New Formula Leverages Proenkephalin A 119-159 (penKid) for Improved GFR Estimation in Steady-State and Critically Ill Patients
• PenKid is a kidney function biomarker that correlates with gold standard GFR measurements in stable and acute kidney injury (AKI) patients.
• Based on penKid, a new formula was developed to estimate the GFR, outperforming widely used conventional equations based on creatinine alone.
• Scientists from Radboud University and Mayo Clinic developed and validated this formula in a large cohort of stable, as well as critically ill patients, laying the foundation for future increased clinical vigilance in kidney health assessment.
Hennigsdorf/Berlin, Germany, October 5, 2023 -
Diagnostic company SphingoTec GmbH (“SphingoTec”) announces that a new, improved formula has been developed for estimating the GFR using its kidney function biomarker penKid (1). According to the data, penKid strongly correlates with the measured GFR (mGFR), while the penKid-based formula for estimating GFR performs better than routinely used equations.
In clinical practice, kidney dysfunction is monitored using creatinine-based estimates of GFR. Creatinine is recognized as a late and insensitive biomarker of GFR, with consensus guidelines emphasizing that a more timely and accurate estimation of GFR in AKI is a relevant unmet medical need (2,3,4).
Researchers from the Radboud University Medical Centre, Netherlands, and Mayo Clinic, USA, have included a cohort of over 1,300 patients in a data-driven approach for developing an equation to estimate the GFR using the kidney function biomarker penKid (1). According to the findings, this novel equation performs better in calculating eGFR compared to creatinine-based equations. The formula can be applied to a wide range of patients since the cohort used for its development and validation included a broad spectrum of patients, such as patients with established chronic kidney disease, and critically ill patients. The compelling data is further strengthened by the fact that gold-standard methods to determine the true mGFR were used in all patients, and penKid concentration was most strongly correlated with mGFR.
Prof. Peter Pickkers (Head of Research in Intensive Care Medicine at Radboud University Nijmegen Medical Centre) summarized, “The innovative biomarker penKid has previously demonstrated significant potential in increasing the clinical vigilance and supporting the management of AKI patients. The penKid-based formula will facilitate in future its implementation in the clinical routine since it translates penKid concentrations into a more accurate GFR estimation that can now be implemented by physicians worldwide.“
Dr. Florian Uhle, Medical Director at SphingoTec, added, “With this landmark research, the first formula using penKid has been successfully established in chronic and acute kidney impairment. Starting from this evidence base, we will focus on further validating this formula in critically ill patients and aiming to overcome the shortcomings of our current diagnostic standards in AKI management. We are looking forward to interacting closely with global healthcare providers in the future to drive this concept to clinical reality.”
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References:
(1) Beunders et. al. Assessing GFR With Proenkephalin, Kidney International Reports, 2023, DOI: https://doi.org/10.1016/j.ekir.2023.08.006
(2) Chawla et al. Acute kidney disease and renal recovery: consensus report of the Acute Disease Quality Initiative (ADQI) 16 Workgroup. Nature Reviews Nephrology 2017; 13: 241-257.
(3) Ostermann et al. Report of the first AKI Round Table meeting: an initiative of the ESICM AKI Section. Intensive Care Med Exp 2019; 7: 69.
(4) Pickkers et al. The intensive care medicine agenda on acute kidney injury. Intensive care medicine 2017; 43: 1198-1209.
About SphingoTec
SphingoTec GmbH ("SphingoTec"; Hennigsdorf near Berlin, Germany) is a commercial-stage diagnostic company focusing on innovative critical care biomarkers for diagnosing, predicting, and monitoring acute medical conditions. SphingoTec’s innovative markers are made 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.
About penKid
Proenkephalin A 119-159 (penKid) is a blood-based biomarker for assessing 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, even under dialysis. 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
• 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
• Boditech Med and SphingoTec announce the launch of the AFIAS sphingotest® penKid® assay, a diagnostic tool designed to aid in kidney function assessment for critically ill patients. • The IVDR-marked assay provides quantitative measurements of Proenkephalin A 119-159 (penKid), supporting clinical decision-making in acute and critical care. • This launch follows a licensing agreement granting Boditech the rights to develop and commercialize penKid-based assays, as well as a market development agreement between the two companies. Gangwon-do, Republic of Korea, and Hennigsdorf/Berlin, Germany, May 6, 2025 - Boditech Med Inc. (“Boditech”) and SphingoTec GmbH (“SphingoTec”) today announced the commercial launch of the AFIAS sphingotest® penKid® assay. The assay is designed to provide clinicians with a tool for assessing kidney function in critically ill patients by measuring Proenkephalin A 119-159 (penKid), a biomarker that reflects real-time kidney function independently of inflammation or comorbidities. The AFIAS sphingotest® penKid® assay is IVDR-marked for its intended use as an automated fluorescence immunoassay for the in vitro diagnostic quantitative determination of Proenkephalin A 119-159 in human whole blood/plasma, serving as an aid in the diagnosis of acute kidney injury (AKI) in adult patients with sepsis or septic shock. It provides additional information to support clinical decision-making in managing critically ill patients at risk of acute kidney injury (AKI). This launch is the result of a strategic collaboration between Boditech and SphingoTec, including a licensing agreement granting Boditech the rights to develop and commercialize penKid-based assays on its diagnostic platforms, as well as a market development agreement aimed at accelerating global commercialization efforts. Eui-Yul Choi, CEO of Boditech Med, commented: “We are proud to introduce the AFIAS sphingotest® penKid® assay to clinicians worldwide. This launch reflects our commitment to delivering innovative diagnostic solutions that address critical needs in healthcare. Our collaboration with SphingoTec has been instrumental in bringing this important tool to market.” Deborah Bergmann, CEO of SphingoTec, added: “The launch of AFIAS sphingotest® penKid® demonstrates how partnerships can drive innovation and improve access to advanced diagnostics. By combining our biomarker expertise with Boditech’s diagnostic capabilities, we are reaching a new chapter in our collaboration. We are streamlining our processes to support the business of our license partners and further expand our global reach. This enables us to provide clinicians with essential tools to enhance patient care.” Scientific insights on penKid PenKid is a biomarker that enables real-time assessment of kidney function (1). Unlike traditional markers such as serum creatinine, penKid levels are not influenced by inflammation or other confounding factors like age or sex (1,2,3). Studies have shown that penKid allows earlier detection of acute kidney injury (AKI), predicting changes in serum creatinine up to 48 hours before conventional diagnostic criteria are met (1,3). This early detection capability is particularly valuable in critically ill patients, including those with sepsis or septic shock (1,3,4). Additionally, penKid has shown potential for monitoring renal recovery under dialysis and could help predict successful weaning from renal replacement therapy (5,6). ## References 1. Hollinger A, et.al. Proenkephalin A 119-159 (Penkid) Is an Early Biomarker of Septic Acute Kidney Injury: The Kidney in Sepsis and Septic Shock (Kid-SSS) Study. Kidney Int Rep. 2018 Aug 22;3(6):1424-1433. doi: 10.1016/j.ekir.2018.08.006. 2. Beunders et al. Assessing GFR With Proenkephalin, Kidney International Reports, 2023, DOI: https://doi.org/10.1016/j.ekir.2023.08.006 3. Caironi et al., Circulating proenkephalin, acute kidney injury, and its improvement in patients with severe sepsis or shock. Clin Chem (2018) DOI:10.1373/clinchem.2018.288068 4. Moledina DG. Penkid: A Novel Biomarker of Reduced GFR in Sepsis. Kidney Int Rep. 2018 Nov 15;4(1):17-19. doi: 10.1016/j.ekir.2018.11.002. 5. 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). doi.org/10.1186/s13054-022-04217-4 6. von Groote T, et al. Evaluation of Proenkephalin A 119-159 for liberation from renal replacement therapy: an external, multicenter pilot study in critically ill patients with acute kidney injury. Crit Care. 2023 Jul 10;27(1):276. doi: 10.1186/s13054-023-04556-w. About Boditech Boditech Med (based in Chuncheon, Gangwon-do, Republic of Korea) is a leading company in the field of point-of-care diagnostics, which has accumulated 25 years of business expertise in the field. The company has more than 80 types of in vitro diagnostic products that detect biomarkers related to infectious diseases, diabetes, cardiovascular diseases, cancer, and hormone-related diseases with its immunofluorescence lateral flow technology, quantitative immunofluorescence technology and spectrophotometric technology. And the list continues to grow with new high-value-added products. With its instrument platform installed in more than 120 countries, the company also has a stable revenue model. The company is currently strengthening its value as a global company by expanding its manufacturing bases in the US, China, India, and Indonesia. About SphingoTec SphingoTec GmbH ("SphingoTec"; Hennigsdorf near Berlin, Germany) is a diagnostic company focusing on the out-licensing of innovative critical care biomarkers 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 Head of Marketing and Communication SphingoTec GmbH Phone +49-3302-20565-0 Email: press@sphingotec.com