ESA Efficacy
The United States (U.S.) Normal HCT Trial by Besarab, et al.1 was the first of a series of randomized controlled trials (RCTs) which cast serious doubt on the assumption that full anemia correction should be achieved in the majority of dialysis patients. A cohort of 1233 prevalent CKD5 HD patients with symptomatic heart failure or ischemic heart disease were allocated to either partial treatment of anemia or full anemia correction, using epoetin-alfa. The eventually achieved HCT values were 31% and 40%, respectively. In the normal HCT group treated with epoetin there were 183 deaths and 19 myocardial infarcts, producing 202 primary events, compared to 164 events (150 deaths, 14 myocardial infarcts) in the group in which anemia was partially corrected with epoetin. The risk ratio for the primary endpoint was 1.3 (95% confidence interval [CI] 0.9–1.9) which did not satisfy the pre-specified criterion for statistical significance (even though the nominal p value was 0.03) after adjusting for interim analyses. The trial was stopped early in a situation where the primary hypothesis was unlikely to be proven and the intervention being tested caused harm: 39% had vascular access clotting in the intervention arm and 29% in the control arm (P=0.001).
The double-blind Canada-Europe trial by Parfrey, et al.2 of 596 incident CKD5 HD patients without symptomatic heart disease (18% with diabetic nephropathy) examined the question whether full anemia correction by epoetin-alfa in the group randomized to a Hb target of 13.5–14.5 g/dl, as compared to partial treatment of anemia in the group randomized to a Hb target of 9.5–11.5 g/dl, had a beneficial effect on left ventricular volume and mass index. The eventually achieved Hb values were 13.1 and 10.8 g/dl, respectively. There was no difference in left ventricular volume index or mass index between the 2 groups during this 96-week study. Of note, patients in the full anemia correction group had a significantly higher stroke incidence (secondary endpoint) than patients in the partial treatment correction group. However, the absolute numbers of patients with stroke were very small. As one might expect, the high Hb group received significantly fewer transfusions than the low Hb group, but extent of the benefit was modest: although 9% in the high Hb arm received at least 1 transfusion compared to 19% in the low Hb arm (P=0.004) during the 96-week study, the transfusions per patient per year was 0.3 in the high Hb arm and 0.7 in the low Hb arm (P<0.0001).
The U.S. CHOIR study by Singh, et al.3 similarly aimed to show superiority of full anemia correction by ESA administration in terms of cardiovascular events and death, as compared to partial treatment of anemia, in patients with CKD not yet on dialysis. In this trial, 1432 CKD 3–4 patients (49% with diabetes) were randomized to Hb targets of 13.5 g/dl and 11.3 g/dl using epoetin alfa. Withdrawal rate was high: 17% due to renal replacement therapy and 21% for other reasons. The study was prematurely stopped after an interim analysis with a median study duration of 16 months. The achieved Hb values were 12.6 and 11.3 g/dl, respectively. At this time point, 125 patients in the complete anemia correction group but only 97 patients in the standard correction group had reached the primary combined cardiovascular endpoint (P=0.03). No differences in quality of life (QoL) were observed comparing the 2 groups; although, again, this finding must be interpreted cautiously because the study was open label.
Finally, the international trial of darbepoetin-alfa in type 2 diabetes and CKD (TREAT) by Pfeffer, et al.4 examined cardiovascular and kidney outcomes in 4038 CKD 3–4 patients. Of note, this is by far the largest ESA trial, and has the best research design, as it was placebo-controlled and double-blinded. Patients received either darbepoetin-alfa to achieve a Hb target of 13.0 g/dl or placebo with rescue darbepoetin-alfa when the Hb concentration was < 9.0 g/dl. The achieved Hb values were 12.5 and 10.6 g/dl, respectively. The median follow-up duration of the study was 29 months. There were no differences in the 2 primary endpoints, which were the composite outcomes of death or a cardiovascular event (first primary endpoint) and death or ESRD (second primary endpoint). The hazard ratio for death/composite cardiovascular event was 1.05 (95% CI 0.94–1.17), and for death or ESRD it was 1.06 (95% CI 0.96–1.19). However, there was a substantial increased risk of stroke (HR 1.92; 95% CI 1.38–2.68), although the absolute risk of stroke overall was modest: 5.0% of the high Hb group had a stroke compared to 2.6% in the placebo group (P< 0.001). The relative increase in risk of stroke was similar in patients with and without a past history of stroke. As a result, the absolute risk of stroke was substantial in the 11% of subjects with a prior history of stroke; 12% in the darbepoetin group compared to 4% in the placebo group. Venous thrombo-embolic events occurred significantly more frequently in the high Hb arm (2.0%) compared to the placebo arm (1.1%, P=0.02). A signal that normalization of Hb with darbepoetin may be harmful in patients with a history of malignancy was reported following a post-hoc analysis: 14/188 (7.4%) of those with a history of malignancy at baseline died from cancer in the darbepoetin arm compared to 1/160 (0.6%) (P=0.002) in the placebo arm. A statistically significant improvement in Functional Assessment of Cancer Therapy-Fatigue (FACT-fatigue) scores was reported at week 26 favoring the darbepoetin group, but the clinical significance of this was modest as 55% of the high Hb group had a clinically important improvement in fatigue score compared to 50% of the placebo group. Transfusions were prescribed relatively frequently and more often in the placebo arm (25%) compared to the high Hb arm (15%). The harm:benefit trade-off in TREAT was 1 stroke for 5 transfusions prevented by the high Hb target. In a large subset of the TREAT patients, QoL was assessed using FACT-fatigue, 36-Item Short Form Survey Instrument (SF-36), and EQ-5D through 97 weeks. Compared to placebo, darbepoetin conferred a consistent, but small improvement over 97 weeks in fatigue and overall QoL, but none in energy and physical function.
Lab Analysis in Renal Patients Treated with ESAs
The Kidney Disease: Improving Global Outcomes (KDIGO) 2012 Anemia Guidelines-Chapter 3 (Use of ESAs and other agents to treat anemia in CKD) 5 regarding frequency of monitoring was reviewed. Recommendations 3.12.1-3.12.3 noted Hb measurement at least monthly during initiation of ESAs. For maintenance therapy in CKD non-dialysis patients, measurement is recommended at least every 3 months and for CKD 5 dialysis patients, at least monthly. Other key recommendations for ESA treatment included the following:
- Address all correctable causes of anemia (including iron deficiency and inflammatory states) prior to initiation of ESA therapy. (Not Graded)
- In initiating and maintaining ESA therapy, potential benefits of reducing blood transfusions and anemia-related symptoms must be balanced against the risks of harm in individual patients (e.g., stroke, vascular access loss, hypertension). (1B)
- Use of ESA therapy with great caution, if at all, in CKD patients with active malignancy, in particular when cure is the anticipated outcome (1B), a history of stroke (1B), or a history of malignancy (2C).
Fishbane and Spinowitz in the Core Curriculum 2018: Update on Anemia in ESRD and Earlier Stages of CKD6 extensively review both the considerable frequency and complexity of iron metabolism in CKD. Certainly before starting ESA treatment, iron status should be optimized. After initiating ESA treatment, the recommendation is made for weekly Hb testing until Hb stability and goals are achieved. A reasonable goal of an increase of 1 g/dL within the first month of treatment is noted. As Hb concentration increases, a large amount of iron is transferred from storage tissues to the developing red cells and iron deficiency is frequently induced. Since this may limit the effectiveness of ESA treatment, these authors of this nephrology fellowship core education curriculum, recommend monthly iron status testing during the initial ESA phase.
Hsu, et al. (2001)7 set out to better delineate relationships between level of renal function and magnitude of reduction in HCT. This study was a cross-sectional one examining 12,055 (8495 women, 3560 men) adult patients with outpatient medical records at Brigham and Women’s Hospital. Racial categorization for this population was ~ 45% white, 25% black, and 30% other. Age averaged 50. Instances of apparent AKI were excluded. Since the anemia of CKD is characterized by normocytic/normochromic RBCs, the analysis was also limited to subjects with RBC parameters falling within normal reference ranges. In this study, renal function was assessed in 2 ways: the Cockcroft-Gault equation for estimated creatinine clearance (CrCl) and Modification of Diet in Renal Disease (MDRD) formula for GFR estimation normalized to body surface area. Results showed that HCT decreased progressively below estimated CrCl 60 mL/min in men and 40 mL/min in women. Compared with male subjects who had a CrCl > 80 mL/min, men with CrCl 60 mL/min had a 1% lower mean HCT, in those with a CrCl 50-40 mL/min the mean HCT was 2.4% lower, in those with a CrCl 40-30 mL/min the mean HCT was 3.7% lower, in those with a CrCl 30-20 mL/min the mean HCT was 3.5% lower, and in those with a CrCl < 20 mL/min the mean HCT reduction was 10% lower. For women, the HCT significantly decreased starting at a CrCl of less than 40 mL/min. With a CrCl of 40-30 mL/min the mean HCT was 1.7% lower, with a CrCl of 30-20 mL/min the mean HCT was 2.9% lower, and at a CrCl < 20 mL/min the mean HCT was 6.3% lower. All these values had a P value < 0.05. These results were similar with a slightly diminished gender difference when indexed to body size. Men with GFRs of 50-40 mL/min/1.73m2, 40-30 mL/min/1.73m2, 30-20 mL/min/1.73m2, and < 20 mL/min/1.73m2 had mean HCTs that were lower by 2.0, 4.4, 5.3, and 9.4% respectively (P < 0.05). Corresponding reductions in women with GFR 50-40 mL/min/1.73m2, 40-30 mL/min/1.73m2, 30-20 mL/min/1.73m2, and < 20 mL/min/1.73m2 were 0.6, 1.6, 3.8, and 5.3% (P < 0.05). For the entirety of this study, the results were similar if Hb was used instead of HCT. Further stratified analysis did not reveal effect modification by race or age. The analyses were limited by smaller numbers of patients in the lowest categories of CrCl and GFR.
Hsu, et al.8 published a separate study the following year which set out to study and quantify the relationship between reduced renal function and Hb level, to assess the iron status of CKD patients, and to estimate the burden of anemia related to CKD. The nationally representative Third National Health and Nutrition Examination Survey (NHANES III) (1988-1994) data of 15,971 patients (8506 women and 7465 men) was utilized with the measurements of creatinine, Hb, and iron stores analyzed. Older people, Mexican Americans and African Americans were oversampled. A statistically significant decrease in Hb was seen in men at CrCl < 70 mL/min and in women starting at < 50 mL/min. At any given level, men had a larger decrease in Hb than women. It was clear that a substantial number of patients with CKD did not have sufficient iron stores to support erythropoiesis. In those patients with CrCl 20-30 mL/min, 46% of women and 19% of men had transferrin saturation levels < 20%. 47% of women and 44% of men had serum ferritin levels < 100 ng/mL. With specific regard to Hb and renal function, the authors divided the subjects into 8 categories of renal function by their Cockcroft-Gault calculated CrCl: > 80 mL/min, >70 to < 80 mL/min, > 60 to < 70 mL/min, 50 to < 60 mL/min, 40 to < 50 mL/min, 30 to < 40 mL/min, 20 to < 30 mL/min, and < 20 mL/min. Hb was examined as the dependent variable in a general linear model. Three different thresholds were used to define anemia: Hb < 10, < 11, and < 12 g/dL. The likelihood of anemia at different levels of renal function was then linearly modeled. The following CrCl characteristics were noted:
The following table notes the predicted change in mean Hb level by renal function*
CrCl |
Women |
Men |
Change in Hemoglobin (g/dl) |
P Value |
Change in Hemoglobin (g/dl) |
P Value |
CrCl > 80 ml/min |
Reference |
|
Reference |
|
80 > CrCl > 70 ml/min |
-0.0 (-0.1, 0.1) |
0.68 |
-0.1 (-0.2, 0.0) |
0.16 |
70 > CrCl > 60 ml/min |
-0.1 (-0.2, 0.0) |
0.08 |
-0.2 (-0.3, -0.0) |
0.02 |
60 > CrCl > 50 ml/min |
-0.1 (-0.2, 0.1) |
0.36 |
-0.3 (-0.5, -0.1) |
0.007 |
50 > CrCl > 40 ml/min |
-0.2 (-0.3, -0.0) |
0.01 |
-0.4 (-0.6, -0.2) |
0.0005 |
40 > CrCl > 30 ml/min |
-0.4 (-0.6, -0.2) |
<0.0001 |
-0.8 (-1.1, -0.6) |
<0.0001 |
30 > CrCl > 20 ml/min |
-1.0 (-1.2, -0.7) |
<0.0001 |
-1.4 (-2.1, -0.6) |
0.0005 |
CrCl < 20 ml/min |
-2.3 (-2.8, -1.9) |
<0.0001 |
-2.7 (-3.8, -1.6) |
<0.0001 |
*Adjusted for age and race/ethnicity; values in parentheses are 95% confidence intervals for parameter estimates. CrCl, creatinine clearance.
And in Table 4 of the study:
Table 4. Predicted likelihood (%) of anemia by renal function in select demographic subgroups (multivariate analysis)
Demographic Subgroup |
Women |
Men |
Likelihood (5) of Hemoglobin Level: |
Likelihood (5) of Hemoglobin Level: |
<10 g/dl |
<11 g/dl |
<12 g/dl |
<10 g/dl |
<11 g/dl |
<12 g/dl |
Non-Hispanic white |
age 31-40 |
CrCl > 80 ml/min |
2 |
4 |
11 |
<1 |
<1 |
1 |
50 > CrCl > 40 ml/min |
3 |
6 |
15 |
<1 |
1 |
2 |
30 > CrCl > 20 ml/min |
10 |
18 |
34 |
2 |
3 |
6 |
age 61-70 |
CrCl > 80 ml/min |
1 |
2 |
7 |
1 |
1 |
3 |
50 > CrCl > 40 ml/min |
1 |
3 |
10 |
1 |
2 |
4 |
30 > CrCl > 20 ml/min |
6 |
12 |
25 |
4 |
7 |
12 |
Non-Hispanic black |
age 31-40 |
CrCl > 80 ml/min |
8 |
15 |
30 |
1 |
2 |
5 |
50 > CrCl > 40 ml/min |
12 |
21 |
38 |
2 |
4 |
7 |
30 > CrCl > 20 ml/min |
29 |
42 |
63 |
7 |
10 |
17 |
age 61-70 |
CrCl > 80 ml/min |
5 |
10 |
22 |
3 |
5 |
9 |
50 > CrCl > 40 ml/min |
7 |
14 |
28 |
5 |
8 |
13 |
30 > CrCl > 20 ml/min |
20 |
32 |
52 |
13 |
18 |
28 |
Mexican-American |
age 31-40 |
CrCl > 80 ml/min |
3 |
6 |
16 |
<1 |
<1 |
1 |
50 > CrCl > 40 ml/min |
5 |
10 |
21 |
<1 |
1 |
2 |
30 > CrCl > 20 ml/min |
15 |
24 |
43 |
2 |
3 |
5 |
age 61-70 |
CrCl > 80 ml/min |
2 |
4 |
10 |
1 |
1 |
2 |
50 > CrCl > 40 ml/min |
3 |
6 |
14 |
1 |
2 |
4 |
30 > CrCl > 20 ml/min |
9 |
17 |
32 |
4 |
6 |
10 |
* CrCl, creatinine clearance.
Compared with subjects with a CrCl > 80mL/min, the decrease in Hb for subjects with CrCl of 20-30 mL/min was 1 g/dL in women and 1.4 g/dL in men.
NKF-K/DOQI Clinical Practice Guidelines5 recommend an evaluation of anemia among patients with CKD when the Hb is < 11g/dL among premenopausal women and < 12 g/dL among adult men and postmenopausal women. ESA treatment is recommended, whether dialysis-dependent or not, to achieve a target Hb of 11-12 g/dL.
El-Achkar, et al.10 evaluated Kidney Early Evaluation Program (KEEP) data in a cross-sectional, community-based study to determine the prevalence of anemia by level of kidney function and by diabetes status. While the latter connection was the focus, the stratified data in this study specific to estimated GFR correlation with Hb levels was reviewed for purposes of this LCD. GFR was calculated using serum creatinine values and categorized as > 90, 60-89, 30-59, and < 30 mL/min/1.73m2. Anemia was defined as Hb < 12 g/dL in men and women older than 50, and < 11 g/dL in women < 50. 5380 subjects were included with mean age of 52.5, race of 43% black/36% white/11% Hispanic/11% other, and 33% male/67% female. 814 subjects were staged CKD 3. Our attention was drawn to the data detail table demonstrating the distribution of anemia prevalence by K/DOQI categories and 10 mL/min/1.73m2 increments of estimated GFR. 40.4% of diabetics in GFR category 31-40 had anemia, 23.5% of diabetics in GFR 41-50 had anemia, and 16.2% in GFR 51-60 had anemia. For non-diabetic subjects, 20.8% of GFR 31-40 were anemic, 10.1% of GFR 41-50 were anemic and 4.8% of GFR 51-60 were anemic. The table detailing mean Hb for the 10 mL/min/1.73m2 increments of estimated GRF showed the following results for CKD stage 3:
EGFR |
Hb for Men w/ DM |
Hb for Men w/o DM |
Hb for Women w/ DM |
Hb for Women w/o DM |
51-60 |
13.9 (P=0.006) |
14.7 |
13.1 |
13.5 |
41-50 |
13.3 (P<0.001) |
14.3 |
12.9 |
13.2 |
31-40 |
12.2 (P<0.001) |
14.2 |
12.4 |
13.0 |
In a much older, but still relevant study, Radtke, et al.11 studied 117 patients not in need of dialysis. Five subgroups were created for CrCl between 2-9, 10-19, 20-29, and 30-39 and 40-90 mL/min/1.73m2. With CrCl plotted against the corresponding HCT, renal anemia was clearly manifest in patients with a CrCl below 40 mL/min/1.73m2. In the range between 2 and 40 mL/min/1.73m2, CrCl and HCT were highly significantly correlated (P < 0.0001) whereas there was no significant correlation existing within the range between 41 and 90 mL/min/1.73m2.
Myelodysplastic Syndrome (MDS) and ESA Use
ESAs including EPO, recombinant human EPO and darbepoetin have been evaluated in the treatment of symptomatic anemia in patients with MDS. Studies in mostly lower risk MDS patients have demonstrated response rates of 40% and 60% in initial trials. Clinical trial results have noted overall response rates to darbepoetin similar to or possibly higher than epoetin. These improved response rates may be related to dosage used (150-300 mcg SQ per week) or to the fact that better-risk patients were enrolled. Predictive features for a better ESA response rate have included low basal serum erythropoietin (sEpo) levels, low percentages of marrow blasts, and fewer prior blood transfusions.
A study from the French myelodysplasia group12 analyzed ESA outcomes (epoetin or darbepoetin), with or without growth colony stimulating factor (G-CSF), in 403 MDS patients with anemia. Based on the International Work Group (IWG) 2000 criteria, the hematologic response rate was 62% with a median duration of 20 months. Based on the IWG 2006 criteria, the hematologic response rate was 50% for a median duration of 24 months. IPSS low- or intermediate-1 (int-1) risk was associated with significantly higher response rates and longer response durations. In comparing outcomes for low vs. int-1 risk subsets with anemia between those treated (N=284) and a historical cohort of untreated patients (N=225), multivariate analysis showed a significant association between treatment with ESAs and survival outcomes.
A phase II study13 evaluated darbepoetin (given Q 2 weeks for 12 weeks), with or without G-CSF (added at 12 weeks in non-responders). The lower risk IPSS group with anemia and sEpo levels < 500 mU/mL had hematologic response rates of 48% at 12 weeks and 56% at 24 weeks. This study also showed QoL improvements among patients with responding disease.
The data is more limited regarding the effectiveness of ESAs in the treatment of anemia in lower-risk patients with del(5q). Retrospective studies from the French MDS group reported hematologic response rates between 46% and 64% with median response duration of 11 months (mean duration, 13-14 months) in patients with del(5q) treated with ESAs, with or without G-CSF.12 Duration of response in these patients was significantly decreased compared to patients without del(5q) (mean duration, 25-27 months). Multivariate analysis showed del(5q) was a significant predictor of a shorter response duration with treatment per the French group.
The 2021 NCCN guidelines14 call attention to the fact that the FDA alerts issued in 2007 and 2008 related to observed increased mortality and possible tumor promotion and thromboembolic events did not involve analysis of MDS patients receiving ESAs. The guidelines note that ESAs have been used safely in large numbers of adult MDS patients and have an important role in improvement of anemia related symptoms related to MDS, often with a decrease in blood transfusion requirements. Studies assessing the long-term use of EPO with or without G-CSF in MDS patients have not shown a negative impact on survival or AML evolution when compared to randomized controls or historical controls.
Jadersten, et al.15 reported improved survival in low-risk MDS patients with low transfusion need after treatment with ESAs. The French group study showed improved survival and decreased AML progression of IPSS low or int-1 risk patients after EPO treatment, with or without G-CSF, compared to the historical control International Myelodysplasia Risk Analysis Workshop (IMRAW) database patients. This is further evidence of lack of a negative impact of ESAs in the treatment of MDS. The NCCN panel has thus recommended the use of ESAs in the management of symptomatic anemia in MDS patients, with a target Hb range of 10-12 g/dL. CMS, in constructing the NCD on the use of ESAs in non-renal disease specifically narrowed the scope of the NCD to cancer and related neoplastic conditions which excluded MDS as it is defined as a premalignant condition rather than an oncologic disease. Thus, local Medicare contractors may continue to make reasonable and necessary determinations on the use of ESAs in MDS and MPN (myeloproliferative neoplasms).
The NCCN Guidelines Panel14 recommends lenalidomide be considered for patients with symptomatically anemic non-del(5q) MDS with anemia that did not respond to initial therapy.
The NCCN Guidelines Panel14 recommends therapeutic options for lower-risk patients based on stratification centered on del(5q) status. Patients with del(5q) abnormalities alone or with 1 other cytogenic abnormality, except those involving chromosome 7, and symptomatic anemia should receive lenalidomide. An alternative option to lenalidomide in these patients includes an initial trial of ESAs only when sEpo levels are < 500 mU/mL. In patients without del(5q) status, alone or with 1 other cytogenetic abnormality and with symptomatic anemia, ESA treatment is recommended if the sEpo level is less than or equal to 500 mU/mL, with or without G-CSF. Patients with normal cytogenetics, < 15% ring sideroblasts and sEpo levels < 500 mU/mL may respond to ESAs if relatively high doses are administered. The EPO dose required is 40,000 to 60,000 SC units 1-2 times per week. Darbepoetin should be given SQ at a dose of 150-300 mcg every other week. Erythroid responses generally are evident within 6-8 weeks.
The NCCN Guidelines14 are clear that iron repletion must be verified before instituting ESA therapy.
Prognostic Stratification in MDS
While there are several risk-based stratifications available, the NCCN Guidelines13 preference for IPSS-R has been noted. The IPSS-R system was derived from analysis of a large dataset from multiple international institutions. It refines the original IPSS by providing more detail for cytogenetic subgroups, detailing subgroups within the “marrow blasts < 5%” group and providing more precision regarding cutoffs for the cytopenias. Other parameters including age, performance status, serum ferritin, LDH and beta-2 microglobulin provide additional prognostic information for survival outcomes. The predictive value of the IPSS-R has been validated in several independent studies based on registration data reviewed by the NCCN workgroup. Other prognostic stratification systems may be used (e.g., IPSS or WPSS) but ESA treatment is generally most effective for patients with very low, low or low intermediate prognostic risk.
The NCCN Guidelines13 reference a multiregional study of MDS patient registry data from Italy (N=646) Messa, et al. (2012) in which the predictive power of the IPSS-R was found to be greater than the IPSS, WPSS and refined WPSS for OS, AML evolution and progression free survival. The Guidelines also reference the Spanish Group of MDS (2012) who performed a retrospective analysis of data from lower-risk MDS (IPSS low or int-1) patients (N=2410) in Spain in which the application of the IPSS-R system appeared to provide prognostic refinement within the IPSS int-1 group with a large proportion of patients (511 of 1096) identified as having poor prognosis (median survival of 21-30 months). IPSS-R performed better in this regard than the refined WPSS (47% vs. 17%). Per the Guidelines, data from the MDS Clinical Research Consortium also demonstrated improved prognostic value of the IPSS-R in 370 AML transforming MDS patients as compared to the IPPS, the global MD Anderson risk model or the transforming MDS MD Anderson models.