Clinical and Economic Outcomes of Erythropoiesis-Stimulating Agent Hyporesponsiveness in the Post-Bundling Era

Influencing factors of clinical efficacy of roxadustat among hemodialysis patients

OBJECTIVE

To explore independent influencing factors for clinical efficacy of roxadustat in hemodialysis patients.

METHODS

Hemodialysis patients treated with roxadustat were enrolled. The plasma trough concentrations of roxadustat were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A multiple logistic regression model was established to determine the factors that affect clinical efficacy of roxadustat in patients undergoing hemodialysis.

RESULTS

A total of 67 hemodialysis patients were enrolled in the study. The results showed that age, blood trough concentration of roxadustat, and baseline hemoglobin (Hb) level were independent factors of clinical efficacy of roxadustat (OR = 1.06, p = .025 for age; OR = 1.001, p = .037 for plasma concentration; and OR = 0.941, p = .003 for baseline Hb), with an AUC score of 0.859.

CONCLUSIONS

Age, blood trough concentration of roxadustat, and baseline Hb level were independent influencing factors of the response to roxadustat in hemodialysis patients.

Renal anemia: from relative insufficiency of EPO to imbalance of erythropoiesis and eryptosis

Chronic kidney disease has emerged as a major health issue both in China and worldwide. Renal anemia frequently occurs in patients with chronic kidney disease, and its severity and incidence rate increase as the disease progresses. Over the last 30 years, the administration of exogenous EPO and EPO stimulants has been employed to alleviate renal anemia, suggesting that a relative deficiency in EPO may be a primary cause. However, this approach has overshadowed other contributing factors, particularly eryptosis, which results from the reduced lifespan of red blood cells. Numerous studies reveal that there are nephrogenic and extrarenal EPO secretion indicating that an absolute deficiency of EPO is not always present in patients. Therefore, this paper speculates that renal anemia may arise when EPO-driven erythropoiesis fails to adequately compensate for aggravating eryptosis. Other factors including iron metabolism disorder, uremic toxin accumulation, inflammatory state, oxidative stress, and secondary hyperparathyroidism affect EPO reactivity bone marrow hematopoiesis and eryptosis, leading to an imbalance between red blood cell production and destruction, and cause anemia ultimately. More further studies on the pathogenesis and treatment of renal anemia would be expected to provide evidence to support our opinion.

Post-transplant renal anemia: a call to action from a national study in routine clinical practice

Background

Post-transplant anemia is a prevalent yet often overlooked condition that poses significant risks. Current guidelines consider the same treatment recommendations and goals for these patients as for chronic kidney disease patients not on dialysis. Previous reports demonstrated a lack of awareness and suboptimal management, indicating a pressing need for improvement. We therefore wanted to update the information on post-transplant anemia. We aimed to describe the present state of anemia management, goals and adherence to guidelines within a representative sample of the kidney transplant (KTx) population.

Methods

We designed a retrospective nationwide multicenter study including outpatients from eight KTx hospitals. Nephrologists gathered data from electronic medical records encompassing demographics, comorbidities, KTx characteristics and immunosuppressive therapy, and information pertaining to anemia management (laboratory values, previously prescribed treatments and subsequent adjustments). The European statement on the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines was the reference for definitions, drug prescriptions and targets. Anemia occurring within the initial 6 months post-transplantation was classified as early onset.

Results

We included 297 patients with post-transplant anemia aged 62.8 years (standard deviation 13.6), 60% of whom were male. They had received a graft from cardiac death or brain death donors (61.6% and 31.1%, respectively) a median of 2.5 years (0.5-8.7) before. Among them 77% (n = 228) were classified as having late post-transplant anemia, characterized by a higher prevalence of microcytic and iron deficiency anemia. A total of 158 patients were on erythropoietic-stimulating agents (ESAs) treatment, yet surprisingly 110 of them lacked iron supplementation. Notably, 44 patients had an indication for iron supplementation and among them, 30 exhibited absolute iron deficiency. Out of the 158 patients receiving ESAs, only 39 surpassed the limit for the ESA resistance index, indicating poor response. This resistance was more frequent among patients with early post-transplant anemia (26.1% vs 9.2%). We have identified iron profile, early post-transplant anemia and estimated glomerular filtration rate as factors associated with the highest risk of resistance.

Conclusion

We found that hemoglobin targets are individualized upwards in post-transplant anemia. In this setting, iron therapy continues to be underutilized, especially intravenous, and iron deficiency and prior events (blood transfusion or hospital admission) explain most of the hyporesponsiveness to ESA. This highlights missed opportunities for precise prescription targeting and adherence to established guidelines, suggesting a need for improved management strategies in post-transplant anemia patients.

Assessment of the safety of Roxadustat for cardiovascular events in chronic kidney disease-related anemia using meta-analysis and bioinformatics

Objective

This study compares the cardiovascular risk in anemic chronic kidney disease patients treated with Roxadustat versus erythropoietin stimulating agents (ESAs). It also explores the cardiovascular impact of Roxadustat.

Methods

We searched PubMed, EMBASE, Cochrane, Scopus, and Web of Science databases up to 13 August 2023, using terms such as "ESA," "Roxadustat," "MACE," "stroke," "death," "myocardial infarction," and "heart failure." Two researchers independently selected and extracted data based on predefined criteria. We assessed the risk of bias with the Cochrane tool and analyzed statistical heterogeneity using the Q and I2 tests. We conducted subgroup analyses by geographical region and performed data analysis with Stata 14.0 and RevMan 5.4 software. Data were sourced from the NCBI database by filtering for "Roxadustat" and "human," and differentially expressed genes were identified using R software, setting the significance at p < 0.01 and a 2-fold logFC, followed by GO enrichment analysis, KEGG pathway analysis, and protein interaction network analysis.

Results

A total of 15 articles encompassing 1,43,065 patients were analyzed, including 1,38,739 patients treated with ESA and 4,326 patients treated with Roxadustat. In the overall population meta-analysis, the incidences of Major Adverse Cardiovascular Events (MACE), death, and heart failure (HF) were 13%, 8%, and 4% in the Roxadustat group, compared to 17%, 12%, and 6% in the ESA group, respectively, with P-values greater than 0.05. In the subgroup analysis, the incidences were 13%, 11%, and 4% for the Roxadustat group versus 17%, 15%, and 5% for the ESA group, also with p-values greater than 0.05. Bioinformatics analysis identified 59 differentially expressed genes, mainly involved in the inflammatory response. GO enrichment analysis revealed that these genes are primarily related to integrin binding. The main pathways identified were the TNF signaling pathway, NF-κB signaling pathway, and lipid metabolism related to atherosclerosis. The protein interaction network highlighted IL1B, CXCL8, ICAM1, CCL2, and CCL5 as the top five significantly different genes, all involved in the inflammatory response and downregulated by Roxadustat, suggesting a potential role in reducing inflammation.

Conclusion

The meta-analysis suggests that the use of Roxadustat and ESA in treating anemia associated with chronic kidney disease does not significantly alter the likelihood of cardiovascular events in the overall and American populations. However, Roxadustat exhibited a safer profile with respect to MACE, death, and heart failure. The bioinformatics findings suggest that Roxadustat may influence integrin adhesion and affect the TNF and NF-κB signaling pathways, along with lipid and atherosclerosis pathways, potentially reducing inflammation.

The Association between High-Dose Allopurinol and Erythropoietin Hyporesponsiveness in Advanced Chronic Kidney Disease: JOINT-KD Study

INTRODUCTION

The aim of the study was to explore the association between urate-lowering agents and reduced response to erythropoietin-stimulating agents in patients suffering from chronic kidney disease G5.

METHODS

We conducted a cross-sectional, multicenter study in Japan between April and June 2013, enrolling patients aged 20 years or older with an estimated glomerular filtration rate of ≤15 mL/min/1.73 m2. Exclusion criteria encompassed patients with a history of hemodialysis, peritoneal dialysis, or organ transplantation. The patients were categorized into four groups based on the use of urate-lowering drugs: high-dose allopurinol (>50 mg/day), low-dose allopurinol (≤50 mg/day), febuxostat, and no-treatment groups. We used a multivariable logistic regression model, adjusted for covariates, to determine the odds ratio (OR) for erythropoietin hyporesponsiveness, defined by an erythropoietin resistance index (ERI) of ≥10, associated with urate-lowering drugs.

RESULTS

A total of 542 patients were included in the analysis, with 105, 36, 165, and 236 patients in the high-dose allopurinol, low-dose allopurinol, febuxostat, and no-treatment groups, respectively. The median and quartiles of ERIs were 6.3 (0, 12.2), 3.8 (0, 11.2), 3.4 (0, 9.8), and 4.8 (0, 11.2) in the high-dose allopurinol, low-dose allopurinol, febuxostat, and no-treatment groups, respectively. The multivariate regression model showed a statistically significant association between the high-dose allopurinol group and erythropoietin hyporesponsiveness, compared to the no-treatment group (OR = 1.98, 95% confidence interval: 1.10-3.57).

CONCLUSIONS

Our study suggests that the use of high-dose allopurinol exceeding the optimal dose may lead to hyporesponsiveness to erythropoiesis-stimulating agents.

The Influence of Precursor Depletion and dose Regimens on Resistance to Erythropoiesis-Stimulating Agents: Insights from Simulations with Instantaneous Dose-Adaptation Algorithm

Erythropoiesis-stimulating agents (ESAs) have been a common treatment for anemia associated with chronic kidney disease (CKD), while 10-20 % of patients continue to suffer from persistent anemia despite receiving ESA treatments. Our previous findings suggested that intensive ESA usage can cause resistance by depleting the erythroid precursor cells. Here, we used a mechanism-based pharmacokinetic/pharmacodynamic (PK/PD) model of ESAs and conducted simulations to evaluate the influence of dose regimens and other factors (such as administration route, individual PK/PD parameters, types of ESAs, and disease status) on ESA resistance with instantaneous dose adaptations in healthy populations and anemic patients. The simulated results show that instantaneous dose-adaptation can reduce ESA resistance, but up to 30 % of subjects still ended up developing ESA resistance in healthy populations. The Smax is markedly higher in hypo-responders than in normal-responders, while hypo-responders possess fewer precursors and experience a faster decline compared to normal-responders. There is a ceiling effect of increasing ESA dosage to improve HGB responses and reduce ESA resistance, and the limit is lower in anemic patients compared to healthy populations. Subcutaneous administrations and ESAs with longer half-lives lead to stronger HGB responses and less resistance at equivalent doses. Taken together, this study indicates that precursor depletion contributes to ESA resistance and dose regimens can greatly influence the occurrence of ESA resistance. Furthermore, ESA treatment for patients showing ESA resistance should avoid continuously increasing doses and instead consider stimulating the renewal of precursors.

Contemporary Practice of Anemia Treatment Among Dialysis Patients in the United States

Introduction

The treatment of anemia is a major activity in the care of patients undergoing maintenance hemodialysis (HD). The comparative effectiveness of new pharmacologic treatments, relative to erythropoiesis-stimulating agents (ESAs), should be anticipated on the bases of controlled trials and current practice. We describe the contemporary practice of anemia treatment in a national cohort of patients undergoing maintenance HD.

Methods

We analyzed the United States Renal Data System (USRDS) data to identify adult patients undergoing in-facility HD in 2016 to 2019. Using the Consolidated Renal Operations in a Web-Enabled Network (CROWNWeb) dataset, we identified hemoglobin and ESA utilization (agent and cumulative dose) during each patient-month, as well as intravenous (IV) iron utilization, ferritin, and transferrin saturation. We compared ESA dosing during the study era to dosing in the Normal Hematocrit Cardiac Trial (NHCT), conducted in the 1990s. We assessed ESA hyporesponsiveness by estimating the prevalence of the following: (i) high erythropoietin resistance index (ERI) and (ii) either 3 or 6 consecutive months with hemoglobin <10 g/dl.

Results

Nearly two-thirds of patient-months had hemoglobin of 10.0 to 11.9 g/dl. Mean ESA utilization was 76.7% per month, with increasing use of pegylated epoetin beta. ESA dosing was stable; epoetin alfa dosing was slightly lower than in the low-target arm of the NHCT. The prevalence of ESA hyporesponsiveness was 22.2% if defined by high ERI, but only 2.1% to 6.0% if defined by 3 to 6 consecutive months with hemoglobin <10 g/dl. Median transferrin saturation was 22.3% with high ERI and persistently low hemoglobin.

Conclusion

Hemoglobin and ESA dosing distributions are stable, with epoetin alfa dosing below the low-target arm of the NHCT. Persistently low hemoglobin occurs infrequently and may reflect iron depletion.

Opportunities to improve the management of anemia in peritoneal dialysis patients: lessons from a national study in routine clinical practice

Background

Current guidelines establish the same hemoglobin (Hb) and iron biomarkers targets for hemodialysis (HD) and peritoneal dialysis (PD) in patients receiving erythropoiesis-stimulating agents (ESAs) even though patients having PD are usually younger, more active and less comorbid. Unfortunately, specific renal anemia [anemia in chronic kidney disease (aCKD)] trials or observational studies on PD are scanty. The aims of this study were to describe current aCKD management, goals and adherence to clinical guidelines, identifying opportunities for healthcare improvement in PD patients.

Methods

This was a retrospective, nationwide, multicentre study including patients from 19 PD units. The nephrologists collected baseline data, demographics, comorbidities and data related to anemia management (laboratory values, previously prescribed treatments and subsequent adjustments) from electronic medical records. The European adaptation of KDIGO guidelines was the reference for definitions, drug prescriptions and targets.

Results

A total of 343 patients (mean age 62.9 years, 61.2% male) were included; 72.9% were receiving ESAs and 33.2% iron therapy [20.7% intravenously (IV)]. Eighty-two patients were receiving ESA without iron therapy, despite 53 of them having an indication according to the European Renal Best Practice guidelines. After laboratory results, iron therapy was only started in 15% of patients. Among ESA-treated patients, 51.9% had an optimal control [hemoglobin (Hb) 10-12 g/dL] and 28.3% between 12-12.9 g/dL. Seventeen patients achieved Hb >13 g/dL, and 12 of them remained on ESA after overshooting. Only three patients had Hb <10 g/dL without ESAs. Seven patients (2%) met criteria for ESA resistance (epoetin dose >300 IU/kg/week). The highest tertile of erythropoietin resistance index (>6.3 UI/kg/week/g/dL) was associated with iron deficiency and low albumin corrected by renal replacement therapy vintage and hospital admissions in the previous 3 months.

Conclusion

Iron therapy continues to be underused (especially IV). Low albumin, iron deficiency and prior events explain most of the ESA hyporesponsiveness. Hb targets are titrated to/above the upper limits. Thus, several missed opportunities for adequate prescriptions and adherence to guidelines were identified.

Predictors of Hyporesponsiveness to Erythropoiesis-Stimulating Agents in Patients with Non-Dialysis-Dependent Chronic Kidney Disease (RADIANCE-CKD Study)

INTRODUCTION

Hyporesponsiveness to erythropoiesis-stimulating agents (ESAs) has been associated with increased mortality and cardiovascular events in patients with chronic kidney disease. We hypothesized that the prediction of ESA resistance during ESA administration would be very useful in deciding on a treatment plan.

METHODS

Patients enrolled in a randomized controlled trial to evaluate renal prognosis in anemic patients with non-dialysis-dependent chronic kidney disease with hyporesponsiveness to ESA were included; the patients had different target hemoglobin levels. A landmark analysis was performed at 3 months into the study. To construct a predictive model for the severe ESA hypo-responder group, in which there was no increase in hemoglobin even with active treatment, background factors and serum test items that affect anemia at study entry were included in a logistic regression model, the area under the curve (AUC) and 95% confidence intervals (CI) were estimated, and sensitivity and specificity were calculated. This study was a post hoc sub-analysis of a randomized controlled trial.

RESULTS

The AUC for the 19 existing risk factors as predictors was 0.783 (95% CI: 0.711-0.855). Among the 19 risk factors, the combination of six factors (hemoglobin level, systolic blood pressure, weight, gender, smoking status, and hypertensive retinopathy) with the largest χ2 statistics were selected by multiple logistics regression. The AUC for these 6 predictors was 0.716 (95% CI: 0.634-0.799). To the six existing risk factors, five serum test items that affect anemia (vitamin B12, vitamin B6, folic acid, parathyroid hormone, and 25-hydroxyvitamin D) were added, for a total of 11 risk factors, with a similar AUC of 0.736 (95% CI: 0.655-0.817), sufficient to predict ESA resistance.

CONCLUSIONS

Our results suggest that existing risk factors and serum test items can be used to predict ESA resistance in patients with non-dialysis-dependent chronic kidney disease on ESA.

Cardiovascular safety of current and emerging drugs to treat anaemia in chronic kidney disease: a safety review

INTRODUCTION

Erythropoiesis-stimulating agents (ESAs) are the standard of treatment for anemia in chronic kidney disease. Hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHI) are small molecules that stimulate endogenous erythropoietin synthesis.

AREAS COVERED

The cardiovascular safety of ESAs and HIF-PHIs. We performed a PubMed search using several key words, including anemia, chronic kidney disease, safety, erythropoiesis stimulating agents, HIF-PH inhibitors.

EXPERT OPINION

ESAs are well-tolerated drugs with a long history of use; there are safety concerns, especially when targeting high hemoglobin levels. HIF-PHIs have comparable efficacy to ESAs in correcting anemia. Contrary to expectations, randomized phase 3 clinical trials have shown that overall HIF-PHIs were non-inferior to ESA or placebo with respect to the risk of cardiovascular endpoints. In addition, some phase 3 trials raised potential safety concerns regarding cardiovascular and thrombotic events, particularly in non-dialysis patients.Today, HIF-PHIs represent an additional treatment option for anemia in patients with chronic kidney disease. This has made the management of anemia in CKD more complex and heterogeneous. A better understanding of the mechanisms causing hypo-responsiveness to ESAs, combined with an individualized approach that balances ESAs, HIF-PHIs and iron doses, could increase the benefits while reducing the risks.

A network meta-analysis of the efficacy of hypoxia-inducible factor prolyl-hydroxylase inhibitors in dialysis chronic kidney disease

BACKGROUND

Five types of HIF-PHIs have been authorized for anemia treatment in CKD patients in China and Japan. These are enarodustat, roxadustat, daprodustat, vadadustat, and molidustat. How effectively they compare to ESAs about clinical results in CKD-DD patients is uncertain. This study examined the RCT evidence about the benefits and risks of HIF-PHIs and ESAs in dialysis CKD patients.

METHODS

We conducted an extensive investigation and network meta-analysis of RCTs. In these RCTs, patients with CKD-DD received one of five different HIF-PHI or ESAs, a placebo, and no medical intervention. Outcomes included hemoglobin, iron parameters, and adverse events, and there were four weeks of follow-up at least. A frequentist framework for multivariate random effects meta-analyzed the results. The effect sizes of categorical variables were displayed as odds ratios. Mean differences were employed for computing continuous outcomes with common units; otherwise, standardized mean differences were applied. The Cochrane tool evaluated the bias risk in RCTs.

RESULTS

26 RCTs with 14945 patients were qualified for inclusion. Compared to the placebo, HIF-PHIs and ESAs dramatically boosted hemoglobin without affecting serum iron. Roxadustat performed better hemoglobin levels than ESAs (MD 0.32, 95% CI 0.10 to 0.53) and daprodustat (0.46, 0.09 to 0.84). Roxadustat (91.8%) was the top hemoglobin treatment among all medical interventions, as determined by the SUCRA ranking. However, roxadustat caused more thrombosis and hypertension than ESAs (1.61, 1.22 to 2.12) and vadadustat (1.36, 1.01 to 1.82). The lowest rates of hypertension and thrombosis were seen in molidustat (80.7%) and ESAs (88.5%). Compared with a placebo, ESAs and HIF-PHIs all affected TSAT levels. Except for molidustat, the other four HIF-PHIs impact different iron parameters. Regarding ferritin reduction, roxadustat (90.9%) and daprodustat (60.9%) came out on top. Enarodustat (80.9%) and roxadustat (74%) placed best and second in lowering hepcidin levels. The former two medicines for TIBC improvement were vadadustat (98.7%) and enarodustat (80.9%).

CONCLUSION

The most effective treatment for hemoglobin correction is roxadustat. The superior efficacy of reducing hepcidin makes roxadustat and enarodustat appropriate for patients with inflammation. However, the increased risk of hypertension and thrombosis associated with roxadustat should be noted. In patients at risk for hypertension and thrombosis, molidustat and ESAs may be preferable options. When administering roxadustat and daprodustat, clinicians should check ferritin to assess iron storage. Lower TSAT in patients receiving HIF-PHIs and ESAs treatment suggests intravenous iron supplements are needed.

Evolving Strategies in the Treatment of Anaemia in Chronic Kidney Disease: The HIF-Prolyl Hydroxylase Inhibitors

Chronic kidney disease (CKD) affects approximately 10% of the worldwide population; anaemia is a frequent complication. Inadequate erythropoietin production and absolute or functional iron deficiency are the major causes. Accordingly, the current treatment is based on iron and erythropoiesis stimulating agents (ESAs). Available therapy has dramatically improved the management of anaemia and the quality of life. However, safety concerns were raised over ESA use, especially when aiming to reach near-to-normal haemoglobin levels with high doses. Moreover, many patients show hypo-responsiveness to ESA. Hypoxia-inducible factor (HIF) prolyl hydroxylase domain (PHD) inhibitors (HIF-PHIs) were developed for the oral treatment of anaemia in CKD to overcome these concerns. They simulate the body's exposure to moderate hypoxia, stimulating the production of endogenous erythropoietin. Some molecules are already approved for clinical use in some countries. Data from clinical trials showed non-inferiority in anaemia correction compared to ESA or superiority for placebo. Hypoxia-inducible factor-prolyl hydroxylase domain inhibitors may also have additional advantages in inflamed patients, improving iron utilisation and mobilisation and decreasing LDL-cholesterol. Overall, non-inferiority was also shown in major cardiovascular events, except for one molecule in the non-dialysis population. This was an unexpected finding, considering the lower erythropoietin levels reached using these drugs due to their peculiar mechanism of action. More data and longer follow-ups are necessary to better clarifying safety issues and further investigate the variety of pathways activated by HIF, which could have either positive or negative effects and could differentiate HIF-PHIs from ESAs.

Erythropoietin-Stimulating Agent Hyporesponsiveness in Patients Living with Chronic Kidney Disease

BACKGROUND

Erythropoietin-stimulating agent (ESA) hyporesponsiveness is commonly observed in patients with anemia secondary to chronic kidney disease (CKD). Because of its complexity, a global consensus on how we should define ESA hyporesponsiveness remains unavailable. The reported prevalence and demographic information on ESA hyporesponsiveness within the CKD population are variable with no consensus definition.

SUMMARY

ESA hyporesponsiveness is defined as having no increase in hemoglobin concentration from baseline after the first month of treatment on appropriate weight-based dosing. The important factors associated with ESA hyporesponsiveness include absolute or functional iron deficiency, inflammation, and uremia. Hepcidin has been demonstrated to play an important role in this process. Mineral bone disease secondary to CKD and non-iron malnutrition among other factors are also associated with ESA hyporesponsiveness. There is continued debate toward determining a gold-standard treatment pathway to manage ESA hyporesponsiveness. The development of hypoxia-inducing factor-stabilizers brings new insights and opportunities in the management of ESA hyporesponsiveness.

KEY MESSAGE

Management of ESA hyporesponsiveness involves a comprehensive multidisciplinary team approach to address its risk factors. The progression of basic and clinical research on identifying risk factors and management of ESA hyporesponsiveness brings greater hope on finding solutions to eventually tackling one of the most difficult problems in the topic of anemia in CKD.

Treatment of Anemia in Kidney Disease: Beyond Erythropoietin

Anemia is common in patients with chronic kidney disease. Treatment with erythropoiesis-stimulating agents has decreased transfusion rates, but has not been consistently shown to improve cardiovascular outcomes or quality of life. Moreover, treatment to hemoglobin levels normal for the general population (13-14 g/dL) has resulted in increased cardiovascular morbidity and mortality versus lower hemoglobin targets, and some patients with chronic kidney disease do not reach these lower hemoglobin targets despite escalating doses of erythropoiesis-stimulating agents. The pathophysiology of anemia in patients with chronic kidney disease has been informed by the discovery of hypoxia-inducible factor and hepcidin pathways. Recent innovations in anemia treatment leverage knowledge of these pathways to effectively raise hemoglobin levels independent of erythropoiesis-stimulating agent administration. Several agents that stabilize hypoxia-inducible factor are undergoing or have completed phase 3 clinical trials. These agents appear to have equal efficacy as erythropoiesis-stimulating agents in raising hemoglobin levels and have not been associated with major safety signals to date. Because of the potential for off-target effects from non-anemia-related gene transcription by hypoxia-inducible factor stabilization, longer-term follow-up studies and registries will be needed to ensure safety. Agents that modulate hepcidin have undergone early clinical trials with mixed results regarding safety and efficacy in increasing hemoglobin levels. Sodium-glucose cotransporter 2 inhibitors, which also decrease hepcidin levels, have been associated with increased hemoglobin levels among patients with chronic kidney disease in clinical trials exploring proteinuria and kidney disease progression.

Managing Anemia across the Stages of Kidney Disease in Those Hyporesponsive to Erythropoiesis-Stimulating Agents

BACKGROUND

Patients with CKD frequently have anemia that results from iron-restricted erythropoiesis and inflammation. Anemia of CKD is currently managed with iron supplements and erythropoiesis-stimulating agents (ESAs) to promote erythropoiesis and with RBC transfusion in severe cases. Hyporesponse to ESAs, or the need for larger than usual doses to attain a given hemoglobin (Hb) level, is associated with increased morbidity and mortality and presents a pressing clinical challenge, particularly for patients on dialysis. This paper reviews ESA hyporesponse and potential new therapeutic options in the management of anemia of CKD.

SUMMARY

The most common causes of ESA hyporesponse include iron deficiency and inflammation, and to a lesser degree, secondary hyperparathyroidism, inadequate dialysis, malnutrition, and concomitant medications. Management of ESA hyporesponse is multipronged and involves treating low level infections, ensuring adequate nutrition, and optimizing iron status and dialysis modality, although some patients can remain refractory. Inflammation directly increases production and secretion of hepcidin, contributes to an impaired response to hypoxia, and suppresses proliferation of erythroid progenitors. Coordination of renal and hepatic erythropoietin (EPO) production and iron metabolism is under the control of hypoxia-inducible factors (HIF), which are in turn regulated by HIF-prolyl hydroxylases (HIF-PHs). HIF-PHs and hepcidin are therefore attractive potential drug targets particularly in patients with ESA hyporesponse. Several oral HIF-PH inhibitors have been evaluated in patients with anemia of CKD and have been shown to increase Hb and reduce hepcidin regardless of inflammation, iron status, or dialysis modality. These sustained effects are achieved through more modest increases in endogenous EPO compared with ESAs. Key Messages: Treatments that address ESA hyporesponse remain a significant unmet clinical need in patients with anemia of CKD. New therapies such as HIF-PH inhibitors have the potential to address fundamental aspects of ESA hyporesponse and provide a new therapeutic option in these patients.