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Pediatric Nephrology (Berlin, Germany) Jan 2024Primary hyperoxaluria type 1 (PH1) is a rare, severe genetic disease causing increased hepatic oxalate production resulting in urinary stone disease, nephrocalcinosis,... (Observational Study)
Observational Study
BACKGROUND
Primary hyperoxaluria type 1 (PH1) is a rare, severe genetic disease causing increased hepatic oxalate production resulting in urinary stone disease, nephrocalcinosis, and often progressive chronic kidney disease. Little is known about the natural history of urine and plasma oxalate values over time in children with PH1.
METHODS
For this retrospective observational study, we analyzed data from genetically confirmed PH1 patients enrolled in the Rare Kidney Stone Consortium PH Registry between 2003 and 2018 who had at least 2 measurements before age 18 years of urine oxalate-to-creatinine ratio (Uox:cr), 24-h urine oxalate excretion normalized to body surface area (24-h Uox), or plasma oxalate concentration (Pox). We compared values among 3 groups: homozygous G170R, heterozygous G170R, and non-G170R AGXT variants both before and after initiating pyridoxine (B6).
RESULTS
Of 403 patients with PH1 in the registry, 83 met the inclusion criteria. Uox:cr decreased rapidly over the first 5 years of life. Both before and after B6 initiation, patients with non-G170R had the highest Uox:cr, 24-h Uox, and Pox. Patients with heterozygous G170R had similar Uox:cr to homozygous G170R prior to B6. Patients with homozygous G170R had the lowest 24-h Uox and Uox:cr after B6. Urinary oxalate excretion and Pox tend to decrease over time during childhood. eGFR over time was not different among groups.
CONCLUSIONS
Children with PH1 under 5 years old have relatively higher urinary oxalate excretion which may put them at greater risk for nephrocalcinosis and kidney failure than older PH1 patients. Those with homozygous G170R variants may have milder disease. A higher resolution version of the Graphical abstract is available as Supplementary information.
Topics: Humans; Child; Adolescent; Child, Preschool; Oxalates; Nephrocalcinosis; Hyperoxaluria, Primary; Kidney Calculi
PubMed: 37458799
DOI: 10.1007/s00467-023-06074-x -
American Journal of Kidney Diseases :... Feb 2023
Topics: Humans; Hyperoxaluria, Primary; Hyperoxaluria; Oxalates
PubMed: 36184293
DOI: 10.1053/j.ajkd.2022.08.005 -
Clinical Journal of the American... Jul 2021In the rare disease primary hyperoxaluria type 1, overproduction of oxalate by the liver causes kidney stones, nephrocalcinosis, kidney failure, and systemic oxalosis.... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND AND OBJECTIVES
In the rare disease primary hyperoxaluria type 1, overproduction of oxalate by the liver causes kidney stones, nephrocalcinosis, kidney failure, and systemic oxalosis. Lumasiran, an RNA interference therapeutic, suppresses glycolate oxidase, reducing hepatic oxalate production. The objective of this first-in-human, randomized, placebo-controlled trial was to evaluate the safety, pharmacokinetic, and pharmacodynamic profiles of lumasiran in healthy participants and patients with primary hyperoxaluria type 1.
DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS
This phase 1/2 study was conducted in two parts. In part A, healthy adults randomized 3:1 received a single subcutaneous dose of lumasiran or placebo in ascending dose groups (0.3-6 mg/kg). In part B, patients with primary hyperoxaluria type 1 randomized 3:1 received up to three doses of lumasiran or placebo in cohorts of 1 or 3 mg/kg monthly or 3 mg/kg quarterly. Patients initially assigned to placebo crossed over to lumasiran on day 85. The primary outcome was incidence of adverse events. Secondary outcomes included pharmacokinetic and pharmacodynamic parameters, including measures of oxalate in patients with primary hyperoxaluria type 1. Data were analyzed using descriptive statistics.
RESULTS
Thirty-two healthy participants and 20 adult and pediatric patients with primary hyperoxaluria type 1 were enrolled. Lumasiran had an acceptable safety profile, with no serious adverse events or study discontinuations attributed to treatment. In part A, increases in mean plasma glycolate concentration, a measure of target engagement, were observed in healthy participants. In part B, patients with primary hyperoxaluria type 1 had a mean maximal reduction from baseline of 75% across dosing cohorts in 24-hour urinary oxalate excretion. All patients achieved urinary oxalate levels ≤1.5 times the upper limit of normal.
CONCLUSIONS
Lumasiran had an acceptable safety profile and reduced urinary oxalate excretion in all patients with primary hyperoxaluria type 1 to near-normal levels.
CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER
Study of Lumasiran in Healthy Adults and Patients with Primary Hyperoxaluria Type 1, NCT02706886.
Topics: Adolescent; Adult; Child; Female; Glycolates; Humans; Hyperoxaluria, Primary; Male; Oxalates; RNA, Small Interfering; Renal Agents; Single-Blind Method; Young Adult
PubMed: 33985991
DOI: 10.2215/CJN.14730920 -
Drugs Feb 2024Lumasiran (Oxlumo), a first-in-class synthetic, double-stranded, ribonucleic acid (RNA) interference molecule targeting glycolate oxidase through silencing HAO1 mRNA, is... (Review)
Review
Lumasiran (Oxlumo), a first-in-class synthetic, double-stranded, ribonucleic acid (RNA) interference molecule targeting glycolate oxidase through silencing HAO1 mRNA, is approved in several countries for patients of any age and stage of kidney function with primary hyperoxaluria type 1 (PH1). Approval was based on results from the phase III ILLUMINATE trials. In the double-blind, placebo-controlled, ILLUMINATE-A trial, subcutaneous lumasiran was significantly more effective than placebo in reducing 24-h urinary oxalate excretion in patients aged ≥ 6 years with PH1; this effect was sustained for ≥ 36 months in ongoing longer-term analyses. In the single-arm ILLUMINATE-B trial, lumasiran reduced urinary oxalate:creatinine ratios and plasma oxalate levels in patients aged < 6 years with PH1. In the single-arm ILLUMINATE-C trial, lumasiran reduced plasma oxalate levels in patients with PH1 receiving dialysis as well as those not receiving dialysis. In secondary and exploratory analyses of these trials, nephrocalcinosis grade, kidney stone event rates and estimated glomerular filtration rates were either stable or improved with lumasiran. Lumasiran had an acceptable tolerability profile that remained consistent in longer-term analyses; the most common adverse events were mild and transient injection-site reactions. Thus, lumasiran is an effective treatment option, with an acceptable tolerability profile, in patients with PH1.
Topics: Humans; Hyperoxaluria, Primary; Oxalates; RNA, Small Interfering; Randomized Controlled Trials as Topic
PubMed: 38252335
DOI: 10.1007/s40265-023-01987-1 -
Clinical Kidney Journal May 2022Primary hyperoxaluria type 1 (PH1) is an autosomal recessive inborn error of metabolism characterized by marked hepatic overproduction of oxalate due to deficiency of... (Review)
Review
Primary hyperoxaluria type 1 (PH1) is an autosomal recessive inborn error of metabolism characterized by marked hepatic overproduction of oxalate due to deficiency of hepatic peroxisomal alanine-glyoxylate aminotransferase caused by gene mutation. One major hallmark of PH1 in developed as well as developing countries (DC) is the diagnostic delay. Notably in DC, where the disease is most prevalent and probably underdiagnosed, there are many challenges in PH1 diagnosis and management, with economic constrains and ethical concerns. This has led to the existing gap in the management of PH1 between developed and DC, which is expected to further deepen with the advent of novel therapeutic agents unless appropriate actions are taken. Until recently, treatment possibilities were limited to supportive measures. Thanks to a better understanding of the molecular basis of the disease a number of new therapies are developed, or being developed, leading to profound changes in management strategies. In this review we discuss the current situation of PH1 in DC as well as the accessibility challenges and the advantages of using promising novel therapeutics to bridge the currently existing gap. We also provide an overview of an integrated approach to ensure equitable access of sustainable therapeutics to PH1 patients in DC. This is expected to reduce global PH1 healthcare disparities, improve its standard of care and reduce disability linked to extrarenal complications of PH1 by implementing personalized medicine.
PubMed: 35592622
DOI: 10.1093/ckj/sfab203 -
Pediatric Nephrology (Berlin, Germany) Jul 2021In patients with primary hyperoxaluria (PH), endogenous oxalate overproduction increases urinary oxalate excretion, leading to compromised kidney function and often... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
In patients with primary hyperoxaluria (PH), endogenous oxalate overproduction increases urinary oxalate excretion, leading to compromised kidney function and often kidney failure. Highly elevated plasma oxalate (Pox) is associated with systemic oxalate deposition in patients with PH and severe chronic kidney disease (CKD). The relationship between Pox and estimated glomerular filtration rate (eGFR) in patients with preserved kidney function, however, is not well established. Our analysis aimed to investigate a potential correlation between these parameters in PH patients from three randomized, placebo-controlled trials (studies OC3-DB-01, OC3-DB-02, and OC5-DB-01).
METHODS
Baseline data from patients with a PH diagnosis (type 1, 2, or 3) and eGFR > 40 mL/min/1.73 m were analyzed for a correlation between eGFR and Pox using Spearman's rank and Pearson's correlation coefficients. Data were analyzed by individual study and additionally were pooled for Studies OC3-DB-02 and OC5-DB-01 in which the same Pox assay was used.
RESULTS
A total of 106 patients were analyzed. A statistically significant inverse Spearman's correlation between eGFR and Pox was observed across all analyses; correlation coefficients were - 0.44 in study OC3-DB-01, - 0.55 in study OC3-DB-02, - 0.51 in study OC5-DB-01, and - 0.49 in the pooled studies (p < 0.0064).
CONCLUSIONS
Baseline evaluations showed a moderate and statistically significant inverse correlation between eGFR and Pox in patients with PH already at early stages of CKD (stages 1-3b), demonstrating that a correlation is present before substantial loss in kidney function occurs.
Topics: Glomerular Filtration Rate; Humans; Hyperoxaluria, Primary; Hyperplasia; Kidney; Oxalates; Renal Insufficiency, Chronic
PubMed: 33515281
DOI: 10.1007/s00467-020-04894-9 -
Clinical Genetics Jan 2023The primary hyperoxalurias are rare disorders of glyoxylate metabolism. Accurate diagnosis is essential for therapeutic and management strategies. We conducted a...
The primary hyperoxalurias are rare disorders of glyoxylate metabolism. Accurate diagnosis is essential for therapeutic and management strategies. We conducted a molecular study on patients suffering from recurrent calcium-oxalate stones and nephrocalcinosis and screened primary hyperoxaluria causing genes in a large cohort of early-onset cases. Disease-associated pathogenic-variants were defined as missense, nonsense, frameshift-indels, and splice-site variants with a reported minor allele frequency <1% in controls. We found pathogenic-variants in 34% of the cases. Variants in the AGXT gene causing PH-I were identified in 81% of the mutation positive cases. PH-II-associated variants in the GRHPR gene are found in 15% of the pediatric PH-positive population. Only 3% of the PH-positive cases have pathogenic-variants in the HOGA1 gene, responsible to cause PH-III. A population-specific AGXT gene variant c.1049G>A; p.Gly350Asp accounts for 22% of the PH-I-positive patients. Pathogenicity of the identified variants was evaluated by in-silico tools and ACMG guidelines. We have devised a rapid and low-cost approach for the screening of PH by using targeted-NGS highlighting the importance of an accurate and cost-effective screening platform. This is the largest study in Pakistani pediatric patients from South-Asian region that also expands the mutation spectrum of the three known genes.
Topics: Humans; Child; Hyperoxaluria, Primary; Mutation
PubMed: 36185032
DOI: 10.1111/cge.14240 -
Canadian Journal of Kidney Health and... 2015To provide transplant physicians with a summary of the pathogenesis and diagnosis of adenine phosphoribosyl transferase (APRT) deficiency and primary hyperoxaluria and,... (Review)
Review
PURPOSE OF REVIEW
To provide transplant physicians with a summary of the pathogenesis and diagnosis of adenine phosphoribosyl transferase (APRT) deficiency and primary hyperoxaluria and, focussed on kidney transplantation, and to discuss interventions aimed at preventing and treating the recurrence of crystalline nephropathy in renal transplant recipients.
SOURCE OF INFORMATION
Pubmed literature search.
SETTING
Primary hyperoxaluria and APRT deficiency are rare inborn errors of human metabolism. The hallmark of these diseases is the overproduction and urinary excretion of compounds (2,8 dihydroxyadenine in APRT deficiency, oxalate in primary hyperoxaluria) that form urinary crystals. Although recurrent urolithiasis represents the main clinical feature of these diseases, kidney injury can occur as a result of crystal precipitation within the tubules and interstitium, a condition referred to as crystalline nephropathy. Some patients develop end-stage renal disease (ESRD) and may become candidates for kidney transplantation. Since kidney transplantation does not correct the underlying metabolic defect, transplant recipients have a high risk of recurrence of crystalline nephropathy, which can lead to graft loss. In some instances, the disease remains undiagnosed until after the occurrence of ESRD or even after kidney transplantation.
KEY MESSAGES
Patients with APRT deficiency or primary hyperoxaluria may develop ESRD as a result of crystalline nephropathy. In the absence of diagnosis and adequate management, the disease is likely to recur after kidney transplantation, which often leads to rapid loss of renal allograft function. Primary hyperoxaluria, but not APRT deficiency, becomes a systemic disease at low GFR with oxalate deposition leading to malfunction in non-renal organs (systemic oxalosis). We suggest that these diagnoses should be considered in patients with low glomerular filtration rate (GFR) and a history of kidney stones. In APRT deficiency, stones may be confused with uric acid stones, unless specialized techniques are used (infrared spectroscopy or X-ray crystallography for urinary crystals or stone analysis; Fourier transform infrared microscopy for crystals in kidney biopsy). Where these are unavailable, and for confirmation, the diagnosis can be made by measurement of enzyme activity in red blood cell lysates or by genetic testing. In patients with primary hyperoxaluria, levels of urinary and plasma oxalate; and the presence of nearly pure calcium oxalate monohydrate in stones, which often also have an unusually pale colour and unorganized structure, increase diagnostic suspicion. Molecular genetic testing is the criterion measure. Lifelong allopurinol therapy, with high fluid intake if appropriate, may stabilize kidney function in APRT deficiency; if ESRD has occurred or is near, results with kidney transplantation after initiation of allopurinol are excellent. In primary hyperoxaluria recognized before ESRD, pyridoxine treatment and high fluid intake may lead to a substantial decrease in urinary calcium oxalate supersaturation and prevent renal failure. In non-responsive patients or those recognized later in their disease, liver transplantation cures the underlying defect and should be considered when the GFR falls below 30 ml/min/1.73 m(2); in those which or near ESRD, liver transplantation and intensive dialysis before kidney transplantation may be considered to reduce the total body oxalate burden before kidney transplantation.
LIMITATIONS
The availability of diagnostic tests varies between countries and centres. Data on long term outcomes after kidney transplantation are limited, especially for APRT deficiency patients.
IMPLICATIONS
Increasing transplant physicians knowledge of APRT deficiency and primary hyperoxaluria should enable them to implement adequate diagnostic and therapeutic interventions, thereby achieving good outcomes after kidney transplantation.
PubMed: 26380104
DOI: 10.1186/s40697-015-0069-2 -
International Journal of Surgery... Dec 2016Although the primary hyperoxalurias (PH) are rare disorders, they are of considerable clinical importance in relation to calcium oxalate urolithiasis and as a cause of... (Review)
Review
Although the primary hyperoxalurias (PH) are rare disorders, they are of considerable clinical importance in relation to calcium oxalate urolithiasis and as a cause of renal failure worldwide. Three distinct disorders have been described at the molecular level. The investigation of any child or adult presenting with urinary tract stones or nephrocalcinosis, must exclude PH as an underlying cause. This paper provides a practical approach to the investigation and diagnosis of PH, indicating the importance of distinguishing between the PH types for the purposes of targeting appropriate therapy. Conservative management is explored and the various transplant options are discussed.
Topics: Adult; Child; Diagnosis, Differential; Disease Management; Female; Humans; Hyperoxaluria, Primary; Male; Nephrocalcinosis; Nephrolithiasis; Oxalates; Renal Insufficiency; Urinary Calculi
PubMed: 27815184
DOI: 10.1016/j.ijsu.2016.10.039 -
Zoological Research Nov 2023Targeting key enzymes that generate oxalate precursors or substrates is an alternative strategy to eliminate primary hyperoxaluria type I (PH1), the most common and...
Targeting key enzymes that generate oxalate precursors or substrates is an alternative strategy to eliminate primary hyperoxaluria type I (PH1), the most common and life-threatening type of primary hyperoxaluria. The compact Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) from the and (Cpf1) protein simplifies multiplex gene editing and allows for all-in-one adeno-associated virus (AAV) delivery. We hypothesized that the multiplex capabilities of the Cpf1 system could help minimize oxalate formation in PH1 by simultaneously targeting the hepatic hydroxyacid oxidase 1 ( ) and lactate dehydrogenase A ( ) genes. Study cohorts included treated PH1 rats ( rats injected with AAV-AsCpf1 at 7 days of age), phosphate-buffered saline (PBS)-injected PH1 rats, untreated PH1 rats, and age-matched wild-type (WT) rats. The most efficient and specific CRISPR RNA (crRNA) pairs targeting the rat and genes were initially screened . experiments demonstrated efficient genome editing of the and genes, primarily resulting in small deletions. This resulted in decreased transcription and translational expression of and . Treatment significantly reduced urine oxalate levels, reduced kidney damage, and alleviated nephrocalcinosis in rats with PH1. No liver toxicity, ex-liver genome editing, or obvious off-target effects were detected. We demonstrated the AAV-AsCpf1 system can target multiple genes and rescue the pathogenic phenotype in PH1, serving as a proof-of-concept for the development of multiplex genome editing-based gene therapy.
Topics: Animals; Rats; Gene Editing; Hyperoxaluria, Primary; Liver; Oxalates
PubMed: 37759334
DOI: 10.24272/j.issn.2095-8137.2022.495