ROCKVILLE, MdEpoetin alfa, or recombinant human
erythropoietin (Epogen, Procrit), reduces the need for red blood cell (RBC)
transfusions among cancer patients with chemotherapy-induced anemia, a report
prepared for the Agency for Healthcare Research and Quality (AHRQ) concludes.
Overall, the report found that epoetin appears most efficacious when it is
initiated as falling hemoglobin (Hb) levels near 10 g/dL.
The study reviewed the outcomes in published studies comparing
epoetin with transfusion alone in patients with therapy- or cancer-related
anemia. In the studies of transplant patients, transfusion supplemented with
epoetin was compared with transfusion alone. The analysis of pooled data was
carried out by the Blue Cross and Blue Shield Association Technology Evaluation
Center Evidence-based Practice Center (EPC).
Among those patients whose anemia stemmed primarily from cancer
therapy, studies show "adequate and consistent" evidence that epoetin
increases hemoglobin levels compared with controls, and this finding held true
in both pediatric and adult patients. "The most robust evidence that
epoetin improves transfusion outcomes in these patients comes from trials in
patient groups with baseline Hb of 10 g/dL or less," the report found.
The overall "number needed to treat" derived for
patients receiving epoetin subcutaneously was 4.4, which suggests that 4 to 5
patients must be treated with epoetin to spare one patient from transfusion.
However, double-blinded studies showed a smaller risk reduction than unblinded
studies: numbers needed to treat of 5.2 vs 2.6.
"In unblinded studies, physicians may be more aggressive
in transfusing patients in the control arm, thus overestimating the observed
effect of epoetin," the report stated.
The study found strong evidence that epoetin improves quality
of life in one randomized double-blind trial of patients with baseline Hb of 10
g/dL or less.
The frequency of adverse events associated with treatment does
not appear to differ markedly between epoetin-treated patients and controls,
the report stated. The only statistically significant difference was a greater
frequency of fatigue in the control arms.
When a patient’s anemia results from the cancer itself, the
review again found that epoetin increases hemoglobin levels; the evidence,
although sparse, also indicates that treatment reduces the need for
transfusions. All patients in the studies reviewed had nonmyeloid hematologic
cancers or myelodysplastic syndrome.
In patients who undergo allogeneic stem cell transplants,
epoetin consistently results in a statistically significant decrease in the
time to red blood cell engraftment, the report said, and may decrease the
number of red blood cell units transfused. However, the new study finds that
epoetin is unlikely to spare such patients from transfusion because they are
uniformly anemic following bone marrow ablation, and their response to
erythropoietin, whether natural or recombinant, is not immediate.
Epoetin does not appear to increase the number of adverse
events in these patients and has no significant effect on days of
There was no evidence to show that epoetin administered to
patients who receive autologous stem-cell transplants has any beneficial effect
on RBC engraftment, RBC transfusion, or length of hospital stay. No significant
adverse events were noted in the autologous patients.
The report said that many questions remain to be answered about
how to use epoetin. "Randomized controlled trials are needed to determine
whether initiating treatment at baseline hemoglobin levels greater than 10 g/dL
provides additional benefits in reducing the need for transfusions or improving
quality of life," the report stated. "More research is needed on how
to predict which patients respond to epoetin and to determine the most
efficient doses and schedules."