Groothoff, Jaap W.

Background Homozygous familial hypercholesterolemia (HoFH), characterized by extremely elevated low‐density lipoprotein cholesterol (LDL‐C) due to severely impaired LDL‐C clearance from circulation, remains challenging to treat. Here, we investigated clinical benefits of monoclonal antibody, evinacumab, inhibiting angiopoietin‐like 3, recently approved in children with homozygous familial hypercholesterolemia. Methods This retrospective, observational study included 13 children with homozygous familial hypercholesterolemia on oral lipid‐lowering therapy and assessed their attainment of LDL‐C goal, need for lipoprotein apheresis (LA), and cardiac plaque formation at initiation of evinacumab and at follow‐up of 2.0 (1.3–3.0) years. Results Evinacumab, initiated at age 11 (8.5–13.5) years, increased number of patients reaching LDL‐C goal from none before initiation to 9 of 13 (69%; P =0.004) at follow‐up. Mean±SD LDL‐C at follow‐up was 111 (44) mg/dL, compared with 206 (61) mg/dL before evinacumab (mean difference, −95 mg/dL [95% CI, −142 to −47]; P <0.001). Before initiation of evinacumab, 11 of 13 children received LA with average interval of 7.8 days. At follow‐up, LA frequency decreased in 7 of 11 children with average interval of 18.9 days; increase between LA sessions was 11.0 days (3.5–18.5; P =0.008), 42% longer session interval. For 3 (15%) children, due to evinacumab initiation, LA remained dispensable over the course of treatment. Coronary computed tomography angiography showed plaque stabilization (n=5), regression (n=3), and no formation (n=2), in 10 of 13 (77%) children, and plaque progression in 3 (23%) children. Conclusions Add‐on evinacumab increased number of children with homozygous familial hypercholesterolemia reaching and maintaining LDL‐C goal, concomitant reduction in LA frequency, and in most patients, stabilization or improvement in coronary computed tomography angiography findings.

Key Points Primary hyperoxaluria type 1 is a genetic disorder associated with hepatic oxalate overproduction, kidney failure, and systemic oxalosis. Lumasiran treatment for up to 60 months was associated with sustained reductions in urinary and plasma oxalate and encouraging clinical outcomes. Lumasiran's safety profile was acceptable with mild injection site reactions being the most common adverse events. Background Primary hyperoxaluria type 1 (PH1) is characterized by hepatic oxalate overproduction, kidney stones, and progressive kidney disease. Lumasiran is the first approved treatment for PH1. Methods ILLUMINATE-A (NCT03681184) was a 60-month pivotal, phase 3, multinational clinical trial of lumasiran which consisted of a 6-month double-blind, placebo-controlled period (6M DB), followed by a treatment extension period of up to 54 months in which all patients received lumasiran. Eligible patients were aged ≥6 years with genetically confirmed PH1, eGFR ≥30 ml/min per 1.73 m 2 , and mean 24-hour urinary oxalate (UOx) excretion ≥0.70 mmol/24 h per 1.73 m 2 . Results Of 39 patients enrolled, 24 of 26 randomized to lumasiran in the 6M DB (lumasiran/lumasiran group) and 13 of 13 randomized to placebo in the 6M DB (placebo/lumasiran group) completed the study. Sustained reductions in 24-hour UOx were observed in both treatment groups. At month 60 relative to study baseline, the mean (SEM) 24-hour UOx percentage reductions were 54 (6) and 54% (8%) in the lumasiran/lumasiran and placebo/lumasiran groups, respectively, and the mean (SEM) plasma oxalate concentrations had decreased by 35 (5) and 38% (7%). eGFR remained stable through the end of the study in both treatment groups. Kidney stone event rates during the study were 0.47 (95% confidence interval, 0.36 to 0.62) and 0.54 (0.37 to 0.78) per patient-year in the lumasiran/lumasiran group and placebo/lumasiran group, respectively. Medullary nephrocalcinosis grade improved at the end of the study in 21 of 28 (75%) patients with nephrocalcinosis at baseline and an end of study assessment. The safety profile of lumasiran was acceptable. Injection site reactions were the most common adverse events during lumasiran treatment. Most adverse events were mild or moderate in severity. Conclusions Lumasiran treatment for up to 60 months in ILLUMINATE-A was associated with sustained reductions in UOx excretion and plasma oxalate concentration, encouraging clinical outcomes including stable eGFR in a population that would be expected to show eGFR decline, reduced kidney stone event rates, improved medullary nephrocalcinosis, and indications of improved health-related quality of life. Clinical Trial registry name and registration number: ClinicalTrials.gov NCT03681184. Podcast This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/CJASN/2026_03_18_CJASNMar.21.3.31820.mp3