Erythropoietin-stimulating agents, one of the treatment options for anaemia, raise haemoglobin levels, reduce the proportion of patients requiring transfusions and improve QOL (
Littlewood et al, 2001;
Österborg et al, 2002;
Boogaerts et al, 2003;
Iconomou et al, 2003). However, recent meta-analyses on QOL have shown that ESAs induce a statistically significant but not clinically meaningful improvement of fatigue as measured with FACT-Fatigue (
Tonelli et al, 2009;
Minton et al, 2010). The ESAs have been approved for the treatment of CIA, and are widely used in the United States and Europe. The EPO is approved and marketed in Europe but not in the United States.
In recent years, however, several randomised clinical trials using ESAs (
Hedenus et al, 2003;
Henke et al, 2003;
Leyland-Jones et al, 2005;
Overgaard et al, 2007;
Wright et al, 2007;
Smith et al, 2008;
Thomas et al, 2008) and meta-analyses (
Bennett et al, 2008;
Bohlius et al, 2009a,
2009b) have raised concerns about the negative impact on overall survival and tumour progression. Such safety issues regarding the use of ESAs in cancer patients have been discussed by regulatory authorities in the United States and Europe for several years (
Juneja et al, 2008). To minimise the risks, both regulatory authorities have revised the labelling for ESAs and restricted their use in cancer patients. One of the restrictions in the United States is not to administer ESAs to patients with potentially curable cancers. Based on the decisions made by the EMA, the current labelling information specifies that ESAs should be administered to cancer patients with CIA whose haemoglobin level is
![[less-than-or-eq, slant]](/corehtml/pmc/pmcents/les.gif)
10

g

dl
–1 and that a sustained haemoglobin level of >12

g

dl
–1 should be avoided. The present study was the first to evaluate the efficacy and safety of ESAs when dosed in accordance with the current labelling approved by the EMA in a randomised, double-blind, placebo-controlled manner. The inclusion criterion with regard to haemoglobin level was 8.0–10.0

g

dl
–1, and the median baseline haemoglobin level was 9.4

g

dl
–1 in the EPO group and 9.3

g

dl
–1 in the placebo group. If the haemoglobin level increased to >12.0

g

dl
–1 during the study period, the study drug was discontinued until the haemoglobin level decreased to
![[less-than-or-eq, slant]](/corehtml/pmc/pmcents/les.gif)
11.0

g

dl
–1.
The results of this study demonstrated that once-weekly EPO administration significantly reduced the proportion of patients requiring RBC transfusions or having a haemoglobin level <8.0

g

dl
–1 after 4 weeks of treatment (10.0%
vs 56.4%,
P<0.001) and also reduced the proportion of patients requiring RBC transfusions (4.5%
vs 19.6%,
P=0.002); however, the dosing strategy in this study was conservative compared with those of previous studies (
Boogaerts et al, 2003;
Iconomou et al, 2003;
Fujisaka et al, 2006;
Morishima et al, 2006;
Nakagawa et al, 2007;
Aapro et al, 2008a,
2008b;
Suzuki et al, 2008;
Bohlius et al, 2009a,
2009b;
Tsuboi et al, 2009). The relatively low percentage of patients receiving transfusions in both groups reflects the fact that most physicians hesitate to prescribe transfusions, preferring to monitor the situation until anaemia symptoms become remarkable. The pretransfusion haemoglobin levels at the time of the first transfusion in the current study were in the range of 5.3–8.1

g

dl
–1.
EPO was well tolerated in this study. The incidence and types of adverse events were similar between the EPO and placebo groups. Previous meta-analyses have indicated that the use of ESAs leads to an increased risk of thromboembolic events (relative risk (RR) 1.67; 95% CI, 1.35–2.06 (
Bohlius et al, 2006) and RR 1.57; 95% CI, 1.31–1.87 (
Bennett et al, 2008)). In the current study, one pulmonary embolism was observed during treatment with EPO, but no death due to thromboembolic events was reported.
The results of the latest Cochrane meta-analysis using individual patient data from 53 ESA trials were recently published in the
Lancet (
Bohlius et al, 2009a,
2009b). In this report, subgroup analysis of data from chemotherapy-treated patients (10

441 patients in 38 trials) indicated that the increase in mortality associated with ESAs was less pronounced in this population (HR for death during the active study periods=1.10; 95% CI, 0.98–1.24,
P=0.12; HR for overall survival=1.04; 95% CI, 0.97–1.11,
P=0.263) than in patients undergoing other anticancer treatments such as radiotherapy, radiochemotherapy or no anticancer treatment (HR 1.33–1.53). However, none of the studies included in the Cochrane meta-analysis used ESAs in accordance with the revised labelling indications (baseline haemoglobin levels, target and ceiling and so on). Although the current study was not designed and not powered to show that EPO did not increase mortality in this dosing scheme and that EPO was safe, the number of patients who died during the study period was one in the EPO group and none in the placebo group. The 1-year overall survival in the EPO group was 58.7% (95% CI 48.4–69.1%) and that in the placebo group was 63.4% (95% CI 53.4–73.3% log-rank,
P=0.560). There have been considerable debates as to the mechanism by which ESAs increase the risk for mortality (
Fandrey and Dicato, 2009). One possible explanation is that aggressive dosing with ESAs to achieve higher target haemoglobin levels (not recommended in the revised labelling information) can cause adverse effects. The FDA has requested that a prospective randomised controlled trial of the use of ESAs be carried out, assessing their safety at haemoglobin levels of <12

g

dl
–1. Such a trial is currently ongoing in patients with non-small cell lung cancer undergoing chemotherapy.
In conclusion, the findings from this study provide new evidence that ESAs are effective and well tolerated when used within the revised labelling indications by the EMA, with the limitation that we did not formally search for thromboembolic events. However, it is important that ESAs be used in accordance with the labelled indications. In addition, the risk of thromboembolic events and possible negative effects on survival should be carefully weighed against the benefits of ESA treatment in patients with CIA, taking into account the patients' comorbidities and the conditions under which they are treated. Further investigations are needed on the effect of ESAs on mortality.