Liberation from renal replacement therapy and early initiation to be supported by the kidney function biomarker Proenkephalin A 119-159 (penKid)
• PenKid identified as a promising kidney function biomarker to support future precision medicine approaches for RRT-dependent AKI.
• A post-hoc analysis of the ELAIN trial indicates that penKid could enable the assessment of kidney function under RRT and guide early and successful liberation of treatment.
• For the risk stratification of AKI patients, penKid may be a useful biomarker in identifying the need for timely RRT initiation.
Hennigsdorf, Germany, December 15, 2022 -
The diagnostic company SphingoTec GmbH (SphingoTec) announces first data on the kidney function biomarker penKid as a promising tool in supporting early initiation and liberation from RRT (1). Although RRT remains a pivotal measure in treating AKI complications, it is also associated with significant risks and its duration should be restricted to a minimum. The current findings show that penKid has the potential to reveal unprecedented insights on the underlying kidney function prior and during ongoing RRT, facilitating an early and successful termination of treatment. This may support timely risk stratification and individualization of treatment pathways.
To allow kidney recovery in critically ill patients with AKI, RRT remains the key rescue therapy. However, no precise prediction tools are currently available to determine RRT liberation, although 5 - 13% of AKI patients have a high need for RRT (2,3). Due to scarcely available options, discontinuation of RRT relies on expert-based recommendations or clinical judgment based on controversial indications such as urine output. And yet, early discontinuation of RRT would not only be beneficial for the patient but also support the allocation of limited intensive care resources, thereby helping to reduce costs of unnecessarily long periods of RRT or unsuccessful termination with subsequent need for re-initiation of RRT (4).
The current analysis has demonstrated that penKid could be a competent marker to monitor kidney function during ongoing RRT (1). Low penKid values during RRT were associated with earlier and successful liberation from RRT, compared to the group presenting high penKid levels. As a consequence, penKid could support clinicians identify those patients with sufficient kidney recovery, suitable for RRT liberation. In addition, at the time point of AKI diagnosis, measuring penKid values could allow the identification of patients who may benefit from early RRT initiation. Supplementary data suggest that prompt intervention may result in shorter RRT duration.
The results of this study are complemented by previous scientific evidence showing that penKid mirrors real-time glomerular filtration rate (GFR) even in non-stable settings (5). Furthermore, penKid is unaffected by non-renal factors such as inflammation, common comorbidities, and gender (6,7,8), making it a suitable biomarker, especially for critically ill patients.
Deborah Bergmann, Director of Marketing and Sales at SphingoTec commented, “The implications of the current findings are of great significance for future individualized approaches in managing RRT-dependent AKI. For the first time, scientists identified a biomarker that has the potential to shed light on clinically hidden developments in patients undergoing RRT, a highly challenging stage. This may benefit patients’ health on short and long term, as well as support healthcare providers reduce costs and better assign resources.”
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References:
1. von Groote T et al. Proenkephalin A 119–159 predicts early and successful liberation from renal replacement therapy in critically ill patients with acute kidney injury: a post hoc analysis of the ELAIN trial. Crit Care 26, 333 (2022). https://doi.org/10.1186/s13054-022-04217-4
2. Hoste EA, Bagshaw SM, Bellomo R, et al. Epidemiology of acute kidney injury in critically ill patients: the multinational AKI-EPI study. Intensive Care Med 2015;41:1411–23.
3. Uchino S, Kellum JA, Bellomo R, Doig GS, Morimatsu H, Morgera S, et al. Acute renal failure in critically ill patients: a multinational, multicenter study. JAMA. 2005;294:813–8.
4. Korkeila M, Ruokonen E, Takala J. Costs of care, long-term prognosis and quality of life in patients requiring renal replacement therapy during intensive care. Intensive Care Med. 2000;26:1824-1831.
5. Beunders R, van Groenendael R, Leijte G, Kox M, Pickkers P. Proenkephalin compared to conventional methods to assess kidney function in critically ill sepsis patients. Shock. 2020 Jan;1
6. Beunders et al. (2017), Proenkephalin (PENK) as a novel biomarker for kidney function, JALM, DOI: 10.1373/jalm.2017.023598
7. Caironi P, Latini R, Struck J, Hartmann O, Bergmann A, Bellato V, et al. Circulating proenkephalin, acute kidney injury, and its improvement in patients with severe sepsis or shock. Clin Chem. 2018;64((9)):1361–9.
8. Donato LJ, Meeusen JW, Lieske JC, Bergmann D, Sparwaßer A, Jaffe AS. Analytical performance of an immunoassay to measure proenkephalin. Clin Biochem. 2018 Aug;58:72–7.
About SphingoTec
SphingoTec GmbH ("SphingoTec"; Hennigsdorf near Berlin, Germany) is a commercial-stage diagnostic company focusing on innovative critical care biomarkers for the diagnosis, prediction and monitoring of acute medical conditions. Sphingotec’s innovative markers are made available on different IVD platforms. SphingoTec's proprietary biomarker portfolio includes bioactive Adrenomedullin 1-52 (bio-ADM), a biomarker for assessment of endothelial function in conditions like sepsis, and Proenkephalin A 119-159 (penKid), a biomarker for assessment of kidney function in critical diseases.
About penKid
Proenkephalin A 119-159 (penKid) is a blood-based biomarker for assessing the kidney function in acute and critical conditions. The biomarker offers a blood-based alternative for the complex and time-consuming in vivo measurement of true glomerular filtration rate (GFR). PenKid is independent of common comorbidities (e.g. hypertension and diabetes) and the frequently occurring inflammation in critically ill patients. Rising penKid blood levels predict acute kidney injury earlier than today’s standard of care and decreasing penKid blood levels indicate the improvement of kidney function. Scientific evidence shows that penKid also reflects kidney function in children, representing a potential biomarker for pediatric AKI.
Media contact:
Ruxandra Lenz
Head of Marketing and Communication
SphingoTec GmbH
Neuendorfstr. 15 A
16761 Hennigsdorf
Tel. +49-3302-20565-0
• New ELISA sphingotest® penKid® enables widespread measurement of the kidney function biomarker Proenkephalin 119-159 (penKid) using standard laboratory equipment. • Only available test to match SphingoTec’s reference chemiluminescence assay, developed with patented high-sensitivity technology to provide consistent results across platforms. Hennigsdorf/Berlin, Germany, April 28 2026 - SphingoTec GmbH announces the launch of the ELISA sphingotest® penKid®, a new assay designed to make testing of its proprietary biomarker broadly accessible to research laboratories and pharmaceutical partners. Providing ease-of-use and precision, the test facilitates large-scale investigations of human kidney function in both acute and broader clinical research contexts. Responding to growing research interest The launch follows increasing demand from the scientific community to study penKid - a biomarker reflecting the current state of kidney function in critical care environments. While SphingoTec’s high-sensitivity sphingotest® penKid® assay serves as the reference method for clinical research and third-party IVD assays, the assay technology requiring dedicated equipment was not easily adoptable in research laboratories. The new ELISA sphingotest® penKid® now allows researchers worldwide to benefit from SphingoTec’s patented detection technology using standard photometers, extending penKid testing capability to a wider range of laboratories. Proven performance and data continuity The ELISA sphingotest® penKid® has been developed to achieve excellent correlation with SphingoTec’s reference chemiluminescence assay, ensuring consistent, high-quality results across different assay platforms. Both methods share the same underlying technology capable of detecting penKid concentrations in the picomolar range. Thanks to this technology transfer, researchers can rely on the same analytical precision and reliability that supported the clinical studies establishing penKid as a valuable kidney function biomarker. The assay’s robust design and German manufacturing ensure durable consistency and reproducibility. With this research-use ELISA, SphingoTec responds to the increasing availability of non-validated assays and encourages researchers to not compromise assay quality and performance to ensure trustworthy results - since data from non-validated tests may reflect assay limitations rather than the true performance of the penKid biomarker. Complementary approaches for clinical use and scientific exploration SphingoTec pursues its commercial strategy for the biomarker penKid through strategic out-licensing partnerships such as Boditech Med, which has developed an IVDR-certified assay for routine clinical use and rapid diagnostics. The newly launched ELISA sphingotest® penKid® represents a complementary initiative, specifically designed to support high-throughput clinical and translational research. Through this dual approach, SphingoTec reaffirms its commitment to fostering scientific collaboration and promoting the broader exploration of penKid across diverse research settings. “Developing the ELISA sphingotest® penKid® reflects our long-term commitment to improving critical care diagnostics,” said Deborah Bergmann, Managing Director and CEO of SphingoTec GmbH. “Beyond its currently validated clinical applications, we see strong potential for penKid to support research and improve diagnostics in other fields where kidney function is relevant. By encouraging scientists worldwide to incorporate penKid into their studies and clinical programs, we aim to accelerate innovation and advance best-fit diagnostic solutions that ultimately improve patient care.” About SphingoTec SphingoTec GmbH ("SphingoTec"; Hennigsdorf near Berlin, Germany) is a biomarker company focusing on the out-licensing of innovative critical care solutions for diagnosing, predicting, and monitoring acute medical conditions. SphingoTec develops its biomarkers to the commercial stage and partners with IVD companies to make them available on different IVD platforms. SphingoTec's proprietary biomarker portfolio includes Proenkephalin A 119-159 (penKid), a biomarker for the assessment of kidney function in critical diseases, and bioactive Adrenomedullin 1-52 (bio-ADM), a biomarker for the assessment of endothelial function in conditions like sepsis. Discover more on www.sphingotec.com Media Contact: Email: press@sphingotec.com Phone +49-3302-20565-0 SphingoTec GmbH Neuendorfstr. 15A 16761 Hennigsdorf, Germany
• PenKid surpasses serum creatinine on Day 1 post-transplant in detecting delayed graft function (DGF), with an AUROC of 0.87 versus 0.56 for creatinine. • PenKid differentiates slow graft function (SGF) from DGF up to 8 days earlier than current methods, supporting more timely clinical decisions. • PenKid levels remain unaffected by kidney replacement therapy (KRT), allowing for more accurate assessment of kidney function. • Independent validation in transplant cohort from Australia confirms performance and broad applicability. Hennigsdorf/Berlin, Germany, July 1, 2025 - Diagnostic company SphingoTec GmbH (“SphingoTec”) announces a landmark study (1) published in Transplant International, led by Heidelberg University Hospital in Germany in collaboration with researchers from Sydney, Australia, which identifies Proenkephalin A 119-159 (penKid) as a reliable biomarker for early and precise assessment of graft function trajectories following kidney transplantation. The research demonstrates that PenKid not only identifies patients at risk for DGF significantly earlier than traditional markers but also distinguishes between slow and delayed graft function with remarkable accuracy, offering clinicians a valuable new tool for patient management. The study prospectively evaluated 159 consecutive kidney transplant recipients at Heidelberg University Hospital and validated findings in an independent cohort from Sydney. PenKid consistently outperformed serum creatinine (SCr) in predicting graft function trajectories, particularly in the critical early post-transplant period. Notably, PenKid’s ability to remain unaffected by KRT—a treatment for severe kidney dysfunction—further sets it apart from SCr, which can be influenced by non-renal factors and KRT itself, thereby enhancing the reliability of graft function assessment. Multivariate analysis confirmed PenKid as the strongest independent predictor of both short-term graft function and 30-day outcomes, underscoring its clinical utility for early risk stratification. The biomarker’s superior granularity allows for nuanced classification of DGF severity, supporting more informed decisions regarding the initiation of dialysis or biopsy and offering potential for individualized patient care. With these findings, penKid steps forward as a practical addition to the transplant clinician’s toolkit, promising to sharpen decision-making for optimal outcomes. Its adoption could help transplant teams act with greater confidence and precision, ultimately strengthening the standard of care in kidney transplantation. ## References 1. Benning L et al. (2025) Proenkephalin A 119-159 in Kidney Transplantation: A Novel Biomarker for Superior Tracking of Graft Function Trajectories. Transpl. Int. 38:14366. doi: 10.3389/ti.2025.14366 About SphingoTec SphingoTec GmbH ("SphingoTec"; Hennigsdorf near Berlin, Germany) is a biomarker company focusing on the out-licensing of innovative critical care solutions for diagnosing, predicting, and monitoring acute medical conditions. SphingoTec develops its biomarkers to the commercial stage and partners with IVD companies to make them available on different IVD platforms. SphingoTec's proprietary biomarker portfolio includes Proenkephalin A 119-159 (penKid), a biomarker for the assessment of kidney function in critical diseases, commercially available on diagnostic platforms AFIAS and Nexus IB10 and bioactive Adrenomedullin 1-52 (bio-ADM), a biomarker for the assessment of endothelial function in conditions like sepsis. Discover more on www.sphingotec.com Contact : Ruxandra Lenz Marketing and Communication SphingoTec GmbH Phone +49-3302-20565-0 Email: press@sphingotec.com