nat Rev Nephrol. 2013; 9: 170-178Crossref PubMed Scopus (171) Google Scholar AS is caused by variants in the COL4A3, COL4A4, and COL4A5 genes, which encode for the α3, α4, and α5 chains of type IV collagen.4Hertz J.M. Thomassen M. Storey H. Flinter F. Clinical utility gene card for: Alport syndrome—update 2014.Eur J Hum Genet. 2015; 23https://doi.org/10.1038/ejhg.2014.254Crossref PubMed Scopus (34) Google Scholar,7Kashtan C.E. Ding J. Garosi G. et al.Alport syndrome: a unified classification of genetic disorders of collagen IV α345: a position paper of the Alport Syndrome Classification Working Group.Kidney Int. 2018; 93: 1045-1051Abstract Full Text Full Text PDF PubMed Scopus (130) Google Scholar The defective type IV collagen leads to basement membrane defects in the inner ear, eye, and glomerular basement membrane, leading to ESRF early in life (median age: 22 years in Europe).6Kruegel J. Rubel D. Gross O. Alport syndrome—insights from basic and clinical research.Nat Rev Nephrol. 2013; 9: 170-178Crossref PubMed Scopus (171) Google Scholar,8Gross O. Licht C. Anders H.J. et al.Early angiotensin-converting enzyme inhibition in Alport syndrome delays renal failure and improves life expectancy.Kidney Int. 2012; 81: 494-501Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar In a mouse model of AS, time to ESRF can be doubled if therapy with the angiotensin-converting enzyme inhibitor (ACEi) ramipril is started before the onset of proteinuria.9Gross O. Beirowski B. Koepke M.L. et al.Preemptive ramipril therapy delays renal failure and reduces renal fibrosis in COL4A3-knockout mice with Alport syndrome.Kidney Int. 2003; 63: 438-446Abstract Full Text Full Text PDF PubMed Scopus (181) Google Scholar This effect in mice confers only a small benefit if therapy is started after progressive proteinuria has taken hold. Registry data demonstrated that treatment with an ACEi also delays ESRF in humans with AS in a time-dependent manner.8Gross O. Licht C. Anders H.J. et al.Early angiotensin-converting enzyme inhibition in Alport syndrome delays renal failure and improves life expectancy.Kidney Int. 2012; 81: 494-501Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar Treatment starting in CKD stage 3 or 4 delays ESRF by a median of 3 years, while treatment starting in CKD stage 2 delays ESRF by a median of 18 years, leaving open the question of whether an even earlier start (CKD stage 0 or 1) is even more effective while remaining safe. Several features of AS pathogenesis facilitate efforts to address this question. First, the evolutionarily highly conserved type IV collagen in mammals allowed preclinical therapeutic approaches in mice with AS.6Kruegel J. Rubel D. Gross O. Alport syndrome—insights from basic and clinical research.Nat Rev Nephrol. 2013; 9: 170-178Crossref PubMed Scopus (171) Google Scholar,10Cosgrove D. Kalluri R. Miner J.H. et al.Choosing a mouse model to study the molecular pathobiology of Alport glomerulonephritis.Kidney Int. 2007; 71: 615-618Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar, 11Funk S.D. Lin M.H. Miner J.H. Alport syndrome and Pierson syndrome: diseases of the glomerular basement membrane.Matrix Biol. 2018; 71–72: 250-261Crossref PubMed Scopus (61) Google Scholar, 12Daina E. Cravedi P. Alpa M. et al.A multidrug, antiproteinuric approach to Alport syndrome: a ten-year cohort study.Nephron. 2015; 130: 13-20Crossref PubMed Scopus (10) Google Scholar The developmental switch of collagens in childen with AS allows a window of opportunity to initiate treatment with an earlier the better potential before structural harm to the glomerular basement membrane has been established.5Hudson B.G. Tryggvason K. Sundaramoorthy M. Neilson E.G. Alport's syndrome, Goodpasture's syndrome, and type IV collagen.N Engl J Med. 2003; 348: 2543-2556Crossref PubMed Scopus (752) Google Scholar,8Gross O. Licht C. Anders H.J. et al.Early angiotensin-converting enzyme inhibition in Alport syndrome delays renal failure and improves life expectancy.Kidney Int. 2012; 81: 494-501Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar,11Funk S.D. Lin M.H. Miner J.H. Alport syndrome and Pierson syndrome: diseases of the glomerular basement membrane.Matrix Biol. 2018; 71–72: 250-261Crossref PubMed Scopus (61) Google Scholar Second, AS can be diagnosed accurately by genetic testing and has a clearly defined course starting with hematuria, microalbuminuria, and proteinuria progressing to renal fibrosis.6Kruegel J. Rubel D. Gross O. Alport syndrome—insights from basic and clinical research.Nat Rev Nephrol. 2013; 9: 170-178Crossref PubMed Scopus (171) Google Scholar Awareness of family history of renal failure improves adherence to the study protocol. The unmet medical need for effective treatment allowed this trial to have a long period of randomized versus placebo treatment, which is unique in a pediatric trial for a serious disease.13Gross O. Friede T. Hilgers R. et al.Safety and efficacy of the ACE-inhibitor ramipril in Alport syndrome: the double-blind, randomized, placebo-controlled, multicenter phase III EARLY PRO-TECT Alport trial in pediatric patients.ISRNPediatr. 2012; 2012: 436046Google Scholar Finally, the pros and cons of renin–angiotensin–aldosterone (RAAS) blockade have been extensively studied in adults.8Gross O. Licht C. Anders H.J. et al.Early angiotensin-converting enzyme inhibition in Alport syndrome delays renal failure and improves life expectancy.Kidney Int. 2012; 81: 494-501Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar However, in children with CKD, the Effect of Strict Blood Pressure Control and ACE Inhibition on the Progression of Chronic Renal Failure in Pediatric Patients (ESCAPE) trial, published in 2009, is still the only large clinical trial evaluating the effect of RAAS blockade in conventional versus intensified blood pressure control.14Wühl E. Trivelli A. Picca S. et al.ESCAPE Trial GroupStrict blood-pressure control and progression of renal failure in children.N Engl J Med. 2009; 361: 1639-1650Crossref PubMed Scopus (650) Google Scholar Recently, post hoc analyses of the ESCAPE trial showed that early proteinuria reduction by ramipril predicted (improved) renal survival in children with CKD.15van den Belt S.M. Heerspink H.J.L. Gracchi V. et al.Early proteinuria lowering by angiotensin-converting enzyme inhibition predicts renal survival in children with CKD.J Am Soc Nephrol. 2018; 29: 2225-2233Crossref PubMed Scopus (46) Google Scholar The baseline characteristics in the ESCAPE trial, with very low estimated glomerular filtration rate (eGFR), and the rationale (therapy to delay further kidney damage) are very different than those in the Early Prospective Therapy European Community Trial in Alport syndrome (EARLY PRO-TECT Alport). Here, we tested the hypothesis that preemptive therapy in children with AS prior to ultrastructural kidney damage is safe and more efficient than later-onset therapy. This question could not be sufficiently answered in registries to justify treatment recommendations in toddlers.16Kashtan C.E. Ding J. Gregory M. et al.Clinical practice guidelines for the treatment of Alport syndrome. a statement of the Alport Syndrome Research Collaborative.Ped Nephrol. 2012; 28: 5-11Crossref PubMed Scopus (99) Google Scholar As a consequence, this trial is the first randomized and placebo-controlled study to investigate the safety and nephroprotective properties of RAAS blockade in children. Prospectively, an evidence synthesis with observational data was planned, including those patients whose parents refused randomization and who were treated open label, and untreated patients prospectively followed in the US Alport registry. This preemptive approach could benefit most patients in early stages of glomerular kidney diseases.17Devuyst O. Knoers N.V. Remuzzi G. Schaefer F. Rare inherited kidney diseases: challenges, opportunities, and perspectives.Lancet. 2014; 383: 1844-1859Abstract Full Text Full Text PDF PubMed Scopus (141) Google Scholar A total of 66 children were eligible for the study at screening (Figure 1). Twenty randomized children and 42 open label–treated children completed the treatment phase. The mean age was 8.8 ± 4.2 years, and many of the children entered the trial before elementary school (18 of 62 [29%] below 6 years of age; Table 1). Baseline albuminuria was comparable in the 2 randomized groups (placebo: 23 [range: 19.1–77.1] versus ramipril: 39.4 [range: 19.8–82.9] mg/g creatinine [gCrea]) (Supplementary Table S2). All patients had normal blood pressure, normal eGFR (Table 1),18Schwartz G.J. Muñoz A. Schneider M.F. et al.New equations to estimate GFR in children with CKD.J Am Soc Nephrol. 2009; 20: 629-637Crossref PubMed Scopus (2393) Google Scholar few comorbidities, and few comedications (Supplementary Tables S8, S9, and S10). Half of our patients (31 of 62; 50%) had relatives with AS who developed ESRF (median age of 35 years, including 4 heterozygous females with X-linked AS; range: 16 to 80 years).Table 1Baseline characteristics of EARLY PRO-TECT AlportCharacteristicEARLY PRO-TECT Alport trialUS registryPlacebo (n = 9)Ramipril (n = 11)Open (n = 42)Placebo (n = 28)Male sex, n (%)9(100.0)11(100.0)40(95.2)28(100)Ethnicity, n (%) Caucasian8(88.9)10(90.9)42(100.0) Turkish1(11.1)1(9.1)0–x-chromosomal, n (%)aPlus 1 boy in the open arm with probably x-chromosomal inheritance (based on the genealogical tree), but not examined in terms of molecular genetics.7(77.8)11(100.0)33aPlus 1 boy in the open arm with probably x-chromosomal inheritance (based on the genealogical tree), but not examined in terms of molecular genetics.(78.6)Autosomal, n (%)2(22.2)0–8(19.0)Disease stadium at baseline, n (%) 05(55.6)5(45.5)11(26.2)19(67.9) I4(44.4)6(54.5)19(45.2)9(32.1) II0–0–12(28.6)––Mean age, yr (SD)7.74.28.34.99.24.1Median age, yr (SD)7.0(5.0–8.0)6.0(3.0–14.0)10.0(5.0–13.0)7.0(5.0–10.0)Mean height, cm (SD)125.330.0133.832.6133.926.7Median height, cm (IQR)115.0(111.4–134.0)122.5(105.4–169.4)135.7(108.8–153.0)Mean z score, height, % (SD)–0.51.60.51.1–0.41.2Median z score, height, % (IQR)–0.5(–1.5 to 0.8)0.5(–0.5 to 1.0)–0.6(–1.1 to 0.4)Mean weight, kg (SD)32.722.534.821.934.319.9Median weight, kg (IQR)25.0(17.3–31.0)26.2(16.7–54.3)29.4(19.4–43.0)Mean z score, weight, % (SD)0.42.10.31.0–0.21.3Median z score, weight, % (IQR)0.2(–1.7 to 1.7)–0.0(–0.6 to 1.2)–0.4(–0.9 to 0.2)Mean body mass index, kg/cm2 (SD)18.64.817.53.517.53.4Median body mass index, kg/cm2 (IQR)17.8(15.5–20.1)16.7(15.1–17.7)16.5(15.7–17.9)Mean systolic heart pressure, mm Hg (SD)111.810.5109.214.4105.19.5Median systolic heart pressure, mm Hg (IQR)108.0(105.0–117.0)110.0(97.0–116.0)103.0(98.0–112.0)Mean z score systolic blood pressure, % (SD)1.31.20.61.10.21.0Median z score systolic blood pressure, % (IQR)1.2(0.9–2.3)0.8(–0.4 to 1.4)0.1(–0.3 to 0.9)Mean diastolic blood pressure, mm Hg (SD)63.48.761.66.761.28.3Median diastolic blood pressure, mm Hg (IQR)61.0(61.0–63.0)59.0(56.0–67.0)60.0(57.0–66.0)Mean z score diastolic blood pressure, mm Hg (SD)0.31.3–0.10.9–0.21.3Median z score diastolic blood pressure, mm Hg (IQR)0.2(–0.7 to 0.6)–0.2(–0.9 to 0.6)–0.3(–1.0 to 0.3)Mean albumin in urine at screening, mg/gCrea (SD)69.972.449.659.7290.6407.2Median albumin in urine at screening, mg/gCrea (IQR)31.3(24.3–99.9)18.1(15.4–61.3)135.0(22.1–272.5)Mean albumin in urine at baseline, mg/gCrea (SD)61.181.376.4101.5284.5395.125.324.3Median albumin in urine at baseline, mg/gCrea (IQR)23.019.1–77.139.419.8–82.994.023.3–364.715.7(9.8–38.8)Mean eGFR at screening, ml/min (SD)126.515.8131.223.6128.129.2Median eGFR at screening, ml/min (IQR)121.5(115.7–134.8)130.1(107.6–151.5)125.0(108.9–152.8)EARLY PRO-TECT Alport, Early Prospective Therapy European Community Trial Alport; IQR, interquartile range.Patients' characteristics at baseline indicated early-phase disease still in the oligosymptomatic stage, very young age, accurate diagnosis (confirmed by genetic testing or kidney biopsy in all patients or their close relatives; see Supplementary Table S1), normal blood pressure, and (for the time being) normal renal function.a Plus 1 boy in the open arm with probably x-chromosomal inheritance (based on the genealogical tree), but not examined in terms of molecular genetics. Open table in a new tab EARLY PRO-TECT Alport, Early Prospective Therapy European Community Trial Alport; IQR, interquartile range. Patients' characteristics at baseline indicated early-phase disease still in the oligosymptomatic stage, very young age, accurate diagnosis (confirmed by genetic testing or kidney biopsy in all patients or their close relatives; see Supplementary Table S1), normal blood pressure, and (for the time being) normal renal function. The duration of patients' therapy added up to a total of 216.4 patient-years on ramipril. Analysis of 465 adverse events (AEs) before disease progression in the randomized arm showed that ramipril therapy was safe (rate ratio 1.00; 95% confidence interval [CI] 0.66–1.53; Figure 2 and Table 2; see Supplementary Table S11 for a complete list of AEs). For the key secondary safety endpoint AEs over the treatment period, the incidence rate of AEs was very similar in the placebo (0.63) and ramipril (0.60) groups (rate ratio 0.96; 95% CI 0.63–1.45). No malignancies or deaths were reported. In the randomized group, none of the 11 serious AEs were, after second assessment by the data safety and monitoring board, drug related or unsuspected. One of 13 serious AEs in the open arm was related to kidney function: a child with dual RAAS blockade (ramipril plus angiotensin-receptor-blocker) developed acute renal failure and hyperkalemia, which resolved without sequelae after hospital admission. The case was discussed extensively with the data safety and monitoring board, and the parents were instructed to avoid dehydration in their child, who remained in the study. Dual RAAS blockade was restarted under intensified surveillance with 1 additional AE—hyperkalemia—which was not rated as severe, until the end of the study. By the end of the study, 19.0% (8 of 42) of children had received an AT1-antagonist (double RAAS blockade) because of progressive albuminuria (see Supplementary Table S4 for the characteristics of pre-treated children in the open-arm). Four of these children were on double RAAS blockade for more than 1 visit, and they had 61 AEs with a slightly increased event rate of 0.76 (95% CI 0.60–0.97) compared to ramipril monotherapy. Dry cough was reported in 9 patients, in 7 of 9 (77.8%) associated with common cold and as possibly related to study medication in only 2; the cough led to unblinding in 1 randomized patient (Figure 3a). The uptitration of ramipril was well tolerated. Dosages were not different between groups (mean 4.4 ± 1.1 mg/m2 placebo; 4.5 ± 0.9 mg/m2 ramipril; 4.8 ± 1.0 mg/m2 in the open arm). Dosages in our normotensive children were very similar to the high dosages reached in the ESCAPE trial with hypertensive children.14Wühl E. Trivelli A. Picca S. et al.ESCAPE Trial GroupStrict blood-pressure control and progression of renal failure in children.N Engl J Med. 2009; 361: 1639-1650Crossref PubMed Scopus (650) Google ScholarTable 2Numbers of patients with disease progression (co-primary efficacy endpoint) and adverse events, serious adverse events (AEs), and events of special interestEventsEARLY PRO-TECT Alport trialPlacebo (n = 9)Ramipril (n = 11)Open (n = 42)Patients with disease progression, n (%)5(55.6)3(27.3)17(40.5)Median time before progression, yr (IQR)3.5(2.1–4.0)3.6(0.5–4.4)Total time on Ramipril, yr11.1aRandomized patients receiving placebo and showing disease progression were unblinded and started on open-label ramipril.41.7163.6Median time on initial treatment, yr (IQR)3.5(2.1–4.0)4.0(3.5–4.5)4.0(3.5–4.6)Median follow-up, yr (IQR)4.1(4.0–5.1)4.1(3.6–4.5)4.0(3.5–4.6)Patients with ≥1 AE, n (%)9(100.0)11(100.0)42(100.0)AEs before progression, n (patient-years)176(277.5)289(456.2)AE event rate before progression, no. events/patient-years (95% CI)0.631(0.45–0.88)0.63(0.49–0.82)AE rate ratio for ramipril vs. placebo before progression (95% CI)1.00 (0.66–1.53)AEs over treatment period, n (patient-years)176(277.5)310(514.1)835(1372.1)AE event rate during treatment period, no. events/patient-years0.631(0.45–0.88)0.603(0.47–0.78)AE rate ratio for ramipril vs. placebo during treatment period (95% CI)0.96 (0.63–1.45)Total no. of serious AEs4(44.4)7(63.6)13(31) Other (planned hospital admission, idiopathic paresis, fatigue)2(22.2)1(9.1)3(7.1) Infection (causing hospital admission)0(0)3(27.3)4(9.5) Epilepsy2(22.2)1(9.1)0(0) Trauma, fracture, or accident (causing hospital admission)0(0)1(9.1)4(9.5) Low blood glucose (asymtomatic)0(0)1(9.1)0(0) Acute renal failure0(0)0(0)1(2.4) Dry cough0(0)0(0)1(2.4)Other events of special interest Hyperkalemia0(0)0(0)2(4.8) Macrohematuria2(22.2)4(36.4)3(7.1)AEs of severe intensity (without hospital admission): neuroborreliosis, tonsilitis, sinusitis, gastric pain0(0)1(9.1)3(7.1)Smoker, n (%)0(0)0(0)0(0)Deaths, n (%)0(0)0(0)0(0)Malignancies, n (%)0(0)0(0)0(0)CI, confidence interval; EARLY PRO-TECT Alport, Early Prospective Therapy European Community Trial Alport; IQR, interquartile range.Data summarize the number of patients with disease progression in the EARLY PRO-TECT Alport trial. In addition, time before disease progression for efficacy analysis, long-term follow-up, the high number of AEs for safety analysis, and serious AEs are listed.a Randomized patients receiving placebo and showing disease progression were unblinded and started on open-label ramipril. Open table in a new tab Figure 3Co-primary and key secondary efficacy endpoints: time to disease progression and albuminuria while on study drug. (a) Progression of renal disease in the randomized arm. Only 27.3% (3 of 11) in the ramipril group, but 55.6% (5 of 9) in the placebo group, progressed to the next disease level. Two of the 3 children who progressed in the ramipril arm did so in the first 12 months during uptitration before the maximum tolerated dose was reached. These 2 premature progression events have a negative effect on our actual data. However, this slow uptitration regimen was used for safety and tolerability reasons. Note that all censors are beyond the 3-year minimum time on therapy (except for 1 child, who was unblinded before month 6 because of dry cough). (b) Progression of renal disease in the open-arm versus untreated boys from the US registry. Even though the US boys were younger, healthier, and in earlier stages of disease, 12 of 28 (42.9%) of them progressed, compared to only 17 of 42 (40.5%) of the sicker patients in the open-arm group. The threshold for progression was harder to reach for most US boys (in level 0, only a tripling of albuminuria defines progression) and easier to reach for our open-treatment arm patients (in level 1, a doubling of albuminuria or albuminuria above 300 mg/gCrea [grams creatinine] defines progression). (c) Systolic and diastolic blood pressure over the treatment period. Note that blood pressure does not drop significantly in the (previous normotensive) randomized ramipril group during the uptitration of ramipril and is not different from the placebo group. (d) Course of estimated glomerular filtration rate (eGFR) over the treatment period as an exploratory endpoint. The decrease of eGFR during the trial is highest in the placebo group and lowest in the ramipril group, which again supports the results of our co-primary efficacy endpoint. (e) Individual course of albuminuria in the randomized arm, supporting the efficacy data in favor of ramipril. The slope of progression of albuminuria is lower in the ramipril group than in the placebo arm. Note that the co-primary efficacy endpoint is a doubling or tripling of albuminuria in randomized patients. Therefore, every significant increase in albuminuria led to unblinding and a premature end to the individual patient curve (because the patient switched to open-label ramipril). Therefore, the fact that the progress rate is twice as high in the placebo arm makes it impossible to show greater differences in the slopes of albuminuria in this figure (see Supplementary Table S6). (f) Individual course of eGFR in the randomized arm supporting the efficacy data in favor of ramipril. Note that, similar to albuminuria in panel (e), the fact that the progress rate is twice as high in the placebo arm makes it impossible to show greater differences in slopes of eGFR in this figure (see Supplementary Table S7). Three years after screening, the placebo group lost 9.8 ml/min of their eGFR, in contrast to the ramipril group, which had no loss in eGFR over the 3-year period. Loss of eGFR in the placebo arm is similar to that in the sicker open-arm group, with a loss of 13.5 ml/min after 3 years.View Large Image Figure ViewerDownload Hi-res image Download (PPT) CI, confidence interval; EARLY PRO-TECT Alport, Early Prospective Therapy European Community Trial Alport; IQR, interquartile range. Data summarize the number of patients with disease progression in the EARLY PRO-TECT Alport trial. In addition, time before disease progression for efficacy analysis, long-term follow-up, the high number of AEs for safety analysis, and serious AEs are listed. In the randomized controlled trial (RCT) arm, results indicate—although not significant in the classical mathematical definition—that ramipril decreased the risk of progression by almost 50% (adjusted hazard ratio (HR) 0.51; 95% CI 0.12–2.20; Figure 2). Only 27.3% (3 of 11) in the ramipril group but 55.6% (5 of 9) in the placebo group progressed during follow-up (Figure 3). Differences between groups favor ramipril, but they are limited in their meaningfulness due to the low number of children whose parents consented to randomization. Therefore, we enriched and confirmed our efficacy data by supplementing the RCT with data comparing the open arm of our trial with untreated children from the US (Figures 2 and 3).19Friede T. Posch M. Zohar S. et al.Recent advances in methodology for clinical trials in small populations: the InSPiRe project.Orphanet J Rare Dis. 2018; 13: 186Crossref PubMed Scopus (25) Google Scholar The beneficial ramipril effect was sustained in comparison to the considerably healthier untreated children from the US with a less-severe genotype, less-severe disease, younger age, and much less albuminuria (see Supplementary Table S3) with an unadjusted HR of 0.86 (95% CI 0.41–1.81). In the open-arm group, 57.1% (24 of 42) of children were pretreated with an ACEi, reflecting a sicker population. However, a high number (12 of 28; 42.9%) of the healthier untreated US patients progressed, and 17 of 42 (40.5%) of the sicker open-arm treatment group progressed (Figure 3). Adjusted for age and disease status at baseline, ramipril again reduced progression by almost 50% (adjusted HR 0.53; 0.22–1.29), although the reduction was not significant according to the classical mathematical definition (Figure 2).19Friede T. Posch M. Zohar S. et al.Recent advances in methodology for clinical trials in small populations: the InSPiRe project.Orphanet J Rare Dis. 2018; 13: 186Crossref PubMed Scopus (25) Google Scholar, 20Röver C. Wandel S. Friede T. Model averaging for robust extrapolation in evidence synthesis.Stat Med. 2019; 38: 674-694Crossref PubMed Scopus (17) Google Scholar, 21Friede T. Röver C. Wandel S. Neuenschwander B. Meta-analysis of few small studies in orphan diseases.Res Syn Meth. 2017; 8: 79-91Crossref PubMed Scopus (98) Google Scholar Using a Bayesian evidence synthesis approach, the findings of the nonrandomized comparison were incorporated into the RCT. This resulted in an HR of 0.52 in virtually the same treatment effect, but a more precise estimate, indicated by a much shorter 95% CI of 0.19–1.39 (compared to 0.12–2.20; Figure 2). The key secondary efficacy endpoint—albuminuria while on study drug—is shown in Figure 3e. The slope of progression of albuminuria is lower in the rami