Primary hyperoxaluria type 1—current practice in the siRNA era: an ERA Genes & Kidney Working Group survey

Background: Primary hyperoxaluria type 1 (PH1) is a rare inherited metabolic disorder leading to the formation of kidney stones, nephrocalcinosis, and kidney failure. Besides, PH1 poses the risk of developing systemic oxalosis, a life-threatening condition with oxalate deposits in multiple organ systems. The rarity of the disorder combined with recent major additions to therapeutic options based on small interfering RNA (siRNA) therapeutics make a formal assessment of current practice and implementation of treatment recommendations an important asset. Methods: An international questionnaire survey was conducted among medical doctors involved in the treatment of patients with chronic kidney disease. The survey included 32 questions addressing demographics, diagnostics and therapeutics, and educational needs related to the care for PH1 patients. Results: 176 participants from 43 countries completed the survey, the majority of them were from Europe. The results indicate clear shortcomings in the availability of recommended diagnostics, especially with regards to plasma oxalate. Genetic testing strategies often do not include patients who may have PH1, e.g. when the underlying cause of kidney failure is unknown or in patients with nephrolithiasis or nephrocalcinosis. Treatment modalities are only partly harmonized and intensified dialysis is not fully implemented across centers. Strategies toward combination of conventional therapeutics such as hyperhydration and pyridoxine with new siRNA therapeutics depend on the treating physician's expertise. The survey identifies clear needs regarding implementation of current treatment recommendations as well as important educational gaps. Conclusion: The advent of targeted treatment opportunities for PH1 comes with an increased need to provide guidance to the field. Filling the existing gaps will ensure that a growing number of patients get access to optimal care and novel life-changing therapies.